Widespread contribution of methane-cycle bacteria to the diets of profundal lake chironomid larvae

Jones, Roger I. and Carter, Clare E. and Kelly, Andrew and Ward, Sue and Kelly, David J. and Grey, Jonathan (2008) Widespread contribution of methane-cycle bacteria to the diets of profundal lake chironomid larvae. Ecology, 89 (3). pp. 857-864. ISSN 0012-9658

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Abstract

Reports of unexpectedly 13C-depleted chironomid larvae in lakes have led to an hypothesis that significant transfer of detrital organic matter to chironomid larvae may occur via methane-cycle bacteria. However, to date little is known of how such transfer might vary across species and lakes. We gathered data from 87 lakes to determine how widespread this phenomenon might be and to define boundaries for its likely magnitude. Carbon stable isotope values of chironomid larvae varied greatly between taxa. Very marked 13C-depletion was evident only in certain taxa, especially Chironomus plumosus, C. anthracinus, and C. tenuistylus, all characteristic of eutrophic or dystrophic lakes and known to be tolerant of low oxygen conditions. Furthermore, marked 13C-depletion was only found in larvae from lakes in which late-summer hypolimnetic oxygen depletion near the sediment surface was below an apparent threshold concentration of 2–4 mg O2/L. Similarly, application of a two-source mixing model suggested that methanotrophic bacteria made the greatest contribution to profundal chironomid growth (0–70% of larval carbon) when the late-summer oxygen concentration dropped below ∼2 mg O2/L. Our study demonstrates that methane-derived carbon is an important, but often neglected, contribution to the flux of carbon through the food webs of many productive or dystrophic lakes.

Item Type:
Journal Article
Journal or Publication Title:
Ecology
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1100/1105
Subjects:
ID Code:
74795
Deposited By:
Deposited On:
29 Jul 2015 15:28
Refereed?:
Yes
Published?:
Published
Last Modified:
11 Feb 2020 08:36