Article

Overcoming the concrete conquest of aquatic ecosystems

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Abstract

In reflecting on the human domination of our planet in the Anthropocene, some have argued that concrete is among the most destructive materials created by humans. Here we explore this idea, specifically in the context of what we consider “the concrete conquest of aquatic ecosystems.” The ubiquitous use of concrete in transportation and building infrastructure has contributed to alterations in freshwater and coastal marine systems. Yet, in some cases, there are no appropriate alternative building materials such that concrete itself is confounded by its application. For example, as the foundation for most dams, concrete fragments rivers and channelizes streams, often creating unnatural systems, yet dams are necessary for hydropower generation and flood control with few alternative materials for construction. In riparian and coastal environments, concrete harbours and inland canal systems are often used to address erosion or reclaim areas for human development. Even when removed (e.g., dam removal, naturalization of shorelines), concrete dust is a major aquatic pollutant. Instances do exist, however, where concrete has been used to benefit aquatic ecosystems – such as the installation of fish passage facilities at barriers or the development of fish-friendly culverts – though even then, there is a movement towards nature-like fishways that avoid the use of harmful materials like concrete. There are also opportunities to achieve conservation gains in the development of seawalls that include more natural and complex features to benefit biota and allow for essential biogeochemical processes to occur in aquatic environments. There have been several innovations in recent years that increase the permeability of concrete, however these have limited application in an aquatic context (e.g., not relevant to dam construction or erosion control but may be relevant in stormwater management systems). We provide a brief overview of the history of concrete, discuss some of the direct and indirect effects of concrete on aquatic ecosystems, and encourage planners, engineers, developers, and regulators to work collaboratively to explore alternatives to concrete which benefit aquatic ecosystems and the services they offer. The status quo of concrete being the default construction material is failing aquatic ecosystems, so we recommend that efforts are made to explore alternative materials and if concrete must be used, to increase structural complexity to benefit biodiversity.

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... Weathering of concrete materials is recognised as a likely contributor to this geochemical modification of urban waterways (Chambers et al., 2016;Davies et al., 2010;Wright et al., 2011), urban wetlands (Belmer et al., 2015;Carroll et al., 2020), and urban riparian soils (Bain et al., 2012;Grella et al., 2014). Concrete materials are commonly used in urban drainage systems typically comprising structures such as pipes, culverts, gutters and canals (Cooke et al., 2020;Davies et al., 2010;Wright et al., 2011). Recycled concrete aggregate (RCA) materials are used world-wide as a construction waste material that is recycled and is widely used as a substitute for gravel (Rahman et al., 2014). ...
... The current research builds on previous studies and highlights the likely contribution of concrete urban materials to the geochemistry of urban waterways (Davies et al., 2010;Kaushal et al., 2013;Cooke et al., 2020). Weed invasion is one of the major environmental degradation issues in urban waterways (Paul & Meyer, 2001) as well as in urban BMUS wetlands (Benson & Baird, 2012;Fryirs et al., 2012). ...
... It would also be valuable to extend the length of plant studies for longer periods and across different plant growth stages. Further research on topics such as this will be vital in many environmental settings, as concrete is a ubiquitous urban material and will continue to be part of the built environment in an increasingly urban world (Cooke et al., 2020;Kaushal et al., 2013). ...
Article
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Urban riparian vegetation is frequently dominated by invasive weeds, whose growth is often attributed to the elevated nitrogen and phosphorous in urban waters and soils. However, less recognition is given to other urban contaminants that may influence riparian vegetation. Previous studies have indicated that the dissolution of concrete modifies water and soil geochemistry and potentially enhances the growth of invasive species. This study investigated the relationship between urban water quality and the growth of an invasive urban riparian weed, willow (Salix spp.), to examine the contribution and influence of concrete materials. The study used water from endangered upland peat wetlands within and adjoining the Greater Blue Mountains World Heritage Area, many of which are in urban catchments and suffer degradation from water pollution and invasive weeds. In this study, willow cuttings were grown in a laboratory using four water treatments: pristine (non-urban), urban, and non-urban water exposed to two different concrete materials. The urban and concrete-exposed water treatments were associated with increased plant growth measures in addition to increased concentrations of barium and strontium that bioaccumulated in plant tissue.
... We focused on concrete, using both smooth and rough surfaces. Concrete continues to be widely used in freshwater environments, such as for erosion control and for harbor infrastructure (Cooke et al., 2020), and is thus a logical material to use for such experiments. And while concrete is not the optimal material for shoreline modification, there are cases of concrete erosion control structures that are an overall benefit to the environment (Cooke et al., 2020). ...
... Concrete continues to be widely used in freshwater environments, such as for erosion control and for harbor infrastructure (Cooke et al., 2020), and is thus a logical material to use for such experiments. And while concrete is not the optimal material for shoreline modification, there are cases of concrete erosion control structures that are an overall benefit to the environment (Cooke et al., 2020). Furthermore, our goal was to inform the design of erosion control structures that minimally disrupt essential turtle behavior such as basking, nesting, and dispersal. ...
... Therefore, future shoreline restorations and modifications should not exceed this slope to ensure that turtles can access terrestrial habitats and basking sites. We used concrete for this experiment given that it is still a commonly used material in shoreline alterations and erosion controls (Cooke et al., 2020). However, alternatives such as rip-rap (a rock armored erosion control) or other nature-like solutions require further study and may overall be more beneficial for biodiversity than concrete. ...
... microroughness; (Berntsson et al., 2000;Fletcher and Callow, 1992), color (Dobretsov et al., 2013;Ells et al., 2016;Lathlean and Minchinton, 2012), and surface chemistry (Anderson, 1996;Sella and Perkol Finkel, 2015; but see Hsiung et al., 2020). During construction, material choice also affects the demand for raw materials, the energy cost for processing and transport, and the CO 2 emissions (Cooke et al., 2020). Research is growing on the partial or total replacement of traditional concrete materials with recycled alternatives (i.e., mixing with by-products of industrial processes) to reduce the carbon footprint and the need for raw materials (Meyer, 2009), whilst still maintaining engineering performance (Becker et al., 2020;Huang et al., 2016). ...
... The use of eco-friendly materials (i.e., concrete made with recycled by-products) did not seem to provide significant colonization benefits for epibiota compared to traditional Portland concretes, as also reported by other authors (Hsiung et al., 2020). It should be noted, however, that the use of eco-friendly materials could provide other crucial ecological benefits for example by reducing raw materials demand, energy costs or CO 2 emissions (Cooke et al., 2020). Eco-friendly materials can replace quarry virgin aggregates and Portland cement with recycled by-products (i.e., shell fragments, fly ash or ground granulated blast furnace slag; (Meyer, 2009). ...
... Reduce energy cost and carbon footprint (Cooke et al., 2020;Dennis et al., 2018;McManus et al., 2018) Autochthonous rocks Improve aesthetical value/ Greater consistency with cultural heritage Nordstrom, 2014) ...
... Habitat that is not well designed by restoration practitioners, especially engineered habitat, can therefore have the opposite effect on prey species and interactions between predators and prey. Examples of design shortcomings include wildlife overpasses that are not wide enough (Brennan et al. 2022), simplification of aquatic ecosystems using unsustainable materials like plastic and concrete to create artificial habitat (Cooke et al. 2020(Cooke et al. , 2023, or the aforementioned creation of predation hotspots (Boulêtreau et al. 2018). ...
Article
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Habitat is a powerful force in ecosystems, and the quantity and quality of habitat can shape ecosystem structure and function. Among the many important roles that habitat plays is as a mediator of ecological interactions, including predator–prey dynamics. In the context of ecosystem restoration, there is great potential to better understand how predator–prey dynamics are influenced by habitat and whether this has implications for how ecosystems are managed. We consider the ways in which habitat serves as an important mediator of interactions between predators and their prey and present four ways in which habitat acts as an intermediary that enhances or diminishes this relationship. We found that habitat provides refuge from predators and shapes the physical traits of prey as they use their surroundings to protect themselves. We also discuss how habitat creates physical resistance and sets the cost of predation for predators and how habitat facilitates apparent competition within a community context. These roles of habitat are well established in ecology, but we believe they are underdeveloped from an applied perspective. We conclude that habitat must be appropriately considered in the context of how it mediates predation. Given the ways that habitat influences predation, restoration efforts should consider if and how physical measures may positively or negatively affect species interactions and whether this could lead to success or failure of overall programs.
... This may be the consequence of bottlenecks to innovative designs or materials. For example, Portland cement has long been the primary material for building urban shoreline armoring, but is potentially hostile to the settlement of many invertebrates due to surface chemistry, texture, form, and complexity (Cooke et al., 2020). It is also an important source of CO 2 to the atmosphere. ...
Article
Full-text available
Armored urban shorelines have historically impoverished life on the waterfront. Materials and forms were chosen to discourage the settlement of marine communities and human access. This has weakened shoreline habitats and adjacent terrestrial and aquatic ecosystems and diminished urban human experiences by reducing links to nature. Augmentation of existing structures and new waterfront designs for specific ecological goals such as salmon habitat improvement are reversing these trends. With the integration of advances in ecology, social science, engineering, architecture, and regulation, urban shorelines can be designed and built to enrich human experience and natural resources through connections rather than through separation and can then be considered “living shorelines.” Such a holistic approach should extend from the subtidal to the terrestrial vegetated and built environment. As with traditional soft sediment living shorelines, life can be included from the outset and be applied as an integral design element providing many functions as well as ecosystem services and social well-being benefits. We present challenges and recommend solutions for broad incorporation of this new vision for urban shorelines. We need data on biological recruitment processes, a better understanding of human social engagement with the urban shore, and continued development of materials for strength, customizability, ecosystem compatibility, and reduced carbon footprint. Measuring and tracing impacts or contributions will be difficult. Improved assessments of investment risk and reward for urban areas are needed to fund these efforts, and regulatory adaptability is needed to allow the transformation of urban shores into living shores.
... Marine "Portland concrete" is the dominant compound in breakwater construction and gradually covers increasing coastline sections [72]. Its mixture has a pH range from 9 to 13 before curing, creating a habitat favoring alkaliphilic organisms [73]. ...
