Contribution of Chemoautotrophic Production to Freshwater Macroinvertebrates in a Headwater Stream Using Multiple Stable Isotopes

Abstract

We estimated the food sources of macroinvertebrates using carbon, nitrogen, and sulfur stable isotopes in a headwater stream. Stream food webs, including macroinvertebrates, rely on production from autochthonous and allochthonous photosynthesis. We found that a freshwater grazer, the snail Semisulcospira libertina, may assimilate different food sources, based on stable carbon and nitrogen isotope evidence from snail muscle and the much lighter sulfur isotope signature than those of other associated macroinvertebrates. Previous studies have shown the importance of methanotrophic and sulfur bacteria in reductive environments (clay and organic‐rich sediments) as food sources for macroinvertebrates. Our results show that the production by chemoautotrophic bacteria contributes to the food sources of a snail in a stream. Thus, the chemoautotrophic bacteria are important in the freshwater food webs, even in mostly aerobic habitats. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Stable isotope analysis reveals detrital resource base sources of the tree hole mosquito, Aedes triseriatus

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Drifting plankton from a reservoir subsidize downstream food webs and alter community structure

“…C and N stable isotope ratios have been increasingly used to analyze food web structures in aquatic ecosystems (e.g., Finlay 2001;Finlay et al 2002;Doi et al 2006;Delong and Thorp 2006). Stable isotope analysis should be a useful tool to estimate the contribution of drifting plankton to food webs.…”

Stable isotopes indicate individual level trophic diversity in the freshwater gastropod Lymnaea stagnalis

“…In lacustrine ecosystems, food source diversity of benthic animals is poorly understood, although benthic invertebrate grazers are generally thought to feed on generalized mixtures of sediment detritus and microalgae (Reavell, 1980;Merritt & Cummins, 1996;Wetzel, 2001). However, recent studies have reported that chironomid larvae and snails feed on chemoautotrophic bacteria and vascular plants in addition to detritus and microalgae (Elger, Barrat-Segretain & Amoros, 2002;Grey, Kelly & Sleep, 2004;Doi et al, 2006a, Arakelova & Michel, 2009. The food sources of lymnaeid snails have been extensively studied because these snails are common in lakes and provide a large contribution to benthic and pelagic food webs (e.g.…”