Project description:Flounder fish were exposed in mesocosms for seven months to a contaminated estuarine sediment made by mixing material from the Forth (high organics) and Tyne (high metals and tributyltin) estuaries (FT) or control sediment from the Ythan estuary (Y). Their gene expression profiles were compatred by cDNA microarrays.
Project description:We used the mummichog (Fundulus heteroclitus) array we developed to test whether our arrays could be used to monitor the efficacy of remediation at an estuarine Superfund site. Shipyard Creek is a chromium-contaminated Superfund site in Charleston, SC undergoing remediation, therefore it provides a unique opportunity to study the efficacy of arrays as a molecular biomarker in of toxicant effects in mummichogs. Mummichogs were captured in Shipyard Creek in Charleston, SC prior to remediation (2000), after remediation began (2003), and as remediation further progressed (2005). Simultaneously, mummichogs were collected from a reference site at the Winyah-Bay National Estuarine Research Reserve (NERR). The hepatic gene expression pattern of fish captured at Shipyard Creek showed wide differences from the fish captured at NERR in 2000. As remediation progressed the gene expression pattern of fish captured at Shipyard Creek became increasingly similar to fish captured at NERR, and the number of genes differently expressed dropped from 22 to 4. The magnitude of differential gene expression of the individual genes also decreased during remediation. The recovering gene expression profile is associated with lower chromium bioavailability, demonstrated through significantly decreased body burden and sediment concentrations. For example, sediment concentrations at Shipyard Creek were 80-fold greater than NERR in 2000, 51-fold greater in 2003, and only 8-fold greater in 2005. However, hydraulic dredging in 2005 stirred up the sediments and increased body burden of chromium even though chromium sediment concentrations continued to drop. Therefore, the number of differentially expressed genes increased to 9. Overall, the data supports our hypothesis that arrays can be used to monitor site mitigation, as the number of genes differentially expressed mimics the body burden and also indicates when on-site remediation is increasing bioavailability. Keywords: Field site
Project description:We used the mummichog (Fundulus heteroclitus) array we developed to test whether our arrays could be used to monitor the efficacy of remediation at an estuarine Superfund site. Shipyard Creek is a chromium-contaminated Superfund site in Charleston, SC undergoing remediation, therefore it provides a unique opportunity to study the efficacy of arrays as a molecular biomarker in of toxicant effects in mummichogs. Mummichogs were captured in Shipyard Creek in Charleston, SC prior to remediation (2000), after remediation began (2003), and as remediation further progressed (2005). Simultaneously, mummichogs were collected from a reference site at the Winyah-Bay National Estuarine Research Reserve (NERR). The hepatic gene expression pattern of fish captured at Shipyard Creek showed wide differences from the fish captured at NERR in 2000. As remediation progressed the gene expression pattern of fish captured at Shipyard Creek became increasingly similar to fish captured at NERR, and the number of genes differently expressed dropped from 22 to 4. The magnitude of differential gene expression of the individual genes also decreased during remediation. The recovering gene expression profile is associated with lower chromium bioavailability, demonstrated through significantly decreased body burden and sediment concentrations. For example, sediment concentrations at Shipyard Creek were 80-fold greater than NERR in 2000, 51-fold greater in 2003, and only 8-fold greater in 2005. However, hydraulic dredging in 2005 stirred up the sediments and increased body burden of chromium even though chromium sediment concentrations continued to drop. Therefore, the number of differentially expressed genes increased to 9. Overall, the data supports our hypothesis that arrays can be used to monitor site mitigation, as the number of genes differentially expressed mimics the body burden and also indicates when on-site remediation is increasing bioavailability. Keywords: Field site
Project description:We used the mummichog (Fundulus heteroclitus) array we developed to test whether our arrays could be used to monitor the efficacy of remediation at an estuarine Superfund site. Shipyard Creek is a chromium-contaminated Superfund site in Charleston, SC undergoing remediation, therefore it provides a unique opportunity to study the efficacy of arrays as a molecular biomarker in of toxicant effects in mummichogs. Mummichogs were captured in Shipyard Creek in Charleston, SC prior to remediation (2000), after remediation began (2003), and as remediation further progressed (2005). Simultaneously, mummichogs were collected from a reference site at the Winyah-Bay National Estuarine Research Reserve (NERR). The hepatic gene expression pattern of fish captured at Shipyard Creek showed wide differences from the fish captured at NERR in 2000. As remediation progressed the gene expression pattern of fish captured at Shipyard Creek became increasingly similar to fish captured at NERR, and the number of genes differently expressed dropped from 22 to 4. The magnitude of differential gene expression of the individual genes also decreased during remediation. The recovering gene expression profile is associated with lower chromium bioavailability, demonstrated through significantly decreased body burden and sediment concentrations. For example, sediment concentrations at Shipyard Creek were 80-fold greater than NERR in 2000, 51-fold greater in 2003, and only 8-fold greater in 2005. However, hydraulic dredging in 2005 stirred up the sediments and increased body burden of chromium even though chromium sediment concentrations continued to drop. Therefore, the number of differentially expressed genes increased to 9. Overall, the data supports our hypothesis that arrays can be used to monitor site mitigation, as the number of genes differentially expressed mimics the body burden and also indicates when on-site remediation is increasing bioavailability. Keywords: Field site
Project description:Microorganisms are key contributors to biogeochemical flux in estuarine ecosystems. In this study, we conducted proteogenomic characterization of microbial communities from estuarine ecosystems.