Article
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The global demand for coastal urbanization is rising with the increasing population. Alas, living close to the ocean threatens human endeavors with high currents, waves, and increasing storm frequency. Accordingly, the need for more coastal defense structures (CDSs) rises. Structures built from complex units meant to prevent and/or mitigate coastal erosion and floods, additionally providing wave protection or wave attenuation, are constructed on and near natural habitats where they alter local ecosystems. Traditional CDSs mostly fail to harbor diverse and abundant communities. However, this can be changed by eco-friendly methodologies and designs that are being tested and implemented to improve CDSs' ecological value. Some of these can be implemented during the construction period, while others can fit on existing structures, such as wave breakers and seawalls. Effective methods include augmenting surface rugosity through strategic perforations, integrating artificial panels for increased complexity, implementing soft (naturally based) engineering solutions such as geotextiles, replacing industrial concrete mixtures for CDS construction with "green concrete" and ecologically friendly mixtures, and using alternative, eco-friendly units in CDS erections. In this mini review, we suggest that by integrating sustainable practices into coastal development, we can significantly mitigate the ecological damage caused by traditional CDSs and promote more harmonious relationships between human construction and the marine environment. This shift towards environmentally conscious coastal defenses is essential and a responsibility for ensuring the long-term sustainability of our coastal communities and the health of our oceans. We present current methodologies used on breakwaters worldwide.
... Hard stabilization methods have traditionally been employed to mitigate coastal erosion. Concrete armour is widely used due to its high level of dependence, robustness, ease of production and cost effectiveness (Cooke et al., 2020;Pikey and Cooper, 2012). It is inevitable that coastline 'armouring' will continue to rise because of the growing human population and urbanization, desire for and value of coastal property, opposed to predicted climate change (Chapman and Underwood, 2011). ...
Conference Paper
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Hard stabilization methods have traditionally been employed to mitigate coastal erosion. Concrete armour is widely used due to its high level of dependence, robustness, ease of production and cost effectiveness (Cooke et al., 2020; Pikey and Cooper, 2012). It is inevitable that coastline ‘armouring’ will continue to rise because of the growing human population and urbanization, desire for and value of coastal property, opposed to predicted climate change (Chapman and Underwood, 2011). The environmental impact of such 'armouring' on coastal systems can be detrimental, resulting in a degradation or destruction of habitats and the loss of ecologically trivial species (Gittman et al., 2015). The CoastalockTM, a single-layer armour unit, aims to blend coastal protection with marine habitat creation. This armour unit is designed to mimic inter- and sub-tidal habitats, with chemical composition of substrate and micro and macro features that provide niches for various species. The key feature of CoastalockTM is the cavity that is integrated into the design, that caters to diverse marine life needs depending on its orientation (ECOncrete Tech Ltd., 2019). CoastalockTM's hydraulic performance is under research. Preliminary tests conducted in the Hydraulic Engineering Laboratory (HEL) of the Technical University of Delft (TUD) on a 2V:3H impermeable slope in deep water conditions highlighted that with tight placement of the units significant pressure gradients across the top layer led to damage. The introduction of spacings between units for enhanced permeability improved stability significantly (Gutiérrez et al., 2023). A redesign of the unit was proposed incorporating protrusions to enforce the spacings between the blocks (Molenkamp, 2022). This research focuses on evaluating the influence of a porous core on the hydraulic performance of a CoastalockTM armour layer, specifically assessing its stability, overtopping, and reflection on a 2V:3H breakwater slope in deep water conditions—from the toe to just below the crest. A pivotal aspect of this research is the investigation of the impact of protrusions on the hydraulic performance. Furthermore, the study explores the influence of different toe configurations, aiming to comprehend the vulnerability of the armour layer to sliding. Toe scour falls outside the scope of this study.
... Concrete serves as the primary material for constructing these infrastructures due to its durability, strength, and adaptability [6,7]. However, extensive concrete use in construction poses significant environmental challenges for marine ecosystems [8,9]. Concrete structures displace natural coastal habitats, altering vital nursery environments like coral reefs, seagrass beds and mangroves [10,11]. ...
Article
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The expanding urbanization of coastal areas has led to increased ocean sprawl, which has had both physical and chemical adverse effects on marine and coastal ecosystems. To maintain the health and functionality of these ecosystems, it is imperative to develop effective solutions. One such solution involves the use of biodegradable polymers as bioactive coatings to enhance the bioreceptivity of marine and coastal infrastructures. Our study aimed to explore two main objectives: (1) investigate PHA-degrading bacteria on polymer-coated surfaces and in surrounding seawater, and (2) comparing biofilm colonization between surfaces with and without the polymer coating. We applied poly(3-hydroxybutyrate) [P(3HB)) coatings on concrete surfaces at concentrations of 1% and 6% w/v, with varying numbers of coating cycles (1, 3, and 6). Our findings revealed that the addition of P(3HB) indeed promoted accelerated biofilm growth on the coated surfaces, resulting in an occupied area approximately 50% to 100% larger than that observed in the negative control. This indicates a remarkable enhancement, with the biofilm expanding at a rate roughly 1.5 to 2 times faster than the untreated surfaces. We observed noteworthy distinctions in biofilm growth patterns based on varying concentration and number of coating cycles. Interestingly, treatments with low concentration and high coating cycles exhibited comparable biofilm enhancements to those with high concentrations and low coating cycles. Further investigation into the bacterial communities responsible for the degradation of P(3HB) coatings identified mostly common and widespread strains but found no relation between the concentration and coating cycles. Nevertheless, this microbial degradation process was found to be highly efficient, manifesting noticeable effects within a single month. While these initial findings are promising, it’s essential to conduct tests under natural conditions to validate the applicability of this approach. Nonetheless, our study represents a novel and bio-based ecological engineering strategy for enhancing the bioreceptivity of marine and coastal structures.
... In addition, the urbanization and hardening of banks or channels reduced the area of riparian zone and floodplains, made rivers lose ecological resilience, and weakened their functions. The development of cascade power stations damaged the habitats of major fish, and consequently species resources declined [21][22][23]. The channelization of rivers destroyed the living environment of animals and plants and caused the ecological imbalance of the river system. ...
... To fulfill these criteria, the study systematically investigated the optimal composition for pervious concrete, employing FABA as a binder and artificial aggregate. FA incorporation reduces concrete's carbon footprint by decreasing cement content, curbing CO 2 emissions, especially in mangrove conservation efforts (Cooke et al., 2020). ...
... Silica dust, particularly in the form of crystalline silica, can have a range of environmental impacts when it enters the waterways. As outlined by Cooke et al. (2020), aquatic ecosystems experience several interacting effects, especially the marine and freshwater habitats that are impacted directly through water extraction and pollution during concrete production. ...
Research Proposal
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This study delves into a crucial yet often overlooked aspect of precast concrete manufacturing in New Zealand—dry grinding. Driven by the need to refine product surfaces, this process generates hazardous silica dust, jeopardizing worker health and environmental integrity. The research responds to industry concerns, particularly in light of the COVID-19 pandemic, by seeking innovative, cost-effective, and worker-centric solutions. It meticulously examines health and safety intricacies, assesses dust contamination repercussions, and presents a comprehensive strategy. The ultimate goal is to transform this research into a practical health and safety business proposal, revolutionizing dry grinding practices while prioritizing worker well-being and environmental responsibility.
... The lower microbial diversity on its surface indicates the slightly toxic nature of this cement to marine bacteria, as previously shown for bacteria in groundwater stored in concrete or earthen ponds, the former being lower in diversity and abundance [114]. Indeed, concrete has been described as having especially deleterious consequences on biodiversity in all aquatic ecosystems [115]; this concords with research suggesting that a relatively mature microbial biofilm on concrete in the marine environment is somewhat generic, differing little from normal structural concrete composition [39][40][41]. ...
Article
Full-text available
Concrete is the most utilized construction material worldwide. In the marine environment, it is subject to chemical degradation through reactions with chloride (the most important ion), and sulfate and magnesium ions in seawater, and to biodeterioration resulting from biological (initially microbiological) activities, principally acid production. These two types of corrosions are reviewed and the failure of attempts to predict the degree of deterioration resulting from each is noted. Chemical (abiotic) corrosion is greatest in the splash zone of coastal constructions, while phenomenological evidence suggests that biodeterioration is greatest in tidal zones. There have been no comparative experiments to determine the rates and types of microbial biofilm formation in these zones. Both chemical and microbiological concrete deteriorations are complex and have not been successfully modeled. The interaction between abiotic corrosion and biofilm formation is considered. EPS can maintain surface hydration, potentially reducing abiotic corrosion. The early marine biofilm contains relatively specific bacterial colonizers, including cyanobacteria and proteobacteria; these change over time, producing a generic concrete biofilm, but the adhesion of microorganisms to concrete in the oceans has been little investigated. The colonization of artificial reefs is briefly discussed. Concrete appears to be a relatively prescriptive substrate, with modifications necessary to increase colonization for the required goal of increasing biological diversity.
... The lower microbial diversity on its surface indicates the slightly toxic nature of this cement to marine bacteria, as previously shown for bacteria in groundwater stored in concrete or earthen ponds, the former being lower in diversity and abundance [112]. Indeed, concrete has been described as having especially deleterious consequences on biodiversity in all aquatic ecosystems [113]; this concords with research suggesting that a relatively mature microbial biofilm on concrete in the marine environment is somewhat generic, differing little with normal structural concrete composition [39]; [40]; [41]. Preprints (www.preprints.org) ...
Preprint
Full-text available
Concrete is the most utilized construction material worldwide. In the marine environment, it is subject to chemical degradation through reactions with chloride (the most important ion), sulfate and magnesium ions in seawater and to biodeterioration resulting from biological (initially microbiological) activities, principally acid production. These two types of corrosion are reviewed and the failure of attempts to predict the degree of deterioration resulting from each is noted. Chemical (abiotic) corrosion is greatest in the splash zone of coastal constructions, while phenomenological evidence suggests that biodeterioration is greatest in tidal zones. There have been no comparative experiments to determine the rates and types of microbial biofilm formation in these zones. Both chemical and microbiological concrete deterioration are complex and have not been successfully modeled. The interaction between abiotic corrosion and biofilm formation is considered. EPS can maintain surface hydration, potentially reducing abiotic corrosion. The early marine biofilm contains relatively specific bacterial colonizers, including cyanobacteria and proteobacteria; these change over time, producing a generic concrete biofilm, but adhesion of microorganisms to concrete in the oceans is little investigated. The colonization of artificial reefs is briefly discussed. Concrete appears to be a relatively prescriptive substrate, with modifications necessary to increase colonization for the required goal of increasing biological diversity.
