Water chemistry and periphyton in an alpine wetland

Abstract

Remote high elevation sites are thought to be good sites to monitor global change and anthropogenic effects on ecosystems. This study was conducted during 1987–1990 in a high elevation wetland (3593 m) located in the Green Lakes Valley, Front Range, Colorado (USA). Salix spp. was the dominant riparian species in this 2 ha. wetland. Small shallow pools ( K+ + Na+; dominant anions were SO inf4 sup−2 ≫ HCO inf3 sup− > NO inf3 sup− ≫ Cl−. Nutrient limitation by P was demonstrated once using nutrient diffusing substrata. No limitation could be shown for NO inf3 sup− , HCO inf3 sup− , or Fe+EDTA. Slow colonization rates of periphyton on tiles were attributed to low temperatures and/or ultraviolet radiation. However, interannual differences in biomass on tiles were as much as 300% after 35 days. A minimum of 16–54 samples would be needed to detect a significant interannual change in biomass on tiles after 35 days assuming that the extreme case for periphyton patchiness. Global climate change is likely to affect discharge and water temperature in this wetland which hill have direct and indirect affects on population dynamics and ecosystem function.