The differing biogeochemical and microbial signatures of glaciers and rock glaciers

Product Type: 

Journal Article

Year: 

2016

Author(s): 

Fegel T.S., J.S. Baron, A.G. Fountain, G.F. Johnson, E.K. Hall

Suggested Citation: 

Fegel T.S., J.S. Baron, A.G. Fountain, G.F. Johnson, E.K. Hall. 2016. The Differing Biogeochemical and Microbial Signatures of Glaciers and Rock Glaciers. Journal of Biogeophysical Research-Biogeosciences 121: 919-932. DOI: 10.1002/2015JG003236

Glaciers and rock glaciers supply water and bioavailable nutrients to headwater mountain lakes and streams across all regions of the American West. Here we present a comparative study of the metal, nutrient, and microbial characteristics of glacial and rock glacial influence on headwater ecosystems in three mountain ranges of the contiguous U.S.: The Cascade Mountains, Rocky Mountains, and Sierra Nevada. Several meltwater characteristics (water temperature, conductivity, pH, heavy metals, nutrients, complexity of dissolved organic matter (DOM), and bacterial richness and diversity) differed significantly between glacier and rock glacier meltwaters, while other characteristics (Ca2+, Fe3+, SiO2 concentrations, reactive nitrogen, and microbial processing of DOM) showed distinct trends between mountain ranges regardless of meltwater source. Some characteristics were affected both by glacier type and mountain range (e.g. temperature, ammonium (NH4+) and nitrate (NO3- ) concentrations, bacterial diversity). Due to the ubiquity of rock glaciers and the accelerating loss of the low latitude glaciers our results point to the important and changing influence that these frozen features place on headwater ecosystems.

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