... Concrete materials are one of the most widely used structural materials used in urban areas and modern urban drainage systems. Urban runoff drains through concrete drainage structures that include pipes, culverts, gutters and canals [22][23][24]. The widespread use of calcareous concrete urban materials has been termed 'urban karst', which can rapidly weather when exposed to low-pH precipitation [6,19]. ...
Article
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The use of recycled concrete aggregates as a construction material is growing and this study was conducted to investigate the potential water quality issues that arise when concrete aggregates are exposed to water. The water used in the study was from a high-conservation-value wetland. It was dilute (17.8 µS cm−1), acidic (pH 5.97) and poorly buffered. The ionic composition comprised sodium, bicarbonate and chloride ions. Water was recirculated for 60 min through a control treatment and three treatments containing recycled concrete aggregates (RCAs) of different fragment sizes (10 mm, 20 mm and 60 mm). The fragment size influenced the final water quality, but the response patterns varied between the attributes tested. Post-recirculation, the RCA treatments increased the electrical conductivity by 6 to 12 times; pH by 2.3 to 3.8 pH units; and concentrations of calcium, potassium, bicarbonate and sulphate. The water exposed to RCA materials also increased the concentrations of several metals (aluminium, arsenic, copper, lead and zinc), resulting in hazardous concentrations for aquatic species according to ecological water quality guidelines. Strontium concentrations in water exposed to RCAs increased by 30 to 120 times background levels. The results from this study added further support to a growing body of evidence that the exposure of concrete materials to water can produce environmentally hazardous water quality.
... Steel and concrete GHG emissions also exceeded those for the life cycle of CCA-treated piles (Bolin and Smith 2012). The production of Portland cement, an essential component of concrete, is highly energy intensive and consequently has a large carbon footprint (Meyer 2009;Cooke et al. 2020). Therefore, each project should consider the surrounding environment and determine an appropriate approach on a case-by-case basis within a system level analysis. ...
Article
Full-text available
Small docks and floats are common in estuaries and coastal waters worldwide. These structures serve a role in coastal recreation by facilitating access to waterways. However, they can impact shoreline ecological function. While individual environmental impacts are generally minor, increasing dock proliferation and overlap with sensitive coastal resources can result in cumulative impacts that pose threats at the ecosystem level. Docks promote changes in habitat and aquatic communities through alteration of environmental conditions. Here, we review the potential environmental impacts of docks on estuarine and coastal flora and fauna and discuss best management practices (BMPs) to avoid or minimize such impacts with a focus on New England. We consider impacts in relation to the structural components of docks: the piles, decking, and floats. Impacts to salt marsh and submerged aquatic vegetation are a particular focus given the important ecosystem services these vegetated habitats provide and their vulnerability to dock-induced habitat alteration. Potential environmental impacts depend on structure size, design, and location, and can include both short-term (e.g., turbidity from pile installation) and long-term (e.g., salt marsh loss from chronic shading) effects. Such effects can be minimized through BMPs (e.g., construction outside sensitive time-of-year periods, designs to reduce shading). As BMPs tend to reduce rather than avoid environmental effects, cumulative impacts also need to be considered in the permitting process. We recommend that managers develop plans or bylaws that identify sensitive habitats where dock construction should be avoided as well as BMPs to make remaining dock proliferation less impactful.
... Ceramic modules with tighter surface-pore densities may reduce biofouling and/or enhance targeted species-specific settlement (Johari et al., 2010). Companies are already creating "ecologically active" concrete materials that modify composition and surface texture to support specific marine fauna and flora (Perkol-Finkel and Sella, 2014), lowers the carbon footprint of artificial habitat construction (Dennis et al., 2018), and addresses the concern of concrete waste in aquatic ecosytems (Cooke et al., 2020). One could even consider expanding and adapting this method to test biofilm or antibiofouling coatings that reduce or promote targeted biotic build-up (Tamburri et al., 2008). ...
Article
Full-text available
Identifying features of biogenic (i.e., living) habitat that attract and retain organisms is a key pursuit in ecological habitat selection research. Here we present an integrative method for creating aquatic artificial habitat modules that allow the user to isolate and flexibly manipulate structural and compositional features of replicated biogenic habitats for a range of habitat selection study designs in aquatic environments: This method combines techniques from engineering (3D scanning and printing), paleontology, and visual art (moulding and casting) into a stream-lined work flow that is likely to perform on par with or better than other techniques widely used to create artificial replicas of biogenic habitats in terms of design accessibility (availability and cost of construction materials and equipment, and training requirements), scalability (durability, ease of deployment, and reproducibility), and the ecology of the artificial habitat module (degree to which structural and compositional features of the habitat elicit appropriate visual, chemosensory, and auditory cues, and impact of the structure on the surrounding environment). This method can be flexibly modified to answer a variety of questions regarding habitat selection cues, for a range of aquatic biogenic habitat types, and can be adapted for theoretical and applied contexts including cue studies and restoration planning.
... The same cannot be said for ocean environments, where comparable manmade barriers to movement that fragment habitats do not exist. While docks and jetties may create obstacles to movement (Cooke et al. 2020), they do not fragment the landscape in the same way as land-based structures which would otherwise restrict or prevent movement. Indeed, the ocean has no fences. ...
Article
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Understanding and ultimately predicting how marine organisms will respond to urbanization is central for effective wildlife conservation and management in the Anthropocene. Sharks are upper trophic level predators in virtually all marine environments, but if and how their behaviors are influenced by coastal urbanization remains understudied. Here, we examined space use and residency patterns of 14 great hammerheads Sphyrna mokarran , 13 bull sharks Carcharhinus leucas , and 25 nurse sharks Ginglymostoma cirratum in proximity to the coastal metropolis of Miami, Florida, using passive acoustic telemetry. Based on the terrestrial urban carnivore literature, we predicted sharks would exhibit avoidance behaviors of areas close to Miami, with residency patterns in these urban areas increasing during periods of lower human activity, such as during nocturnal hours and weekdays, and that dietary specialists (great hammerhead) would exhibit comparatively lower affinity towards highly urbanized areas relative to dietary generalists (bull and nurse shark). However, we did not find empirical support for these predictions. Space use patterns of tracked sharks were consistent with that of ‘urban adapters’ (species that exhibit partial use of urban areas). Modeling also revealed that an unmeasured spatial variable was driving considerable shark residency in areas exposed to high urbanization. We propose several hypotheses that could explain our findings, including food provisioning from shore-based activities that could be attracting sharks to urban areas. Ultimately, the lack of avoidance of urban areas by sharks documented here, as compared to terrestrial carnivores, should motivate future research in the growing field of urban ecology.
... In addition, the urbanization and hardening of banks or channels reduced the area of riparian zone and floodplains, made rivers lose ecological resilience, and weakened their functions. The development of cascade power stations damaged the habitats of major fish, and consequently species resources declined [21][22][23]. The channelization of rivers destroyed the living environment of animals and plants and caused the ecological imbalance of the river system. ...
Article
Full-text available
With global warming, urbanization, and the intensification of human activities, great pressures on river ecosystems have caused ecosystem degradation, the decline in habitats and biodiversity, and the loss of function. Ecological restoration technologies (ERTs) in rivers are effective measures for improving habitat and biodiversity, which has the advantage of recovering ecosystems and biodiversity and promoting the formation of healthy rivers. Several applications of ERTs, including ecological water transfer, fish passage construction, dam removal/retrofit, channel reconfiguration, river geomorphological restoration, natural shoreline restoration, floodplain reconnection, revegetation, etc., are summarized. The classifications of ERTs are highlighted, aiming to distinguish the difference and relationship between structure and the processes of hydrology, physics, geography, and biology. The pros and cons of these technologies are discussed to identify the applicability and limitations on the river ecosystem. In the dynamic processes in the river, these interact with each other to keep ecosystem balance. ERTs are more helpful in promoting the restoration of the natural function of the river, which contribute to the management of river ecological health. Some proposals on river management are suggested. Establishing a unified river health evaluation system will help promote positive feedback on rivers and the further development of ERTs.
... The availability of water from groundwater aquifers in the United States has been associated with a trend towards settlement away from surface waters since the industrial revolution (Fang and Jawitz 2019). Increased proportions of individuals living in urban areas may give the illusion of reductions in impacts to surface waters, but in many urban areas such water sources are filled in (wetlands; Davidson 2014, Mao et al. 2018 or constrained in concrete channels (Cooke et al. 2020). Pumping of groundwater has also reduced river flow and depleted wetlands such that development away from the valley will not remove all impacts to the stream (de Graaf et al. 2019). ...
Article
Decades ago, Dr Noel Hynes eloquently summarized the inherent interconnectedness of a stream and its valley and made the case that human alteration of the valley would have direct negative consequences for freshwater systems. Currently, the freshwater biodiversity crisis extends across all continents and demands urgent attention from environmental planners, practitioners, and policymakers to protect streams and their valleys. As we work to slow losses of freshwater biodiversity and restore freshwater ecosystems, it is time to revisit the important messages from Hynes. One of the most obvious and immediate actions that could be undertaken is to “back off”— that is, to limit human activity and new development in floodplain and riparian areas immediately adjacent to freshwater systems, including streams, rivers, lakes, and wetlands, while minimizing impacts and risks in areas with existing development. From reducing erosion and flood damage to maintaining cool water temperatures, filtering pollutants, protecting critical habitats, and enabling lateral connectivity, intact riparian zones mitigate many of the threats that degrade freshwater ecosystems. There has been much research to identify optimal setbacks and buffer-strip widths to protect against harm. As such, in many areas, our ability to protect the stream and its valley is not limited by natural science but rather our failure to consistently apply floodplain and riparian regulations and the absence of political will. We are too quick to trade off the environment for short-term economic development. In areas that are already developed, solutions are more complicated but, in many cases, represent a key priority for healing damaged ecosystems and for addressing economic and social risks of vulnerable development. We need to redefine our relationship with freshwater ecosystems, and the first step is to back off and give freshwater ecosystems the opportunity to heal while ensuring that as-of-yet intact riparian areas continue to support freshwater resiliency. In doing so, we will also gain climate adaptive benefits, given that maintaining intact riparian areas is an effective nature-based solution. Key words: Biodiversity, climate change, floodplain, fresh water, management, riparia © 2022 The Society for Freshwater Science. All rights reserved.
