PERIPHYTON COMMUNITIES IN HEADWATER STREAMS OF DIFFERENT WATER CHEMISTRY IN THE CENTRAL APPALACHIAN MOUNTAINS

To examine impacts of acidification, we studied periphyton communities in three West Virginia streams whose mean pH varied from 4.2 to 7.8. We measured algal composition, cell densities, chlorophyll a, ash free dry weight, and areal and chlorophyll-specific production in the wint er and spring of 1993 and 1994. The most acidic stream had the lowest species richness and few diatoms and was dominated by a green-alga. Th e most alkaline stream had the highest species richness and was domina ted by Chlamydomonas. Chlorophyll a and ash free dry weight were signi ficantly lower in the most acidic stream. Areal production was not dif ferent between streams, whereas chlorophyll-specific production was hi ghest in the acidic stream.