ArticlePDF Available

A Reef under Siltation Stress: A Decade of Degradation

Authors:

Abstract

The coral reef at Cahuita National Park, Caribbean coast of Costa Rica, has been stressed by sediments from watersheds of rivers that flow to the sea near the Park. A comparison of the reef between the late 1970's - early 1980's and 1993 revealed the following: suspended sediments and the non-carbonate fraction of bottom sediments have increased from eight to nine mg/1, and from 40 to 48%, respectively; live coral cover has decreased, from 40 to 11%, while dead coral, algae covered carbonate susbstrate and coral rubble have increased from 60 to 89%. -from Author
... Several studies have described the effects of sediments on corals, but we will not review them all here (see Johannes, 1975;Rogers, 1990;Fabricius, 2005;Erftemeijer et al., 2012 and references cited therein). Once sediments enter the marine environment, they can settle directly on corals and other reef organisms or remain in suspension, reducing the light required for photosynthesis, growth and calcification (Cortés and Risk, 1985;Richmond, 1993). Sediment characteristics including size, color, and mineralogy dictate settling/suspension dynamics and light attenuation capacities (Storlazzi et al., 2015). ...
... High sediment exposure, from runoff of terrestrial sediments or dredging projects, can have direct and indirect effects on coral communities and nearby habitats. Direct effects include smothering and mortality of corals, while indirect effects include impairment of coral recruitment and associated alteration of colony size frequency distribution (Cortés and Risk, 1985). In a study of coral reefs along an inshore to offshore gradient in the USVI, Smith et al. (2008) noted more old coral mortality (i.e., partial and not recent) and bleaching nearshore suggesting a link with higher sediment exposure from land runoff. ...
Article
Full-text available
Coral reefs in the western Atlantic and Caribbean are deteriorating primarily from disease outbreaks, increasing seawater temperatures, and stress due to land-based sources of pollutants including sediments associated with land use and dredging. Sediments affect corals in numerous ways including smothering, abrasion, shading, and inhibition of coral recruitment. Sediment delivery resulting in deposition and water quality deterioration can cause degradation at the spatial scale of corals or entire reefs. We still lack rigorous long-term studies of coral cover and community composition before, during and after major sediment stress, and evidence of recovery after watershed management actions. Here we present an overview of the effects of terrestrial sediments on corals and coral reefs, with recent advances in approaches to watershed assessment relevant to the delivery of sediments to these ecosystems. We present case studies of northeastern Caribbean watersheds to illustrate challenges and possible solutions and to draw conclusions about the current state of knowledge of sediment effects on coral reefs. With a better understanding of erosion and the pathways of sediment discharge to nearshore reefs, there is the increased potential for management interventions.
... For several decades, natural and anthropogenic disturbances have caused serious decline of coral reefs worldwide (Alutoin et al., 2001;Halpern et al., 2008;NOAA, 2009;Elias, 2018). In the Costa Rican Caribbean, studies have shown that human activities, such as agriculture, untreated sewage discharge, solid waste pollution, marine transport, oil refineries, oil spills and port activities, have adversely affected coral reefs by increasing the sedimentation rates and causing chemical contamination to seawater, sediments and corals (Cortés and Risk, 1985;Mata et al., 1987;Guzmán and Jiménez, 1992;Guzmán and García, 2002;Cortés and Jiménez, 2003;Acuña-González et al., 2004;Cortés et al., 2010;Cortés, 2016). ...
... van Wendel de Joode et al. (2016) found Mn and derivative Mn compounds in soil and drinking water from villages situated near banana plantations, demonstrating that mancozeb use is an important source for Mn pollution. In this regard, it has been shown that sediments from banana plantations drain to the Caribbean coast (Cortés and Risk, 1985;Roder et al., 2009). Also, Mn could enter the marine environment by wastewater discharges (Howe et al., 2004), which could be a pollution source for Moín considering the population growth and the lack of sewage treatment. ...
Article
Moín, on the Caribbean coast of Costa Rica, is a multi-use coastal zone with a variety of human activities that can cause metal pollution. With the purpose of assessing the current environmental burden due to heavy metal presence in the marine environment of Moín, and their bioaccumulation in organisms of the nearby coral reef, we determined seven metals in samples of bottom sediments, macroalgae (Cryptonemia crenulata) and sponge (Cinachyrella kuekenthali). The results were compared with samples from the southern Caribbean, an area with little human activity. Using ICP-MS, results showed a concentration range for sediments Mn > Cu > Zn > Cr > Ni > Pb > Cd, algae Mn > Cu > Zn > Ni > Cr > Pb > Cd and sponge Mn > Cu > Zn > Ni > Cr > Cd > Pb, relatively low concentrations overall and no differences observed between sites. Bioconcentration factor > 1 was determined for Cd, Cu, Ni and Zn, while concentrations in sediments were below the SQG thresholds. Our study provides the first data on metal concentrations in a macroalgae and a sponge from the Costa Rican Caribbean.