... Steel and concrete GHG emissions also exceeded those for the life cycle of CCA-treated piles (Bolin and Smith 2012). The production of Portland cement, an essential component of concrete, is highly energy intensive and consequently has a large carbon footprint (Meyer 2009;Cooke et al. 2020). Therefore, each project should consider the surrounding environment and determine an appropriate approach on a case-by-case basis within a system level analysis. ...
Article
Full-text available
Small docks and floats are common in estuaries and coastal waters worldwide. These structures serve a role in coastal recreation by facilitating access to waterways. However, they can impact shoreline ecological function. While individual environmental impacts are generally minor, increasing dock proliferation and overlap with sensitive coastal resources can result in cumulative impacts that pose threats at the ecosystem level. Docks promote changes in habitat and aquatic communities through alteration of environmental conditions. Here, we review the potential environmental impacts of docks on estuarine and coastal flora and fauna and discuss best management practices (BMPs) to avoid or minimize such impacts with a focus on New England. We consider impacts in relation to the structural components of docks: the piles, decking, and floats. Impacts to salt marsh and submerged aquatic vegetation are a particular focus given the important ecosystem services these vegetated habitats provide and their vulnerability to dock-induced habitat alteration. Potential environmental impacts depend on structure size, design, and location, and can include both short-term (e.g., turbidity from pile installation) and long-term (e.g., salt marsh loss from chronic shading) effects. Such effects can be minimized through BMPs (e.g., construction outside sensitive time-of-year periods, designs to reduce shading). As BMPs tend to reduce rather than avoid environmental effects, cumulative impacts also need to be considered in the permitting process. We recommend that managers develop plans or bylaws that identify sensitive habitats where dock construction should be avoided as well as BMPs to make remaining dock proliferation less impactful.
... The deterioration of steel reinforcement due to corrosion in the concrete environment leads to frequent maintenance and repair of reinforced concrete (RC) structures, thus adversely impacting the economy [1]. Nevertheless, environmental concerns such as global warming due to increased concrete [2] and steel production and unbalanced river ecosystems due to water consumption [3] are rising international interests. In addition, the coastal infrastructure is a vital factor in a country's economic development. ...
Article
Glass fiber reinforced polymer (GFRP) rebars reinforced in concrete are susceptible to degradation in harsh alkaline environments such as moist reinforced concrete and seawater and sea sand concrete. The residual tensile strength of GFRP rebar is essential in designing guidelines for GFRP reinforced concrete in different codes. The residual tensile strength is reflected as an environment reduction factor (C E) to incorporate long-term environmental exposure effects. For this purpose, an extensive database comprising 715 tested specimens were collected from literature to develop GEP tree-based model. Aging tests of GFRP rebars were carried out in the laboratory to test the trained model. Initially, nine gene expression programming (GEP) tree-based models were initially developed using RMSE, MAE, and RSE as fitness functions while varying the numbers of genes. The models were developed employing a random selection of 70% of the conditioned specimens for the training purpose in accordance with the literature. The trained models were validated using the remaining 30% data. A model was chosen to create a prediction formula evaluated from the GEP-expression trees (ETs) and derived MATLAB model based on a broader range of statistical errors and correlations. The chosen model was tested using 36 experimental accelerated aging results, which yielded a comparable statistical evaluation to training and validation data. Two types of GFRP rebars, Type-I (volume fraction of 0.50) and Type-II (volume fraction of 0.60) of three different rebar sizes, i.e., 9.5 mm, 12.7 mm, and 15.9 mm were investigated for determining tensile strength retention (TSR) and C E. The results concluded that smaller Type-I rebars are more susceptible to degradation as compared to Type-II rebars of larger size. A value of 0.76 is recommended for a uniform C E based on the upper bound of 95% confidence interval for design life of 100 years.
... The deterioration of steel reinforcement due to corrosion in the concrete environment leads to frequent maintenance and repair of reinforced concrete (RC) structures, thus adversely impacting the economy [1]. Nevertheless, environmental concerns such as global warming due to increased concrete [2] and steel production and unbalanced river ecosystems due to water consumption [3] are rising international interests. In addition, the coastal infrastructure is a vital factor in a country's economic development. ...
Article
Full-text available
Glass fiber reinforced polymer (GFRP) rebars reinforced in concrete are susceptible to degradation in harsh alkaline environments such as moist reinforced concrete and seawater and sea sand concrete. The residual tensile strength of GFRP rebar is essential in designing guidelines for GFRP reinforced concrete in different codes. The residual tensile strength is reflected as an environment reduction factor (CE) to incorporate long-term environmental exposure effects. For this purpose, an extensive database comprising 715 tested specimens were collected from literature to develop GEP tree-based model. Aging tests of GFRP rebars were carried out in the laboratory to test the trained model. Initially, nine gene expression programming (GEP) tree-based models were initially developed using RMSE, MAE, and RSE as fitness functions while varying the numbers of genes. The models were developed employing a random selection of 70% of the conditioned specimens for the training purpose in accordance with the literature. The trained models were validated using the remaining 30% data. A model was chosen to create a prediction formula evaluated from the GEP-expression trees (ETs) and derived MATLAB model based on a broader range of statistical errors and correlations. The chosen model was tested using 36 experimental accelerated aging results, which yielded a comparable statistical evaluation to training and validation data. Two types of GFRP rebars, Type-I (volume fraction of 0.50) and Type-II (volume fraction of 0.60) of three different rebar sizes, i.e., 9.5 mm, 12.7 mm, and 15.9 mm were investigated for determining tensile strength retention (TSR) and CE. The results concluded that smaller Type-I rebars are more susceptible to degradation as compared to Type-II rebars of larger size. A value of 0.76 is recommended for a uniform CE based on the upper bound of 95% confidence interval for design life of 100 years.
... This is problematic in many ways: rivers are naturally four-dimensional systems that depend on a high degree of connectivity (Ward, 1989;Auerswald et al., 2019), and there are hardly any free-flowing rivers in the world any more (Grill et al., 2019). Practically all hydropower development depends on the introduction of concrete structures into rivers, resulting in habitat fragmentation; indeed, Cooke et al. (2020) have proposed that the concrete conquest of aquatic ecosystems should cease. The creation of impoundments, urbanization, and catchment land use have been identified as the most important factors affecting fish community composition in streams (Bierschenk et al., 2019a;Mueller et al., 2020a). ...
... For a benthic species, such as a freshwater mussel, this situation should be carefully evaluated and guide the future implementation of nature based solutions (see Palmer et al., 2015). Given the dominance of structures made of concrete in aquatic ecosystems and due to their negative effects on many ecological aspects (for a review, see Cooke et al., 2020), future studies should aim at developing more eco-friendly and sustainable materials. These new materials, including more permeable concrete and fibrous materials such as fuzzy ropes , may not only benefit biota but also humans (e.g. through improved biogeochemical cycling), with lower environmental, social and economic costs (Palmer et al., 2015). ...
Article
Anthropogenic freshwater habitats may provide undervalued prospects for long‐term conservation as part of species conservation planning. This fundamental, but overlooked, issue requires attention considering the pace that humans have been altering natural freshwater ecosystems and the accelerated levels of biodiversity decline in recent decades. We compiled 709 records of freshwater mussels (Bivalvia, Unionida) inhabiting a broad variety of anthropogenic habitat types (from small ponds to large reservoirs and canals) and reviewed their importance as refuges for this faunal group. Most records came from Europe and North America, with a clear dominance of canals and reservoirs. The dataset covered 228 species, including 34 threatened species on the IUCN Red List. We discuss the conservation importance and provide guidance on how these anthropogenic habitats could be managed to provide optimal conservation value to freshwater mussels. This review also shows that some of these habitats may function as ecological traps owing to conflicting management practices or because they act as a sink for some populations. Therefore, anthropogenic habitats should not be seen as a panacea to resolve conservation problems. More information is necessary to better understand the trade‐offs between human use and the conservation of freshwater mussels (and other biota) within anthropogenic habitats, given the low number of quantitative studies and the strong biogeographic knowledge bias that persists.
... For example, mega-nourishments employing waves and currents to naturally redistribute sand along the coast are implemented for coastal safety as well as creating opportunities for ecology and society (e.g. Stive et al., 2013;De Vriend et al., 2015;Cooke et al., 2020). Similarly, many NbS have been tested and implemented in fluvial environments, ranging from catchment-scale natural flood management (e.g. ...
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Biogeomorphology has been expanding as a discipline, due to increased recognition of the role that biology can play in geomorphic processes, as well as due to our increasing capacity to measure and quantify feedbacks between biological and geomorphological systems. Here, we provide an overview of the growth and status of biogeomorphology. This overview also provides the context for introducing this special issue on biogeomorphology, and specifically examines the thematic domains of biogeomorphological research, methods used, open questions and conundrums, problems encountered, future research directions, and practical applications in management and policy (e.g. Nature based solutions). We find that whilst biogeomorphological studies have a long history, there remain many new and surprising biogeomorphic processes and feedbacks that are only now being identified and quantified. Based on the current state of knowledge, we suggest that linking ecological and geomorphic processes across different spatio‐temporal scales emerges as the main research challenge in biogeomorphology, as well as the translation of biogeomorphic knowledge into management approaches to environmental systems. We recommend that future biogeomorphic studies should help to contextualise environmental feedbacks by including the spatio‐temporal scales relevant to the organism(s) under investigation, using knowledge of their ecology and size (or metabolic rate). Furthermore, in order to sufficiently understand the ‘engineering’ capacity of organisms, we recommend studying at least the time period bounded by two disturbance events, and recommend to also investigate the geomorphic work done during disturbance events, in order to put estimates of engineering capacity of biota into a wider perspective. Finally, the future seems bright, as increasingly inter‐disciplinary and longer‐term monitoring are coming to fruition, and we can expect important advances in process understanding across scales and better informed modelling efforts.
