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Oil spill impacts on mangroves: Recommendations for operational planning and action based on a global review
Abstract
Mangrove tidal wetland habitats are recognized as highly vulnerable to large and chronic oil spills. This review of current literature and public databases covers the last 6 decades, summarising global data on oil spill incidents affecting, or likely to have affected, mangrove habitat. Over this period, there have been at least 238 notable oil spills along mangrove shorelines worldwide. In total, at least 5.5 million tonnes of oil has been released into mangrove-lined, coastal waters, oiling possibly up to around 1.94 million ha of mangrove habitat, and killing at least 126,000 ha of mangrove vegetation since 1958. However, there were assessment limitations with incomplete and unavailable data, as well as unequal coverage across world regions. To redress the gaps described here in reporting on oil spill impacts on mangroves and their recovery worldwide, a number of recommendations and suggestions are made for refreshing and updating standard operational procedures for responders, managers and researchers alike.
... In Nigeria, particularly in the Niger Delta region, poorly regulated oil and gas exploration, overharvesting, land conversion, and the spread of alien and invasive nipa palm are the leading causes of mangroves degradation (Numbere, 2018;Nababa et al., 2020;Zabbey et al., 2021). For example, damaged pipelines caused by rupture or vandalism result in oil spills that kill mangrove plants and animals (Duke, 2016;Gundlach, 2018;Onyena and Sam, 2020;Sam et al., 2022). When crude oil or its derivatives coat the breathing and stilt roots of the mangroves, it suffocates the plants, and cause death of affected plants (Numbere, 2018;Nababa et al., 2020). ...
... In 2008, the Bodo Creek experienced two major operational oil spills that destroyed the livelihood structures, local economy, and considerable ecological system of over 69,000 households (Pegg and Zabbey, 2013). As a result of the spills, an estimated 1000 hectares of mangroves were degraded (Duke, 2016), and 81% of the intertidal macrozoobenthos (animals >0.5 mm that live in or on sediment), including important food species, were extirpated (Zabbey and Uyi, 2014). Re-oiled by numerous minor spills caused by artisanal oil refining (Gundlach, 2018;Gundlach et al., 2022), the local communities lost a significant proportion of their fishing and farming livelihoods, as well as some age-long cultural practices (Pegg and Zabbey, 2013;Fentiman and Zabbey, 2015;Zabbey and Olsson, 2017). ...
... NGOs have the capacity to access funding for mangrove restoration. Mangrove rehabilitation and restoration is a long-term initiative (Duke, 2016), requiring sustained education and sensitization. Many assisted mangrove restoration projects last between 3 and 5 years, which enables only short-term monitoring of the preliminary success indicators. ...
Mangroves are significant sinks for organic carbon, and there is increased interest to restoring and conserving them for greenhouse gas emissions mitigation. However, mangrove ecosystems are significantly threatened by anthropogenic factors, resulting in mangrove loss at an unprecedented rate and scale. In contrast to the global trend of reducing mangrove loss, mangroves in the Niger Delta of Nigeria, the hub of Africa's largest expanse of mangroves, are being significantly degraded, primarily by human activities. This will continuously limit the capacity of the region to contribute to, and achieve carbon neutrality, create decent jobs for the local population, provide ecosystem goods and services, and enhance sustainable development goals. This research initiates a conceptual framework to inspire and drive sustainable mangrove restoration and conservation in the Niger Delta, and other regions where mangrove restoration is in its early stages due to lack of enabling policies Leveraging the recently launched Principles for Ecosystem Restoration to guide the United Nations Decade for Ecosystem Restoration (2021-2030), we discussed broadly the contextual preconditions for sustainable mangrove restoration and adaptive management. To achieve the nonet loss targets of global conservation, integrative knowledge and policy-driven restoration, co-management and bespoke community science regimes, economic and energy diversification, and an effective oil spill management contingency plan are outlined as the key enablers.
... Oil behavior and persistence in marsh and mangrove habitats are influenced by the regional and local differences in wave energy, tidal frequency and amplitude, and vegetation described previously. Factors affecting the behavior and persistence of oil in marshes and mangroves are summarized below (Duke 2016;Hoff et al. 2014;Michel and Rutherford 2013). ...
... The number of spills reported to have adversely impacted mangroves far exceeds the number of studies documenting these impacts. The number of oil spills of 500-20,000 bbl known to have impacted mangroves from 1958 to 2016 includes 95 crude oil spills, two diesel spills, and one spill of condensate, based on data compiled by Duke (2016). Review of the literature on impacts from oil spills and response found data from five median-range size spills, one of which was experimental, were adequate for characterizing oil impacts to mangroves (Table 7-2 and Figure 7-8). ...
... Pathways by which recovery (or loss) of undisturbed and oil impacted mangroves are outlined in Figure 7-9. Recovery of mangroves from heavy and persistent oiling often takes decades, while sublethal impacts may be followed by recovery in 1-10 years if there are live trees from which to recover a canopy (Duke 2016;Duke and Burns 1999). Recovery following tree mortality requires much more time due to the need for seedling recruitment, establishment, and growth of trees, and as long as 25-30 years for recovery of a mature forest (Duke 2016), if recovery occurs at all. ...
This chapter reviews salt marsh and mangrove impacts and recovery from median-sized oil spills ranging from 500–20,000 barrels of crude oil, condensate, or diesel. A separate earlier publication deals with large oil spills >20,000 barrels.
... Pathways by which recovery (or loss) of undisturbed and oil impacted mangroves are outlined in Figure 7-9. Recovery of mangroves from heavy and persistent oiling often takes decades, while sublethal impacts may be followed by recovery in 1-10 years if there are live trees from which to recover a canopy (Duke 2016). Recovery following tree mortality requires much more time due to the need for seedling recruitment, establishment, and growth of trees, as long as 25-30 years for recovery of a mature forest (Duke 2016), if recovery occurs at all. ...
... Recovery of mangroves from heavy and persistent oiling often takes decades, while sublethal impacts may be followed by recovery in 1-10 years if there are live trees from which to recover a canopy (Duke 2016). Recovery following tree mortality requires much more time due to the need for seedling recruitment, establishment, and growth of trees, as long as 25-30 years for recovery of a mature forest (Duke 2016), if recovery occurs at all. ...
... Long recovery periods for mature mangrove forests appear inevitable if they are heavily impacted by an oil spill. The extent of mangrove loss and recovery can be measured using aerial photography, which has been used successfully for long-term monitoring (Duke 2016). This method can be used to differentiate between and track sublethal and lethal impacts and to monitor previously impacted mangroves that have not been tracked for many years. ...
1 Ecological Services
The structure and form of salt marsh and mangrove communities are a function of wave exposure, tidal range, salinity, sediment type, plant species, and faunal communities. Salt marsh, mangrove, and adjacent habitats provide a range of ecosystem services including: nursery grounds for commercial and recreational species; bird nesting and foraging habitat; habitat for invertebrates such as crabs, snails, and mollusks; fish habitat and trophic support; sediment storage and transport; pollutant capture; nutrient mineralization and recycling; moderation of coastal inundation and erosion; carbon sequestration; and human recreation. Marshes and mangroves provide an estimated $8,236/hectare/year in reduced hurricane damages alone.
2 Oil Spill Behavior and Persistence
Studies of oil in mangroves and marshes indicate persistence is greatest where large volumes of thick oil are deposited in sheltered areas on extreme high tides and when extreme cold or dryness slows the process of weathering. Lighter oils are more volatile and form thin slicks or sheens, thus are less likely to heavily contaminate these habitats. Heavier oils can adhere to aboveground vegetation and roots; penetrate sediments via crab burrows, cleanup activities, or other pathways; and persist for years to decades. Leafy marsh grasses (e.g., Spartina alterniflora) accumulate more oil than plants with leaves tightly attached around the stem (Juncus roemerianus). In mangroves, pneumatophores and prop roots provide a large surface area to which oil can adhere. Fringing marshes and mangroves receive more wave and tidal energy than interior communities, which means oil may be washed from vegetation and sediment surfaces or washed away with dead vegetation and eroding sediments.
3 Impacts of Oil Exposure and Shoreline Treatment
Salt marshes and mangroves are vulnerable to the effects of oil that coats or smothers plant surfaces and soils, direct oil toxicity (especially from lighter oils and oil that is less weathered), and cleanup activities. Results of numerous studies indicate light oiling of marshes with little or no sediment contamination is removed by natural processes within months. Sediment oiling due to oil penetration via crab burrows and dead shoot/root cavities, burial, and/or soil mixing during cleanup operations can persist for years to decades and expose roots and rhizomes to chronic oiling. Mangroves appear more susceptible to impacts than salt marshes, primarily due to aboveground roots that can be coated with oil, reducing oxygen uptake. Only lightly oiled mangroves where oil was removed quickly by waves and tides appear to recover in a few years. A mature forest can take 20–30 years to re-establish after heavy oiling damage.
Lightly oiled salt marshes typically recover in 1–2 growing seasons, particularly in the absence of cleanup treatments. Heavily oiled salt marsh may require 10 years or more for recovery and may not recover at all if belowground biomass is lost, which can lead to erosion and loss of marsh substrates. Recovery of salt marshes is longest for spills with heavy, persistent, and prolonged oiling; cold and/or arid climates; sheltered settings; oils that penetrate or become mixed into the soils; oils that form persistent thick residues; and intensive or overly aggressive cleanup. Recovery is shortest for spills in warm, humid climates, with light to heavy oiling of the vegetation only (not the soils), and less intensive (or no) cleanup activities.
Salt marsh and mangrove invertebrates can experience direct toxicity, physical smothering and fouling, habitat alterations, and altered species interactions. Impacts to mangrove-associated invertebrates from oiling can be severe because surface oil can cover prop roots, replacing former habitat. Salt marsh invertebrate recovery is strongly influenced by the amount of oiling and the corresponding loss of habitat in marshes. In mangroves, faunal recovery may precede vegetation recovery where hydrology is restored but oil-hardened surface sediments delay mangrove establishment.
... Because they flourish in coastal areas, mangroves are highly prone to terrestrial and marine pollution (Lewis et al., 2011). They are at the forefront of offshore oil spills and, therefore, frequently struck by large pollution events (Duke, 2016). In 2019, over 3000 km of mangrove coastline was affected by the largest oil spill in Brazil's history (Lourenço et al., 2020). ...
... habitats and resources to wildlife and acting as coastal kidneys (Duke et al., 2007). They are, however, highly vulnerable to oil spills (Duke, 2016). Crude oil and petroleum products are made of a complex cocktail of hydrocarbons that is toxic toward plants in several ways (Lassalle et al., 2020;Lewis and Pryor, 2013). ...
... Once stranded in sediments, hydrocarbons can remain trapped for years owing to slow weathering and degradation rates (Burns et al., 1994;Renegar et al., 2022;Robin and Marchand, 2022), leading to a permanent exposure of mangrove forests unless tides flush oil away. In the short term (<2 years), oil spills can lethally impact mangroves, causing large diebacks and canopy gaps that take decades to recover (Connolly et al., 2020;Duke, 2016;Renegar et al., 2022). Conversely, sublethal effects (also termed chronic stress), expressed as long-term alterations in mangrove plant health, remain poorly documented. ...
Oil spills cause long-lasting mangrove loss, threatening their conservation and ecosystem services worldwide. Oil spills impact mangrove forests at various spatial and temporal scales. Yet, their long-term sublethal effects on trees remain poorly documented. Here, we explore these effects based on one of the largest oil spills ever recorded, the Baixada Santista pipeline leak, which hit the mangroves of the Brazilian southeastern coast in 1983. Historical, Landsat-derived normalized difference vegetation index (NDVI) maps over the spilled mangrove reveal a large dieback of trees within a year following the oil spill, followed by a heigh-year recolonization period and a stabilization of the canopy cover, however 20-30% lower than initially observed. We explain this permanent loss by an unexpected persistence of oil pollution in the sediments based on visual and geochemical evidence. Using field spectroscopy and cutting-edge drone hyperspectral imaging, we demonstrate how the continuous exposure of mangrove trees to high levels of pollution affects their health and productivity in the long term, by imposing permanent stressful conditions. Our study also reveals that tree species differ in their sensitivity to oil, giving the most tolerant ones a competitive advantage to recolonize spilled mangroves. By leveraging drone laser scanning, we estimate the loss of forest biomass caused by the oil spill to 9.8-91.2 t ha-1, corresponding to 4.3-40.1 t C ha-1. Based on our findings, we encourage environmental agencies and lawmakers to consider the sublethal effects of oil spills on mangroves in the environmental cost of these accidents. We also encourage petroleum companies to use drone remote sensing in monitoring routines and oil spill response planning to improve mangrove preservation and impact assessment.
... Petrogenic hydrocarbon spills (PHS) are one of the most harmful types of marine pollution due to high recurrence, the environmental damage caused and socioeconomic implications Duke, 2016). Petrogenic hydrocarbons are compounds associated with products or sources of petroleum; in addition to this type of hydrocarbon, there are also biogenic ones (produced by metabolic processes of organisms) and pyrogenic ones (derived from the incomplete combustion of organic material) (Neff et al., 2005;Wang et al., 2014). ...
... Mangroves are sensitive to the effects of PHS. It has been estimated that approximately 1.94 million hectares of mangroves have been affected by PHS globally, with at least 126,000 ha lost (Duke, 2016). Petroleum spills in mangroves cause short-and long-term damage to biodiversity, socioeconomic systems, and human health (de Oliveira et al., 2021;Duke, 2016). ...
... It has been estimated that approximately 1.94 million hectares of mangroves have been affected by PHS globally, with at least 126,000 ha lost (Duke, 2016). Petroleum spills in mangroves cause short-and long-term damage to biodiversity, socioeconomic systems, and human health (de Oliveira et al., 2021;Duke, 2016). ...
