Use of Chironomidae for paleolimnological reconstructions in Northern Patagonia

What is it about?

Chironomid larvae are a paleo-proxy because in addition to their environmental sensitivity, their chitinous cephalic capsules are well preserved in lacustrine sediments, allowing their recovery and identification. We analysed the effects of a recent volcanic eruption (Puyehue-Cordón Caulle Volcanic Complex 2011) on the chironomid community based on their cephalic remains accumulated following the ash deposition process. Two pulses of ash deposition were distinguished: a first stage comprising the immediate coarse ash fall and a delayed finer volcanic deposition. An abrupt decline in chironomid taxa and their densities were noted during the first coarse pulse, followed by an attempt of community recovery through the second finer pulse, characterised by main taxa turnover, observing an alternative community functional structure. Based on these results and comparing with past volcanic depositions, we observed different chironomid responses according to their particular ecological habits, and we noted possible percolation effects, mainly in coarse tephras, and probably a delayed record of very low abundance taxa.

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