CGRG Bibliography of Canadian Geomorphology
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Author : Douglas, M.S.V.; and Smol, J.P.
Date : 1992.
Title : The paleolimnological record from shallow ponds in the Canadian High Arctic
Publication : Paper presented at the 12th International Diatom Symposium, The Netherlands, August 30, 1992.
Issue :
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Abstract
Until recently, limnological and paleolimnological studies of high latitude sites were relatively uncommon, largely due to the inaccessibility of these regions. Although thousands of lakes and especially shallow ponds are common to the Arctic landscape, little baseline data exist. High latitude regions have now been identified as crucial reference sites for the study of global environmental change as they are sensitive to even small climatic changes. By examining the paleolimnological record of lakes and ponds, it is hoped that past environmental conditions in these regions will be established. This study examines the diatom stratigraphic profiles from several ponds located on Cape Herschel (78 37 N, 74 42 W). Cape Herschel is located on the east-central coast of Ellesmere Island, the northernmost island in the Canadian Arctic archipelago. It is a unique region in that there is 4 years of baseline physical, chemical and biological data for thenumerous (40+) ponds located on the rugged peninsula. These ponds are shallow (Zm < 20 - 50cm), and remain frozen to the bottom for 10 months of th year. Although one may first suspect that such sites could not preserve useful stratigraphic profiles (e.g., because of cryoturbation), we have several lines of evidence to suggest the contrary. Cores from the frozen sediments of these ponds were retrieved using a modified Lingston piston corer. The length of the core recovered and subsequent diatom analyses reveal that these ponds are stable bodies that have existed for lengthy periods of time. Marked species shifts appear in the stratigraphy. We use data from our taxonomic and autecologic investigations of current diatom assemblages to aid in our paleolimnological interpretation of the diatom stratigraphies. Due to the shallow nature of these ponds, no planktonic diatoms occur. Instead, th benthic diatom assemblages appear to be controlled bymicrohabitat availability. Early assemblages are dominated by a "Fragilaria" complex which is no longer present on the Cape. The recent history reveals the introduction of periphytic species such as Cymbella, Achnanthes, Nitzschia, possibly reflecting the vegetational development of the catchment. These data are used to interpret and decipher pond ontogeny in high latitude sites.
Bibliography of Canadian Geomorphology