... For a benthic species, such as a freshwater mussel, this situation should be carefully evaluated and guide the future implementation of nature based solutions (see Palmer et al., 2015). Given the dominance of structures made of concrete in aquatic ecosystems and due to their negative effects on many ecological aspects (for a review, see Cooke et al., 2020), future studies should aim at developing more eco-friendly and sustainable materials. These new materials, including more permeable concrete and fibrous materials such as fuzzy ropes , may not only benefit biota but also humans (e.g. through improved biogeochemical cycling), with lower environmental, social and economic costs (Palmer et al., 2015). ...
Article
Freshwater mussels are declining globally, and effective conservation requires prioritizing research and actions to identify and mitigate threats impacting mussel species. Conservation priorities vary widely, ranging from preventing imminent extinction to maintaining abundant populations. Here, we develop a portfolio of priority research topics for freshwater mussel conservation assessment. To address these topics, we group research priorities into two categories, intrinsic or extrinsic factors. Intrinsic factors are indicators of organismal or population status, while extrinsic factors encompass environmental variables and threats. An understanding of intrinsic factors is useful in monitoring, and of extrinsic factors are important to understand ongoing and potential impacts on conservation status. This dual approach can guide conservation status assessments prior to the establishment of priority species and implementation of conservation management actions.
Article
Habitat fragmentation is a major threat to aquatic biodiversity loss. However, much of the focus is on the connectivity of freshwaters, with much less attention given to marine ecosystems. We contend that coastal infrastructure including bridges, causeways, tidal turbines, land infilling and harbours, wharfs, quays, piers and docks have resulted in underappreciated impacts on the connectivity of fish movements resulting in passage challenges at sea. For each type of marine infrastructure, we synthesised the present status of knowledge to characterise the problems and future challenges and also identify mitigation options and passage solutions to restore connectivity for fishes. Bridges can disrupt currents, generate light and noise/vibration, and emit electromagnetic signals, so more work is needed to modify in‐water designs to minimise the negative impacts on fishes. Causeways involve infilling, resulting in full in‐water barriers, requiring fishes to circumnavigate these structures and there is limited research on mitigation (e.g., fishways). Tidal turbines are placed in areas with high currents, which can hinder movements and result in entrainment; however, monitoring fish movements is challenging in these unique areas. Offshore energy has grown in recent years and can impact fish connectivity via altered sediment dynamics and water currents, as well as through the generation of noise pollution and electromagnetic fields. Land filling results not only in habitat loss but also in fragmentation, and it will be imperative to identify important habitats and corridors to minimise impacts there. Finally, infrastructure associated with boats (e.g., harbours, docks) negatively impacts nearshore habitat, which can alter movement trajectories. In the collective, we found evidence that diverse types of marine infrastructure can impact connectivity and, ultimately, fish movement and migrations. Interestingly,bespoke fish passage solutions in marine environments seem rare. As coastal development will increase in the future, it is imperative that we assess the potential connectivity issues resulting from marine infrastructure and that we generate solutions to mitigate these issues for marine organisms.
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Under growing recognition of the need to restore marine ecosystems and promote the sustainable use of ocean resources, this research delves into an analysis of studies on artificial reefs in the marine environment spanning from 1996 to 2024 to explore how they have evolved in supporting biodiversity growth and fishery management while also promoting ecosystem sustainability over time. Using tools like CiteSpace 6.3. R1 and VOSviewer 1.6.18, a total of 586 research publications were examined to pinpoint authors, current trends in research, and emerging focal points. This study highlights the roles played by countries such as the United States, China, and Australia, as well as esteemed institutions, like NOAA and the Chinese Academy of Fisheries Sciences leading the field. In this field of study, there are topics like restoring the environment to its natural state and making fisheries more sustainable by creating habitats with diverse structures and elements; this shows how artificial reef research involves different areas of expertise working together for a common goal. The findings suggest a trend towards using tools such as ecofriendly materials and 3D printing to improve the design and ecological functionality of reefs. However, some challenges still exist, such as conducting assessments on the long-term effects on the environment and finding a balance between promoting biodiversity and meeting the needs of people in terms of economic aspects. This research highlights the importance of countries working together and adapting their strategies to ensure that artificial reefs play a role in protecting marine life and using ocean resources in a sustainable way. By charting out the existing knowledge landscape, this study lays the groundwork for research endeavors focused on tackling these obstacles and propelling the field forward.
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Organic modification can generally endow inorganic materials with novel and promotional characteristics to fit into new functionalities. In this paper, new cement-based composite materials, with Portland cement as the substrate and polyacrylamide (PAM, alone) and PAM/chitosan as the functional components mixed with cement (bulk modified) or served as the surface coating (surface modified), were prepared and engineered as sampling substrates for biofilm and coral co-culture. In comparison to the bulk modified substrate and pure cement material, the surface modified substrate showed a balanced mechanical property, considering both bending and compressive strengths and distinctive surface features toward facilitating biofilm and coral growth, as characterized by spectroscopic, morphological, mechanical, and biofilm and coral co-culture experiments. We, thus, believe that the as-prepared surface modified substrate has the very potential to be applied as a substitute/alternative for the conventional cement material in the construction and engineering of artificial facilities with ecological protection functions.
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The structural complexity of aquatic habitats is often reduced by the installation of retaining walls designed to stabilize shorelines and decrease erosion. Alternative armoring techniques such as wall panels that imitate natural habitat complexity are being developed, but they require knowledge of how different structural elements are used by fishes with varied body sizes. In this study, we examined the effects of incorporating four distinct habitat features and textures into experimental retaining wall panels on the behavior of bluegill (Lepomis macrochirus) across a range of body sizes, in comparison to a control (plain) panel. The proportion of times that fish spent near the treatment panels generally increased with panel complexity but there was variation among fish size classes, with larger bluegill preferring medium complexity structure and smaller bluegill preferring the greatest level of complexity. We did not observe any differences in times to visit the panels between treatments or size classes. These findings will help inform and refine the design of retaining walls, providing structural habitat complexity to benefit freshwater fishes across a range of body sizes and life history stages.
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Concrete pavements are integral to sustainable infrastructure, offering longevity and resilience in construction and transportation. This study focuses on optimizing concrete pavements through the incorporation of steel and carbon fibers with Ground Granulated Blast Furnace Slag (GGBS) to enhance mechanical strength, reduce fracture development, and minimize carbon emissions. Utilizing 25 mixing designs with a consistent water-to-cement ratio of 0.40, varying ratios of GGBS, steel fibers, and carbon fibers (0.5%, 1%, and 1.5% based on concrete volume) were explored. A comprehensive evaluation, including slump, compressive strength, flexural strength, split tensile strength, water absorption, abrasion resistance tests, carbon dioxide emissions, and cost analysis, was conducted at different curing stages. Results revealed a decline in compressive strength for all mix designs at 28 days, attributed to reduced cement strength with GGBS substitution. The 1.5% steel fiber and 50% GGBS mix demonstrated minimal compressive strength reduction (30.1 MPa, 5.5% less than control), outperforming other mixtures. Steel fibers surpassed carbon fibers, likely due to superior distribution. Notably, 1.5% steel fibers showed superior results, particularly with 50% GGBS. Compressive strength generally increased with GGBS content, except for 1% fibrous samples where 40% GGBS produced optimal results. At 90 days, compressive strength increased for most designs, with G50S1.5 exhibiting over 38% growth compared to the control. Steel fiber-containing samples outperformed carbon fiber-containing ones, showcasing the efficacy of steel fibers in enhancing compressive strength. Split tensile strength generally decreased, but steel fibers improved it, emphasizing their positive influence. Flexural strength increased in 28 and 90 days, with steel fiber-containing designs outperforming. G30S1.5 showed the most significant increase (33.3%) at 28 days, and G30S1.5 exhibited the highest growth (32.22%) at 90 days. Abrasion resistance tests indicated steel fibers and GGBS positively impacted abrasion reduction. G50S1.5 demonstrated the highest abrasion resistance (25% increase over control). The environmental evaluation revealed lower CO2 emissions for GGBS-containing designs. G50S0.5 showed a 40.34% reduction compared to the control sample. Cost analysis showed GGBS reduced costs, but fiber addition, particularly carbon fibers, increased costs. G30C1.5 had the highest cost increase (208.5%), while G50S1.5 showed a marginal rise (3.9%) compared to the control. Therefore, steel fibers in concrete pavements offer improved mechanical properties, durability, and reduced environmental impact, making them a viable choice despite a slight increase in cost. Conversely, carbon fibers are cautioned against due to their higher cost and inferior mechanical properties.
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Since the anthropogenic era, biodiversity has dwindled, prompting scientists to advocate the "nature positive" initiative, aiming to reverse nature loss by 2030, based on a 2020 baseline. However, many regions, especially locally, lack comprehensive scientific surveys for baselines. To address this gap, we propose utilizing local residents' memories as references for biodiversity restoration. In a qualitative study in Dakenggu, a small fishing village in Yilan, Taiwan, we interviewed residents who highlighted the significance of crab memories in their lives but expressed concerns about declining crab abundance. We queried them about crab species, abundance, habitats, interactions, and reasons for decline based on their memories. Surprisingly, residents identified 14 crab species and vividly recalled past abundance and activities involving crabs. Variations in memories were noted based on age and gender. Residents attributed the decline to factors such as climate change, wastewater, industrial river water diversion, pesticides, and over-concretization. Leveraging these memories, we aim to reconstruct crab habitats and biodiversity to approximate their original states, serving as restoration indicators for the region and materials for conservation education. Social science research involving local residents' memories can thus serve as valuable references for restoring the natural environment, especially in regions lacking substantial research or records.