... Rafa koralowa ulega jednak stopniowej degradacji, na co wskazywali badacze już w XX w. (Cortes, 1996;Hughes, 1994;Johannes, 1975;McClanahan, 1988;Pendleton, 1995). Zagrożenie dla bioróżnorodności raf koralowych stanowią głównie ocieplenie i zakwaszenie oceanów, spowodowane zarówno czynnikami globalnymi (emisja gazów cieplar-nianych), jak i lokalnymi (zanieczyszczenia chemiczne, nadmierne rybołówstwo). ...
... At each site in 5 m depth, six traps were deployed 1 m above the bottom for 3-day periods. Sediments were rinsed with fresh water to remove salts before determining their dry weights (Cortés and Risk, 1985). The sedimentation rate (kg m − 2 d − 1 ) was estimated with Eq. (2): ...
Article
A sclerobiont is any organism capable of fouling hard substrates. Sclerobionts have recently received attention due to their notable calcium carbonate contributions to reef structures and potential to offset drops in carbonate budgets in degraded reefs. However, due to their encrusting nature, it is difficult to quantify net calcium car-bonate production at the level of individual taxonomic groups, and knowledge regarding the main environmental factors that regulate their spatial distributions is limited. In addition, the material types used to create experimental substrates, their orientations, and their overall deployment times can influence settlement and the composition of the resulting communities. Thus, comparative evaluations of these variables are necessary to improve future research efforts. In this study, we used calcification accretion units (CAUs) to quantify the calcium carbonate contributions of sclerobionts at the taxonomic group level and evaluated the effects of two frequently used materials [i.e., polyvinyl chloride (PVC) and terracotta (TCT) tiles] on the recruitment and calcification of the sclerobiont community in the tropical Mexican Pacific and the Midriff Island Region of the Gulf of California over 6 and 15 months [n = 40; 5 CAUs x site (2) x deployment time (2) x material type (2)]. The net sclerobiont calcification rate (mean ± SD) reached maximum values at six months and was higher in the Mexican Pacific (2.15 ± 0.99 kg m − 2 y − 1) than in the Gulf of California (1.70 ± 0.67 kg m − 2 y − 1). Moreover, the calcification rate was slightly higher on the PVC-CAUs compared to that of the TCT-CAUs, although these differences were not consistent at the group level. In addition, cryptic microhabitats showed low calcification rates when compared to those of exposed microhabitats. Crustose coralline algae and barnacles dominated the exposed experimental surfaces, while bryozoans, mollusks, and serpulid polychaetes dominated cryptic surfaces. Regardless of the site, deployment time, or material type, barnacles made the greatest contributions to calcimass production (between 41 and 88%). Our results demonstrate that the orientation of the experimental substrate, and the material to a lesser extent, influence the sclerobiont community and the associated calcification rate. Upwelling-induced surface nutrient levels, low pH levels, and the aragonite saturation state (Ω Ar) limit the early cementation of reef-building organisms in the tropical Mexican Pacific and promote high bioerosion rates in corals of the Gulf of California. Our findings demonstrate that sclerobionts significantly contribute to calcium carbonate production even under conditions of high environmental variability.
... However, as the direct links between specific algal turf compositions and these processes remains unclear, our capacity to make inferences beyond this is currently limited. Quantifying these links in future studies is important considering stressors such as sediment mobilisation from dredging activities (Pollock et al., 2014;Fisher et al., 2018;Evans et al., 2020) and increased terrestrial derived sediment inputs from land-clearing (Cortés and Risk, 1985;Bainbridge et al., 2018;Wenger et al., 2020), could lead to higher accumulated particulate loads in algal turfs and associated changes in algal turf composition. ...
Article
Algal turfs trap and retain particulates, however, little is known about the relationship between particulate accumulation and taxonomic composition of algal turfs. We investigated how particulate mass related to algal turf structure (length and density) and community composition (taxonomic and functional) on two disparate reefs. Particulate mass was positively related to algal turf length. By contrast, the relationship between particulate mass and turf density was more complex and followed a negative parabolic shape; density increased with particulate mass before stabilising and then declining. Community analyses showed taxonomic, but not functional group compositions differed significantly between reefs and with increasing particulate mass. Our results suggest high loads of particulates accumulated in algal turfs are related to a longer, lower density turf structure, typified by filamentous forms such as Cladophora. Changes in algal turf structure and composition could have a variety of bottom-up influences on coral reef ecosystems.
... clearer, warmer water in shallow-marine areas, which may have promoted increased carbonate production and sedimentation rates. This is supported by agaricid corals, which are known to tolerate high sedimentation rates, being present only in the DS3 clinoforms (Cortes and Risk 1985;Edinger and Risk 1994). ...
