Esposito, RheaÌý1Ìý;ÌýHorn, ShannonÌý2Ìý;ÌýMcKnight, DianeÌý3Ìý;ÌýCox, MichaelÌý4Ìý;Grant, M.Ìý5Ìý;ÌýSpaulding, SarahÌý6Ìý;ÌýDoran, PeterÌý7Ìý;ÌýStanish, LeeÌý8
8ÌýPresenting Author
1Ìý±õ±·³§°Õ´¡´¡¸é
2Ìý
3Ìý±õ±·³§°Õ´¡´¡¸é
4Ìý
5Ìý
6Ìý±õ±·³§°Õ´¡´¡¸é, USGS
7ÌýUniversity of Illinois at Chicago
8Ìý±õ±·³§°Õ´¡´¡¸é
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.
Doran, P. T., et al. 2002. Antarctic climate cooling and terrestrial ecosystem response: Nature, v. 415, p. 517–520.