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The movement of the construction industry towards sustainable development has drawn attention to the revision of concrete. In addition to reducing pollution, the use of nano-materials should lead to the provision of higher quality concrete in terms of regulatory items (workability, resistance characteristics, durability characteristics, microstructure). The present study investigates 15 key characteristics of concrete modified with nano-CaCO3, nano-clay, nano-TiO2, and nano-SiO2. The results of the study showed that nanomaterials significantly have a positive effect on the hydration mechanism and the production of more C-S-H gel. The evaluation of resistance characteristics also indicates the promising results of these valuable materials. The durability characteristics of nano-containing concrete showed significant improvement despite high dispersion. Concrete in coastal areas (such as bridges or platforms), concrete exposed to radiation (such as hospitals), concrete exposed to impact load (such as nuclear power plants), and concrete containing recycled aggregate (such as bricks, tiles, ceramics) can be effectively improved by using nanomaterials. It is hoped that the current review paper can provide an effective image and idea for future applied studies by other researchers.
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For millennia humans have extracted biological and physical resources from the planet to sustain societies and enable the development of technology and infrastructure. Growth in the human population and changing consumption patterns have increased the human footprint on ecosystems and their biodiversity, including in fresh waters. Freshwater ecosystems and biodiversity face many threats and it is now widely accepted that we are in a biodiversity crisis. One means of protecting and restoring freshwater biodiversity is to better manage the exploitation of freshwater biota and aggregate resources (e.g., sand, gravel, and boulders). Here we outline the threats arising from such exploitation and identify response options to ensure that methods and levels of extraction are sustainable and allow recovery of over-exploited freshwater biodiversity and ecosystems. The guidance we provide will enable practitioners, policy-makers, and resource stewards to embrace effective, sustainable, and evidence-based approaches to resource extraction. Response options for managing species exploitation include strengthening assessment and reporting, using science-based approaches to reduce overexploitation and support recovery, embracing community engagement, and building or tightening legislation. Response options for managing exploitation of freshwater aggregate resources include reducing demand for harvest, strengthening governance, reporting, and monitoring of environmental impacts, and promoting the restoration of degraded ecosystems or compensating for losses. Diverse case studies highlight examples of where various management actions have been implemented in an effort to consider how they can be scaled up and adapted to other contexts. Managing exploitation will be a key aspect of broader initiatives needed to protect and restore freshwater biodiversity around the globe.
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India is on development path and construction of various infrastructures work is happening at increasing pace and magnitude. The cement and reinforcement are most essential materials required for a infrastructure projects. Both cement and steel production produce large amount of carbon di oxide and also require large amount of energy for production. This is one main aspect of environmental destruction. Ship building activities are ever increasing in India and so construction of new shipyards and modernization of existing shipyards. Launching of ship is one of the most important operations in the entire ship construction process. Getting permissions for such construction involves various authorities and agencies such as concerned Industrial Development Corporation, River Navigation Department, Caption of Ports, Coastal Regulation Zone Authority, Pollution Control Board to name a few. This paper presents some important aspects of environmentally sustainable, ecologically conservable and economical solution Design and Construction Solution of Ship Side Launching Wharfby substituting conventional RCC piles by rammed stone columns to a large extent and use of gabion walls for closing the face of jetty in place of steel or RCC sheet pile making use of locally available quarry stones.
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With 39,400 km2 of coastal and marine areas artificialized and an increasing demand due to the growing global population—9 billion by 2050—it has become necessary to find ways to mitigate futures constructions impacts on biodiversity. This study explores how civil engineering can take further technical measures to enhance marine biodiversity, in a real and valuable “win-win” strategy. The global aim is to integrate eco-engineering practices within coastal projects and include ecological targets (e.g., the diversity and speed of biological colonization) early, at the project design stage, with the same level efforts for technical, social, and economic studies. Concrete is the most useful material for coastal infrastructure construction. Therefore, enhance its positive impact on colonization that is by far one of the key points for developers and coastal managers. To this end, the latest research regarding the bioreceptivity of concrete is reviewed, focusing on the characteristics of the marine environment that affect the colonization of concrete and the organisms involved. From this base of publications, the intrinsic and environmental parameters that can influence the intrinsic and the extrinsic bioreceptivity of concrete have been updated, specifically operating the link with the mechanisms leading to the colonization of concrete and biofilm formation, which hasn't been done before. Based on the persistence of their significant effect (after 78 days of immersion in seawater), the intrinsic parameters that support greater biocolonization are classified from more to less effective in the following order: surface roughness (190%) > chemical composition (slag cement instead Portland cement) (136%) > chemical composition (presence of formwork oil) (106%). Lastly, both the ecological effect and the positive and negative effects of biofilm formation on the durability of concrete were analysed to provide clear and operational results for future concrete coastal construction implementation for decision makers.
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Water microorganisms contribute to the key components of ecosystems in dryland waters, which are extremely important for wildlife. However, the distribution patterns of water microbes across different basal water sources are still largely unknown. This study was conducted to compare microorganisms in the water bodies of different types of water sources in the Kalamaili Mountain Ungulate Nature Reserve in China. Bioinformatic analysis revealed that the undirected microbial co-existence network consisted of 15 main modules referring to different water sources, which indicated specific molecular co-existence relationships. It was found that the most dominant phyla (namely Proteobacteria, Patescibacteria, Firmicutes, Bacteroidota, and Actinobacteriota) of the molecular ecological network shared the same structures as the microbial community, which justified the construction of the network via a random network formation. Principal coordinate analysis (PCoA) based on Bray–Curtis distances revealed that there were still considerable variations among different habitats, showing separate sample clusters. Additionally, the different topological roles of subnetworks trimmed to a uniform size indicated different co-existence patterns in the microbiome. The artificially recharged water from concrete pond substrate (ARC) subnetworks had a relatively discrete co-occurrence, while the natural water sources (NRE) and artificially recharged water from earthen pond substrate (ARE) groups were more compact with giant modules. The NRE and ARE groups were also richer in microbial composition and had a higher number of species with low abundance. Consequently, concrete substrates may contribute to dysfunction in water microbiomes. Moreover, the functional diversity of the NRE and ARE groups is due to more intra-module connections and more inter-module connections, indirectly leading to a stable function resilient to external environmental influences. In conclusion, the microecology of the NRE was more stable than that of the concrete substrate, and artificial transportation had less effect on the microbial community.
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Increasing frequency of extreme weather events, driven by climate change, coupled with growing population densities, have contributed to an increasing demand for coastal structures to protect and stabilize shorelines. Concrete seawalls are a common category of coastal protection structures, designed with the primary objectives of absorbing wave action, preventing coastline erosion, and alleviating flooding. Much research has been carried out on improving concrete seawall performance. This work is a review of the current state-of-the-art in concrete seawalls focusing on design aspects including wave loading and innovative seawall designs, ecological considerations, and durability performance. Different conventional seawalls and their advantages and disadvantages are reviewed. Wave loads on seawalls have received significant attention; and multiple approaches for the quantification for the different types of loads are presented. However, wave load quantification remains a challenging task, especially for novel designs, and performance under load for such designs must be quantified through testing in wave tanks. Drawing inspiration from natural shorelines, modification of surface complexity at a multitude of scales can improve the otherwise poor ecological performance of seawalls. Ecological performance can also be improved by the incorporation of natural materials or structures in seawalls although the exact influence of concrete and other material chemistry on benthic diversity is unclear. The corrosion of the steel is a major durability concern, and the use of non-corrosive reinforcement can increase seawall durability toward corrosion. Other durability concerns include alkali silica reaction and sulfate attack, which can be mitigated through proper mixture design, including through the use of supplementary cementitious materials. Examples of innovative seawall designs and systems which have the capability to outperform conventional seawalls are discussed. Advances in structural design, ecological engineering, and infrastructure materials science will drive the development of multi-functional seawalls which are sustainable, durable, and resilient.
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Hydropower production is one of the greatest threats to fluvial ecosystems and freshwater biodiversity. Now that we have entered the Anthropocene, there is an opportunity to reflect on what might constitute a ‘sustainable’ Anthropocene in the context of hydropower and riverine fish populations. Considering elements of existing practices that promote favorable social-ecological outcomes (i.e., ‘bright spots’) is timely given that there are plans to expand hydropower capacity in previously undammed rivers, intensify dam development in some of the world’s largest river systems, and re-license existing facilities. We approach this from a pragmatic perspective: for the foreseeable future, hydropower will likely remain an important source of renewable electricity. To offer support for moving toward a more ‘sustainable’ Anthropocene, we provide syntheses of best practices during the siting, design, construction, operation, and compensation phases of hydropower development to minimize impacts on inland fish. For each phase, we offer positive examples (or what might be considered ‘bright spots’) pertaining to some of the approaches described within our syntheses, acknowledging that these projects may not be viewed as without ecological and (or) societal detriment by all stakeholders. Our findings underscore the importance of protecting critical habitat and free-flowing river reaches through careful site selection and basin-scale planning, infrastructure designs that minimize reservoir effects and facilitate safe passage of fish, construction of hydropower plants using best practices that minimize long-term damage, operating guidelines that mimic natural flow conditions, and compensation that is lasting, effective, inclusive, and locally relevant. Learning from these ‘bright spots’ may require engagement of diverse stakeholders, professionals, and governments at scales that extend well beyond a given site, river, or even basin. Indeed environmental planning that integrates hydropower development into broader discussions is important for conserving regional biodiversity and ecosystem services.
Chapter
The rapid global spread of the Anthropocene concept across disciplines, languages, cultures and religions has been extraordinary and is unique in scientific history for a basic concept.
Chapter
Land use and land cover (LULC) such as agriculture, urbanization, and natural resource extraction are major determinants of water quality worldwide. Shifts from natural landscapes to anthropogenic LULC drive chemical, physical, and biological aspects of water quality through alterations in catchment hydrology, sedimentation and fluvial geomorphology, habitat structure, nutrient availability, and contaminant pollution. These alterations affect the abundances and diversity of aquatic biota in many ways. Conservation approaches including riparian buffers and restoration of streams and wetlands can partially mitigate the effects of LULC change. However, water protection policies and novel management approaches are needed to safeguard water resources in the face of human population growth, climate change, and landscape conversion.
