Biomonitoring past salinity changes in an athalassic subarctic lake |
| |
| Authors: | R Pienitz I R Walker B A Zeeb J P Smol P R Leavitt |
| |
| Institution: | (1) Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University, K7L 3N6 Kingston, Ontario, Canada;(2) Present address: Department of Biology, Okanagan University College, V1Y 4X8 Kelowna, British Columbia, Canada;(3) Department of Zoology, University of Alberta, T6G 2E9 Edmonton, Alberta, Canada |
| |
| Abstract: | A short sediment core was taken from a small saline lake located on an intermontane plateau in the central Yukon Territory,
Canada. In July 1990, chemical analyses indicated that, although the lake was shallow (Zmax=1.1 m), it was also chemically stratified, with hyposaline (9.9 to 10.0 g L−1) surface waters and slightly mesosaline (22.0 g L−1) deeper waters. The surface water was dominated by Na+ and HCO
3
−
. To our knowledge, this is the northernmost athalassic saline lake yet recorded.
Quantification of algal (diatom, chrysophyte, and pigment) and invertebrate (chironomid, ceratopogonid, andChaoborus) fossils at four stratigraphic levels indicated that the lake sediments preserved numerous biological indicators that could
be used to infer recent lake development. Many of the taxa are found in other athalassic salt lakes. The most striking stratigraphic
change was a remarkable drop in the species richness of diatoms and invertebrates in the recent sediments, which parallels
the elimination of species characteristic of less saline conditions. Halophilous taxa dominate the most recent sediments,
indicating the development of more saline conditions. At the same time, a significant shift in chrysophyte cyst composition
was observed. Fossil carotenoids and chlorophylls indicated a decrease in total algal abundance in recent sediments, as green
and blue-green algae replaced diatoms and chrysophytes. Together, these paleolimnological data suggest a recent shift to drier
conditions or increased evaporation in the central Yukon Territory. |
| |
| Keywords: | paleolimnology saline lakes athalassic lakes diatoms chrysophytes pigments Yukon Territory subarctic |
| 本文献已被 SpringerLink 等数据库收录！ |
|