Petrogenic hydrocarbon spills (PHS) are harmful to mangrove ecosystems along tropical coastlines in the short and long term. The aim of this study was to assess the environmental risk of recurrent PHS on mangrove ecosystems in Tumaco municipality, Colombian Pacific. Mangrove characteristics and management aspects led to subdividing the study area into 11 units-of-analysis (UAs) for which threats, vulnerability, potential impacts, and risks were assessed based on environmental factors and the formulation and use of indicators in a rating scale with five categories, which are very low, low, moderate, high, and very high. The results showed that all UAs are highly (64%; 15,525 ha) or moderately (36%; 4,464 ha) threatened by PHS, highly (45%; 13,478 ha) or moderately (55%; 6,511 ha) vulnerable to this kind of pollution, and susceptible to high (73%; 17,075 ha) or moderate (27%; 2,914 ha) potential impacts. The environmental risk was high in 73% (17,075 ha) of the UAs, indicating likely irreversible damage to mangrove ecosystems by PHS, thus pointing to the need of urgent intervention by responsible authorities to ease their recovery and conservation. The methodology and results of this study become technical inputs that serve for environmental control and monitoring, which can be incorporated into contingency and risk management plans.
... One type of disturbance that mangroves can be particularly vulnerable to is oil spills. The pneumatophore root structure easily traps oil residues in the sediment, which, coupled with the relatively slow turnover of aboveground biomass, contributes to longterm negative impacts on plant health (Lewis et al., 2011;Duke, 2016). Oiling also suffocates mangroves by coating leaves and pneumatophores, which can weaken and kill plants for years following initial oiling (Duke, 2016). ...
... The pneumatophore root structure easily traps oil residues in the sediment, which, coupled with the relatively slow turnover of aboveground biomass, contributes to longterm negative impacts on plant health (Lewis et al., 2011;Duke, 2016). Oiling also suffocates mangroves by coating leaves and pneumatophores, which can weaken and kill plants for years following initial oiling (Duke, 2016). Following the 2010 Deepwater Horizon (DWH) oil spill, ecosystem recovery in mixed mangrove-marsh systems was dominated by marsh vegetation (Lin and Mendelssohn, 2012;Shapiro et al., 2016), suggesting enhanced oil sensitivity in mangroves. ...
... Avicennia species of mangroves are generally more sensitive to oil than other mangrove species (Lewis et al., 2011), whereas S. alterniflora is less sensitive to oiling than other marsh grasses (Michel and Rutherford, 2014). Although there were no differences in mangrove height or belowground biomass between the two sites, the majority (70%) of oil residues were detected in mangrove sediments at the moderately oiled site, possibly because pneumatophores trap oil in sediments (Duke, 2016). Re-suspension of oil residues, such as occurs during the slurrying process, can reduce denitrification rates (Levine et al., 2017a). ...
Coastal salt marshes provide valuable ecosystem services but are subjected to multiple concomitant stressors that may impact their ability to provide those services. Global climate change has led to the poleward expansion of mangroves into salt marshes on each continent where mangroves and marshes co-occur. In the northern Gulf of Mexico, warming winter temperatures have resulted in the expansion of Avicennia germinans (black mangrove) into forb-dominated salt marshes, resulting in a shift in ecosystem structure that can impact the ecosystem services marshes provide, including biogeochemical processes such as nitrogen removal. There have been limited studies addressing how mangrove expansion impacts nitrogen removal rates in salt marshes, but it is possible that mangroves enhance microbial nitrogen removal capacity through more efficient oxygen translocation to sediments. However, mangroves are more sensitive to oiling (such as occurred during the 2010 Deepwater Horizon spill) than marsh plants, such as Spartina alterniflora, which have a higher turnover. Thus, even if they enhance nitrogen removal, if they cannot withstand disturbances such as oiling, there still may be a loss of function associated with woody encroachment. We conducted a field study to assess the impact of woody encroachment in mediating biogeochemical recovery 7 to 8 years after the Deepwater Horizon oil spill. We collected sediments from S. alterniflora- and A. germinans-dominated plots in the Chandeleur Islands (LA, United States), a chain of barrier islands in the northern Gulf of Mexico subjected to a range of oiling following the spill. We compared nitrate reduction rates (denitrification and dissimilatory nitrate reduction to ammonium), microbial community composition, and denitrifier marker gene abundance at sites subjected to light and moderate oiling using a combination of isotope pairing on sediment slurries, 16S sequencing, and qPCR. We predicted that overall, denitrification rates and microbial functional capacity would be enhanced in mangrove-dominated sediments. We also predicted that these enhancements would be diminished at the more intensely oiled site due to the higher susceptibility of A. germinans to oiling. Denitrification potential rates were higher in mangrove sediments at the lightly oiled site, whereas dissimilatory nitrate reduction to ammonium potential rates were higher in marsh sediments. Indicator analysis of 16S rRNA data selected putative sulfur cycling taxa as indicators of marsh sediments, suggesting that changes in oxygen availability associated with encroachment may be driving the differences in process rates. There was no difference in process rates between plant types at the moderately oiled site, where heavily weathered oil residue was still present. Sediment nutrient stocks were lower in moderately oiled mangrove plots than in lightly oiled mangrove plots, suggesting that sediment fertility recovery following the spill may have been slower in the mangroves, contributing to a change in ecosystem function. This study shows that woody encroachment has the potential to impact both the biogeochemical services that marshes provide and their response to and recovery from disturbances.
... Studies of oil impacts to mature mangroves have reported leaf yellowing (chlorosis) and defoliation, mortality, stunted growth, leaf deformities, bark fissuring, epithelial scarring, lenticel expansion, reduced lenticel numbers, reduced leaf number, reduced pneumatophore density, limb loss, reduced water flux through roots, and genetic damage such as variegated leaves (NOAA, 2014;Tansel et al., 2015;Duke, 2016). In mangrove seedlings and juveniles, observed impacts include reduced germination/establishment, increased mutation rates, stunted/ deformed propagules, reduced plant height, reduced leaf number, reduced chlorophyll content, reduced root length and diameter, reduced relative root growth rate, and chlorophyll deficient propagules (Böer, 1993;Proffitt et al., 1995;Duke, 2016;Naidoo, 2016;Naidoo and Naidoo, 2017). ...
... Studies of oil impacts to mature mangroves have reported leaf yellowing (chlorosis) and defoliation, mortality, stunted growth, leaf deformities, bark fissuring, epithelial scarring, lenticel expansion, reduced lenticel numbers, reduced leaf number, reduced pneumatophore density, limb loss, reduced water flux through roots, and genetic damage such as variegated leaves (NOAA, 2014;Tansel et al., 2015;Duke, 2016). In mangrove seedlings and juveniles, observed impacts include reduced germination/establishment, increased mutation rates, stunted/ deformed propagules, reduced plant height, reduced leaf number, reduced chlorophyll content, reduced root length and diameter, reduced relative root growth rate, and chlorophyll deficient propagules (Böer, 1993;Proffitt et al., 1995;Duke, 2016;Naidoo, 2016;Naidoo and Naidoo, 2017). ...
... Initial acute effects are related to physical intrusion of oil into the mangrove forest environment, with death of associated animals, defoliation of adult trees, and loss of seedlings and juveniles (Burns et al., 1993;Mackey and Hodgkinson, 1996;Proffitt, 1997;Hensel et al., 2010;Lewis et al., 2011;Santos et al., 2011). Over time, mature trees are lost Michel and Rutherford, 2014;Duke, 2016). The effects of oil exposures in mangrove environments thus follow a pattern of short-term acute effects, with associated secondary and residual effects which ultimately lead to recovery or loss (Duke, 2016). ...
The TRopical Oil Pollution Investigations in Coastal Systems (TROPICS) experiment, conducted on the Caribbean coast of Panama, has become one of the most comprehensive field experiments examining the long-term impacts of oil and dispersed oil exposures in nearshore tropical marine environments. From the initial experiment through more than three decades of study and data collection visits, the intertidal and subtidal communities have exhibited significantly different impact and recovery regimes, depending on whether the sites were exposed to crude oil only or crude oil treated with a chemical dispersant. This review provides a synopsis of the original experiment and a cumulative summary of the results and observations, illustrating the environmental and ecosystem trade-offs of chemical dispersant use in mangrove, seagrass, and coral reef environments.
... For example, Zhang et al. (2008) reported an annual rate of 5 to 9 lightning "flashes" per square kilometer in mangroves of the Everglades National Park, United States. Furthermore, the distribution of mangroves along coastlines makes them highly exposed to humaninduced disturbances like offshore oil spills (Duke, 2016). Noticeable examples include the Deepwater Horizon platform failure in 2011, and vessel leakages along Brazilian and Mauritian coasts in 2019 and 2020, respectively (Magris & Giarrizzo, 2020;Nixon et al., 2016;Rajendran et al., 2021). ...
... On a broad scale, large mangrove dieback is sometimes observed in response to major disturbances such as extreme weather events (Abhik et al., 2021;Duke, 2016). However, a common consequence of disturbances is the onset of medium to large canopy gaps (10 to 1000 m 2 and more), which can be defined as round to elliptic discontinuities in mature canopies resulting from the death of several, neighboring mangrove trees (Amir & Duke, 2019). ...
... For example, gaps formed by cutting or wood-borer insects tend to be smaller in area than those caused by lightning strikes (Feller & McKee, 1999;Rasquinha & Mishra, 2021). Gaps resulting from oil spills may lead to permanent mangrove loss if seedling recruitment failsfor example, because of persistent pollution (Duke, 2016). Hence, mangroves may comprise a mosaic of canopy gaps from different stages, sizes, and shapes, which inform on the disturbances that occurred over the three last decades. ...
Mangroves are among the most ecologically valuable ecosystems of the globe. Reliable remote sensing solutions are required to assist their management and conservation at broad scale. Canopy gaps are part of forests' turnover and reju-venation, but yet no method has been proposed to map their occurrence and recovery in mangroves. Here, were propose an approach based on a deep learning framework called Mask R-CNN to achieve automatic detection and delin-eation of gaps using very-high-resolution satellite imagery (<1 m). The Mask R-CNN combines a series of neural network architectures to identify and delin-eate gaps, determine their recovery stage, and estimate their morphological attributes. The approach was tested on four mangroves from different regions of the globe with high concentration of gaps of various origins (lightning strikes, oil spills, cutting, pests). The Mask R-CNN performed well to detect gaps, and accurately delineated gap contours (F1-score of segmentation ≥0.89). The model also succeeded in distinguishing among five recovery stages of gaps, from their onset to closure (Overall Accuracy = 91.4, Kappa = 0.89). Accurate retrieval of gap area, eccentricity, and compactness-three relevant morphological attributes-were obtained (R 2 ≥ 0.83, NRMSE ≤10%). Several sources of confusion and misdelineation were identified. Our approach shows promising transferability to other mangrove sites and optical sensors and could help monitor canopy recovery in mangroves. It also opens promising perspectives for identifying the origin of gaps (natural or human-induced). It is intended to assist environmental managers and field experts in the management and conservation of these fragile ecosystems.
... Between one and five years, the impacts may not be lethal, allowing the ecosystem to recover. However, if the trees die, it is possible the permanent degradation of the ecosystem in the long term, as much as its recovering, that takes between five to more than 25 years, since the growing of new plants is necessary, taking at least 25 years for them to reach maturity (Duke, 2016). ...
... Some of the common impacts of oil spills in the mangroves are suffocation of their typical aerial roots and reduction of the leaves' transpiration and breathing taxes, taking to eventual defoliation (Connolly et al., 2020), besides the death of trees, decreased growth of the reminiscent trees, morphological changes, and deformations (Duke, 2016). ...
... Due to the interdependency between flora and fauna, if plants were affected, animal will be also impacted. The crabs, for instance, influence the structure of the mangroves, and sessile sponges protect the mangroves' roots and help in the nutrients' absorption (Duke, 2016). The fishes do not tend to retain and accumulate oil compounds, however, their metabolism may be injured (Saadoun, 2015). ...
From August 2019 to December 2019, eleven Brazilian coastal states, most of them located in the country’s northeast, were reached by oil from a spill of unknown origin. There were oil traces and stains detected in many marine and coastal Conservation Unities (UC), including the Environmental Protection Area of Costa dos Corais (APACC), the widest federal marine UC. This article had the objective to gather information about the locations reached by the oil inside APACC, and about possible socioenvironmental impacts caused by the disaster in the affected municipalities. The geoprocessing software ArcGIS® 10.5 was used for this purpose, as well as research in scientific databases and institutional platforms about social, economic, and environmental aspects of the studied area. The authors verified that the municipalities of Maragogi, Japaratinga, and Porto de Pedras were the ones that presented the highest concentrations of reached locations in APACC and that the sectors of fishery and tourism may have been strongly impacted by this disaster. The results point to the necessity of evaluating, accompanying, and mitigating the oil impacts caused in the area, considering its socioeconomic and environmental relevance, especially related to the preservation of mangroves and coral reefs, and its ecosystemic services, that sustain the fishery and tourism in the region.
... Oil floating on the water's surface can be deposited directly on coral habitats when the intertidal zone experiences low tide [20]. Mangroves are trees and shrubs usually found in coastal and estuarine shorelines in tropical and sub-tropical regions across the globe [21]. Mangroves are significant to the ecology as they provide shoreline protection to inland areas from intense storms and habitat for various mammals, birds, insects, plants, and algae attached to the roots of trees [22]. ...
... Mangroves are significant to the ecology as they provide shoreline protection to inland areas from intense storms and habitat for various mammals, birds, insects, plants, and algae attached to the roots of trees [22]. The oil can adhere to the exposed surface and roots of mangrove trees when exposed to the flow of tidal waters [21]. When smothered with oil contamination, plants and animals cannot survive within the mangrove ecosystem [21]. ...
... The oil can adhere to the exposed surface and roots of mangrove trees when exposed to the flow of tidal waters [21]. When smothered with oil contamination, plants and animals cannot survive within the mangrove ecosystem [21]. Salt marshes (characterized by salt-tolerant plants and grass) develop in the intertidal zones of muddy shores. ...
