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The differing biogeochemical and microbial signatures of glaciers and rock glaciers
Author(s) -
Fegel Timothy S.,
Baron Jill S.,
Fountain Andrew G.,
Johnson Gunnar F.,
Hall Ed K.
Publication year - 2016
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2015jg003236
Subject(s) - glacier , meltwater , glacial period , geology , biogeochemistry , physical geography , biogeochemical cycle , oceanography , environmental science , hydrology (agriculture) , geomorphology , environmental chemistry , chemistry , geography , geotechnical engineering
Abstract 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, metals, nutrients, complexity of dissolved organic matter (DOM), and bacterial richness and diversity) differed significantly between glacier and rock glacier meltwaters, while other characteristics (Ca 2+ , Fe 3+ , SiO 2 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 (NH 4 + ) and nitrate (NO 3 − ) concentrations, and 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.