What midges can tell us about climate
Non-biting midges (chironomids) are common organisms in many sources of freshwater, ranging from high-altitude glacier streams to the water-lily ponds in the Museum’s botanical garden. At EECRG, midges are at the focus of a major research project on climate change, ecology and improved methodology.
A widely-used method of reconstructing past temperatures is to core sediments from freshwater lakes. Sediments reveal numerous animal and plant remains, including those of midges. The distribution of individual midge species is mostly governed by temperature. and the species composition in the sediments can tell us how warm or cold it has been at different times in the past. This is now a well-known method, which provides material for several scientific publications every year.
When temperature reconstructions are compared among many sites, however, the results are often larger than expected from local variations in climate. Hence, our research at EECRG focuses on inferring past climates from midges and at the same time on method improvements.
We examine patterns in the vertical (down-core in lake sedimentary deposits) and horizontal (between-lake) changes in biota from lakes at Bylot Island (Arctic Canada) and Spitsbergen (Arctic Norway). The lakes are positioned along a gradient with the oldest lakes facing the sea and the youngest facing glaciers. We focus on developing a better understanding of lake conditions during early lake evolution in newly formed landscapes and their influence on aquatic biota. The research focuses on understanding how environmental conditions shape the community structure in cold habitats. This may aid in understanding future responses to environmental change of northern ecosystems.
We also investigate the climate history of Bylot Island and Spitsbergen by use of fossil midges. Paleoclimate records from Bylot Island and Spitsbergen, where one is situated at the northern limit of the North Atlantic Current, can potentially provide valuable information on the influence of the North Atlantic Current on North Atlantic climates.
Main research focus of project Succession of aquatic invertebrates in recently deglaciated terrain: mapping the magnitude and impact of climate change (AQUACLIM):
- Investigate the lake development and how the macro-invertebrate faunal succession and distribution are influenced by the primary physical, chemical, and biological factors
- Investigate the no-analogue problem in palaeoclimatic reconstructions
- Investigate the climate history of Svalbard and Bylot Island
- Predict the possible impact of a climate warming on high latitude ecosystems
- Survey the aquatic fauna of Bylot Island and Svalbard
Côté, G., Pienitz, R., Velle, G. and Muir. 2010. Impact of geese on the limnology of lakes and ponds from Bylot Island (Nunavut, Canada). International Review of Hydrobiology 95: 105-129
Larocque, I., Velle, G., and Rolland, N. 2010. Effect of removing small (<150 µm) chironomids on inferring temperature in cold lakes. Journal of paleolimnology 44: 709-719. DOI 10.1007/s10933-009-9313-z
Velle, G., Bjune, A.E., Larsen, J., Birks, H.J.B. 2010. Holocene climate and environmental history of Brurskardstjørni, a lake in the catchment of Øvre Heimdalsvatn, south-central Norway. Hydrobiologia 642: 13-34
Kernan, M., Ventura, M., Bitusik, P., Brancelj, A., Clarke, G., Velle, G., Raddum, G., Stuchlik, E., Catalan, J. 2009. Regionalisation of remote European mountain lake ecosystems according to their biota: environmental vs. geographical patterns. Freshwater Biology 24: 2470-2493