Kelly, Andrew and Jones, Roger and Grey, Jonathan (2004) Stable isotope analysis provides fresh insights into dietary separation between Chironomus anthracinus and C. plumosus. Journal of the North American Benthological Society, 23 (2). pp. 287-296. ISSN 0887-3593
Full text not available from this repository.Abstract
We used stable isotope analysis to investigate dietary differences between 2 sympatric species of tubicolous chironomid larvae, Chironomus plumosus and C. anthracinus, from the profundal sediments of 6 eutrophic lakes in the UK and Germany. We found striking variation between lakes in both δ13C (−29.8 to −56.3‰) and δ15N (−7.8 to 14.7‰) in the 2 chironomid species. Moreover, C. plumosus was consistently depleted in both 13C and 15N relative to C. anthracinus. Our data support previous reports of interspecific dietary variations between the 2 species, which suggest niche separation partly on the basis of diet. However, reported differences in the feeding modes of the 2 species could not explain the extreme 13C- and 15N-depletion observed in chironomid larvae from several of the lakes. We suggest that the low δ13C signatures result from the ingestion of methanotrophic bacteria and subsequent incorporation of biogenic methane-derived C. Further, the chironomid larvae enhance methanotrophic activity via bioturbation of the surrounding sediment. Significant isotope differences between the 2 species may result from their variable tube morphologies or physiology.