Short-term environmental changes in Lake Morenito (41°S, 71°W, Patagonia, Argentina) from the analysis of sub-fossil chironomids

Changes of sub-fossil chironomid assemblages associated with volcanic sediment deposition in an Andean lake (38°S), Chile

“…Previous investigations report changes in chironomid diversity during tephra depositions (Massaferro & Corley 1998, Massaferro et al 2005, and we suggest such differences could be explained by the characteristics of the tephra.…”

“…Their results also indicate the complete absence of chironomid fauna within the tephra layers and a rapid recovery of diversity and equitability to their predisturbance levels once the tephra deposition had terminated. Massaferro et al (2005) found evidence of tephra impacts on chironomid fauna in Lake Morenito (41º S, 71º W). The abundance and diversity of chironomids decreased drastically along with organic content during episodes of volcanic sediment deposition.…”

“…Human intervention in the lake by dam construction and a volcanic event in 1960 provoked increased diversity and the reappearance of Ablabesmyia, Paracladopelma, Phaenopsectra, and Dicrotendipes taxa. Massaferro et al (2005) suggest that the increase in Chironomus towards the upper part of the core and the decline of Tanytarsus gr., together with increased OM, could reflect more productive conditions within the lake. Nevertheless, they suggest that, due to the synchronicity of both the natural (1960 volcanic event) and anthropic (dam construction) impacts, it is difficult to track a direct cause and effect relationship for the changes in the chironomid assemblages.…”

“…Only a few references address the impact of volcanic eruptions on chironomid assemblages and other aquatic biota in South America (Massaferro & Corley 1998, Massaferro et al 2005, although Eastwood et al (2002) found that volcanic eruptions can have substantial impacts on natural ecosystems and that volcanic depositions provide an opportunity to evaluate species interactions and ecosystem resilience (Lotter & Birks 1993, Barker et al 2000.…”

“…Heinrichs et al (1999) reported changes in chironomid assemblages at Kilpoola Lake (British Columbia) after the deposition of an ash layer, and Tsukada (1967) found decreased abundance of Tanytarsus genuinus after two events of volcanic sediment deposition in Lake Nojiri, Japan. Recently, Massaferro et al (2005) used chironomid assemblages to reveal short term environmental changes in Lake Morenito of the Argentinean Patagonia (41º S, 71º W), with volcanism being the most important factor affecting the chironomids.…”