In February 2014, a coal ash spill on Duke Energy's Dan River Plant in Eden, NC released approximately 39,000 tons of coal ash into the Dan River. It took approximately one week to stop the spill. Starting in February 2015, drinking water utilities using the Dan River experienced a series of taste and odor (TandO) events described as "earthy" or "musty". Similar TandO events were not documented before the coal ash spill. This research attempted to understand causes of the TandO events and if the coal ash spill was connected. A variety of water quality analyses were performed on twelve sites from August 2016 to September 2017 on the Dan and Smith Rivers. The Smith River served as the control. From concentrations of coal ash indicators (particularly Ba, Sr, As, V, and Br-), there was a signature of coal ash on the Dan River that was not present on the Smith River. The signature could not be attributed to the coal ash spill, as the signature was present upstream of the spill. Chronic ecosystem toxicity due to metals was low and not significantly different between the Dan and Smith Rivers. No substantial TandO events occurred during the period of this study. All monitored odorants were detected with varying frequencies in both the Dan and Smith Rivers. No significant change in odorant concentration was found above and below the location of the coal ash spill. / MS

No description available.

Små öar har kännetecken som gör dem särskilt sårbara för påfrestningar orsakade av klimatförändringar, och Marinduque är inget undantag. Marinduques miljö är fortfarande kontaminerad efter 27 års metallbrytning samt en av Filippinernas största gruvincidenter som ännu inte återställts. Marinduques samhälle är påverkad av en fattigdom som kan göra det särskilt sårbara för yttre påfrestningar. Studien är en litteraturbaserad sådan som syftar på att utreda hur Marinduque specifikt kan väntas påverkas av klimatförändringar, samt att studera vilken påfrestning metallkontaminering från gruvbrytning innebär för ön. En sådan översikt kan vidga förståelsen kring hur dessa två faktorer tillsammans kan påverka Marinduques samhälle, om det finns en risk att de förstärker varandras effekter eller en möjlighet att de minskar dem. Arbetet är en litteraturstudie och avgränsningar gjordes till att undersöka Marinduques jordbruk, kustområden och marina resurser, samt vattenresurser. Marinduque kommer påverkas av klimatförändringar på flera sätt och orsaka en påfrestning för samhället. Jordbrukets produktivitet kommer till största trolighet minska på grund av klimatförändringar, och detta kommer drabba den stora andel invånare som har jordbruket som sin huvudsakliga försörjningskälla. Fiskerinäringen har likväl en stor betydelse för invånare och kommer också påverkas av klimatförändringar då både fiskbestånd och livsmiljöer, så som korallreven, drabbas. Vattenresurserna väntas minska under torrperioderna, och Marinduques vattenhushållning är generellt inte redo för ett förändrat klimat. Vidare förväntas extremväder öka både sett till frekvens och intensitet till följd av klimatförändringar, och ekosystem som vanligtvis ger ett skydd för dessa extremväder tros likväl de försvagas till följd av ett förändrat klimat. Marinduques jordbruk, marina miljö och vattenresurser har alla påverkats av metallkontamineringen på olika sätt. Metallernas beteendemönster i jord och vatten påverkar metalltillgängligheten och på så sätt dess spridning på ön. Öns dominerande jordart är lera och detta både kan hämma och bidra till metallspridningen. Jordbruket kan vid konstbevattning riskera att sprida metallerna till områden som inte har en förorenad mark. Fiskbestånd har minskat efter de största gruvincidenterna inträffade, då både viktiga korallrev och mangroveskogar i Marinduques marina miljö påverkats av metallkontamineringen. Vattentillgängligheten har också minskat då öns två största floder är förorenade av gruvbrytningen. Upptag av dessa metaller genom både grödor från kontaminerad mark, fiskar från kontaminerade kustmiljöer, och kontaminerad vatten innebär en risk för metallackumulering hos invånare. Detta kan resultera i att människohälsan på ön försämras om halterna når skadliga nivåer. Sammanfattningsvis kan slutsatsen dras att klimatförändringarna och metallkontamineringen på flera sätt förstärker varandras effekter på både Marinduques jordbruk, kustområden och marina resurser, samt vattenresurser. / Small islands have characteristics that make them particularly vulnerable to stress caused by climate change, and Marinduque is no exception. Marinduque’s environment is still contaminated after 27 years of metal mining and one of the Philippine’s largest mining incidents that has not yet been restored. Marinduque’s society is affected by poverty, which can make it particularly vulnerable to external pressure. The study is a literature-based one that aims to investigate how Marinduque can