Project description:Compared to freshwater ecosystems, the health status of estuarine waters remains little studied despite their importance for many species. They also represent a zone of interest for Human settlements that make them the final sink of pollution in both the water column and sediment. Once in sediments, pollutants could represent a threat to benthic as well as pelagic estuarine species through resuspension events. In the Seine estuary, the copepod Eurytemora affinis has been previously presented as a relevant species to assess resuspended sediment contamination through the use of fitness-related effects at the individual level. The aim of the present study was to use E. affinis copepods to assess estuarine sediment-derived elutriates toxicity using both a molecular (i.e. transcriptomics) and a behavioral approach. Two sites along the Seine estuary were sampled. They were both under anthropic pressures from the industrial-port activities or wastewater treatment plants (i.e. Tancarville) or agricultural pressure from freshwater affluent (i.e. Fatouville). The analysis of sediments used to prepare elutriates reveals that both sites have close contamination profiles. The transcriptomic analysis reveals that exposure to both sites triggers the dysregulation of genes involved in biological function as defense response, immunity, ecdysone pathway or neurotoxicity. This analysis also reveals a higher count of dysregulated genes in the Fatouville site compared to the Tancarville despite their close contamination profile. These results emphasize the sensitivity of this molecular approach to assess environmental matrix toxicity with E. affinis. The analysis of the swimming behavior of E. affinis did not highlight significant effects after both sites elutriate exposure. However, our strategy to assess E. affinis swimming behavior (i.e the combination of the DanioVision observation chamber and the EthoVision analysis software) allows the discrimination of basal swimming behavior in this species. Thus, it represents a promising standardized tool to assess copepods swimming behavior in ecotoxicological studies.
Project description:Coastal marine sediments, as locations of substantial fixed nitrogen loss, are very important to the nitrogen budget and to the primary productivity of the oceans. Coastal sediment systems are also highly dynamic and subject to periodic natural and anthropogenic organic substrate additions. The response to organic matter by the microbial community involved in nitrogen loss processes was evaluated using mesocosms of Chesapeake Bay sediments. Over the course of a 50-day incubation, rates of anammox and denitrification were measured weekly using 15N tracer incubations, and samples were collected for genetic analysis. Rates of both nitrogen loss processes and gene abundances associated with them corresponded loosely, probably because heterogeneities in sediments obscured a clear relationship. The rates of denitrification were stimulated more by the higher organic matter addition, and the fraction of nitrogen loss attributed to anammox slightly reduced. Furthermore, the large organic matter pulse drove a significant and rapid shift in the denitrifier community as determined using a nirS microarray, indicating the diversity of these organisms plays an essential role in responding to anthropogenic inputs. We also suggest that the proportion of nitrogen loss due to anammox in these coastal estuarine sediments may be underestimated due to temporal dynamics as well as from methodological artifacts related to conventional sediment slurry incubation approaches.
Project description:We established simple synthetic microbial communities in a microcosm model system to determine the mechanisms that underlay cross-feeding in microbial methane-consuming communities. Co-occurring strains from Lake Washington sediment were used that are involved in methane consumption, a methanotroph and two non-methanotrophic methylotrophs.
Project description:We investigated a contaminant-degrading microbial community by sequencing total RNA (without rRNA depletion) from microcosms containing sediment from a hypoxic contaminated aquifer fed with isotopically labeled toluene.