Wastewater stabilization ponds (WSPs) are commonly used to treat municipal wastewater in Arctic Canada. The biological treatment in the WSPs is strongly influenced by climatic conditions. Currently, there is limited information about the removal of fecal and pathogenic bacteria during the short cool summer treatment season. With relevance to public health, the objectives of this paper were to determine if treatment in arctic WSPs resulted in the disinfection (i.e., removal of fecal indicator bacteria, Escherichia coli) and removal of selected human bacterial pathogens from the treated effluent. The treatment performance, with focus on microbial removal, was assessed for the one-cell WSP in Pond Inlet (Nunavut [NU]) and two-cell WSP in Clyde River (NU) over three consecutive (2012-2014) summer treatment seasons (late June-early September). The WSPs provided a primary disinfection treatment of the wastewater with a 2-3 Log removal of generic indicator E. coli. The bacterial pathogens Salmonella spp., pathogenic E. coli, and Listeria monocytogenes, but not Campylobacter spp. and Helicobacter pylori, were detected in the untreated and treated wastewater, indicating that human pathogens were not reliably removed. Seasonal and annual variations in temperature significantly (p
Institute of Biodiversity Research (IRBio), Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain. Electronic address: firstname.lastname@example.org.
Global changes, and particularly the massive release of CO2 to the atmosphere and subsequent global warming, have altered the baselines of carbon and oxygen stable isotopic ratios. Temporal shifts in these baselines can be advantageously monitored through cetacean skin samples because these animals are highly mobile and therefore integrate in their tissues the heterogeneity of local environmental signals. In this study, we examine variation of d13C and d18O values in the skin of fin whales sampled over three decades in two different North Atlantic feeding grounds: west Iceland and northwest Spain. These locations are situated about 2700?km apart and thus represent a wide latitudinal range within the North Atlantic Ocean. The d13C decrease in both areas is attributed to the burning of fossil fuels and increased deforestation worldwide, the so-called Suess effect. The dissimilarity in the magnitude of the shift between the two areas is coincidental with previous information on local shifts and lies within the ranges of variation observed. d18O values experienced a minimal, yet significant change in fin whales from W Iceland (a decline of -0.44‰ between 1986 and 2013) but not in those from NW Spain. This is in concordance with a higher rise in temperatures in the former area than in the latter. The study validates the use of cetacean skin to monitor temporal and geographical shifts in stable isotopic values and alerts that, when applying this tool to ecological research, comparisons between sample sets should take into account temporal and latitudinal scales.
Mercury (Hg) biotransformation and biomagnification are processes that affect Hg burdens in wildlife. To interpret variation in Hg in seabird eggs, used as Hg bioindicators in the Arctic, it is important to understand how Hg biomagnifies through the food web. We evaluated the use of d34S, along with other commonly used stable isotope signatures (d15N and d13C), for the determination of possible sources of Hg in an Arctic food web (56 individuals of 15 species of fish and invertebrates). Hg correlated with d34S (R2?=?0.72). When the combined effects of d34S and d15N were considered in mixed-effects models, both d34S and d15N together described Hg patterns in Arctic food webs better than either isotope alone. Our results demonstrate the usefulness of d34S to account for variation in Hg among marine animals and to study the possible underlying effects that MeHg production may have on Hg pathways in Arctic ecosystems.