Impacts of the Changing Global Environment at Nunavut?s Northern Frontier
Paleolimnological approach for examining carbon pathways in high latitude lake food webs
The arctic lake ecosystems are sensitive to environmental change, and under the ongoing climate change it is expected that the allochthonous carbon transport to such lake systems will increase. Allochthonous carbon affects many limnological properties and may alter the functionality of benthic food webs. In this study functionality and carbon sourcing of benthic chironomid communities are examined on spatiotemporal scales from paleoassemblages, through analysis of fossil remains of the chironomids. Stable isotopes are useful for tracing sources and cycling of organic matter, and have recently been succesfully applied to paleolimnological studies. Thus analytical methods include stable isotope analysis (C & N) of the chironomid remains, isotopic and elemental (C & N) composition of the sediment organic matter, paleopigment analysis and other supporting physicochemical and biological proxies. The taxonomic analysis of fossil chironomids is performed and functional feeding guilds are assigned accordingly. Methods are applied to surface sediment data to investigate the influence of various limnological and catchment variables to chironomid functionality and the understanding is further applied to down core analysis to trace long term changes in carbon dynamics and benthic food web functionality during Late Holocene (last ca. 4000 yrs).
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