Assessing the effects of climate and volcanism on diatom and chironomid assemblages in an Andean lake near Quito, Ecuador

  • Neal Michelutti | nm37@queensu.ca Queen's University, Canada.
  • Jillian L. Lemmen Queen’s University, Canada.
  • Colin A. Cooke Government of Alberta, Canada.
  • William O. Hobbs Washington State Department of Ecology, United States.
  • Alexander P. Wolfe University of Alberta, Canada.
  • Joshua Kurek Queen’s University, Canada.
  • John P. Smol Queen’s University, Canada.

Abstract

The tropical Andes are undergoing climate changes that rival those occurring anywhere else on the planet, and are likely to have profound consequences for ecosystems. Paleolimnological investigations of remote mountain lakes can provide details of past environmental change, especially where monitoring data are absent. Here, we reconstruct fossil diatom and chironomid communities spanning the last several hundred years from an Andean lake located in an ecological reserve near Quito, Ecuador. Both diatoms and chironomids recorded assemblage shifts reflective of changing climate conditions. The diatoms are likely responding primarily to temperature-related limnological changes, recording an increase in the number of planktonic taxa in the most recent sediments. This change is consistent with warmer conditions that result in enhanced periods of thermal stratification, allowing planktonic species to proliferate. The chironomids appear to respond mainly to a change in precipitation regime, recording a greater number of terrestrial and semi-terrestrial taxa that have been transported to the lake. A thick tephra deposit at the base of the sediment core affected both diatom and chironomid assemblages. The diatoms registered a change in species composition highlighting the ability of certain taxa to rapidly colonize new environments. In contrast, the chironomids showed a marked drop in abundance immediately following the tephra, but no change in species composition. In both cases the ecological response was short-lived, illustrating the resiliency of the lake to return to baseline conditions following volcanic inputs.

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Author Biographies

Neal Michelutti, Queen's University
Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology
Jillian L. Lemmen, Queen’s University
Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology
Joshua Kurek, Queen’s University
Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology
John P. Smol, Queen’s University
Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology
Published
2015-12-30
Info
Issue
Section
Original Articles
Supporting Agencies
Natural Sciences and Engineering Research Council of Canada (NSERC), National Geographic Society (NGS)
Keywords:
Tropical Andes, Ecuador, paleolimnology, diatoms, Chironomids, climate change, Tephra, mercury.
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How to Cite
1.
Michelutti N, Lemmen JL, Cooke CA, Hobbs WO, Wolfe AP, Kurek J, Smol JP. Assessing the effects of climate and volcanism on diatom and chironomid assemblages in an Andean lake near Quito, Ecuador. J Limnol [Internet]. 2015Dec.30 [cited 2020Nov.30];75(2). Available from: https://www.jlimnol.it/index.php/jlimnol/article/view/jlimnol.2015.1323