Project description:The consistent cold temperatures and large amount of precipitation in the Olympic and Cascade ranges of Washington State are thought to increase atmospheric deposition of contaminants in these high elevation locations. Total mercury and 28 organochlorine compounds were measured in composite, whole fish samples collected from 14 remote lakes in the Olympic, Mt. Rainer, and North Cascades National Parks. Mercury was detected in fish from all lakes sampled and ranged in concentration from 17 to 262 ug/kg wet weight. Only two organochlorines, total polychlorinated biphenyls (tPCB) and dichlorodiphenyldichloroethylene (DDE), were detected in fish tissues (concentrations <25 ug/kg wet weight). No organochlorines were detected in sediments (MRL ≈1-5 ug/kg), while median total and methyl mercury in sediments were 30.4 and 0.34 ug/kg (dry weight), respectively. Using a targeted rainbow trout cDNA microarray with known genes, we detected significant differences in liver transcriptional responses, including metabolic, endocrine, and immune-related genes, in fish collected from a contaminated lake compared to a lake with a lower contaminant load. Overall, our results suggest that local urban areas are contributing to the observed contaminant patterns, while the transcriptional changes point to a biological response associated with exposure to these contaminants in fish. Specifically, the gene expression pattern leads us to hypothesize a role for mercury in disrupting the metabolic and reproductive pathways in fish from high elevation lakes in western Washington. Keywords: High altitude lakes, mercury, salmonids, organochlorines Overall design: Overall, 5 independent samples from Wilcox lake and 3 independent samples from Skymo lake were used for microarray. All the 8 samples were cross hybridized using reference RNA obtained from Rainbow trout liver samples. Dye-swapping was also followed.
2007-05-01 | GSE6886 | GEO
Project description:studies of microbial diversity in lake sediments
Project description:We report here the release of a multi organ transcriptome developped for the Arctic char Salvelinus alpinus. This reference set was obtained using the 454 GS FLX+ technology. A pool of one-year-old, immature offspring of wild, anadromous Arctic charr originating from Lake Varflusjoen, Svalbard (79oN), including both lean and fat individuals, and three-years-old mature offspring of charr originating from Lake Vårflusjøen, North-Norway (70oN) was sampled. In order to maximize the diversity of expressed transcripts, we sampled a variety of organs and tissues; the whole brain, gill and head kidney and pieces of the liver, gonad, abdominal fat and muscle.
2016-08-18 | E-MTAB-3522 | ArrayExpress
Project description:Bacterial diversity of a seasonally-stratified lake
Project description:Functional redundancy in bacterial communities is expected to allow microbial assemblages to survive perturbation by allowing continuity in function despite compositional changes in communities. Recent evidence suggests, however, that microbial communities change both composition and function as a result of disturbance. We present evidence for a third response: resistance. We examined microbial community response to perturbation caused by nutrient enrichment in salt marsh sediments using deep pyrosequencing of 16S rRNA and functional gene microarrays targeting the nirS gene. Composition of the microbial community, as demonstrated by both genes, was unaffected by significant variations in external nutrient supply, despite demonstrable and diverse nutrient–induced changes in many aspects of marsh ecology. The lack of response to external forcing demonstrates a remarkable uncoupling between microbial composition and ecosystem-level biogeochemical processes and suggests that sediment microbial communities are able to resist some forms of perturbation. Overall design: nirS gene diversity from two salt marsh experiments, GSM (4 treatments, 8 samples, duplicate arrays, four replicate blocks per array, 8 arrays per slide) and PIE (2 treatments, 16 samples, duplicate arrays four replicate blocks per array, 8 arrays per slide)