Integral Strategy for Evaluation of Fecal Indicator Performance in Bird-Influenced Saline Inland Waters

Abstract

Wild birds are an important nonpoint source of fecal contamination of surface waters, but their contribution to fecal pollution is mostly difficult to estimate. Thus, to evaluate the relation between feces production and input of fecal indicator bacteria (FIB) into aquatic environments by wild waterfowl, we introduced a new holistic approach for evaluating the performance of FIB in six shallow saline habitats. For this, we monitored bird abundance, fecal pellet production, and the abundance of FIB concomitantly with a set of environmental variables over a 9-month period. For estimating fecal pellet production, a new protocol of fecal pellet counting was introduced, which was called fecal taxation (FTX). We could show that, over the whole range of investigated habitats, bird abundance, FTX values, and FIB abundance were highly significantly correlated and could demonstrate the good applicability of the FTX as a meaningful surrogate parameter for recent bird abundances and fecal contamination by birds in shallow aquatic ecosystems. Presumptive enterococci (ENT) were an excellent surrogate parameter of recent fecal contamination in these saline environments for samples collected at biweekly to monthly sampling intervals while presumptive Escherichia coli and fecal coliforms (FC) were often undetectable. Significant negative correlations with salinity indicated that E. coli and FC survival was hampered by osmotic stress. Statistical analyses further revealed that fecal pollution-associated parameters represented one system component independent from other environmental variables and that, besides feces production, rainfall, total suspended solids (direct), and trophy (indirect) had significant positive effects on ENT concentrations. Our holistic approach of linking bird abundance, feces production, and FIB detection with environmental variables may serve as a powerful model for application to other aquatic ecosystems.Wild waterfowl are known to be an important nonpoint source of fecal contamination of surface waters (1,8,15,25,30). Wild birds have been reported to excrete large amounts of fecal indicator bacteria (FIB) (8, 25) and occasionally harbor enteric pathogens (20,21). Especially for public swimming beaches, fecal contamination by wild birds can therefore impose a severe problem for the persons in charge to meet the legal limits for FIB. Locating the source of contamination, however, is often a tricky business, and the contribution of wild birds to the total contamination of surface waters is mostly difficult to estimate. Thus, it would be considerably helpful to better understand the relations between feces production by wild waterfowl and their input of FIB into aquatic environments.We therefore monitored, over a 9-month period, the relations between bird abundances, their fecal pellet production, and three groups of FIB in six shallow, modestly saline aquatic environments. As the investigated saline pools are nearly exclusively visited by birds and no other animals and because they exhibit a steep gradien...

Impact of waterbirds on chemical and biological features of water and sediments of a large, shallow dam reservoir

“…The high correlation between the density of birds and the amount of Escherichia coli confirmed that bird droppings are scattered sources of fecal contamination in the inland water bodies (Kirschner et al 2004;Meerburg et al 2011). Meerburg et al (2011) showed that gull feces contain a higher average concentration of E. coli per gram than geese or coot feces.…”

Microsporidian Species Known To Infect Humans Are Present in Aquatic Birds: Implications for Transmission via Water?

“…The prevalence of microsporidiosis was statistically higher in waterfowl, and the aquatic status of an avian host was a predisposing factor for microsporidian infection. These findings are epidemiologically important, as most of the world's waterfowl species (i) are protected by environmental laws and occur in large numbers, (ii) have unlimited access to surface waters (including waters used for production of drinking water), and (iii) usually migrate quite long distances; in addition, most of the daily activity of these birds involves grazing in shallow waters, and the birds defecate into the water (24). It has been established by epidemiologists and the drinking water industry that the presence of aquatic birds in source water reservoirs is associated with declining water quality (1,9,18,24).…”

Phylogenetic Diversity and Molecular Detection of Bacteria in Gull Feces

“…As waterfowl are an important source of pollution in beach areas (17,26) and can serve as potential reservoirs of human infections (13,36), the assays described herein would be useful in health risk-based analyses (i.e., epidemiological studies and quantitative microbial risk studies) of nonhuman fecal pollu- on May 7, 2018 by guest http://aem.asm.org/ tion in recreational waters. Additionally, having gull-specific markers in the fecal source-tracking toolbox will help beach managers better assess potential causes of beach postings beyond familiar fecal pollution sources such as municipal wastewater and therefore implement remediation practices that target the most relevant sources of pollution.…”