specifically be expected to be affected by climate change, and to study what stress metal contamination from mining means for the island. Such an overview can broaden the understanding of how these two factors together can affect Marinduque’s society, if there is a risk that they reinforce each other’s effects or a possibility that they reduce them. The work is a literature study and limitations were made to investigate Marinduque’s agriculture, coastal areas and marine resources and finally its water resources. Marinduque will be affected by climate change in several ways and cause a strain on society. Agricultural productivity will most likely decrease due to climate change, and this will affect the large proportion of inhabitants who have agriculture as their main source of livelihood. The fishing industry is nevertheless of great importance to residents and will also be affected by climate change as both fish stocks and habitats, such as coral reefs, are affected. Water resources are expected to decline during dry periods, and Marinduque’s water management is generally not ready for a changing climate. Furthermore, extreme weather is expected to increase both in terms of frequency and intensity as a result of climate change, and ecosystems that usually provide protection against these storms and typhoons are believed to weaken as a result of a changing climate. Marinduque’s agriculture, marine environment and water resources have all been affected by the metal contamination in different ways. The behavior of metals in soils and water affect the availability of the metals and thus its spread on the island. The island’s dominant soil is clay and this can both inhibit and contribute to the metal spreading. In the case of irrigation, agriculture may risk spreading the metals to areas that do not have contaminated soil. Fish stocks have declined after the mining incidents occurred, as both important coral reefs and mangrove forests in Marinduque’s marine environment were affected by metal contamination. Water availability has also decreased due to the largest rivers are being polluted by mining. Uptake of these metals by both crops from contaminated land, fish from contaminated costal environments and contaminated water poses a risk of metal accumulation in residents. This can result in human health on the island deteriorating if levels reach harmful levels. In summary, it can be concluded that climate change and metal contamination in several ways reinforce each other’s effects on both Marinduque’s agriculture, coastal areas and marine resources, as well as water resources.

Relationships between trace metals and nanoparticles were investigated using analytical transmission electron microscopy (aTEM) and asymmetric flow field flow fractionation (aFlFFF) coupled to both multi-angle laser light scattering (MALLS) and high resolution-inductively coupled plasma mass spectroscopy (HR-ICPMS). Riverbed sediment samples were taken from the Clark Fork River in Montana, USA where a large-scale dam removal project has released reservoir sediment contaminated with toxic trace metals (namely Pb, Zn, Cu and As) which accumulated from one and a half centuries of mining activities upstream. An aqueous extraction method was used to attempt to separate the nanoparticles from the bulk sediment. After analysis of initial results, it was found that low density clays were being selected for in this process and made up a major portion of the particles within the extracts. However, it was also realized that the metals of interest were associated almost exclusively with nano-sized Fe and Ti oxides. In order to more fully examine these relationships, a density separation method, using sodium polytungstate (2.8g/cm3), was developed to separate these higher density oxides from the lower density clays. The heavy fraction was then subjected to an aqueous extraction routine to extract the nanoparticulate fraction. FFF results indicated a smaller size distribution and more ideal fractionation with this method. The aFlFFF-HR-ICPMS profiles for Fe and Ti also matched strongly with the data for the trace metals. The majority of particles analyzed with the TEM were nano-sized Fe and Ti oxides (most commonly goethite, ferrihydrite and brookite), which typically had trace metals associated with them. In many cases, it was aggregates of these nano oxides that were found hosting trace metals. Nanoparticles and aggregates are known to behave differently than their bulk mineral phases or constituent particles, respectively. Nanoparticles are also capable of extended transport in the environment. For these reasons, it is important that their associations with toxic trace metals be extensively evaluated, as they will affect the bioavailability and toxicity of these metals with implications for any type of contaminant sediment relocation, dam removal or metal contaminated site. / Ph. D.