Oil spills are of great concern because they impose a threat to the marine ecosystem, including shorelines. As oil spilled at sea is transported to the shoreline, and after its arrival, its behavior and physicochemical characteristics change because of natural weathering phenomena. Additionally, the fate of the oil depends on shoreline type, tidal energy, and environmental conditions. This paper critically overviews the vulnerability of shorelines to oil spill impact and the implication of seasonal variations with the natural attenuation of oil. A comprehensive review of various monitoring techniques, including GIS tools and remote sensing, is discussed for tracking, and mapping oil spills. A comparison of various remote sensors shows that laser fluorosensors can detect oil on various types of substrates, including snow and ice. Moreover, current methods to prevent oil from reaching the shoreline, including physical booms, sorbents, and dispersants, are examined. The advantages and limitations of various physical, chemical, and biological treatment methods and their application suitability for different shore types are discussed. The paper highlights some of the challenges faced while managing oil spills, including viewpoints on the lack of monitoring data, the need for integrated decision-making systems, and the development of rapid response strategies to optimize the protection of shorelines from oil spills.
... Furthermore, the resistance capacities of various land cover types vary. While a forest may be able to withstand pollutants for a long period, equal levels of pollution could suffocate grassland or other ecosystems that are more vulnerable [20]. For mapping the exposure of broad regions like the Niger Delta, spatial methodologies based on this knowledge are required. ...
... Mangroves are abundant along most coastal shorelines in the tropics as intertidal plant species, making them vulnerable to oil spills, such as in Nigeria's Niger Delta. These salt-tolerant mangrove species have well-developed and maintained root systems, but their roots are usually partially submerged, exposing them to surface oils and resulting in osmoregulation and respiration impairment, which eventually leads to mortality [20]. ...
This research work applied geospatial and weight of evidence approach to ecological risk assessment for quantifying environmental exposure to oil pollution in the Niger Delta. Spatial data for Pipelines, Oil spills and Land Cover were used to quantify the extent of Ecological resources exposed to oil pollution using a data-process model. Regional scale risk assessment was done using the combination of geospatial and statistical approaches. Hotspot and Proximity analysis were used for geospatial analysis while weight of evidence was adopted for statistical computation. Ecological resources were identified from land cover maps and ranked according to their perceived importance. Hotspots of oil spill incidents were determined using spatial autocorrelation. Ecological resource vulnerability was determined using buffer zoning of 5 km and 10 km respectively as high and low risk zones, with sample maps made to show extents of resources at risk. Areal extent of ecological resources at risk were calculated and standardized for each of the delineated buffer zones. An aggregate of the weight of each ecological resources and area was computed to categorize the risk as either high, medium or low. This study has successfully assembled and produced relevant spatial and attribute data sets and applied integrated geostatistical analytical techniques to understand the distribution and impacts of oil spills in the Niger Delta. The procedure was seen as an alternative to existing management processes used for monitoring and management of oil spill events.
... A second objective addresses gaps related to longer-term oil spill impacts on mangroves and their recovery as outlined by Duke (2016). A key unknown involves the natural restorative capacity of mangrove ecosystems and the speed at which natural recovery occurs, even where continuing impacts may be occurring. ...
... Using a 2-m spacing between plants (2500/ha) indicates that ∼2 million plants is required to repopulate the 788.8 ha devoid of vegetation (Table 4). The rate of natural recovery derived for Area A (Bodo) in this analysis equates to ∼3.5 ha/year (24.6 ha over 7 years), implying that full natural recovery of the remaining 788.8 ha would take over two hundred years, several times greater than the maximum of ∼30-50 years estimated in other studies (Duke, 2016). The difference here is that recurring spills continued since the initial impacts and showed documented effects on planted mangrove seedlings . ...
The study area encompasses the largest remedial effort ever undertaken in oil-contaminated mangrove habitats (∼1000 ha) and includes planting of ∼2 million mangrove seedlings to initiate the restoration process. To establish a reference point for both the initial planting and long-term monitoring, and to investigate the longer-term effects of numerous oil spills, mangrove distribution (with minor quantities of nipa palm) was determined using 0.1 and 0.5 m resolution imagery from 2013 and 2020, supported by numerous ground surveys and low-altitude overflights. A review of pre-spill mangrove location and elimination of pipeline and road corridors determined that 829 ha of former mangrove habitat was suitable for restorative planting.
After testing each method, existing vegetation was classified using a supervised object-based classification method (Support Vector Machine) and mean shift segmentation, trained with ten manually classified plots of 1 ha and validated against seven additional plots. Initial classification errors occurred due to false positives caused by surface algae, which were manually removed. The accuracy assessment to determine overall mangrove cover (ha) and ability to encounter mangroves at a specific location within randomly selected 0.785 m² circles increased to ≥95% within validation plots. In contrast to losses found in other areas of the Niger Delta, vegetation increased in the core area of study (15.6 ha–40.2 ha) but represented only 4.8% of the total 829 ha to be planted. To the west, a 10% vegetation gain was found; to the east where oil theft activities were common, there was a 16% loss. A comparison to a West Africa 20-m data set shows comparative values within 5%, with notable differences when reviewed in detail. Monitoring of the area as it is replanted is expected to continue to 2027 and will use these results as a comparison. This study serves as guidance for analysis and monitoring of future mangrove restorations in the Niger Delta.
... They form a relatively small, but distinctive biome that delivers unique ecosystem services to coastal communities, and that serves as a nursery for many marine species. Oil contamination from ship transportation spillages and accidents during exploitation and pipeline transport, has severely affected these ecosystems (Duke, 2016). Mangroves often occur within large bay areas in tidal areas and river mouths in the tropics and subtropics, where important ports have been and are being constructed. ...
... Over the last six decades, over 200 prominent oil contamination incidents were reported to have negatively affected mangroves across the world. Together, these account for at least 5 million tons of oil that have been released upon up to 2 million ha of mangrove, killing or altering over 126,000 ha of mangrove flora (Duke, 2016). With less than 15 million ha of mangrove cover left as of 2020, this renders mangroves as one of the biomes most affected by the oil and gas industry. ...
Aim: This chapter explains hydrocarbon extraction and discusses its effects on inland water resources.
Main concepts covered: Section “Hydrocarbon extraction overview” provides an overview of the history of hydrocarbon extraction, the occurrence, and formation of hydrocarbon resources, and explains the conventional and unconventional hydrocarbon extraction techniques. Section “Risk and impacts on water resources” discusses the main impacts associated with conventional and unconventional oil and gas extraction on freshwaters. This discussion covers distinct water resource impacts associated with hydrocarbon extraction, acute, ecological, and legacy impacts on surface water and groundwater resources, and water-related socio-economic impacts. Section “Management of oil and gas extraction” covers management tools to minimize negative impacts. Throughout, case studies that mostly stem from Africa and South America are used to illustrate impacts and related management options. A detailed glossary explains technical concepts.
Conclusion: The discussion of impacts clearly illustrates that oil and gas extraction imperils water resources next to fueling climate change. Considering the Paris Agreement of limiting global temperature increases to 1.5 °C, governments should therefore limit fossil fuel extraction and pursue sustainable development to ensure a livable planet for current and future generations.
... In addition, according to literature reviews, government bulletins and field surveys, we found oil spills and plastic garbage were crucial sources to pollute the mangrove ecosystems. Oil spills caused by shipping accidents often have a devastating impact on the mangrove ecosystem (Duke, 2016). China Marine Disasters Bulletin (https://www. ...
... This disruption could directly lead to capacity decline in ecosystem services of mangroves, like coastline protection and biodiversity maintenance. In the Niger Delta in Nigeria, oil spills have become an alarming issue with an estimated 100,000 tons of oil per decade impacting mangroves (Duke, 2016). Moreover, owing to weak environmental awareness, plastic waste is common in several NMNRs, impeding the growth of mangroves and aggravating the survival risk of living species because poisonous plastic particles are easily permeated into mangrove sediments and the surrounding seawater by photooxidation and mechanical abrasion (Maghsodian et al., 2022). ...
Mangroves are high-productive ecosystems and globally protected. Establishing nature reserves aimed at counteracting the negative effects of anthropogenic activities is one of the most pivotal approaches to conserve mangrove ecosystems. Evaluation of the conservation effectiveness for mangrove nature reserves is thus indispensable for making knowledge-based conservation policies and funding-decisions by government and managers. In this study, using composited Landsat images by the Google Earth Engine cloud platform and object-oriented deep learning classification method, the land cover maps of national mangrove nature reserves (NMNRs) in China were obtained from 1987 to 2019. The systematic evaluation of conservation effectiveness for each NMNR was conducted by landscape metrics and an entropy weight model. Combined with the dynamics in mangrove distribution, human interference intensity, and natural environment change, the driving force factors affecting the conservation effectiveness for NMNRs were investigated. The results show that the total mangrove area in all NMNRs increased 968.6 ha during the study period, a 21.8 % rate of increase. Except for one NMNR with a slight decline, the conservation of remaining NMNRs was considered effective with increase varied from 14.8 % to 87.5 % in the level of protective efficacy. The conservation effectiveness of NMNRs was affected by both anthropogenic and natural factors, while the improvement to the conservation effectiveness was largely attributed to the implementation of protection policies, such as reforestation engineering. Further direct or indirect challenges in mangrove conservation effectiveness, e.g., pollution, natural disasters, and exotic species invasion, still require close attention. This study provides an effective and efficient approach to quantify the conservation effectiveness of mangrove nature reserves, which would facilitate mangrove conservation and management in the future.
... Nansingh and Jurawan (1999) have categorized mangrove ecosystems under the greatest index of environmental sensitivity relative to oil spills. The historical data for the major oil spill in the mangrove habitat as well as their adverse impact on the mangrove ecosystems has been documented (see review Lewis et al. 2011;Duke 2016). It is well known that PAHs are one of the major components of crude oil; for example, the PAHs proportion of light oil, heavy oil, intermediate fuel oil and bunker oil is 10-35%, 15-40%, 40-60% and 30-50%, respectively (e.g., Fingas 2014; Yoon et al. 2021). ...
... Several factors may affect the concentration of PAHs in coastal/mangrove water ways, including; • Concentration of PAHs in nearby industrial and urban effluents (Eduok et al. 2010); • Rate of atmospheric deposition and sedimentation in the region (Golomb et al. 2001); • Intensity of agricultural and industrial activities in the region (Zaghden et al. 2022); • River runoff (Herrmann and Hiibner 1982); • The occurrence of oil spills in the region, whether accidental or chronic (Duke 2016); and • Intensity of coal preparation and washing in nearby areas (e.g., Ambade et al. 2021). ...
Although coastal ecosystems such as mangroves have substantial productive and protective rules, this ecosystem is threatened due to inorganic and organic contaminants including polycyclic aromatic hydrocarbons (PAHs). PAHs are lipophilic, persistent, carcinogenic, mutagenic and considered as a global concern. We reviewed the occurrence, distribution and sources of PAHs in the mangrove ecosystem, providing a comprehensive discussion on this information and giving recommendations for future research. Through systematic literature search, this review considered existing studies on PAHs in the different compartments (water, sediment, aquatic fauna and plants) of mangrove system collected from field investigations. Little information is available for the levels and sources of PAHs in the water compartment of the mangrove systems. PAHs in the mangrove sediments are reported for 18 countries, and most of the levels of PAHs in mangrove sediments are considered as being low (0—100 ng g⁻¹ dry weight, DW) to moderate (100–1000 ng g⁻¹ DW). Different diagnostic ratios have been applied in order to determine the potential source of PAHs in the mangrove sediments, that are mainly attributed to mixed sources (pyrogenic and petrogenic). Studies have documented the biomonitoring of PAHs in mangrove systems, the majority of which use bivalves. Additionally, there are published studies for PAHs levels in 12 species of mangrove plants; showing a general tendency of residual PAHs accumulation in the leaves, if compared to root samples (leaves > roots). As a result of atmospheric PAH accumulation in leaf surfaces, leaves have higher concentrations of PAHs; implying that mangrove leaves can be used to monitor air quality relative to PAH pollution in coastal environments. This review has implications for future research in this field as well as coastal environmental management.
Graphical abstract
... They are formed by dense forests, which shelter a wide diversity of living organisms and provide more than 20 ecological services and 45 natural products (Barbier, 2016;Hogarth, 2015;Lewis et al., 2011;Vo et al., 2012). Because they colonize the transition zone between terrestrial and marine environments, mangroves act as "coastal kidneys" by limiting land contaminant transport and as natural barriers against waves (Duke, 2016). More importantly, their carbon production rate (up to 700 Tg C.year − 1 ) equals that of tropical forests, making mangrove ecosystems one of the most valuable contributors to the global blue carbon pool (Alongi, 2012). ...
... In particular, humaninduced mangrove loss falls into four categories according to Makowski and Finkl (2018): resource exploitation (e.g., wood, oil, medicine), competition for space (aquacultural, urban, and industrial development), human modification (freshwater resource diversion) and pollution (oil spills, wastewater), and management failure (i.e., failures in planning policies and ecosystem evaluation). In addition, sea-level rise, global warming, genetic isolation, and pests are becoming severe threats to mangroves, which are now among the most preoccupying ecosystems worldwide even though they represent less than 0.5% of the global forest coverage (Duke, 2016;Krauss et al., 2014;Ward et al., 2016). Therefore, monitoring mangrove forests is critical to maintaining their invaluable services in the long term. ...
