Stable isotope analysis of benthic fauna and their food sources in boreal lakes

作者：Premke Katrin^*; Karlsson Jan; Steger Kristin; Gudasz Cristian; von Wachenfeldt Eddie; Tranvik Lars J

来源：Journal of the North American Benthological Society, 2010, 29(4): 1339-1348.

DOI：10.1899/10-002.1

• autochthonous
• allochthonous
• dissolved organic C
• stable isotopes
• boreal lakes

The origin of organic C supporting zoobenthic communities in 8 boreal lakes with different concentrations of dissolved organic C (DOC) was assessed by stable-isotope analysis. Profundal zoobenthos was depleted in (13)C compared to littoral zoobenthos, and this difference increased with decreasing DOC concentration. The delta(13)C of littoral zoobenthos suggested reliance on benthic algae, whereas depleted (13)C of profundal zoobenthos could be explained by contributions from allochthonous and autochthonous C sources. In deeper lakes, profundal zoobenthos diets also included C processed by methanotrophic bacteria. Littoral zoobenthos delta(13)C decreased with increasing DOC concentration in the lake water. Our results suggest that littoral benthic fauna are mainly supported by benthic algae in low-DOC lakes and by phytoplankton and allochthonous organic C in high-DOC lakes and that this difference is a result of light absorbance and energy supply by allochthonous organic C. Increasing allochthonous DOC inputs, as expected in a warmer and wetter climate, might reduce benthic algal production and alter the organic C base for benthic food webs in lake ecosystems.

• 出版日期2010-12