Metal contamination is a considerable environmental problem because metals are persistent contaminants. Ion exchange is one of the most commonly used treatment options for trace metal removal. This research develops and evaluates a redox active modified ion exchange system that has the potential to reduce the ionic strength of ion exchange regeneration streams. Poly-L-cysteine (PLC) was selected as the redox active, adsorbing functional group on the surface of a reticulated vitreous carbon (RVC) electrode. PLC is an excellent soft acid metal chelator and is unique in that its thiol groups can form disulfide bonds with each other. The reduction of available thiols changes the metal binding capacity of the peptide since the thiol is the primary binding group. RVC provides a macroporous conductive monolithic resin to support the peptide. An experimental apparatus was designed to study the properties of this system and estimate performance. Distinct oxidized and reduced states of PLC on the surface of the RVC were confirmed by changes in metal binding characteristics. Adsorption edges showed a sharper pH dependence for the reduced electrode compared to the oxidized electrode from pH 3-7. Adsorption isotherms performed at pH 7 showed increased capacity for the reduced electrode. The change was reversible by chemical and electrical reduction. This difference was confirmed at the molecular level with Cd- EXAFS of oxidized and reduced electrodes. A greater degree of cadmium-sulfur coordination was observed on the reduced electrode and a greater cadmium-oxygen coordination was apparant on an oxidized electrode. A multidentate adsorption model was developed to model the pH dependent behavior of cadmium adsorption on the PLC-RVC surface. Nickel adsorption showed increased adsorption in the oxidized state. The most likely explanation is increased carboxylate complexation. The electronically switchable ion exchange system (ESIE) provides a framework for modifying traditional ion exchange processes. The system has 5 to 10 times less specifc capacity than current ion exchange systems, but uses solutions 10-100 times lower in ionic strength for regeneration. Further studies on the effect of ionic strength on adsorption and current usage are necessary to compare the cost of the ESIE process to traditional ion exchange. / text

Orientador: Marina Corrêa Côrtes / Resumo: A fragmentação dos ambientes naturais pode gerar consequências negativas para a diversidade genética, a evolução e a conservação da biodiversidade. Esses efeitos podem se tornar ameaças à relevância dos ecossistemas para conservação da biodiversidade ao longo prazo e podem impulsionar a ocorrência de fenômenos evolutivos como a adaptação local em populações isoladas. Consequências negativas resultantes da fragmentação podem ser amplificadas por outras pressões negativas comuns em ambientes isolados, incluindo a poluição por metais pesados. A primeira parte desta tese avalia importantes mecanismos evolutivos que promovem a adaptação de plantas a solos contaminados por metais pesados. Informações sobre ecologia populacional, genômica e identificação de genes importantes para adaptação à alta concentração de elementos tóxicos, incluindo Fe, Pb, Cu, Al e Zn, foram usadas para testar mecanismos evolutivos. O estudo revela estratégias ecológicas e genes importantes para o crescimento de Cattleya liliputana em solos contaminados. Melhores ferramentas para a gestão da paisagem e maior integração de áreas protegidas e paisagens produtivas são importantes para reverter a tendência global de fragmentação e uso insustentável dos recursos naturais. A segunda parte da tese fornece ferramentas e análises para promover a conectividade, a integração e o manejo efetivo da paisagem. No segundo capítulo, uma ferramenta de análise espacial de fácil utilização para apoiar projetos com objetivo de ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The fragmentation of natural environments has pervasive consequences to genetic diversity, evolution and the conservation of biodiversity. These effects are important threats to the long-term relevance of ecosystems, and may drive evolutionary responses such as the local adaptation of isolated populations. Negative consequences resulting from fragmentation can be amplified by other common negative pressures in isolated environments, including pollution by heavy metals. Species that survive after contamination play an important role for restoration but face strong selective pressure for adaptation to the contaminants within an isolated environment. The first part of the thesis shed light on important evolutionary mechanisms that drive plant adaptation to soils contaminated by heavy metals. Information regarding population ecology, genomics, and identification of important genes for adaptation to the high concentration of toxic elements, including Fe, Pb, Cu, Al and Zn were used to test major evolutionary mechanisms. The study revealed ecological strategies and genes important for Cattleya liliputana adaptation to contaminated soils. Better tools for landscape management and enhanced integration of protected areas and production landscapes are important strategies