Longitudinal Patterns in Algal Abundance and Species Distribution In Meltwater Streams In Taylor Valley, Southern Victoria Land, Antarctica
- John C. Priscu
Published Online: 16 MAR 2013
Copyright 1998 by the American Geophysical Union.
Ecosystem Dynamics in a Polar Desert: the Mcmurdo Dry Valleys, Antarctica
How to Cite
Mcknight, D. M., Alger, A., Tate, C., Shupe, G. and Spaulding, S. (1998) Longitudinal Patterns in Algal Abundance and Species Distribution In Meltwater Streams In Taylor Valley, Southern Victoria Land, Antarctica, in Ecosystem Dynamics in a Polar Desert: the Mcmurdo Dry Valleys, Antarctica (ed J. C. Priscu), American Geophysical Union, Washington, D. C.. doi: 10.1029/AR072p0109
- Published Online: 16 MAR 2013
- Published Print: 28 JAN 1998
Print ISBN: 9780875908991
Online ISBN: 9781118668313
- Desert ecology—Antarctica—McMurdo Dry Valleys
The abundance and distribution of algal mats were studied in three streams flowing into Lake Fryxell, located in lower Taylor Valley. Algal mats were most abundant at sites which have moderate gradients and streambeds composed of large cobbles arranged in a flat stone pavement through periglacial processes. Algal abundance was less at high gradient and deltaic sites. Most of the length of the three streams can be characterized as “large cobble” and the total chlorophyll-a in each stream was estimated from measurements made at representative sites. Four algal mat types were used to characterize the stream biota. Black-, orange-, and green-colored algal mat types occurred at most sites, but red-colored mats occurred in only one of the streams. At all sites, black-colored mats were found near the channel margins and green-colored mats were found on the underside of rocks in the main channel. Orange- and red-colored mats occurred in flowing water habitats, either in the main channel or in rivulets draining the hyporheic zone at the stream margins. Thus similarities in physical characteristics of the stream habitat appeared to determine the occurrence of the different algal mats rather than differences in water quality. The species composition of the different mat types was consistent among sites. The black-colored algal mats were dominated by Nostoc sp., with a low average evenness of 0.13±0.07. The green-colored algal mats were also essentially unialgal, composed chiefly of Prasiola calophylla or P. crispa, and having a low average evenness of 0.17±0.10. The orange- and red-colored algal mats were composed of species of Oscillatoria and Phormidium and were much more diverse in composition, with average evenness values of 0.55±0.16 and 0.48±0.21, respectively. The orange- and red-colored mats also had a high degree of intrasite heterogeneity.