Alpine stream diversity is due in part to different hydrological sources including snowpack, surface glaciers, and rock glaciers; climate change threatens to homogenize these sources. Surprisingly little is understood about algal communities in these stream types. We characterized algal communities and water chemistry among ten alpine streams from these sources in the Teton Range, Wyoming, USA. Late summer sampling (2019-2021) included diatoms, anions, cations, and water quality parameters. Data were analyzed using one- and two-way analysis of variance, principal component analysis, and nonmetric multidimensional scaling. There were statistically significant differences among some or all hydrologic sources for temperature, dissolved oxygen, conductivity, bicarbonate, calcium, and sulfate; however, there were no significant annual variation within each stream type. Icy seeps were characterized by the highest conductivity (mean 123.23 uS/cm) associated with high calcium, magnesium, and potassium concentrations. Icy seeps had moderate diatom densities (mean 409 cells/mm2 ) and low diversity (mean 12) dominated by upright Gomphonema spp. Surface glacier-fed streams had the lowest conductivity (mean 5.50 uS/cm) and lowest streambed stability. Diatom densities and species richness were lowest in surface glacier-fed streams (mean 50 cells/mm2 and mean 11, respectively). Snowmelt-fed streams were characterized by high temperature, highest diatom densities (mean 1,570 cells/mm2 ), and highest species richness (mean 21). Both surface glacier and snowmelt-fed sites were dominated by Hannaea arcus, Odontidium mesodon, and Encyonema spp. This research centers around the valuable baseline data describing little-known algal communities of alpine streams representing a heterogeneity of hydrologic sources and will be vital to monitoring change as the climate warms.
alpine stream, algal communities, Teton range, diatom
Weld, Shannon. "Diatom Response to Different Hydrologic Sources in Alpine Streams: A Teton Range Case Study." (2022). https://digitalrepository.unm.edu/wr_sp/193