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Differences in feeding behaviour among Chironomus species revealed by measurements of sulphur stable isotopes and cadmium in larvae.

Proulx, Isabelle; Hare, Landis (2014). Differences in feeding behaviour among Chironomus species revealed by measurements of sulphur stable isotopes and cadmium in larvae. Freshwater Biology , vol. 59 , nº 1. p. 73-86. DOI: 10.1111/fwb.12247.

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Résumé

1. We set out to determine the feeding behaviours of 15 Chironomus species collected from 16 boreal forest lakes by measuring cadmium (Cd) and stable isotopes of carbon (C), nitrogen (N) and sulphur (S) in larvae.

2. Measurements of S stable isotopes and Cd discriminated between Chironomusspecies that feed mainly on oxic particles from those that feed mainly on anoxic particles. Our results suggest that C. dilutus, C. entis, C. plumosus and C. staegerifeed mainly on oxic particles (in the water column, in sediment or both), whereasC. anthracinus, C. bifurcatus, C. cucini, C. decorus‐group sp. 2, C. harpi,C. nr. atroviridis (sp. 2i), C. ochreatus, C. spp. NAI‐NAIII and C. ‘tigris’ feed mainly on anoxic sediments.

3. In our study lakes, larval C isotopic signatures were relatively high, which suggests that they feed little on methanotrophic bacteria. Although larval C and N signatures differed between some sympatric Chironomus species, these differences were not consistent among lakes. The absence of a trend among lakes suggests that lake‐specific factors determine larval C and N signatures.

4. Differences in feeding habits and Cd concentrations among sympatric (cohabiting) Chironomus species suggest that pooling them in ecological, palaeolimnological or ecotoxicological studies could obscure trends in nature, thereby limiting their use as monitors of climate change or pollution.

Type de document: Article
Mots-clés libres: cadmium; Chironomus species; feeding behaviour; lakes; stable isotopes
Centre: Centre Eau Terre Environnement
Date de dépôt: 19 oct. 2018 13:30
Dernière modification: 19 oct. 2018 13:30
URI: http://espace.inrs.ca/id/eprint/5627

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