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Riparian vegetation along urban streams and wetlands is frequently dominated by invasive weeds. Elevated nitrogen and phosphorous in urban waters and soils are well-known to encourage invasive urban weeds, but this research demonstrates that other urban geochemical contaminants may also be influential. Previous studies have demonstrated that the dissolution of urban concrete is a poorly recognised source of modified water and soil geochemistry, which may enhance the growth of some invasive weeds. This study investigated the relationship between urban water quality and the growth of an invasive urban riparian weed, willow ( Salix spp.) to examine the contribution of concrete materials. The study used water from a wetland in the Greater Blue Mountains World Heritage Area. These wetlands have a unique biodiversity but are fragile and susceptible to degradation from human activity. Many are in urban catchments and are frequently dominated by invasive weeds, including Salix spp. In this study, willow cuttings were grown in a laboratory using four water treatments: pristine, urban, and pristine water exposed to two different concrete materials. The urban and concrete water treatments had higher pH, salinity, calcium, potassium, and higher concentration of several metals and were associated with increased growth of Salix spp. We suggest that the modification of urban water and riparian soil chemistry by urban concrete materials may contribute to the success of invasive species in urban wetlands and riparian zones. Some metals (barium, strontium) were present in urban water and in pristine water exposed to concrete and bioaccumulated in plant tissue.
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Increasing frequency of extreme weather events, driven by climate change, has resulted in an increasing demand for coastal structures to protect and stabilize shorelines. Concrete seawalls are a common category of coastal protection structures, designed with the primary objectives of absorbing wave action, preventing coastline erosion, and alleviating flooding. Much research has been carried out on improving the seawall performance. This work is a review of the current state-of-the-art in concrete seawalls focusing on design aspects including wave loading and innovative seawall designs, ecological considerations, and durability aspects. Wave loads on seawalls have received significant attention; however, their quantification remains a challenging task especially for novel designs. Drawing inspiration from natural shorelines, modification of surface complexity at a multitude of scales can improve the otherwise poor ecological performance of seawalls. The corrosion of the steel is a major durability concern, and the use of non-corrosive reinforcement can increase seawall durability towards corrosion. Examples of innovative seawall designs and systems which have the capability to outperform conventional seawalls are discussed. Advances in structural design, ecological engineering, and infrastructure materials science will drive the development of multi-functional seawalls which are sustainable, durable, and resilient.
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We tagged 12 Carcharhinus limbatus with acoustic transmitters and monitored their presence at five piers along the north‐east coast of South Carolina, USA in 2016 and four piers in 2017 using acoustic receivers. Data were analysed with pier association indices (PAI), mixed models and fast Fourier transformation analyses to identify potential factors related to residence time and presence at piers and any cyclical patterns in visits to piers. While the majority of monitored C. limbatus were infrequently detected at piers, three (25.0%) were highly associated with piers (PAI ≥ 0.50). Of the C. limbatus that were detected after initial capture, three (25.0%) recorded detection events only at the pier where they were tagged and two individuals (16.7%) recorded at least one detection event at all monitored piers. The best‐fit model explaining C. limbatus residence time at piers included terms for pier location and diel cycle (wi = 0.88), whereas the best fit model explaining presence–absence of C. limbatus at piers included terms for tidal height, diel cycle, barometric pressure and angler count (wi = 0.98). Carcharhinus limbatus did not appear to display cyclical patterns in their visits to piers. Along the north‐east coast of South Carolina, association of C. limbatus with piers is a phenomenon for a proportion of mature individuals, but continued research is necessary to understand if this behaviour is driven by attraction to and feeding on angler discards or increased foraging opportunities resulting from the attraction of potential prey to the physical structure provided by piers.
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Urban streams are degraded through multiple mechanisms, including severely altered flow regimes, elevated concentrations of waterborne contaminants, removal of riparian vegetation and the loss of a mosaic of heterogeneous aquatic habitats. Engineering of urban stream reaches using concrete is a widespread and extreme case of deliberate alteration of flow regimes and concomitant habitat simplification. To assess the effect of such engineering practices on stream ecosystems, we compared aquatic macroinvertebrate communities from concrete-lined engineered urban reaches, non-engineered urban reaches with natural substrates and reference reaches flowing through minimally disturbed forested subcatchments and with natural substrates, in the Sydney metropolitan region, Australia. The communities from all urban reaches were impoverished and distinctly different from more diverse communities in forested reference reaches. Despite low aquatic habitat heterogeneity, engineered urban reaches had very high abundances of Diptera and some other tolerant taxa. Diptera and/or Gastropoda were dominant in non-engineered urban reaches. Multivariate community structures were dissimilar between the urban reaches and forested reference reaches and between non-engineered and engineered urban reaches. However, the low family-level richness and SIGNAL scores in both urban reach types indicated they were severely ecological impaired, whether engineered or not. Most macroinvertebrate taxa in the regional pool that were hardy enough to inhabit urban reaches with natural substrates were also present in nearby concreted reaches. The results add weight to the growing evidence that in urban landscapes, regional-scale changes in water quality and flow regimes limit the establishment of diverse macroinvertebrate communities, which cannot be addressed through the provision of increased reach-scale habitat heterogeneity.
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The geochemical signature of freshwater streams can be used to determine the extent and nature of modification to stream water geochemistry due to urban development. This approach used the Gibbs (1970) diagram as a model for evaluation of changes to ionic composition linked to urban development. In this multi-year study, the geochemistry of 21 waterways in the Georges River catchment, Sydney, were monitored and compared with the level of urban development as measured by sub-catchment imperviousness and directly connected imperviousness. The results reflect a strong relationship between the intensity of sub-catchment urban development and stream geochemistry. All major geochemical attributes increased with escalating levels of urban development. The largest increase was for bicarbonate, which increased 18 times from a mean of 6.4 mg L–1 at non-urban streams to a mean of 118 mg L–1 at urban streams. Similarly, mean concentrations of calcium increased by 14 times (from 2 to 27.9 mg L–1). Mean salinity was enriched in the most urban streams, compared with non-urban streams, by more than 6 times. We attribute this, in part, to the influence of urban geology, notably concrete stormwater infrastructure. Changes in stream geochemistry due to urban development are an important element of the urban stream syndrome.
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Significance A volcanic ash–lime mortar has been regarded for centuries as the principal material constituent that provides long-term durability to ancient Roman architectural concrete. A reproduction of Imperial-age mortar based on Trajan’s Markets (110 CE) wall concrete resists microcracking through cohesion of calcium–aluminum–silicate–hydrate cementing binder and in situ crystallization of platey strätlingite, a durable calcium-aluminosilicate mineral that reinforces interfacial zones and the cementitious matrix. In the 1,900-y-old mortar dense intergrowths of the platey crystals obstruct crack propagation and preserve cohesion at the micron scale. Trajanic concrete provides a proven prototype for environmentally friendly conglomeratic concretes that contain ∼88 vol % volcanic rock yet maintain their chemical resilience and structural integrity in seismically active environments at the millenial scale.
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Eight to 10 percent of the world's total CO2 emissions come from manufacturing cement. The global warming gas is released when limestone and clays are crushed and heated to high temperatures. Green concrete is defined as a concrete which uses waste material as at least one of its components, or its production process does not lead to environmental destruction, or it has high performance and life cycle sustainability. Various efforts have been conducted by researchers to arrive at some alternatives that are able to significantly reduce high energy consumed and environmental impacts during fabrication process of cement, including implementing the concept of industrial ecology and green chemistry as well as nanoengineering that study the behavior of the structure and organization of nanoparticles of cement in the mix for achieving higher performance. The cleaner technologies in concrete production, such as substituting relatively high percentage of cement by fly ash (up to 100%), the use of other natural pozzolans, development of concrete with recycling or waste materials, and developing nanoconcrete by integrating CNT's or self sensing CNT's in the concrete mix for higher performance in terms of strength, stiffness, and durability, have been developed and are addressed in this paper. Several efforts that have been done so far in implementing the concept of green concrete and material development of nanosilica in Indonesia is discussed. Finally, problems in the realization of and potential barriers to green concrete as well as political scenarios that have been adopted by several countries through implementation of various priorities and deregulation in various fields are also discussed.
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This overview and synthesis paper focuses on the evolution of urban biogeochemical cycles across time. We synthesize empirical data and review existing literature, including papers in this special issue, and we propose the concept of ''urban evolu-tion.'' The built environment often changes quickly in response to human activities, thus contributing to an urban evolution that affects structure, function, and ecosystem services of human settlements over time. Depending upon management, these changes can result in rapid losses of ecosystem functions/services or progress towards restoration. We explore urban evolution through empirical examples such as: (1) land development and nitrogen inputs within a metropolitan region over half a century; (2) watershed drainage by different forms of stormwater manage-ment over decades; (3) human-accelerated weathering in urbanized watersheds over decades; and (4) global salinization of freshwater across urbanizing landscapes over a century. We also synthesize con-cepts relevant to studying urban evolution of infra-structure and ecosystems including: (1) urban watersheds have challenged our whole notion of the ''watershed approach'' due to complex hydrologic boundaries and flow paths over time; (2) the urban hydrologic cycle evolves due to changing infrastruc-ture and human water use over time; (3) the impor-tance of extending research beyond individual sites using an urban watershed approach over space and time; (4) salinization as a universal tracer of watershed urbanization over time; (5) human-accelerated weath-ering of concrete and construction materials contrib-uting to an ''urban karst'' over time; (6) human alteration of the carbon cycle in urban watersheds over time; and (7) detecting distinct biogeochemical sig-natures across cities globally over time. Our synthesis and this special issue suggest that urban biogeochem-ical cycles have exerted a major influence on the elemental composition of the Earth's surface from local to global scales. A new global research agenda is needed to track the evolution of urban biogeochemical cycles as land development proceeds and infrastruc-ture/management changes so we can better evaluate potential losses in ecosystem services, set realistic watershed and river restoration goals, and formulate effective environmental policy for Earth's growing urban population.
