Use of fatty acid analysis to determine dispersal of caspian terns in the Columbia River Basin, USA

Exposure to synthetic hydraulic fracturing waste influences the mucosal bacterial community structure of the brook trout (Salvelinus fontinalis) epidermis

Production of natural gas using unconventional technologies has risen as demand for alternative fuels has increased. Impacts on the environment from waste generated from these processes are largely unexplored. In particular, the outcomes of organismal exposure to hydraulic fracturing waste have not been rigorously evaluated. We evaluated the effects of exposure to surrogate hydraulic fracturing waste (HF waste) on mucosal bacterial community structure of the brook trout (Salvelinus fontinalis) epidermis. Brook trout are fish native to streams at risk to HF waste exposure. Here, fish were exposed to four treatments (control, 0.00%; low, 0.01%; medium, 0.10%; and high, 1.0% concentrations) of surrogate HF waste synthesized to mimic concentrations documented in the field. Epidermal mucus samples were collected and assessed 15 days post-exposure to determine if the associated bacterial community varied among treatments. We observed differences in epidermal mucosal bacterial community composition at multiple taxonomic scales among treatments. These community changes reflected compositional differences in taxa dominance and community similarity rather than losses or gains in taxonomic richness. The dominant bacterial genus that explained the greatest variation in community structure between exposed and unexposed fish was Flavobacterium. Two genera associated with salmonid diseases, Flavobacterium and Pseudomonas, were statistically more abundant in high treatments than controls. These results suggest that exposure to low levels of HF waste influences bacterial colonization and may lead to a disruption that favors bacterial populations associated with fish disease.

Egg yolk fatty acids as a proxy to quantify diets of female Spectacled Eiders (Somateria fischeri)

Determining the diets of threatened Spectacled Eiders (Somateria fischeri (Brandt, 1847)) in relation to life-history stages will provide information to help identify and characterize their critical habitats. Quantitative fatty acid signature analysis (QFASA) is a novel tool that estimates the proportion of diet items in consumers from their fat depots. We conducted feeding experiments to validate the use of QFASA to estimate the mixed diets of captive female Spectacled Eiders using egg yolk fatty acids (FA) collected in 2008 and 2009. Calibration coefficients (CCs) for individual FA were developed to account for FA modification (due to eider lipid metabolism) from diets of eiders into egg yolk. We also compared the FA profiles between fertile and infertile eggs. Egg yolk FA profiles did not differ significantly between infertile and fertile eggs collected in either year. Using the CCs developed from eggs collected in 2008, QFASA closely estimated the 2009 diet composition of eiders. We conclude that using infertile eggs has the potential to provide a noninvasive method to elucidate diets of breeding female Spectacled Eiders and possibly other avian species, and to provide insight into understanding the sources (i.e., marine wintering or freshwater breeding habitat) and timing (i.e., prebreeding or breeding) of nutrient acquisition during reproduction.