Mangrove forests are vulnerable ecosystems that require broad-scale monitoring. Various solutions based on satellite imagery have emerged for this purpose but still suffer from the lack of methods to accurately delineate individual tree crowns (ITCs). Within-stand variability in crown size and shape, crown clumping and fragmentation, and understory vegetation hamper the delineation in these ecosystems. To cope with these factors, the proposed method combines a deep learning-based enhancement of ITCs with a marker-controlled watershed segmentation algorithm. The MT-EDv3 neural network is employed to compute the normalized Euclidean distance of crown pixels to treetops and a Laplacian of Gaussian filter is applied to the resulting image to enhance crown borders before segmentation. The method was applied to WorldView imagery over four mangrove sites worldwide and compared to previously published methods using standardized metrics. Accurate detection (Overall Accuracy ≥ 0.93 and Kappa ≥ 0.87) and area estimation (R2 ≥ 0.66, NRMSE ≤ 12%) of crowns was achieved for all sites using either the panchromatic band or a combination of the pan-sharpened visible-near-infrared bands. Based on Precision, Recall, and F1-score, the proposed method outperformed previous watershed segmentation and software-based algorithms of crown delineation, as well as the Mask R-CNN segmentation framework. The viewing geometry of images and the forest heterogeneity were identified as important contributors to the delineation accuracy. This study is the first to achieve accurate delineation of ITCs in mangrove forests across sites, opening perspectives of applications to satellite-based monitoring. The method shows promising transferability to other very-high-resolution satellite sensors as well as to aerial and unmanned aerial vehicle imagery and could be improved by including more spectral information and LiDAR-derived canopy height models.
... Shorter plants usually die within days of being smothered in oil. On the other hand, taller mature trees and bushes may survive for six or more months if only their exposed roots and sediments are oiled (Duke, 2016). Furthermore, the impact level rankings were related to the density of the oil, with light oils being more hazardous than heavy crude oils. ...
... Furthermore, the impact level rankings were related to the density of the oil, with light oils being more hazardous than heavy crude oils. The heavy crude oils have long-term persistence, especially with heavy accumulations (Duke, 2016). ...
... For example, when the intertidal zone experiences low tide, oil floating on the water surface can be directly deposited onto coral habitats (Guzman et al. 2020). Mangroves are trees and shrubs commonly found along the coasts and estuaries of tropical and subtropical regions (Duke 2016). They provide coastal protection for inland areas from strong storms and provide habitats for various mammals, birds, insects, plants, and algae attached to tree roots (Iturbe-Espinoza et al. 2022). ...
Frequent marine oil spills have led to increasingly serious oil pollution along shorelines. Microbial remediation has become a research hotspot of intertidal oil pollution remediation because of its high efficiency, low cost, environmental friendliness, and simple operation. Many microorganisms are able to convert oil pollutants into non-toxic substances through their growth and metabolism. Microorganisms use enzymes’ catalytic activities to degrade oil pollutants. However, microbial remediation efficiency is affected by the properties of the oil pollutants, microbial community, and environmental conditions. Feasible field microbial remediation technologies for oil spill pollution in the shorelines mainly include the addition of high-efficiency oil degrading bacteria (immobilized bacteria), nutrients, biosurfactants, and enzymes. Limitations to the field application of microbial remediation technology mainly include slow start-up, rapid failure, long remediation time, and uncontrolled environmental impact. Improving the environmental adaptability of microbial remediation technology and developing sustainable microbial remediation technology will be the focus of future research. The feasibility of microbial remediation techniques should also be evaluated comprehensively.
... Seagrass beds may take several years to recover following an oil spill. marshes and mangrove swamps (Kingston 2002;Duke 2016), and on a range of marine biota including mammals (Fair et al. 2000), seabirds (Schultz et al. 2017) invertebrates, and plankton (Brussaard et al. 2016). It can also cause commercial damage to fisheries ) and aquaculture such as mussel beds, together with wild mussels (Soriano et al. 2006). ...
Oil is a generic term that can cover a very wide range of natural hydrocarbon-based substances and also refined petrochemical products. Crude oil and petroleum products can have a range of physical properties on the basis of which their behaviour in the marine environment can differ widely. These properties range from viscosity (the rate at which liquid flows), density, and specific gravity (density relative to water).
... However, the need to evaluate how all these advances can afford the mangrove mapping at detailed and semi-detailed scales remains, specially focused on mangroves in brackish water habitats (Elmahdy et al., 2020). This powerful management tool of coastal green areas is especially important for Environmental Sensitivity Maps in case of accidents with marine and coastal pollution involving hydrocarbons (Duke, 2016;Lu and Wang, 2021). ...
... Oil spill accidents are the main cause of the destruction of marine ecosystems, resulting in a high frequency of accidents and enormous damage. Numerous studies on oil spills have been conducted over a long period of time using various research methods and parameters, including diffusion models, spectral analysis, remote sensing, ecosystem impacts, risk assessment, and control strategies (Fingas and Brown, 2014;Duke, 2016;Spaulding, 2017;Chen et al., 2020;Viallefont-Robinet et al., 2021). Meanwhile, research on HNS is still at a basic stage because it is relatively new compared to the research on oil spills. ...
A hazardous noxious substance (HNS) spill accident is one of the most devastating maritime disasters as it is accompanied by toxicity, fire, and explosions in the ocean. To monitor an HNS spill, it is necessary to develop a remote sensing–based HNS monitoring technique that can observe a wide area with high resolution. We designed and performed a ground HNS spill experiment using a hyperspectral sensor to detect HNS spill areas and estimate the spill volume. HNS images were obtained by pouring 1 L of toluene into an outdoor marine pool and observing it with a hyperspectral sensor capable of measuring the shortwave infrared channel installed at a height of approximately 12 m. The pure endmember spectra of toluene and seawater were extracted using principal component analysis and N-FINDR, and a Gaussian mixture model was applied to the toluene abundance fraction. Consequently, a toluene spill area of approximately 2.4317 m2 was detected according to the 36% criteria suitable for HNS detection. The HNS thickness estimation was based on a three-layer two-beam interference theory model. Because toluene has a maximum extinction coefficient of 1.3055 mm at a wavelength of 1,678 nm, the closest 1,676.5 nm toluene reflectance image was used for thickness estimation. Considering the detection area and ground resolution, the amount of leaked toluene was estimated to be 0.9336 L. As the amount of toluene used in the actual ground experiment was 1 L, the accuracy of our estimation is approximately 93.36%. Previous studies on HNS monitoring based on remote sensing are lacking in comparison to those on oil spills. This study is expected to contribute to the establishment of maritime HNS spill response strategies in the near future based on the novel hyperspectral HNS experiment.
... For instance, between 1958 and 2016, there have been 17 and 23 cases of major oil spills in East Africa and West Africa, respectively. A large concentration of these cases occurred in the Niger Delta region of Nigeria and was grossly underreported (Duke, 2016). As such, with regard to the identification of environmental degradation, the scope of this research is limited to atmospheric quality. ...
The pollution haven hypothesis postulates a transfer of unsustainable production practices by multinational corporations (MNCs) to their operational bases in developing economies with lax environmental regulations. However, little is known about the role of natural resource rents in this relationship. To this end, the study empirically investigates the interaction effects of the operational behaviours of multinational corporations (MNCs) through foreign direct investment (FDI) and natural resource rents on environmental sustainability in 34 African countries over the period 1990 to 2017. Identifying two main pathways through which this can occur, we specify two models with CO 2 emissions and renewable energy as separate response variables. Employing both the System Generalized Method of Moments (SYS-GMM) and Method of Moments Quantile regression (MM-QR) estimation techniques, the empirical results suggest that natural resource rents play a vital moderating role in determining how the operational behaviours of MNCs affect environmental sustainability. The interaction term of foreign investment and natural resource rents correlates negatively and positively with environmental pollution and renewable energy transition respectively. This suggests that at a certain level of natural resource rents, the strength of the operational behaviours of MNCs to increase environmental degradation is reduced. Furthermore, in countries with lower levels of natural resource rents, an increase in foreign investment deteriorates the environment, while in countries with lower levels of foreign investment, an increase in resource rents degrades the environment. The dynamics follow the reverse direction when renewable energy is the response variable. These findings, therefore, have policy implications for achieving Africa's goal of carbon neutrality.
... Para identificação do perigo, considerase que os acidentes envolvendo derramamento de HD se concentram em áreas com elevado tráfego de navios e extração de hidrocarbonetos (DUKE, 2016). Seguidamente, baseiase no fato de os acidentes dos últimos anos estarem tipicamente relacionados com as seguintes causas: ...
... Duke, 2016;Renegar et al., 2022). PHS potential impacts on mangrove ecosystem of Tumaco can be high and moderate, resulting in damage that would require mitigation and recovery actions in the short (1-2 years), medium (2-5 years) and long term (> 5 years).Negative impacts of PHS can be cumulative and recurrent over time. ...
Petrogenic hydrocarbon spills (PHS) are harmful to mangrove ecosystems along tropical coastlines both in the short and long term. The aim of this study was to assess the environmental risk of recurrent PHS on mangrove ecosystems in Tumaco municipality, Colombian Pacific. Mangrove characteristics and management aspects led to subdividing the entire the study into 11 units-of-analysis (UA) for which threats, vulnerability, potential impacts, and risks were assessed based on environmental factors and the formulation and use of indicators in a rating scale with five categories, which are very low, low, moderate, high, and very high. The results showed that all UAs are highly (64%) or moderately (36%) threatened by PHS, highly (45%) or moderately (55%) vulnerable to this kind of pollution, and susceptible of high (73%) or moderate (27%) potential impacts. Environmental risk was high in 73% of the UAs, indicating likely irreversible damage to mangrove ecosystems by PHS, thus pointing to the need of urgent intervention by responsible authorities to ease their recovery and conservation. The methodology and results of this study become technical inputs that serve for environmental control and monitoring, which can be incorporated into contingency and risk management plans.
... Mangrove ecosystem is exposed to various heavy metals due to pollutants discharged from various types of waste caused by shipping activities (Defew et al., 2005;Banerjee et al., 2012), industrial and domestic sewage (Banerjee et al., 2012;Mitra and Ghosh, 2014), untreated solid waste disposal sludge (Singare, 2012;Ranjan et al., 2018), agrochemicals, and pesticides (de Souza et al., 2008;Sturve et al., 2016). These metals adversely affect flora, fauna, and mangrove habitats (Hensel et al., 2010;Lewis et al., 2011;Duke, 2016;Kantharajan et al., 2017). The mangrove ecosystem faces immense heavy metal problems due to various types of toxic waste and poor water quality. ...
Mangroves provide various ecosystem services, carbon sequestration, biodiversity depository, and livelihoods. They are most abundant in marine and coastal ecosystems and are threatened by toxic contaminants like heavy metals released from various anthropogenic activities. However, they have significant potential to survive in salt-driven environments and accumulate various pollutants. The adverse effects of heavy metals have been extensively studied and recognized as toxic to mangrove species. This study sheds light on the dynamics of heavy metal levels, their absorption, accumulation and transport in the soil environment in a mangrove ecosystem. The article also focuses on the potential of mangrove species to remove heavy metals from marine and coastal environments. This review concludes that mangroves are potential candidates to clean up contaminated water, soil, and sediments through their phytoremediation ability. The accumulation of toxic heavy metals by mangroves is mainly through roots with limited upward translocation. Therefore, promoting the maintenance of biodiversity and stability in the coastal environment is recommended as an environmentally friendly and potentially cost-effective approach.
... Based on data from the government, the damage to mangrove forests around 5.9 million hectares or 69 percent. [19,20,21,22,23] Until now, several efforts have been made to maintain the continuity of the mangrove forest ecosystem through rehabilitation and conservation activities, with approaches such as community empowerment and reforestation programs. Reforestation activities carried out on forests that have been deforested are one of the rehabilitation efforts which has purposes to restore aesthetic value and the ecological function of the mangrove forest area. ...
Indonesia has three main ecosystems, mangroves, coral reefs and sea grass bed ecosystems as characteristics of a coastal countries. However, the three ecosystems are getting more and more damaged daily. This is caused by activities carried out by humans such as very fast infrastructure of coastal areas, marine debris and overfishing, and other consequences. To overcome this, the government has issued various policies, especially regarding protecting biodiversity in the three ecosystems. One of the actions taken by the government is to ratify the biodiversity convention (CBD) through Law Number 5 of 1994. Since the agenda for the Sustainable Development Goals (SDGs) as a global development established, the implementation of the biodiversity convention must be aligned with the SDGs, to create equitable development and ensure human welfare. Subsequently, a conflict emerged, was how to align policies to provide effective protection for the conservation of the three marine ecosystems while continuing to develop globally so that the marine environment preservation was maintained and developed for the community, especially in coastal areas continued to develop. This study uses a normative approach by analyzing international conventions and related national regulations and then be written down by descriptive analysis. This research has purposed to find the perfect concept of policy for the implementation of CBD to give protection and conservation the environment in the Indonesia sea. Research shows that it is necessary to make legal regulations that contain strict sanctions against perpetrators of destroying marine ecosystems because so far, there have been no strict sanctions given by law enforcement officers against those who violate these rules.
... Severe damage has been done to the aquatic environment as a result of artisanal refining which has led to the loss of the mangrove plants in the region (Plate 2 B, E, and G). Duke (2016) noted that a review of crude oil impact on mangroves shows that 37% of the global impact had occurred in the Niger Delta. Artisanal refining has caused pollution in many intertidal creeks which have left the mangroves denuded of leaves and stems, leaving roots coated in a bitumen-like substance sometimes 1cm or thicker. ...
Crude oil is the major source of revenue in Nigeria with the vast majority of exploration from the Niger Delta. Illegal refining of stolen oil is a major cause of oil spills and comes with steep environmental, economic, and social costs in the region. Oil theft, artisanal refineries, and ecosystem pollution are simultaneously linked. Therefore, the review paper seeks to highlight the effect of illegal refineries on the region's ecosystems currently exacerbated by black soot pollution, the causes of increasing artisanal refineries, the implication of illegal oil destruction, and possible solutions. The review revealed that illegal crude oil refining has a denudating impact on flora and fauna, air, soil, aquatic ecosystems, and the mangroves. Causes of illegal refineries include poverty and low standard of living, the pragmatic collaboration between security authorities and other actors, the relatively low setup cost, and the lackadaisical attitude of oil companies towards the replacement damaged oil facilities. The common practice of burning recovered stolen crude further damages the ecosystem. The need for government agencies, laws, and policies for environmental protection to be active while creating synergy with security outfits to curb the menace and engaging in regular cleanups through phytoremediation are possible solutions. We recommend the following; shutdown of all illegal refineries, stakeholders' synergies to guard against oil pollution and biodiversity loss, environmental education, and youth empowerment through vocational training and cleaning, afforestation, and reforestation of degraded sites.
