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Antarctic climate cooling and response of diatoms in glacial meltwater streams
Author(s) -
Esposito R. M. M.,
Horn S. L.,
McKnight D. M.,
Cox M. J.,
Grant M. C.,
Spaulding S. A.,
Doran P. T.,
Cozzetto K. D.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl025903
Subject(s) - diatom , meltwater , streams , glacial period , dominance (genetics) , environmental science , oceanography , ecology , geology , biology , geomorphology , computer network , computer science , biochemistry , gene
To understand biotic responses to an Antarctic cooling trend, we analyzed diatom samples from glacial meltwater streams in the McMurdo Dry Valleys, the largest ice‐free area in Antarctica. Diatoms are abundant in these streams, and 24 of 40 species have only been found in the Antarctic. The percentage of these Antarctic diatom species increased with decreasing annual stream flow and increasing harshness of the stream habitat. The species diversity of assemblages reached a maximum when the Antarctic species accounted for 40–60% of relative diatom abundance. Decreased solar radiation and air‐temperatures reduce annual stream flow, raising the dominance of these Antarctic species to levels above 60%. Thus, cooling favors the Antarctic species, and lowers diatom species diversity in this region.