Article
A Miocene (Langhian–Tortonian, ca. 15–10 Ma) tropical ramp system exposed in southern Puerto Rico is characterized by shallow-water facies consisting of heterozoans, red algae, large benthic foraminifera (LBF), and corals, which occur as isolated corals, segment- and cluster-type reefs, and reworked accumulations. Photozoan association components are limited to corals (Montastraea, Porites, Goniopora, and Agaricia) and LBF (amphisteginids, soritids, gypsinids, miliolids) that have been documented to tolerate elevated nutrients, turbidity, and cooler water conditions. Similar shallow-water carbonate systems are found throughout the Caribbean, and this regional development is thought to have resulted from the well-documented upwelling in the Caribbean during the Miocene. Sea-level fluctuations also exerted a major control on facies distributions and shifts in the Puerto Rico ramp, including a vertical facies pattern that occurs in each of three sequences. Basal parts of sequences, deposited during sea-level rises, are dominantly composed of mollusks, echinoderms, red algae, LBF, bryozoans, and solitary corals that formed in low-energy seagrass-bed environments with local associated higher-energy shoal environments. Coral facies occur only in upper parts of sequences and formed in shallow-water, low- to high-energy environments closely associated with seagrass beds during late highstands and sea-level falls. A similar vertical facies pattern occurs in time-equivalent sequences elsewhere around the Caribbean. Strontium-isotope age data indicate two sequence boundaries reflecting sea-level falls formed at about 12.3 Ma and 11.1 Ma. Correlation with time-equivalent unconformities in other well-dated areas in the Caribbean and to sea-level lows on eustatic curves suggests a global signature for sequence development. The connection between the Caribbean and the Pacific along the Central American Seaway (CAS), impacted by local tectonic episodes and sea-level fluctuations during the Miocene, affected nutrient influx and upwelling in the Caribbean, which may be reflected in the vertical facies pattern in shallow-water carbonate sequences. Times of restricted connection during sea-level falls and lows resulted in reduced nutrients and upwelling, which may have been more conducive to coral development. Time-equivalent tropical carbonate systems in the Mediterranean and Indo-Pacific show similarities to those in the Caribbean, indicating influence of global processes (cooling, temperature gradients, oceanographic circulation). Differences between areas indicates the importance of local and regional controls, which in the Caribbean was dominantly the opening and closure of the CAS.
Chapter
Costa Rica has coasts on both the Caribbean Sea and Pacific Ocean side, each with very different geomorphological characteristics. The Caribbean coast is 212 km long. To the north of the port area of Moín-Limón, the coast is rectilinear, with high-energy sandy beaches and coastal lagoons. To the south, fossil reef promontories intersperse with sandy beaches, with only two mangrove forests, numerous seagrass beds, and coral reefs. The Pacific coast is 1254 km long with two enclosed gulfs, Nicoya and Dulce, and open gulfs of Santa Elena, Papagayo, and Coronado. Rocky promontories are made of volcanic or sedimentary rocks, with beaches with many different types of sands in between. Isla del Coco, an oceanic island 500 km offshore in the Pacific, is characterized by basaltic outcrops, many cobble beaches, two sandy beaches, and two bays protected from the predominant southern wave activity.
Article
Full-text available
Las comunidades ícticas de los sistemas arrecifales están siendo presionadas como consecuencia del cambio climático sobre los ecosistemas marinos, especialmente por el aumento de la temperatura, la acidificación y la proliferación de algas. Así como por factores antrópicos que actúan de forma sinérgica. El objetivo de este trabajo es analizar el impacto de las afectaciones del cambio climático sobre la comunidad de peces en el Caribe Sur de Costa Rica. Se realizaron 21 inmersiones en el Parque Nacional de Cahuita, donde se efectuaron 42 video transectos a tres profundidades en los parches arrecifales. Se encontraron 90 especies de peces en total. En la profundidad de 1 m se reportan 50 especies, a 6 m de profundidad se reportan 63 y a 10 m de profundidad, 48 especies. Algunas especies más vulnerables sufrirán procesos de migración como consecuencia de la tolerancia a la temperatura, buscando aguas más frías hacia el hemisferio norte o sur mientras que otras menos tolerantes podrían desaparecer. Algunos peces que se alimentan específicamente de corales, pueden verse afectados porque se han reportado afectaciones de las comunidades arrecifales. Estos procesos son complejos y podrían cambiar la estructura y composición de las comunidades de peces a corto o a largo plazo. Se concluye que la comunidad íctica del arrecife es vulnerable a las presiones ejercidas por el cambio climático, y puede tender a simplificarse en respuesta a la adaptación a estos cambios.
Chapter
The previous chapters have described how chemical and biological processes are active on all coasts, although it is the physical processes that determine the patterns of morpho-sedimentary evolution. However, on many coasts, chemical and biological processes exert the main control of sedimentation and, therefore, are directly responsible for coastal morphology. Carbonate coasts and reefs, as part of these systems, are the best example of coasts controlled by chemical and biological processes.
Proceedings of the colloquium on global aspects of coral reefs RSMAS), 1994, pp 254-260. The reefs of the Abrolhos area (the southernmost coral reefs in the Atlantic) have an undoubted importance for scientific
  • K P Kikuchi
K. P. Kikuchi, in: Proceedings of the colloquium on global aspects of coral reefs, Miami, 1993, ed R.N. Ginsburg & F.G.W. Smith, (University of Miami, RSMAS), 1994, pp 254-260. The reefs of the Abrolhos area (the southernmost coral reefs in the Atlantic) have an undoubted importance for scientific