... Previous spill events showed that when oil comes into contact with mangroves, it degrades (Duke, 2016). Because of their complexity and accessibility, these ecosystems are difficult to protect and clean up (NOAA, 2014a), and the impact may last years (Burns et al., 1993). ...
Ecosystems remain vulnerable, reducing their resilience without informed planning and management to update oil spill vulnerabilities. An oil spill from an offshore platform was simulated to predict probable oil landing zones off the east coast of Trinidad. Climate, land use, and sedimentation were used to classify the east coast of Trinidad and to identify the geomorphic features that are most susceptible to oil spills. In ArcGIS, physical and biological resources were used to modify NOAA's estuarine classification and build an environmental sensitivity index (ESI) map representing wet and dry seasonal changes. Leatherback sea turtle nesting sites are highly vulnerable; thus, the shoreline classification reflects this. This research identified six intertidal ecosystem indices along the east coast of Trinidad, namely ESI-1, ESI-3, ESI-4, ESI-6 and ESI-10. Mangroves were considered the most sensitive habitat, whereas high wave energy locations were ranked the lowest. This study provides first responders and environmental officials with a methodological approach to determine the locations and areas most vulnerable and develop appropriate response and cleanup strategies/plans before the oil reaches land.
... In addition to these natural conditions, mangroves are also challenging by human activities because of their vicinity with towns, industries, aquatic farms and harbours. Meiofauna is affected by direct contact with potential pollutants that may accumulate in mangrove sediments, including heavy metals, oil spills, organic compounds or sewage (Bartolini et al. 2011;Lewis et al. 2011;Molnar et al. 2013;Zhang et al. 2014;Duke, 2016). ...
Mangroves are a challenging and extreme habitat. Since they are relevant for humans, different anthropogenic pressures affect them. In this study, the Kinorhyncha populations inhabiting a moderately impacted mangrove in Mayotte Archipelago (south-western Indian Ocean) are studied. Two species of the genus Echinoderes were found in the studied area, and their unique combination of morphological characters seems to indicate they are undescribed species. These species are characterized by having an enlarged sieve-plate (nephridiopore) consisting of an anterior, convex area with numerous pores and a posterior, concave region with a single pore. This feature, together with the fact of living in an intertidal environment affected by strong salinity fluctuations, suggest their affiliation to the so-called Echinoderes coulli-group. The studied Kinorhyncha populations seem not to be particularly affected by the sewage emissions from nearby towns. Evidence for significant differences in density or richness between the areas more impacted by this pollution and the less impacted areas was not found, but differences in the community species composition seem to be present. However, further analysis including more samples and quantitative ecological data are needed in order to confirm this assumption.
... Some studies have been carried out to evaluate the effects of oil spills on the structure and survival of mangrove plants (Rodrigues et al. 1999;Moreira et al. 2011;Camargo et al. 2013). In elsewhere published data (Touchette et al. 1992;Duke 2016), seedling germination was highly susceptible to oil exposure, representing more than 96% of deaths in Avicennia marina seedlings controls (Grant et al. 1993). ...
The development of Rhizophora mangle and Avicennia schaueriana seedlings impacted by marine diesel oil (MDO) was evaluated in the presence or absence of a hydrocarbon-degrading bacterial consortium (HBC). The bioassays were conducted in a greenhouse during 6 months and consisted of three different treatments (control, MDO only and MDO + HBC). The bacterial consortium was mainly composed of Bacillus spp. (73%), but Rhizobium spp., Pseudomonas spp., Ochrobactrum spp., and Brevundimonas spp. were also present. After 6 months, A. schaueriana seedlings showed higher mortality compared to those of R. mangle; R. mangle exhibited 68% (control), 44% (MDO alone) and 50% (MDO + HBC) seedlings survivorship compared to 42% (control), 0% (MDO alone) and 4% (MDO + HBC) for A. schaueriana. This variability may be due to differences in species physiology. Stem growth, diameter and number of leaves remained constant during the 6 months of the experiment with marine diesel oil and hydrocarbon-degrading bacterial consortium (MDO + BBC). For both mangrove species, bacterial enzymatic activity in the sediments was sufficient to maintain cell counts of 107 cells cm-3 in the rhizospheric soil and possibly synthetize the extracellular polymeric substances (EPS) that may emulsify and solubilize oil products.
... For additional perspective on the context and wide variety of spill mapping theory, methods, and applications over the past 50 years, Nelson and Grubesic [22] use co-citation analysis to highlight key areas of research and seminal papers, connecting the physical and social branches of the spill modeling literature. In short, oil spill mapping is highly effective, informative, and used widely [53][54][55][56]. Further, one can use spill modeling to provide foresight into the seasonal variation of spill behavior in the Gulf of Paria and the potential response resources required to minimize environmental and ecological impacts. ...
The FSO Nabarima is a floating storage facility and offloading vessel in the Gulf of Paria, between Venezuela and the island of Trinidad. During the latter half of 2020, the Nabarima was disabled, holding approximately 1.3 million barrels (55 million gallons) of crude oil onboard. In October 2020, the vessel was tilting and potentially at risk of spilling its payload into open water. Although all of the oil on the Nabarima was successfully offloaded by April 2021, the threat of large crude oil releases is ubiquitous and persistent in many coastal regions, threatening local ecosystems and livelihoods in coastal communities. This paper aims to highlight a framework for evaluating the potential spatial vulnerability of coastlines should oil be released from near-shore storage facilities. We use the Nabarima as a broadly representative case study and simulate a range of potential spills through space and time to highlight coastal vulnerabilities in the region. The results suggest strong spatiotemporal variability in spill behavior and impact(s) throughout the Gulf of Paria. In addition, we detail potential spill cleanup and mitigation strategies and discuss the challenges of coordinating cross-national responses to these types of spill scenarios.
... In addition, they sequester disproportionate amounts of carbon for their area coverage and are considered important long-term carbon sinks (Donato et al., 2011;Alongi, 2014); a capacity and role that has drawn increasing attention in the context of climate-change mitigation (Murdiyarso et al., 2015;Taillardat et al., 2018). Yet, despite their ecological, societal, and economical importance, mangroves have been threatened by human activities, particularly land conversion for aquaculture, agriculture and urban development (Richards and Friess, 2016), as well as pollution (Duke, 2016). ...
... Mangrove vegetation is also adversely affected by oil pollution. Duke has reported that about 5.5 million tonnes of oil have killed at least 126,000 ha of mangrove vegetation by entering mangrovelined coastal waters since 1958 (Duke 2016). Because the accumulation of pollutants in animal and plant tissues can result in offspring mortality or mutation, hydrocarbon-contaminated soil causes significant harm to local ecosystems (Alvarez et al. 1991). ...
Petrochemicals are important hydrocarbons, which are one of the major concerns when accidently escaped into the environment. On one hand, these cause soil and fresh water pollution on land due to their seepage and leakage from automobile and petrochemical industries. On the other hand, oil spills occur during the transport of crude oil or refined petroleum products in the oceans around the world. These hydrocarbon and petrochemical spills have not only posed a hazard to the environment and marine life, but also linked to numerous ailments like cancers and neural disorders. Therefore, it is very important to remove or degrade these pollutants before their hazardous effects deteriorate the environment. There are varieties of mechanical and chemical methods for removing hydrocarbons from polluted areas, but they are all ineffective and expensive. Bioremediation techniques provide an economical and eco-friendly mechanism for removing petrochemical and hydrocarbon residues from the affected sites. Bioremediation refers to the complete mineralization or transformation of complex organic pollutants into the simplest compounds by biological agents such as bacteria, fungi, etc. Many indigenous microbes present in nature are capable of detoxification of various hydrocarbons and their contaminants. This review presents an updated overview of recent advancements in various technologies used in the degradation and bioremediation of petroleum hydrocarbons, providing useful insights to manage such problems in an eco-friendly manner.
... Severe damage has been done to the aquatic environment as a result of artisanal refining which has led to the loss of the mangrove plants in the region (Plate 2 B, E, and G). Duke (2016) noted that a review of crude oil impact on mangroves shows that 37% of the global impact had occurred in the Niger Delta. Artisanal refining has caused pollution in many intertidal creeks which have left the mangroves denuded of leaves and stems, leaving roots coated in a bitumenlike substance sometimes 1cm or thicker. ...
Crude oil is the major source of revenue in Nigeria with the vast majority of exploration from the Niger Delta. Illegal refining of stolen oil is a major cause of oil spills and comes with steep environmental, economic, and social costs in the region. Oil theft, artisanal refineries, and ecosystem pollution are simultaneously linked. Therefore, the review paper seeks to highlight the effect of illegal refineries on the region's ecosystems currently exacerbated by black soot pollution, the causes of increasing artisanal refineries, the implication of illegal oil destruction, and possible solutions. The review revealed that illegal crude oil refining has a denudating impact on flora and fauna, air, soil, aquatic ecosystems, and the mangroves. Causes of illegal refineries include poverty and low standard of living, the pragmatic collaboration between security authorities and other actors, the relatively low setup cost, and the lackadaisical attitude of oil companies towards the replacement damaged oil facilities. The common practice of burning recovered stolen crude further damages the ecosystem. The need for government agencies, laws, and policies for environmental protection to be active while creating synergy with security outfits to curb the menace and engaging in regular cleanups through phytoremediation are possible solutions. We recommend the following; shutdown of all illegal refineries, stakeholders' synergies to guard against oil pollution and biodiversity loss, environmental education, and youth empowerment through vocational training and cleaning, afforestation, and reforestation of degraded sites.
... Salt marshes are valuable habitats that provide a number of ecosystem services, including coastal erosion mitigation, carbon sequestration, water quality enhancement, and faunal support (Pennings and Bertness 2001;Barbier et al. 2011;Duke 2016;Gorman and Turra 2016;CPRA 2017). Vegetation in these salt marshes is subjected to a number of environmental stressors, including flooding, anoxic soils, and increased salinity (Pennings and Bertness 2001;Alleman and Hester 2010;Lonard et al. 2017). ...
Oil spills are a significant stressor to coastal and maritime environments worldwide. The growth responses of Batis maritima and Avicennia germinans seedlings to weathered Deepwater Horizon oiling were assessed through a mesocosm study using a factorial arrangement of 4 soil oiling levels (0 L m⁻², 1 L m⁻², 2 L m⁻², 4 L ⁻m⁻²) × 3 tissue oiling levels (0% of stem height, 50% of stem height, 100% of stem height). Overall, growth metrics of B. maritima displayed much greater sensitivity to both tissue and soil oiling than A. germinans, which exhibited a relatively high tolerance to both routes of oiling exposure. Batis maritima in the 4 L m⁻² soil oiling treatment demonstrated significant reductions in cumulative stem height and leaf number, whereas no significant effects of soil oiling on A. germinans were detected. This was reflected in the end of the study biomass partitioning, where total aboveground and live aboveground biomass were significantly reduced for B. maritima with 4 L m⁻² soil oiling, but no impacts to A. germinans were found. Tissue oiling of 100% did appear to reduce B. maritima stem diameter, but no effect of tissue oiling was discerned on biomass partitioning, suggesting that there were no impacts to integrated growth. These findings suggest that B. maritima would be more severely affected by moderate soil oiling than A. germinans.
The ecosystems of the marine coasts of Iraq are known to be poor in vegetation. As these coasts are exposed to continuous erosion due to waves and the movement of ships in the navigational channels, with a shrinkage in their biodiversity. The study aims at finding out the possibility of cultivating the Iraqi coasts with mangrove trees of the gray mangrove type Avicennia marina (Forssk.) Vierh., in order to preserve these coasts from erosion by increasing the vegetation cover, which achieves an upsurge in the biodiversity of the coastal marine environment. Two sites were chosen to conduct the experiment, the first in the Khor Al-Zubair oil port, which speaks for one of the Iraqi internal coasts, and the second in the Al-Faw Grand port at the entrance to Khor Abdullah, which represents the outer coast open to the sea. The experiment was carried out by planting 50 seedlings in each site at 5 lines parallel to the coast, each line contains 10 seedlings for the period from March 2020 to February 2021, in order to study the possibility of acclimatization of gray mangrove plants in these environments. Experimental measurements of vegetative growth indicators, total chlorophyll content, and survival rates for four seasons were taken during the study period. The results demonstrated a normal growth of plants in the Khor Al-Zubair oil port site, as the increase in the rate of height of seedlings reached 93.8 cm during the study period (12 months) at a daily rate of 0.256 cm.day-1, and the total content of chlorophyll pigment in the leaves increased from 43.68 µg.cm-2 when transplanting to 52.10 µg.cm-2 after one year of cultivation, while achieving survival rates of 78% at the end of the experiment. Compared to the site of the Al-Faw Grand port, which achieved medium vegetative growth during the first six months of the experiment, after which the plants began to deteriorate, and thus to the destruction of all seedlings after 12 months of the experiment's life.
Also, two experiments were carried out on the gray mangrove plant, A. marina, in one of the private orchards in the Abu al-Khaseeb district of Basra Governorate, for a period of 180 days, from 9/11/2021 to 9/5/2022. First was to study the effect of salt stress on the growth gray mangrove seedlings, and second to study the response of gray mangrove seedlings to crude oil contamination and their resistance to petroleum hydrocarbon pollutants, using a tidal bioreactor as a model of environmental conditions in the sea coasts. In the saline concentrations experiment, two-month-old (2m) and 24-month-old (24m) seedlings were used at planting, and five salinity levels TS1 (9.9 ms.cm-1), TS2 (25.9 ms.cm-1), TS3 (41.0 ms.cm-1), TS4 (57.0 ms.cm-1), and TS5 (41.0 ms.cm-1). Four treatments for crude oil concentrations were used in the experiment of petroleum hydrocarbon pollutants, which are the control treatment TO1 (0.191 mg/l), TO2 (0.885 mg/l), TO3 (5.812 mg/l), and TO4 (11.181 mg/l). In this experiment 9 seedlings of gray mangrove plant for each oil concentration were used, 6 seedlings were two-month-old (2m), which were placed in two levels, the first level (FL) consisting of 3 seedlings so that the seedlings are completely covered during the flow of water in the bioreactor system, and the second level (SL) consisting of 3 seedlings that are higher than the water level and are not completely submerged, in order to study the potential to which these seedlings are affected by immersion in crude oil floating on the surface of the water. And 3 seedlings of the third level (TL) at the 24-month-old (24m) to find out the relationship of the effect of petroleum pollutants with the age of the plant. Two experiments were conducted using a completely randomized design of a factorial experiment with three replications, and the averages were compared according to the Least Significant Difference test (L.S.D). at a probability level of 0.05.