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Growing human populations are driving the development of coastal infrastructure such as port facilities. Here, we used passive acoustic telemetry to examine the effects of a jetty and artificial light on the rates of predation of flatback turtle (Natator depressus) hatchlings as they disperse through nearshore waters. When released near a jetty, around 70% of the tagged hatchlings were predated before they could transit the nearshore, irrespective of the presence or absence of artificial light. Only 3 to 23% of hatchlings encountered predators at a second study site nearby where there was no jetty and a similar amount of nesting activity. Evidence for predation was provided by rapid tag detachment due to prey handling by a predator or the extensive movement of the tags within the receiver array suggesting that the tag (and hatchling) was inside the stomach of a predator. We found that 70% of the fish predators that consumed tags used the jetty as a refuge during the day and expanded their range along nearshore waters at night, predating on hatchlings in areas adjacent to the jetty with the highest nesting density. Sampling of potential predators including lutjanid reef fishes under the jetty revealed the presence of turtle hatchlings in their gut contents. By providing daytime refuges for predators, nearshore structures such as jetties have the potential to concentrate predators and they may pose a significant threat to populations of vulnerable species. Such effects must be taken into consideration when assessing the environmental impacts associated with these structures.
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Stormwater control measures (SCMs) are designed to mitigate the deleterious impacts of urban runoff on the water quality of receiving waters. To assess the cumulative effects of SCMs at the watershed scale, we monitored longitudinal changes in storm discharge and stream water chemistry at high temporal resolution in a suburban headwater stream in Charlotte, NC. SCMs significantly decreased or stabilized instream concentrations of reactive solutes (nitrate, soluble reactive phosphorus, and dissolved organic carbon) relative to the upstream control site. However, SCM outflows minimally influenced concentrations of less reactive solutes (major ions) which increased with urbanization. Additionally, instream concentration variability correlated with antecedent moisture conditions – representative of watershed storage availability – highlighting the role that SCM storage availability plays in the timing of solute delivery to the stream. Our results show that SCMs decrease instream concentrations of biogeochemically reactive solutes but the mitigation potential is temporally dynamic and influenced by antecedent conditions.
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In the 12 years since Dudgeon et al. (2006) reviewed major pressures on freshwater ecosystems, the biodiversity crisis in the world's lakes, reservoirs, rivers, streams and wetlands has deepened. While lakes, reservoirs and rivers cover only 2.3% of the Earth's surface, these ecosystems host at least 9.5% of the Earth's described animal species. Furthermore, using the World Wide Fund for Nature's Living Planet Index, freshwater population declines (83% between 1970 and 2014) continue to outpace contemporaneous declines in marine or terrestrial systems. The Anthropocene has brought multiple new and varied threats that disproportionately impact freshwater systems. We document 12 emerging threats to freshwater biodiversity that are either entirely new since 2006 or have since intensified: (i) changing climates; (ii) e‐commerce and invasions; (iii) infectious diseases; (iv) harmful algal blooms; (v) expanding hydropower; (vi) emerging contaminants; (vii) engineered nanomaterials; (viii) microplastic pollution; (ix) light and noise; (x) freshwater salinisation; (xi) declining calcium; and (xii) cumulative stressors. Effects are evidenced for amphibians, fishes, invertebrates, microbes, plants, turtles and waterbirds, with potential for ecosystem‐level changes through bottom‐up and top‐down processes. In our highly uncertain future, the net effects of these threats raise serious concerns for freshwater ecosystems. However, we also highlight opportunities for conservation gains as a result of novel management tools (e.g. environmental flows, environmental DNA) and specific conservation‐oriented actions (e.g. dam removal, habitat protection policies, managed relocation of species) that have been met with varying levels of success. Moving forward, we advocate hybrid approaches that manage fresh waters as crucial ecosystems for human life support as well as essential hotspots of biodiversity and ecological function. Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gap between the aspirations of conservation biologists and the accelerating rate of species endangerment.
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Mangroves are tropical and subtropical coastal trees able to resist severe conditions including hurricanes and tropical storms. A potential characteristic of their resilience property is their complex root systems, which can be highly efficient to dissipate tidal energy. To further understand the key hydrodynamic parameters of mangrove trees, we modeled the rigid mangrove root system with a simplified array of circular cylinders (patch) and presented the simulation of the patch wake structure. Five patch porosities ranging from = % % (= −) were considered in numerical simulations with ANSYS Fluent. The complex two-dimensional flow structure of the cylinder wake was captured for various streamwise location including far wake region. In addition, the vorticity, and turbulence intensity contours were computed and analyzed. We compared the wake signature of the patch with a single cylinder of the same diameter. We found that, unlike the canonical cylinder, the vorticity field for the porous patch delays the formation of von Kármán vortex street due to the small vortices in the near wake. An increase in patch porosity gives rise to the delay of vortex street formation and decays the wake vorticity and turbulent kinetic energy. The characteristic of the wake structure behind the patch could be used as guiding reference for coastal protection structures inspired by mangrove roots. Additionally, we present mangrove application in coastal protection.
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Surface physical properties, hydrodynamics, biochemical cues, orientation and temporal scales play an important role in invertebrate larval recruitment on artificial substrates. In the present study, invertebrate recruitment on four different substrates (acrylic, stainless steel, ceramic and concrete panels) was investigated in two different orientations (vertical and horizontal) in the central Red Sea. Results showed significant variations in the abundance of benthic invertebrates between the different substrates. While barnacles and bivalves preferred panels placed in vertical positions, the abundance of bryozoans was high on horizontal panels. Artificial panel submersion season plays a significant role in the recruitment of benthic invertebrates on surfaces in the Red Sea. In conclusion, this study supports the overall notion that marine invertebrate recruitment on hard substrates is regulated by a combination of factors which include substrate type, orientation and submersion season.
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Seawalls made from rock and concrete are engineered to defend coastlines and infrastructure from sea level rise, storm surge and shoreline erosion. However, while they provide a poor substitute for natural intertidal habitat, emerging designs addressing this biodiversity deficit have incorporated eco-engineering concepts with promising results. This study tested whether adding inexpensive household flower boxes (artificial rock pools) to a seawall in a tropical region would support benthic flora and fauna, and whether simple orientation of boxes improves benthic assemblage colonization. Boxes were positioned at mean tide height (1.1 m AHD) along a seawall in tropical Townsville, Australia. Nine boxes were deployed: three positioned vertically on the seawall, while three positioned at 45° facing towards the sea, and three positioned at 45° facing towards the land. Tilting the artificial rock pools at 45° compared overhang walls (simulating rocky shoreline ledge microhabitat) to vertical walls of artificial rock pools. After 12mths, boxes had accumulated (particularly inside on overhang walls compared to outside walls) a greater surface cover of algae and invertebrates. After the second year, box inside walls supported vastly different assemblages compared to outside box walls regardless of orientation, with the most diverse benthic assemblage found on overhang walls, giving support to the conclusion that artificial rock pools on seawalls support more biodiversity (of native species, with no non-indigenous species found) from tilting and creating overhangs. The turbid nature of this coastal region contributed to sediment accumulation at about 25 mm/yr, regardless of box orientation, which may pose maintenance problems (and cost) for managers, and if unchecked could negate any advantages offered by these engineered pool features.
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This paper presents the feasibility of wastewater from small scale water treatment plants located in residential buildings as mixing water in Ordinary Portland Cement (OPC). Fourteen water treatment plants were found out in the Narasaraopet municipality region in Guntur district, Andhra Pradesh, India. Approximately, from each plant, between 3500 and 4000 L/day of potable water is selling to consumers. All plants are extracting ground water and treating through Reverse Osmosis (RO) process. During water treatment, plants are discharging approximately 1,00,000 L/day as wastewater in side drains in Narasaraopet municipality. Physical and chemical analysis was carried out on fourteen plants wastewater and distilled water as per [1]. In the present work, based on the concentrations of constituent’s in wastewater, four typical plants i.e., Narasaraopeta Engineering College (NECWW), PatanKhasim Charitable Trust (PKTWW), MahmadhKhasim Charitable Trust (MKTWW) and Amara (ARWW) were considered. The performance of four plants wastewater on physical properties i.e., setting times, compressive strength, and flexural strength of Ordinary Portland Cement (OPC) were performed in laboratories and compared same with reference specimens i.e., made with Distilled Water (DW) as mixing water. No significant change was observed in initial setting time but significant change was observed in finial setting time. No significant change was observed in 90 days compressive strengths in four plants wastewater compared to that of reference specimens. XRD technique was employed to find out main hydration compounds formed in the process.
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Paulo J. M. Monteiro, Sabbie A. Miller and Arpad Horvath provide an overview of the challenges and accomplishments in reducing the environmental burden of concrete production.
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The covering of native soils with impervious surfaces (e.g. roofs, roads, and pavement) prevents infiltration of rainfall into the ground, resulting in increased surface runoff and decreased groundwater recharge. When this excess water is managed using stormwater drainage systems, flow and water quality regimes of urban streams are severely altered, leading to the degradation of their ecosystems. Urban streams restoration requires alternative approaches towards stormwater management, which aim to restore the flow regime towards pre-development conditions. The practice of stormwater infiltration—achieved using a range of stormwater source-control measures (SCMs)—is central to restoring baseflow. Despite this, little is known about what happens to the infiltrated water. Current knowledge about the impact of stormwater infiltration on flow regimes was reviewed. Infiltration systems were found to be efficient at attenuating high-flow hydrology (reducing peak magnitudes and frequencies) at a range of scales (parcel, streetscape, catchment). Several modelling studies predict a positive impact of stormwater infiltration on baseflow, and empirical evidence is emerging, but the fate of infiltrated stormwater remains unclear. It is not known how infiltrated water travels along the subsurface pathways that characterise the urban environment, in particular the ‘urban karst’, which results from networks of human-made subsurface pathways, e.g. stormwater and sanitary sewer pipes and associated high permeability trenches. Seepage of groundwater into and around such pipes is possible, meaning some infiltrated stormwater could travel along artificial pathways. The catchment-scale ability of infiltration systems to restore groundwater recharge and baseflow is thus ambiguous. Further understanding of the fate of infiltrated stormwater is required to ensure infiltration systems deliver optimal outcomes for waterway flow regimes.
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This chapter introduces important problems related to crude oil, the main feedstock of most polymer-based materials. These problems include interstate wars and environmental disasters. The latter is the most worrisome, such as the recent Deep Water Horizon oil spill that released approximately 780. million liters of crude oil on the Gulf of Mexico. Some historical examples on the use of bio-admixtures in construction materials are presented. The importance of biopolymers and biotech admixtures for eco-efficient construction materials is summarized. A brief review on the role of promising biotech-based materials, like cellulose nanocrystals for eco-efficient construction, is given. An outline of the book is also given.