to counter the global trend on fragmentation and unsustainable use of natural resources. The second part of the thesis provides tools and analysis to promote connectivity, integration and effective landscape managemen... (Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2016-08-10T10:44:14Z (GMT). No. of bitstreams: 1 MARIANA BERNARDES BORGES BENCHIMOL.pdf: 15746292 bytes, checksum: 6f409bc1d98f40023f1239cbe314ec0c (MD5) Previous issue date: 2011-08-30 / This study was conducted in the Araguaia and Tocantins basins in the State of Goiás, during the drought period, and aimed to evaluate the content of polluting metals: aluminum, cadmium, lead, copper, chromium, iron, manganese and zinc in different trophic levels of fishes, and to compare the concentrations of these metals between the different trophic levels, sampling sites and between the two basins. Tests for determining the concentration of metals were performed by atomic absorption spectrometry, flame mode (AAS-flame). The similarity of the median concentrations of metal pollutants between trophic groups, between sampling sites and between basins was investigated by nonparametric Kruskal-Wallis test. The metals that most contributed to the pollution of basins studied were aluminum and manganese, possibly due to soil typical of the region (Oxisol) and the type of handling close to watercourses. The highest concentrations of metals were found in the Araguaia basin. There was significant difference in the levels of aluminum, iron and zinc between the basins. The trophic level most affected by metal pollution was the insectivore. Significant difference in the concentrations of pollutant metals (except lead) between trophic levels was observed. The data analysis indicates that the source of metal contamination of fish is the sediment of the aquatic environment. Results show a possible contamination of fish Araguaia and Tocantins basins with metal pollutants. Human activities observed in these basins appear to contribute to these results. / Esse estudo foi realizado nas bacias dos rios Araguaia e Tocantins, no Estado de Goiás, durante o período de estiagem, e teve como objetivo avaliar o teor de metais poluentes: alumínio, cádmio, chumbo, cobre, cromo, ferro, manganês e zinco em diferentes níveis tróficos de peixes, bem como comparar as concentrações destes metais entre os diferentes níveis tróficos, locais de coleta e entre as duas bacias hidrográficas. As análises para a determinação da concentração dos metais foram realizadas por espectrometria de absorção atômica, modalidade chama (EAA chama). A similaridade das concentrações medianas de metais poluentes entre os grupos tróficos, entre os locais de coleta e entre as bacias foi investigada pelo teste não-paramétrico de Kruskal-Wallis. Os metais que mais contribuíram para a poluição das bacias estudadas foram o alumínio e o manganês, possivelmente em decorrência do solo típico da região (Latossolo) e do tipo de manejo próximo aos cursos d água. As maiores concentrações de metais foram encontradas na bacia do rio Araguaia. Observou-se diferença significativa nos teores de alumínio, ferro e zinco entre as bacias. O nível trófico mais afetado pela poluição por metais foi o insetívoro. Diferença significativa nas concentrações de metais poluentes (exceto para o chumbo) entre os níveis tróficos foi verificada. Análises dos dados indicam que a fonte de contaminação dos peixes por metais é o sedimento do ambiente aquático. Resultados mostram uma possível contaminação de peixes das bacias dos rios Araguaia e Tocantins com metais poluentes. As atividades antrópicas observadas nestas bacias parecem contribuir para esses resultados.

En ohållbar resursanvändning har lett till att resurser länge lagts i osorterade deponier, vilket leder till att farliga ämnen lakas ur och förorenar sjöar och vattendrag. Klimatförändringar som förväntas leda till stigande havsnivåer gör att deponier i närheten till hav, sjöar och vattendrag kan komma att sprida föroreningar i större utsträckning än de gör idag. För att bidra till ytterligare kunskap kring ämnet har metallhalten i två gamla deponier intill Mälaren undersökts. Studien baseras på en fältundersökning där mark och grundvattenprover samlats in, analyserats och kategoriserats enligt MIFOs principer: farlighet, föroreningsnivå och spridningsrisk. Utgångspunkten är att skyddsvärdet är stort då området angränsar till Mälaren. Det undersökta området omfattas av två deponier (Ekudden och Uddhagen) i anslutning till varandra och undersöks därför samtidigt. Studiens syfte är att identifiera områden med punktkällor där åtgärder bör vidtas för att minimera risken för en kontaminering av Mälarens vatten nu och i framtiden. Studien visade att samtliga provpunkter överskred halter för KM (känslig markanvändning) för en eller flera metaller. Genom en visualisering kunde sex områden identifieras där en eller flera provpunkter visade på halter där minst tre ämnen överskrider halten för MKM (mindre känslig markanvändning), eller där en eller flera ämnen överskrider halten för FA (farligt avfall). Då områdets avgränsning inte var tillräckligt tydlig kunde inte alla provpunkterna ses som punktkällor. Två områden