The results of the salt concentrations experiment showed the response of the gray mangrove seedlings to the medium salt concentrations, as the vegetative growth indicators increased in the TS3 treatment plants for both seedling ages, while the lowest values were recorded in the plants treated with the high concentrations of salt TS5. While the fresh weight and the percentage of dry matter increased in the high salt concentrations TS5, while the treatment TS4 recorded the lowest fresh weight, while no significant differences were observed in the percentage of dry matter for plants for all saline treatments. The results of the chemical properties indicators showed that there was no significant effect on the total content of chlorophyll in the leaves of gray mangrove plants treated with different salt concentrations, as the highest content was recorded in the TS3 treatment plants of 24m seedlings, which amounted to 62.4 µg.cm-2. Plants treated with high salt concentration TS5 recorded the highest content of Malondialdehyde (MDA) for seedlings 2m and 24m, while seedlings of 24m recorded the lowest content of (MDA) content at treatment TS3, and seedlings of 2m recorded the lowest concentration when treating TS1. The highest content of the chemical elements (N, P, Na, K, Ca and Mg) in the leaves and roots when treated TS3. The results of the levels of the amino acids under study (Ala, Asn, Asp, Glu, Gly, Pro, Met, Leu, Phe, and Ser) in the leaves and roots indicated an increase in the concentrations of each of the amino acids (Ala, Asn, Asp, Glu, Gly, Pro and Ser) in the leaves and roots of gray mangrove plants in the TS3 treatment plants, while the amino acids Met, Leu and Phe decreased in the same treatment.
Gray mangrove plants also showed tolerance to different crude oil concentrations TO1, TO2, TO3 and TO4 by measuring vegetative growth indicators and chemical characteristics of the plant, where the results of the oil concentrations experiment showed a decrease in vegetative growth indicators such as plant height, total number of leaves, total leaf area and number of side branches of the plant, while the total value of fresh weight of the plant increased with the increase in oil concentrations, while no significant differences were observed in the percentage of dry matter in crude oil treatment plants. Chemical characteristics such as the total content of chlorophyll in the leaves, the concentrations of chemical elements (N, P, Na, K, Ca and Mg) and the levels of amino acids in the roots decreased with the increase in oil concentrations in the medium, while the content of malondialdehyde (MDA) increased in the roots of the gray mangrove plant compared to control treatment TO1. The study showed the effect of crude oil immersion on the growth and survival of gray mangrove plants.
Marine pollution presents a pressing environmental issue in the oceanic realm. To examine the identification, detection, and mitigation technologies employed for marine pollution, a chronological review and analysis were conducted using a systematic search of 90,893 peer-reviewed Scopus-indexed journal articles on the SCOPUS database. From 1990 to 2022, research on marine pollution encompassed a wide range of topics including heavy metal pollution, oil spills, microplastics, and eutrophication. Detection technologies such as image processing, biomonitoring, spectroscopy, and microscopy emerged as prominent technologies, while mitigation strategies revolved around physical, chemical, and biological methods. In order to enhance the effectiveness of marine pollution mitigation, emerging technologies such as cloud-native platforms, decision intelligence, artificial intelligence (AI) and machine learning (ML) should be employed. This review highlights the importance of interdisciplinary involvement and the need to reinforce scientific areas to prevent future marine disasters and pollution, such as the recent incident with the X-Press Pearl.
Mangroves are found in tropical and subtropical areas and very important ecosystem. Integrated urbanization, industrialization, and climate change are major factors contributing serious threat to mangrove ecosystem. Mangrove forests are very efficient carbon sinks. The impact of global climate change such as sea level rise, acidifying oceans, melting snow, oscillating weather patterns is putting mangrove forests at high risk. Arising the sea level will have the greatest impact on mangrove confronting overall decreasing in the sediment elevations, where the area for landward migration is limited. Anthropogenic activities such as aquaculture, tourism, over-exploitation of forests, construction of industries induced climate change coupled with urbanization play a major role for depletion of mangrove. Urbanization, industrialization, and land conversion of mangrove habitat into agricultural and urban area accelerated the mangrove impairment. This chapter highlighted on the impact of climate change and urbanization on mangrove ecosystem.KeywordsMangroveClimate changeUrbanizationMangrove degradation
Majority of Lamu people depend on mangrove and fishery for trade and livelihood. However, their livelihood is now threatened by climate change which is increasingly becoming a local threat in the region. Due to destructive impacts of climate change on mangroves ecosystem, most of mangrove traders and fisherfolk in Lamu Kenya have seen their source of livelihood shrinking day by day. The study examined the impact of climate change on mangrove -dependent livelihoods in Lamu county through a climate justice lens. The study was based in Lamu County that is one of the six coastal counties in Kenya. The study adopted quantitative and qualitative research approach. For quantitative approach, descriptive survey research design was adopted with data being collected using data collection sheet and house hold survey. The climate variables of concern included mean sea level, rainfall, and temperatures. Qualitative approach adopted focus group discussion and key informant interview to collect needed data. Data was analysed using SPSS and Microsoft excel. The descriptive statistics used in the study included mean, minimum, maximum and graphs. Inferential statistics adopted included regression, Paired t test and Mann-Kendall non-parametric test. Qualitative data was transcribed and analysed using content analysis technique. The analysis involved identifying themes developed from research questions and narrative responses from the respondents in the FGD and KII. The erratic climate conditions experienced in Lamu have impacted on mangroves and mangrove dependent livelihood via destruction of properties and infrastructure, reduced availability of mangrove products, destruction of recreational sites and beaches, fresh drinking water problems, the emergence of livestock and animal diseases among others. The study suggests increased funds allocation to programs aimed achieving climate justice. The study contributes to body of knowledge on the nexus between climate change and ecosystem dependent livelihoods. The study reveals how temperature, rainfall and sea level variability is impacting mangrove dependent livelihoods.
Oil spills are one of the marine pollution events triggered by the results of tanker operations (air ballast), ship repairs and maintenance (docking), mid-ocean loading and unloading terminals, air bilge (drainage of water, oil, and engine-processed lubricants), ship scrapping, and the most common accidents/collisions of tankers. The impacts vary from the death of marine organisms, especially fish, changes in reproduction and behavior of organisms, plankton contamination, fish migration, as well as ecosystem damage, and economic loss. Bio-based absorbents such as biochar can be an environmentally friendly alternative to chemical sorbents that works to adsorb oil spills faster. In this study, the effectiveness of magnetic biochar in oil spill removal was investigated. It also includes the synthesisation of magnetic biochar from agricultural waste (bagasse, rice husks, and sawdust) using the hydrothermal method at a temperature of 200°C. Hydrothermal carbonization is considered a cost-effective method for biochar production because the process can be carried out at low temperatures around 180°- 250°C. Biochar characterization was carried out with a Scanning Electron Microscope and Energy Dispersive X-Ray (SEM-EDX), Fourier Transform Infrared Spectroscopy (FTIR), and X-Ray Diffraction (XRD). The Brunauer, Emmett, and Teller (BET) and Barrett–Joyner–Halenda (BJH) were used to analyse the surface area and pore size distribution. Based on the results of the SEM-EDX analysis, only biochar was made from rice husk and sugarcane bagasse which contained Fe elements, as a result of the FeCl3.6H2O reaction. This condition is also proven by the presence of the FeO on both samples based on FTIR. The three synthesized biochar are amorphous and categorized as mesopores due to pore size around 15 to 16 nm, which can absorb petroleum spills with a percentage of 81% for sugarcane bagasse-based biochar, 84% for rice husk-based biochar, and 70% for sawdust-based biochar. Biochar from rice husk has excellent adsorption effectiveness with an adsorption capacity of 0.21 g/g in 60 min due to its large functional group area and the excellent attachment of magnetic compound into the biochar surface to form magnetic biochar.
Mangrove distribution maps are used for a variety of applications, ranging from estimates of mangrove extent, deforestation rates, quantify carbon stocks, to modelling response to climate change. There are multiple mangrove distribution datasets, which were derived from different remote sensing data and classification methods, and so there are some discrepancies among these datasets, especially with respect to the locations of their range limits. We investigate the latitudinal discrepancies in poleward mangrove range limits represented by these datasets and how these differences translate climatologically considering factors known to control mangrove distributions. We compare four widely used global mangrove distribution maps - the World Atlas of Mangroves, the World Atlas of Mangroves 2, the Global Distribution of Mangroves, the Global Mangrove Watch. We examine differences in climate among 21 range limit positions by analysing a set of bioclimatic variables that have been commonly related to the distribution of mangroves. Global mangrove maps show important discrepancies in the position of poleward range limits. Latitudinal differences between mangrove range limits in the datasets exceed 5°, 7° and 10° in western North America, western Australia and northern West Africa, respectively. In some range limit areas, such as Japan, discrepancies in the position of mangrove range limits in different datasets correspond to differences exceeding 600 mm in annual precipitation and > 10 °C in the minimum temperature of the coldest month. We conclude that dissimilarities in mapping mangrove range limits in different parts of the world can jeopardise inferences of climatic thresholds. We expect that global mapping efforts should prioritise the position of range limits with greater accuracy, ideally combining data from field-based surveys and very high-resolution remote sensing data. An accurate representation of range limits will contribute to better predicting mangrove range dynamics and shifts in response to climate change.
Protected Areas (PAs) are an important nature-based solution for mangrove conservation and rehabilitation. We evaluated spatial effectiveness of PAs for mangroves toward achieving Global Conservation Targets (GCTs). The hypothesis for this study was that PAs with different attributes have insignificant effects on mangrove conservation. We assessed the proportions of the most vulnerable mangroves inside PAs, and focused on a typical mangrove country (Madagascar). First, based on remote sensing technology and big data in Google Earth Engine (GEE), we identified the exposure location of mangroves, and determined the environmental factors significantly influencing mangrove distribution. Then, Vulnerability Assessment and Hot-Spot Analysis models were used to measure spatial vulnerability and hotspots of those values, respectively. Finally, we implemented the statistics for the most vulnerable mangroves inside PAs. It was found that: i. Mangroves were mainly abundant in west and east coasts with low latitudes, and the most typical environmental factor influencing mangrove distribution was elevation and; ii. PAs sheltered 486.18 km² (22.16%) of the most vulnerable mangroves in Madagascar. Overall, PAs in Madagascar failed to match 30% of spatial requirements proposed by GCTs (A key proportion of spatial requirements used to reverse trends in biodiversity loss). This study provides a quantitative paradigm for verifying the spatial efficiency of PAs, and will inform local decision-makers on places where mangroves are facing adaption loss to optimize mangrove conservation in future.
Tropical peatlands store globally significant quantities of carbon and are ecologically and culturally important, but little is known about their vulnerability to oil and gas exploration and extraction. Here, we analyse the exposure of tropical peatlands to the activities of the petroleum industry and review what is known about the sensitivity of peatlands to these activities. We find that 8.3% (107,000 km ² ) of the total area of tropical peatlands overlaps with a 30-km buffer area around oil and gas infrastructure. Major areas of overlap include the Sumatra Basin (Indonesia), the Niger Delta (Nigeria) and the Putumayo-Oriente-Marañón Basin (Peru/Ecuador/Colombia). Documented environmental impacts include deforestation and habitat loss associated with the exploration and development of oil fields, and contamination from spills of oil and produced water (well brine). Peatlands, and the ecosystem services they provide, are sensitive to these impacts due to unique aspects of their ecology and hydrology, the easy spread of contamination by flowing water, the long-term storage of contaminants in peat, and the slow degradation of oil under anoxic, waterlogged conditions. Given the potential negative consequences for human health, resource security, biodiversity, and carbon storage, we propose a research agenda to provide an improved evidence base to support effective governance.
The riches of mangroves have attracted people on every continent over the course of thousands of years. Mangroves have been exploited in many countries, including Vietnam, Malaysia, East Africa, Madagascar, for their wood to produce charcoal, poles, wood vinegar, to construct houses and boats, to make handicrafts, amongst others. Despite mangrove ecosystems are rich and diverse, they are being threatened by human activities such as shrimp farming, coastal development, oil spills, and tourism. Because mangroves provide significant socioeconomic benefits to coastal communities, there is an urgent need for their sustainable management, protection, and rehabilitation. To ensure sustainable management of ecosystems in a given area, a few goals need to be addressed: ecological, economic and social sustainability. Immediate sustainability measures can allow people to enjoy the benefits of these forests again.
The Kinorhyncha community inhabiting a mangrove forest impacted by domestic sewage discharges in the past has been explored in Mayotte Archipelago (southwestern Indian Ocean). Two new species of Echinoderes, which putatively belong to the Echinoderes coulli-group, are described: E. cyaneafictus sp. nov. And E. parthenope sp. nov. Echinoderes cyaneafictus sp. nov. has short, poorly sclerotized, weakly articulated spines in middorsal position on segment 4 and sublateral position on segments 6–7, plus tubes in lateroventral position on segment 5, lateral accessory position on segment 8 and laterodorsal position on segment 10. Echinoderes parthenope sp. nov. has the same kind of spines in middorsal position on segment 4, lateroventral position on segment 6, sublateral position on segment 7 and lateral accessory position on segment 8, plus tubes in lateroventral position on segments 5 and 8 and laterodorsal position on segment 10 (only males). Both species are characterized by having an enlarged sieve plate (nephridiopore) consisting of an anterior, convex area with numerous pores and a posterior, concave region with a single pore, which characterizes the species group. This combination of characters, together with their intertidal environment affected by strong salinity fluctuations, led us to assign both species to the E. coulli-group tentatively. Apart from these characters, the new species possess a unique combination of morphological features that unambiguously differentiates them from their congeners. The studied kinorhynch community seems not to be negatively affected by the domestic sewage emissions from the nearby town Malamani. We did not find evidence for significant differences in density or richness between the area more impacted by this pollution and the pristine area.
