Biological, Earth and Environmental Sciences - Journal Articles

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    Exposure to microplastics reduces attachment strength and alters the haemolymph proteome of blue mussels (Mytilus edulis)
    (Elsevier Ltd, 2019) Green, Dannielle S.; Colgan, Thomas J.; Thompson, Richard C.; Carolan, James C.; Irish Research Council
    The contamination of marine ecosystems with microplastics, such as the polymer polyethylene, a commonly used component of single-use packaging, is of global concern. Although it has been suggested that biodegradable polymers, such as polylactic acid, may be used to replace some polyethylene packaging, little is known about their effects on marine organisms. Blue mussels, Mytilus edulis, have become a “model organism” for investigating the effects of microplastics in marine ecosystems. We show here that repeated exposure, over a period of 52 days in an outdoor mesocosm setting, of M. edulis to polyethylene microplastics reduced the number of byssal threads produced and the attachment strength (tenacity) by ∼50%. Exposure to either type of microplastic altered the haemolymph proteome and, although a conserved response to microplastic exposure was observed, overall polyethylene resulted in more changes to protein abundances than polylactic acid. Many of the proteins affected are involved in vital biological processes, such as immune regulation, detoxification, metabolism and structural development. Our study highlights the utility of mass spectrometry-based proteomics to assess the health of key marine organisms and identifies the potential mechanisms by which microplastics, both conventional and biodegradable, could affect their ability to form and maintain reefs. © 2018; Conventional microplastics alone reduced the attachment strength of blue mussels but both conventional and biodegradable micoplastics altered the haemolymph proteome. © 2018
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    Fine-scale population structure and connectivity of bottlenose dolphins, Tursiops truncatus, in European waters and implications for conservation
    (John Wiley and Sons Ltd, 2019) Nykänen, Milaja; Louis, Marie; Dillane, Eileen; Alfonsi, Eric; Berrow, Simon; O'Brien, Joanne; Brownlow, Andrew; Covelo, Pablo; Dabin, Willy; Deaville, Rob; de Stephanis, Renaud; Gally, François; Gauffier, Pauline; Ingram, Simon N.; Lucas, Tamara; Mirimin, Luca; Penrose, Rod; Rogan, Emer; Silva, Mónica A.; Simon-Bouhet, Benoit; Gaggiotti, Oscar E.; CIRCE; Devolved Administrations of Scotland and Wales; GECC; National Museum of Ireland; Department for Environment, Food and Rural Affairs, UK Government, Defra; University of Aberdeen
    Protecting species often involves the designation of protected areas, wherein suitable management strategies are applied either at the taxon or ecosystem level. Special Areas of Conservation (SACs) have been created in European waters under the Habitats Directive to protect bottlenose dolphins, Tursiops truncatus, which forms two ecotypes, pelagic and coastal. The SACs have been designated in coastal waters based on photo-identification studies that have indicated that bottlenose dolphins have relatively high site fidelity. However, individuals can carry out long-distance movements, which suggests potential for demographic connectivity between the SACs as well as with other areas. Connectivity can be studied using genetic markers. Previous studies on the species in this area used different sets of genetic markers and therefore inference on the fine-scale population structure and demographic connectivity has not yet been made at a large scale. A common set of microsatellite markers was used in this study to provide the first comprehensive estimate of genetic structure of bottlenose dolphins in European Atlantic waters. As in previous studies, a high level of genetic differentiation was found between coastal and pelagic populations. Genetic structure was defined at an unprecedented fine-scale level for coastal dolphins, leading to identification of five distinct coastal populations inhabiting the following areas: Shannon estuary, west coast of Ireland, English Channel, coastal Galicia, east coast of Scotland and Wales/west Scotland. Demographic connectivity was very low among most populations with <10% migration rate, suggesting no demographic coupling among them. Each local population should therefore be monitored separately. The results of this study have the potential to be used to identify management units for bottlenose dolphins in this region and thus offer a significant contribution to the conservation of the species in European Atlantic waters. Future studies should prioritize obtaining biopsies from free-living dolphins from areas where only samples from stranded animals were available, i.e. Wales, west Scotland and Galicia, in order to reduce uncertainty caused by sample origin doubt, as well as from areas not included in this study (e.g. Iroise Sea, France). Furthermore, future management strategies should include monitoring local population dynamics and could also consider other options, such as population viability analysis or the incorporation of genetic data with ecological data (e.g. stable isotope analysis) in the designation of management units. © 2019 John Wiley & Sons, Ltd.