anses ha två eller fler punktkällor som sprider föroreningar. Punktkällorna är belägna på en kampingplats där halter för KM inte bör överskridas. Fyra områden anses ha delområden som utgörs av provpunkterna där halterna är högre än övriga provpunkter. Fyra punkter anses även ligga så pass nära strandkanten att en höjning av Mälaren skulle kunna leda till en översvämning av provpunkterna vilket kan innebära en ökad risk för kontaminering av ytvattnet. En åtgärd som föreslås för att minimera risken för fortsatt urlakning är en välplanerad bioremediering i kombination med fytoremediering då stora delar idag används i rekreationella syften. Structor miljöteknik AB på uppdrag av Kungsörs kommun / The unsustainableuse of resources has resulted inresiduesbeing put into unsorted landfills for a long time, this practice has ledto hazardous substances being leached out and polluting lakes and watercourses. Climate changeis leadingto rising sea levels, whichmay result inthat landfills in vicinity of seas, lakes and watercourses may spread pollution to a greater extent than they do today. To contribute to further knowledge about thissubject, the metal content in two old landfills next to Lake Mälaren has been investigated. The study is based on a field survey where soil and groundwater samples were collected, analyzed and categorized according to MIFO's principles: hazard, pollution level and risk of spreading. The starting point is that the protection value is large as the area borders Lake Mälaren. The investigated area is covered by two landfills (Ekudden and Uddhagen) adjacent to each other and because of that the areas areinvestigated at the same time. The purpose of the study was to identify hotspots of pollutants,where measures should be taken to minimize the risk of contamination of the lakenow and in the future. The study showed that all test points exceeded levels for KM (sensitive land use) for one or more metals. Through a visualization, six areas could be identified where one or more test points showed levels where at least three substances exceed the level for MKM (less sensitive land use), or where one or more substances exceed the level for FA (hazardous waste). As the demarcation of the area was not clear enough, not all test points could countas hotspots.Two areas are considered to have two or morehotspotsthat spread pollutants. The hotspot-areasare located on a campsite where levels for KM should not be exceeded. Four areas are considered assub-areas, these sub-areasconsist of the test points where pollutantsare high, but the demarcation of the area is uncertain.Four areasare also considered to be at risk if lake Mälaren shouldincrease which could lead to a flood of the test pointsandmay entail an increased risk of contamination of the surface water. One measure that is proposed to minimize the risk of continued leaching is a well-planned bioremediation in combination with phytoremediation as large parts of the investigated area iscurrently used for recreational purposes

Les processus de bioturbation constituent un exemple classique d’ingénierie de l’écosystème. Ils sont le fait d’espèces bioturbatrices qui contribuent à la structuration physique et biogéochimique des environnements sédimentaires. Dans les environnements marins meubles, les thalassinidés comptent parmi les bioturbateurs les plus influents. Ainsi, la crevette de vase Upogebia cf. pusilla est à l’origine d’un important remaniement sédimentaire et d’une large bioirrigation des sédiments dans le bassin d’Arcachon. Ces activités de bioturbation modulent les processus de minéralisation de la matière organique et les flux biogéochimiques à l’interface eau-sédiment. L’intensité de la bioturbation de U. cf. pusilla dépend de son état physiologique, celui-ci pouvant être altéré par divers facteurs de stress. Une approche couplant études de terrain et expérimentations en laboratoire a permis d’évaluer l’influence du parasitisme et de la contamination métallique sur les activités de U. cf. pusilla. Ce travail avait pour objectifs de (1) caractériser la pression parasitaire chez U. cf. pusilla à l’échelle locale, (2) déterminer les niveaux de base des éléments métalliques chez cet organisme dans le bassin d’Arcachon et d’évaluer le potentiel rôle des parasites dans les processus d’accumulation des métaux et (3) estimer l’impact du parasitisme et de la contamination métallique, seuls et en interaction, sur U. cf. pusilla et ce à deux échelles d’organisation, moléculaire et comportementale. In situ, un suivi spatial et un suivi temporel ont permis de caractériser la dynamique spatio-temporelle de deux parasites chez U. cf. pusilla¸ un bopyre infestant la cavité branchiale (Gyge branchialis), et un trématode (Maritrema sp.), infectant l’ensemble des organes de l’animal. Au sein de leur hôte, ces deux parasites sont négativement associés, le bopyre limitant probablement les processus d’infection par le trématode. Par ailleurs, un suivi saisonnier d’un an a permis de noter de faibles concentrations en métaux chez U. cf. pusilla, dans le bassin d’Arcachon. Ces concentrations ont été mises en parallèle avec le statut parasitaire des spécimens échantillonnés. Aucune corrélation n’a