Recent ENSO-related, extreme low oscillations in mean sea level, referred to as 'Taimasa' in Samoa, have destabilised shoreline mangroves of tropical northern Australia, and possibly elsewhere. In 1982 and 2015, two catastrophic Taimasa each resulted in widespread mass dieback of~76 km 2 of shoreline mangroves along 2,000 km of Australia's Gulf of Car-pentaria. For the 2015 event, we determined that a temporary drop in sea level of~0.4 metres for up to six months duration caused upper zone shoreline mangroves across the region to die from severe moisture deficit and desiccation. The two dramatic collapse events revealed a previously unrecognised vulnerability of semi-arid tidal wetland habitats to more extreme ENSO influences on sea level. In addition, we also observed a relationship between annual sea level oscillations and mangrove forest productivity where seasonal oscillations in mean sea level were co-incident with regular annual mangrove leaf growth during months of higher sea levels (March-May), and leaf shedding during lower sea levels (September-November). The combination of these periodic fluctuations in sea level defined a mangrove 'Goldilocks' zone of seasonal productivity during median-scale oscillations, bracketed by critical threshold events when sea levels became unusually low, or high. On the two occasions reported here when sea levels were extremely low, upper zone mangrove vegetation died en masse in synchrony across northern Australia. Such extreme pulse impacts combined with localised stressors profoundly threaten the longer-term survival of mangrove ecosystems and their benefits, like minimisation of shoreline erosion with rising sea levels. These new insights into such critical influences of climate and sea level on mangrove forests offer further affirmation of the urgency for implementing well-considered miti-gation efforts for the protection of shoreline mangroves at risk, especially given predictions of future re-occurrences of extreme events affecting sea levels, combined with ongoing pressure of rapidly rising sea levels.
Long-term monitoring of an oil spill carried out along the coast of São Paulo (Brazil). indicate that the forest was seriously damaged. Reduction of the basal area was 40%, and 24% for forest density. Loss of basal area was greatest for Avicennia, indicating that it was the most vulnerable mangrove species present. The three species showed a continuous increase of leaf area after the spill, which caused initial high rate of defoliation, 25,9% for R. mangle, 43,4% for L. racemosa, and 64,5% for A. schaueriana. There was a reduction of herbivory on all three species. Propagule density was reduced and accompanied by atrophy and malformations. The affected area was rapidly colonized by new seedlings but followed by a 100% mortality. Ten years after the pollution event, field observations indicate that the mangrove area under study is at the begining of the recovery stage. These results may be useful to develop a methodology for impact assessment of oil pollution in mangrove areas.
Climate change with human direct pressures represent significant threats to the resilience of shoreline habitats like mangroves. A rapid, whole-of-system assessment strategy is needed to evaluate such threats, better linking innovative remote sensing with essential on-ground evaluations. Using the Shoreline Video Assessment Method, we surveyed around 190 km of the mostly mangrove-fringed (78%) coastline of Kien Giang Province, Vietnam. The aim was to identify anthropogenic drivers of degradation, establishing baseline for specific rehabilitation and protection strategies. Fish traps occupy at least 87% of shoreline mangroves, around which there were abundant human activities – like fishing, crabbing, farming, plus collecting firewood and foliage. Such livelihoods were associated with remnant, fringing mangrove that were largely degraded and threatened by erosion retreat, herbivory, and excessive cutting. Our assessment quantified associated threats to shoreline stability, along with previous rehabilitation intervention measures. The method offers key opportunities for effective conservation and management of vulnerable shoreline habitats.
Exploration and exploitation of oil in Nigeria since the discovery of oil in the commercial quantities in 1958 have sustained the country economy and contributed greatly to the enhancement of its citizenries’ well-being. However, the negative impacts of the introduction of unwanted byproducts into the ecological system during oil exploration and exploitation by way of relentless flaring of gas and oil spillage cannot be ignored. This present study, therefore, reports the economics and environmental impacts of oil exploration and exploitation in Nigeria. Data were collected and analyzed on the volume of gas produced and flared in Nigeria between 1970 and 2010; also collected are the barrels of oil produced between 1970 and 2020 and the average price of barrel oil and gallon of gas between the said period. Results of analysis indicate that about $669 billion was generated from the sales of crude oil between 1970 and 2010. Analysis of the collected data also showed that, between 1999 and 2010, 742,983,000 m3 of gas was produced, equivalent to $192 billion if harnessed and 587,375,000 m3 flared, representing $151.3 billion loss of revenue. The exploitation and exploration of oil therefore not only are a source of revenue for the country but also contributed greatly to the pollution of the environment and the need to collect the gas for effective utilization.
We build on previous work to construct a comprehensive database of shoreline oiling exposure from the Deepwater Horizon (DWH) spill by compiling field and remotely-sensed datasets to support oil exposure and injury quantification. We compiled a spatial database of shoreline segments with attributes summarizing habitat, oiling category and timeline. We present new simplified oil exposure classes for both beaches and coastal wetland habitats derived from this database integrating both intensity and persistence of oiling on the shoreline over time. We document oiling along 2113 km out of 9545 km of surveyed shoreline, an increase of 19% from previously published estimates and representing the largest marine oil spill in history by length of shoreline oiled. These data may be used to generate maps and calculate summary statistics to assist in quantifying and understanding the scope, extent, and spatial distribution of shoreline oil exposure as a result of the DWH incident.
Mangrove forests are the dominant intertidal plant community along most low wave energy shorelines in the tropics (Macnae 1968; Lugo and Snedaker 1974). Their value as habitat and detrital food sources for marine organisms as well as their direct commercial value as lumber, firewood and tanning agents are well documented (Odum and Heald 1972; Chapman 1976).
Recent field studies at five oil spill sites where mangroves were affected provide a broad base of information on the response of mangrove communities to oiling. Three study sites in Florida (two in the Florida Keys, one in Tampa Bay) and two in eastern Puerto Rico were visted in 1978, 1979, and 1980. At each site, impacts on mangroves were assessed by the compartmental method, which uses statistical comparisons of ecological parameters between impacted and comparison stations and produces an array of biological and geomorphic data sets that allows spill sites to be compared.
Despite many differences in the size of the spills and the spill sites, the responses of the oiled-mangrove communities were similar in terms of tree mortality; leaf defoliation, deformation, and stunting; seedling deformation and mortality; lenticel expansion; adventitious growth of pneumatophores; and changes in the density and distribution of plants and animals. Each spill site differed mainly in the magnitude of the stress response. Observations of the spills showed that differences in the physical environment, such as the degree of exposure to waves and currents and geomorphic features like the terrain, greatly influence the distribution and persistence of oil within different mangrove forest types. From these studies, mangrove forest types can be ranked by their predicted sensitivity to oil. This differentiation in ranking increases the value of the Environmental Sensitivity Index, especially where it is desirable to assign priorities in a campaign to protect oil-sensitive habitats from oil spills along mangrove-dominated coastlines.
This chapter provides an overview of mangrove management, assessment, and monitoring. It addresses the need for integrated planning and management, based on sound legal principles. The central part of the chapter covers mangrove conservation and planting. Conserving existing mangrove forest is often more effective than planting new forests. When a decision for planting has been made, one has to differentiate between planting on degraded and non-degraded sites and distinguish between replanting, rehabilitation, restoration, and afforestation. Emphasis is put on the need for careful selection of appropriate sites and species and on an ecosystem-based approach to mangrove planting and management which uses and supports natural regeneration and other natural processes. Since the primary intention with any rehabilitation intervention works is for improved protection of existing seedlings and forests from degradation or destruction, then planting should be undertaken only if absolutely necessary. Involving local communities in mangrove management is an effective way of maintaining and enhancing the protection function of the mangrove forest while providing livelihood for local people and contributing to better assessment and governance of natural resources. Assessment of the status of mangrove forests is essential for better conservation planning and management. This includes research and economic assessment and valuation. The last section highlights the importance of applied/participatory as well as academic and long-term monitoring (see also chapter “Mangroves: Unusual Forests at the Seas Edge”).
Mangrove Coasts are shorelines fringed by mangrove and saltmarsh vegetation. They form a significant part of coastal tidal wetlands as distinctive habitats of tropic and temperate shorelines. Tidal wetlands have vegetation of varying complexities from forested mangrove woodlands, thick mangrove and saltmarsh shrubbery, low dense samphire plains, to microlagal covered saltpans (Tomlinson 1994). In the tropics, mangroves are often the dominant shoreline ecosystem comprised chiefly of flowering trees and shrubs uniquely adapted to coastal and estuarine tidal conditions (Duke 2011). They form distinctly vegetated and often densely structured habitat of verdant closed canopies cloaking coastal margins and tidal waterways of equatorial, tropical and subtropical regions of the world. Normally, but not exclusively, these vegetation assemblages grow in soft sediments above mean sea level in the intertidal zone of sheltered coastal environments and estuarine margins (Fig. 1).
The plants of Mangrove Coasts are well-known for their morphological and physiological adaptations coping with salt, saturated anoxic soils and regular tidal inundation; notably with specialised attributes like: exposed air-breathing roots above ground; extra, above-ground stem support structures; salt-excreting leaves; low water potentials and high intracellular salt concentrations to maintain favorable water relations in saline environments; and viviparous water-dispersed propagules. With such attributes, these habitats have essential roles in coastal productivity and connectivity, often supporting high biodiversity and biomass not possible in upland vegetation, especially in more arid regions.
Mangrove Coasts are key sources of primary production with highly dependant trophic linkages between plants and animals, as nursery and breeding sites of benthic and arboreal life, as well as physical shelter and protection from severe storms, river flows and large tsunami waves. Within tropical latitudes, mangrove coasts nestle mostly between two other iconic ecosystems of coral reefs and tropical rainforests. All three are intimately inter-connected, providing mutual protection and sustenance. Each of these ecosystems also create biota-structured environments, where the organisms themselves provide and build the physical structure amongst which associated life is nurtured and sheltered. Without this living structure, these habitats and the many organisms dependant on them, simply would not exist. This essentially identifies how such a large group of plants and animals are so vulnerable.
For example, bordering Mangrove Coasts, colonial coral reefs often flourish in the shallow warm seas created and protected from land runoff by mangrove vegetation (Duke & Wolanski 2001). Mangroves absorb unwanted nutrients and sediments of turbid waters to stabilize eroding and depositional shorelines. In modern human times, this buffering role also includes the capture of harmful chemicals in runoff waters from agricultural lands. The specialised plant assemblages of Mangrove Coasts provide a broad range of essential, and often under-valued, ecosystem services along with their more acknowledged roles as habitats of high productivity, and as fishery nursery sites (Robertson & Duke 1990). In such ways, the consequences of disturbing Mangrove Coast habitats are expected to have far-reaching implications and impacts on neighbouring ecosystems and dependant biota.
See: http://www.springerreference.com/index/chapterdbid/350631
The coastal area of the Niger Delta is the home to oil explorations and exploitations in Nigeria. Oil spill incidents are common along the Nigeria. The main sources of oil spill on the Niger Delta are: vandalisation of the oil pipelines by the local inhabitants; ageing of the pipelines; oil blow outs from the flow stations; cleaning of oil tankers on the high sea and disposal of used oil into the drains by the road side mechanics. By far the most serious source of oil spill is through the vandalisation of pipelines either as a result of civil disaffection with the political process or as a criminal activity.
To reduce the rate of oil incidents along the Nigerian Coast particularly as a result of vandalisation, the Federal Government through an act of the National Assembly created the Niger Delta Development Commission (NDDC). Part of the responsibilities of the commission is to develop a master plan for the development of the Niger Delta, provide infrastructure and create an enabling environment for industrialisation and employment. There are also several other laws dealing with issues related to oil pollution in the environment. Also, standards for the development of the environmental sensitivity index maps for the coast of Nigeria have been developed by the Environmental Systems Research institute (ESRI). These standards are to be used by all the oil companies to prepare ESI maps for their areas of operations in Nigeria. Furthermore, apart from the mechanical and chemical oil spill cleaning methods that have been used in managing oil spill problems, oil spill models have on several occasions being used to manage oil spills on the Nigerian Coast.
A number of Federal and state agencies deal with the problems of oil spill in Nigeria. The agencies include: the Department of Petroleum Resources (DPR), the Federal Ministry of Environment, the State Ministries of Environment and the National Maritime Authority. There is also the “Clean Nigeria Associates” which is an umbrella through which the Oil companies tackle major oil spills.
There is a need to create serious awareness among the populace on the implications of oil spill incidents on the environment. Governments must assist the rural communities in claiming their rights on oil spills and ensure that digital ESI maps are readily available for managing oil spill maps. Government should have strict rules for local oil tankers that would ply our coastal and inland waters as a result of the new cabotage law that is just being passed into law in the country.
A multidisciplinary long-term field experiment was conducted to evaluate the use of chemical dispersants to reduce the adverse environmental effects of oil spills in nearshore, tropical waters. Three study sites, whose intertidal and subtidal components consisted of mangroves, seagrass beds, and coral reefs, were studied in detail before, during, and after exposure to untreated crude oil or chemically dispersed oil. This study simulated an unusually high (“worst case”) exposure level of dispersed oil and a moderate exposure level of untreated oil. The third site served as an untreated reference site. Assessments were made of the distribution and extent of contamination by hydrocarbons over time, and the short- and long-term effects on survival, abundance, and growth of the dominant flora and fauna of each habitat. The whole, untreated oil had severe, long-term effects on survival of mangroves and associated fauna, and relatively minor effects on seagrasses, corals, and associated organisms. Chemically dispersed oil caused declines in the abundance of corals, sea urchins, and other reef organisms, reduced coral growth rate in one species, and had minor or no effects on seagrasses and mangroves. Conclusions were drawn from these results on decision making for actual spills based on trade-offs between dispersing or not dispersing the oil.
