Open AccessDynamic processing of DOM: Insight from exometabolomics, fluorescence spectroscopy, and mass spectrometry
Author(s) -
Smith H. J.,
Tigges M.,
D'Andrilli J.,
Parker A.,
Bothner B.,
Foreman C. M.
Publication year - 2018
Publication title -
limnology and oceanography letters
Language(s) - English
Resource type - Journals
ISSN - 2378-2242
DOI - 10.1002/lol2.10082
Subject(s) - dissolved organic carbon , biogeochemical cycle , carbon cycle , glacier , environmental chemistry , organic matter , carbon fibers , environmental science , chemistry , oceanography , ecosystem , ecology , geology , biology , geomorphology , materials science , organic chemistry , composite number , composite material
Dissolved organic matter (DOM) in freshwater environments is an important source of organic carbon, supporting bacterial respiration. Frozen environments cover vast expanses of our planet, with glaciers and ice‐sheets storing upwards of 6 petagrams of organic carbon. It is generally believed that DOM liberated from ice stimulates downstream environments. If true, glacial DOM is an important component of global carbon cycling. However, coupling the release of DOM to microbial activity is challenging due to the molecular complexity of DOM and the metabolic connectivity within microbial communities. Using a single environmentally relevant organism, we demonstrate that processing of compositionally diverse DOM occurs, but, even though glacially derived DOM is chemically labile, it is unable to support sustained respiration. In view of projected changes in glacier DOM export, these findings imply that biogeochemical impacts on downstream environments will depend on the reactivity and heterogeneity of liberated DOM, as well as the timescale.