HR: 16:30h
AN: B24A-05    [Abstracts]
TI: Algal Community Responses to Substratum Movement in Arctic Headwater Streams
AU: * Parker, S M
EM: parke003@bama.ua.edu
AF: University of Alabama, Department of Biological Sciences Box 870206, Tuscaloosa, AL 35487-0206 United States
AU: Huryn, A D
EM: huryn@bama.ua.edu
AF: University of Alabama, Department of Biological Sciences Box 870206, Tuscaloosa, AL 35487-0206 United States
AB: Nutrient availability, invertebrate grazing, and substratum movement are important factors affecting algal community structure in streams. We investigated the effects of substratum movement on algal communities of twenty headwater streams on the North Slope of Alaska. Substratum movement was measured indirectly using estimates of tractive forces and particle size distribution and directly using rocks marked in situ. Algae were sampled from natural and artificial substrata made from natural fiber ropes. In a pilot study of two streams with contrasting levels of substratum movement (low and high), we found that 23 out of 28 algal species were present in both streams. Total chlorophyll was more variable in the high substratum-movement stream (30.7 μg cm^-1 rope) than in the low substratum-movement stream (18.7 μg cm^-1 rope). Variability in total chlorophyll in the high substratum-movement stream was associated with flooding and related bed movement. Chlorophyll in the stable stream remained relatively constant. In the Arctic, structural attributes of algal communities colonizing artificial substrata in high substratum-movement streams are presumably regulated by abiotic factors such as abrasion associated with bed movement, while communities in low substratum-movement streams are controlled by biotic factors such as grazing.
DE: 9315 Arctic region
DE: 9901 NABS Student Award - Basic Research
SC: Biogeosciences [B]
MN: 2005 Joint Assembly