été notée entre la présence des trématodes et les quantités de métaux accumulées. A l’inverse, les observations de terrain ont permis d’envisager que le parasite bopyre puisse interférer avec les processus d’accumulation des métaux chez cet organisme. Cette dernière hypothèse a été testée en laboratoire au cours d’expérimentations visant à évaluer l’influence d’une contamination métallique (en utilisant le cadmium comme contaminant modèle) et du parasite bopyre, seuls et en interaction, sur U. cf. pusilla. A l’échelle moléculaire, le bopyre n’a été associé à aucune modification de l’expression d’une dizaine de gènes cibles. Par ailleurs, à l’échelle comportementale, ce parasite réduit peu le remaniement sédimentaire de son hôte, à l’inverse de ce qui avait été montré au cours d’une étude antérieure. En ce qui concerne l’influence du cadmium, ce métal module amplement l’expression de gènes codant notamment des protéines impliquées dans la réponse au stress oxydant et dans les mécanismes de détoxication. Ces observations suggèrent que U. cf. pusilla est capable de mettre en place des mécanismes de lutte contre le stress métallique. Au niveau comportemental, le cadmium semble stimuler le remaniement sédimentaire des organismes. Finalement, les expériences « doubles stress » ont montré un effet antagoniste du bopyre et du cadmium à la fois à l’échelle génique et à l’échelle comportementale. Ainsi, cette étude souligne la complexité des interactions entre facteurs de stress multiples et la nécessité d’effectuer de telles expérimentations. [...] / Bioturbation is a typical example of ecosystem engineering. Bioturbating species are mainly epi- or endobenthic organisms, which profoundly affect the physical structure and biogeochemical properties of sediments. In marine soft-bottom environments, thalassinidean mud shrimp are considered as one of the most prominent bioturbating organisms. Among these species is the mud shrimp Upogebia cf. pusilla, which is recognized as an important sediment reworker, also significantly contributing to the bioirrigation of sediments. In fine, this species greatly modulates organic matter mineralization and biogeochemical fluxes at the sediment-water interface. The influence of U. cf. pusilla in ecosystem functioning depends on the intensity of its bioturbation and thus on its fitness. Several factors can affect the physiological status of organisms, potentially resulting in behavioural changes and causing modifications of their activities. Amongst potential stressors, we evaluated the influence of parasitism and trace metal contamination on the mud shrimp U. cf. pusilla in Arcachon Bay, France. Field surveys and laboratory experiments were undertaken in order to evaluate (1) the parasite infestation levels in the mud shrimp at the local scale, (2) the metal contamination background and potential relationship between the metal accumulation and the parasitic status of organisms in the field and (3) estimate the distinct and interactive impacts of parasitism and metal contamination on two scales of organisation, by targeting a molecular (gene expression) and a behavioural (sediment reworking) endpoint.A large spatial and temporal survey conducted in Arcachon Bay showed that at least two parasites species occur in mud shrimp: a bopyrid isopod (Gyge branchialis), living in one of the gill chambers of its host, and a trematode parasite (Maritrema sp.), infecting the whole body of mud shrimp. These two parasite species are negatively associated within their host, in which the bopyrid likely interferes with trematodes establishment. Additionally, a one year seasonal sampling demonstrated that mud shrimp displayed very low levels of metals in Arcachon Bay. The bopyrid parasite could interfere with the process of metal accumulation in mud shrimp, while such correlation was not found for the trematode parasite. Finally, complementary laboratory experiments highlighted that, at the molecular level, the bopyrid parasite did not affect the expression of the genes targeted in this study in mud shrimp. Similarly, at the behavioural level, and conversely to a previous study, the effects of the bopyrid parasite were minor, i.e. only associated to small modifications of the bioturbation activity of its host. Indeed, the intensity of the sediment reworking of mud shrimp was slightly reduced when organisms were infested with this parasite. Regarding trace metal contamination, we noticed that mud shrimp largely accumulated cadmium. This accumulation was associated to an important modulation of gene expression, especially of genes encoding proteins involved in detoxification processes, highlighting, at this organisation level, the capability of mud shrimp to deal with the deleterious effect of cadmium. At the behavioural scale, cadmium contamination positively affected the sediment reworking activity of mud shrimp. Finally, double-stress experiments evidenced an antagonistic effect of both stressors on the two targeted endpoints. This study highlights the complexity of the interactions between multiple stressors and that the response of organisms cannot be predicted from “single-stress” experiments. [...]

No description available.