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    Revealing chlorinated ethene transformation hotspots in a nitrate-impacted hyporheic zone
    (Elsevier Ltd, 2019) Weatherill, John J.; Krause, Stefan; Ullah, Sami; Cassidy, Nigel J.; Levy, Amir; Drijfhout, Falko P.; Rivett, Michael O.; Environment Agency; Keele University
    Hyporheic zones are increasingly thought of as natural bioreactors, capable of transforming and attenuating groundwater pollutants present in diffuse baseflow. An underappreciated scenario in the understanding of contaminant fate in hyporheic zones is the interaction between point-source trichloroethene (TCE) plumes and ubiquitous, non-point source pollutants such as nitrate. This study aims to conceptualise critical biogeochemical gradients in the hyporheic zone which govern the export potential of these redox-sensitive pollutants from carbon-poor, oxic aquifers. Within the TCE plume discharge zone, discrete vertical profiling of the upper 100 cm of sediment pore water chemistry revealed an 80% increase in dissolved organic carbon (DOC) concentrations and 20–60 cm thick hypoxic zones (<2 mg O2 L−1) within which most reactive transport was observed. A 33% reduction of nitrate concentrations coincided with elevated pore water nitrous oxide concentrations as well as the appearance of manganese and the TCE metabolite cis-1,2-dichloroethene (cDCE). Elevated groundwater nitrate concentrations (>50 mg L−1) create a large stoichiometric demand for bioavailable DOC in discharging groundwater. With the benefit of a high-resolution grid of pore water samplers investigating the shallowest 30 cm of hypoxic groundwater flow paths, we identified DOC-rich hotspots associated with submerged vegetation (Ranunculus spp.), where low-energy metabolic processes such as mineral dissolution/reduction, methanogenesis and ammonification dominate. Using a chlorine index metric, we show that enhanced TCE to cDCE transformation takes place within these biogeochemical hotspots, highlighting their relevance for natural plume attenuation.
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    Ozone depletion, ultraviolet radiation, climate change and prospects for a sustainable future
    (Springer Nature Ltd., 2019-06-24) Barnes, Paul W.; Williamson, Craig E.; Lucas, Robyn M.; Robinson, Sharon A.; Madronich, Sasha; Paul, Nigel D.; Bornman, Janet F.; Bais, Alkiviadis F.; Sulzberger, Barbara; Wilson, Stephen R.; Andrady, Anthony L.; McKenzie, Richard L.; Neale, Patrick J.; Austin, Amy T.; Bernhard, Germar H.; Solomon, Keith R.; Neale, Rachel E.; Young, Paul J.; Norval, Mary; Rhodes, Lesley E.; Hylander, Samuel; Rose, Kevin C.; Longstreth, Janice; Aucamp, Pieter J.; Ballaré, Carlos L.; Cory, Rose M.; Flint, Stephan D.; de Gruijl, Frank R.; Häder, Donat-P.; Heikkilä, Anu M.; Jansen, Marcel A. K.; Pandey, Krishna K.; Robson, T. Matthew; Sinclair, Craig A.; Wängberg, Sten-Åke; Worrest, Robert C.; Yazar, Seyhan; Young, Antony R.; Zepp, Richard G.; University of Wollongong; United States Global Change Research Program; Loyola University New Orleans; Australian Research Council; National Science Foundation
    Changes in stratospheric ozone and climate over the past 40-plus years have altered the solar ultraviolet (UV) radiation conditions at the Earth’s surface. Ozone depletion has also contributed to climate change across the Southern Hemisphere. These changes are interacting in complex ways to affect human health, food and water security, and ecosystem services. Many adverse effects of high UV exposure have been avoided thanks to the Montreal Protocol with its Amendments and Adjustments, which have effectively controlled the production and use of ozone-depleting substances. This international treaty has also played an important role in mitigating climate change. Climate change is modifying UV exposure and affecting how people and ecosystems respond to UV; these effects will become more pronounced in the future. The interactions between stratospheric ozone, climate and UV radiation will therefore shift over time; however, the Montreal Protocol will continue to have far-reaching benefits for human well-being and environmental sustainability.
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    Too hot to handle? An urgent need to understand climate change impacts on the biogeochemistry of tropical coastal waters
    (John Wiley & Sons, Inc., 2023-12-12) Carreira, Cátia; Joyce, Patrick W. S.; Morán, Xosé Anxelu G.; Carvalho, Susana; Falkenberg, Laura; Lønborg, Christian; Danmarks Frie Forskningsfond
    Tropical regions contain ecologically and socio‐economically important habitats, and are home to about 3.8 billion people, many of which directly depend on tropical coastal waters for their well‐being. At the basis of these ecosystems are biogeochemical processes. Climate change is expected to have a greater impact in the tropics compared to temperate regions because of the relatively stable environmental conditions found there. However, it was surprising to find only 660 research articles published focusing on the impact of climate change on the biogeochemistry of coastal tropical waters compared to 4823 for temperate waters. In this perspective, we highlight important topics in need of further research. Specifically, we suggest that in tropical regions compared to temperate counterparts climate change stressors will be experienced differently, that organisms have a lower acclimation capacity, and that long‐term baseline biogeochemical datasets useful for quantifying future changes are lacking. The low number of research papers on the impacts of climate change in coastal tropical regions is likely due to a mix of reasons including limited resources for research and limited number of long time series in many developing tropical countries. Finally, we propose some action points that we hope will stimulate more studies in tropical coastal waters.