This report deals only with the major results of the study. A large number of parameters were monitored, but in the interest of brevity only the most important aspects of the study are reported here. A detailed description of the methods used and a complete presentation and discussion of results is given in Ballou et al.²
A jet fuel spill in Ensenada Honda, Naval Station Roosevelt Roads, Puerto Rico, was investigated to determine impacts on mangrove communities and to develop a mitigation plan to reverse the damage. The spill caused rapid, widespread damage to mangroves, killing almost six hectares of forest. Residual contamination of water and sediments was very low.
Mitigation recommendations were developed for this incident and other mangrove forests affected by oil spills. The recommendations place primary emphasis on natural recovery, with additional actions to increase colonization and/or survival of propagules as needed.
On August 11, 2006 more than 2 million liters of Bunker C oil spilled in southern Guimaras Island, central Philippines. Over 200 kilometers of coastline have been affected including the traditional livelihood in the island. The immediate effects involved death of marine fauna and massive mortality of mangroves which accounted to almost one hectare and two years after the incident some albino propagules of Rhizophora stylosa were observed. Additionally, some species of mangroves found in heavily impacted sites exhibited significant reduction of leaf sizes. Monitoring of the deforested mangrove areas three years after the incident showed a varying recruitment-to-mortality ratio. Recruitment and settlement of seedlings was impaired in areas where dead trees are extracted mainly for firewood purposes. The harvesting of dead trees created a forest gap, exposed the area to surging waves and thus increased the hydrodynamics. On the other hand, faster recovery dynamics was observed in area where the dead trees are not harvested. The presence of logs trapped the available propagules and facilitated the colonization of new cohorts. Quantification of polyaromatic hydrocarbons (PAHs) in mangrove sediments showed higher rate of decomposition. Three years after the oil spill, the level of PAHs in sampled sites were within the safe level based on the National Oceanic and Atmospheric Administration (NOAA) standards. However, sub-lethal, long term monitoring should be carried out further to focus on the species-specific long term responses.
The valuation of ecosystem services is a complex process as it includes several dimensions (ecological, socio-cultural and economic) and not all of these can be quantified in monetary units. The aim of this paper is to conduct an ecosystem services valuation study for mangroves ecosystems, the results of which can be used to inform governance and management of mangroves. We used an expert-based participatory approach (the Delphi technique) to identify, categorize and rank the various ecosystem services provided by mangrove ecosystems at a global scale. Subsequently we looked for evidence in the existing ecosystem services literature for monetary valuations of these ecosystem service categories throughout the biogeographic distribution of mangroves. We then compared the relative ranking of ecosystem service categories between the monetary valuations and the expert based analysis. The experts identified 16 ecosystem service categories, six of which are not adequately represented in the literature. There was no significant correlation between the expert based valuation (the Delphi technique) and the economic valuation, indicating that the scope of valuation of ecosystem services needs to be broadened. Acknowledging this diversity in different valuation approaches, and developing methodological frameworks that foster the pluralism of values in ecosystem services research, are crucial for maintaining the credibility of ecosystem services valuation. To conclude, we use the findings of our dual approach to valuation to make recommendations on how to assess and manage the ecosystem services provided by mangrove ecosystems.
In a review of the literature on impacts of spilled oil on marshes, 32 oil spills and field experiments were identified with sufficient data to generate recovery curves and identify influencing factors controlling the rate of recovery. For many spills, recovery occurred within 1-2 growing seasons, even in the absence of any treatment. Recovery was longest for spills with the following conditions: Cold climate; sheltered settings; thick oil on the marsh surface; light refined products with heavy loading; oils that formed persistent thick residues; and intensive treatment. Recovery was shortest for spills with the following conditions: Warm climate; light to heavy oiling of the vegetation only; medium crude oils; and less-intensive treatment. Recommendations are made for treatment based on the following oiling conditions: Free-floating oil on the water in the marsh; thicker oil (>0.5cm) on marsh surface; thinner oil (<0.5cm) on marsh surface; heavy oil loading on vegetation; and light to moderate oil loading on vegetation.
This article examines the role of a particular area of the law of contract in a specific commercial context involving the relationship of a general building contractor and a sub-contractor. The focus is upon the formation of agreement through the submission of bids to carry out work put out to tender. An empirical examination of the attitudes of these builders to the tendering procedure has been carried out and is related to proposals to change the law on "firm offers". To what extent do those in business rely on legal sanction as a method of guaranteeing the expectations to which a promise may give rise?
The aim of this article is to provide a case study for Weber's discussion of the extent that the law of contract is required to support the development of commercial relations in a market economy. This article forms part of a limited literature empirically examining the use and non-use of law by the business community. It also reflects upon the legitimising force of the general principles of classical contract law.
Duke, N.C. 2013. ‘World Mangrove iD: expert information at your fingertips’ App Store Version 1.0 for iPhone and iPad, Dec 2013. MangroveWatch Publication, Australia – e-book. https://itunes.apple.com/us/app/mangrove-id/id761487621?mt=8
The World Mangrove iD app is an e-book, and a living expert guide to all mangrove plants worldwide. Do you have an interest in the fascinating world of mangroves? Do you have questions like; What mangrove is that?; or What mangroves grow in my country? Maybe also, Why are mangroves important? You will find all your answers, and more, in the World Mangrove iD e-book app.
It is just like having your very own mangrove expert on call. This nearly complete botanical guide has descriptions and images at your fingertips of all known mangrove plants. It has been compiled and written by Dr Norman C Duke, long time mangrove ecologist and marine science specialist, for MangroveWatch Ltd, the charitable, not-for-profit environmental monitoring NGO for tidal wetlands.
The guide provides more than 500 exquisite images, world distribution records and authoritative botanical descriptions of all 85 mangrove plant species, hybrids and varieties occurring worldwide; plus a selection of 15 common Associate plants you are likely to come across. The information and data presented provides the very latest up-to-date botanical information from Dr Duke's Mangrove Flora Project conducted over the last three decades.
The purpose of the guide is two-fold: one, to show off the diversity and distribution of these plants; and two, to improve our knowledge of them. For this, you are invited to contribute by helping fill remaining gaps revealed in the guide. It could be a new image, or just a better one, or, it could be more information on peak flowering and fruiting periods, or even a new species! Such observations are essential information for understanding what is happening in the world around us! And, things are changing more and more rapidly. Scientists and environmental managers everywhere need your help. The knowledge you have of local occurrences and events is essential and much needed!
Check out the list for any selected country, and let Dr Duke know if that country species list needs correction or updating. In so doing, please use the Capture facility to send a message and photograph showing diagnostic parts of the specimen to verify your observations; along with the location where it was growing. Your contribution maybe more important than you might imagine; you will be acknowledged, especially when any of your information is used in future upgrades of the guide.
So, come and find out more about these absolutely fascinating plants. You will not be disappointed!
The British Petroleum Deepwater Horizon Oil Spill in the Gulf of Mexico was the biggest oil spill in US history. To assess the impact of the oil spill on the saltmarsh plant community, we examined Advanced Visible Infrared Imaging Spectrometer (AVIRIS) data flown over Barataria Bay, Louisiana in September 2010 and August 2011. Oil contamination was mapped using oil absorption features in pixel spectra and used to examine impact of oil along the oiled shorelines. Results showed that vegetation stress was restricted to the tidal zone extending 14 m inland from the shoreline in September 2010. Four indexes of plant stress and three indexes of canopy water content all consistently showed that stress was highest in pixels next to the shoreline and decreased with increasing distance from the shoreline. Index values along the oiled shoreline were significantly lower than those along the oil-free shoreline. Regression of index values with respect to distance from oil showed that in 2011, index values were no longer correlated with proximity to oil suggesting that the marsh was on its way to recovery. Change detection between the two dates showed that areas denuded of vegetation after the oil impact experienced varying degrees of re-vegetation in the following year. This recovery was poorest in the first three pixels adjacent to the shoreline. This study illustrates the usefulness of high spatial resolution airborne imaging spectroscopy to map actual locations where oil from the spill reached the shore and then to assess its impacts on the plant community. We demonstrate that post-oiling trends in terms of plant health and mortality could be detected and monitored, including recovery of these saltmarsh meadows one year after the oil spill.
On 24 April 1984 a barge sank in the Bonny Estuary, spilling 250 barrels of Nigerian crude oil. The incident occurred in an area where a baseline survey was already in progress. These data, plus additional studies at the spill-site enabled the impact of the incident to be determined. At the spill-site there was a near to total elimination of the littoral infauna and a highly significant oyster mortality, plus a 30% oiling of mangrove prop roots and 32% oiling of seedlings, which resulted in partial defoliation and death of seedlings within a 500 m2 area. There were no significant effects on Uca tangeri density at the spill-site, and no effects at the nearest baseline survey transect 5 km away. The spillage was considered to be minor in terms of the quantity spilled, the effects observed, and their ecological significance.
The increased prominence of the petroleum industry in Nigeria since the 1960s has given rise to a concomitant upsurge of real and imagined ecological disturbances, especially in the oil-producing areas of the country. An overview of the growth and development of the oil and petrochemical industry in Nigeria is presented. Notable cases of polluting disturbances during the 25 years of its existence are also cite dto highlight the causes and effects on the social, economic, agricultural and ecological characteristics of human and other biotic occupants of the oil regions.
The imminent expansion schemes could expose the environment to disturbances from exploration and drilling activities, gas flares, refinery effluents and refractory products and massive spillages due to handling operations.
The existing regulating governing the control of environmental pollution are viewed as inadequate and needing revision and overhauing. Recommendations are given as guides for the activities of the Nigerian National Petroleum Corporation in the prevention, control, and treatment of oil and petrochemical pollution.
Observations on the effects of oil pollution on tropical marine habitats are reported. The pollution was caused by the wreckage
of a tanker off the Atlantic entrance to the Panama Canal. Infralittoral communities such as coral reefs remained unaffected
because no detergents have been used in eliminating the oil. Repopulation of intertidal rocks covered by dried tar took place
2 months after the incident. Greatest damage occurred on microfauna and intertidal organisms in sandy beaches and mangroves.
This short review article summarizes the results from long term assessment of an oil spill into a coastal fringe mangrove ecosystem in Panama. The study combined chemical and biological assessment methods to demonstrate that a time period of up to 20 years or longer is required for deep mud coastal habitats to recover from the toxic impact of catastrophic oil spills. This is due to the long term persistence of oil trapped in anoxic sediments and subsequent release into the water column.
This chapter provides an overview of mangrove management, assessment, and monitoring. It addresses the need for integrated planning and management, based on sound legal principles. The central part of the chapter covers mangrove conservation and planting. Conserving existing mangrove forest is often more effective than planting new forests. When a decision for planting has been made, one has to differentiate between planting on degraded and non-degraded sites and distinguish between replanting, rehabilitation, restoration, and afforestation. Emphasis is put on the need for careful selection of appropriate sites and species and on an ecosystem-based approach to mangrove planting and management which uses and supports natural regeneration and other natural processes. Since the primary intention with any rehabilitation intervention works is for improved protection of existing seedlings and forests from degradation or destruction, then planting should be undertaken only if absolutely necessary. Involving local communities in mangrove management is an effective way of maintaining and enhancing the protection function of the mangrove forest while providing livelihood for local people and contributing to better assessment and governance of natural resources. Assessment of the status of mangrove forests is essential for better conservation planning and management. This includes research and economic assessment and valuation. The last section highlights the importance of applied/participatory as well as academic and long-term monitoring (see also chapter “Mangroves: Unusual Forests at the Seas’ Edge”).
Mangroves form distinct sea-edge forested habitat of dense, undulating canopies in both wet and arid tropic regions of the world. These highly adapted, forest wetland ecosystems have many remarkable features, making them a constant source of wonder and inquiry. This chapter introduces mangrove forests, the factors that influence them, and some of their key benefits and functions. This knowledge is considered essential for those who propose to manage them sustainably. We describe key and currently recommended strategies in an accompanying article on mangrove forest management (Schmitt and Duke 2015).
The damage to mangrove communities and fisheries were studied following extensive oil pollution of the coastal areas of northern Ecuador and southern Colombia in 1976. During the acute phase of the oil spill oil covered 2–3 m vertically on the mangrove trees along the sea front, and had penetrated 20–70 m horizontally. Acute effects on the mangrove communities included defoliation of trees, mortality of sessile organisms, and migration of semi-sessile and mobile crustaceans and molluscs. Dead fishes, sea snakes and sea birds were also found. The relatively large tidal range caused considerable washing off of the deposited oil from roots and trunks, and four months later the major part of the oil on the mangrove trees had disappeared. Previously defoliated mangroves had, with some exceptions, recovered, and mobile organisms had re-entered the affected area. In some areas where mangrove had died there was erosion of the substrate.
The oil spill affected the local fishery in a number of ways; for example, the absence of tuna in the region during that year suggested oil avoidance reactions in this group.
Significance
This study quantifies the proximate drivers (i.e., replacement land uses) of mangrove deforestation across Southeast Asia between 2000 and 2012. Mangrove forests in the region were lost at an average rate of 0.18% per year. Aquaculture was a major pressure on mangrove systems during this period, but its dominance was lower than expected, contrary to popular development narratives. Rice agriculture has been a major driver of mangrove loss in Myanmar, and oil palm expansion is a key but under-recognized threat in Malaysia and Indonesia. The threat of oil palm to mangroves is likely to increase in the future as new frontiers open up in Papua, Indonesia. Future research and policy responses must consider the diversity of drivers of mangrove deforestation.