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Metabolism of mineral‐sorbed organic matter and microbial lifestyles in fluvial ecosystems
Author(s) -
Hunter William Ross,
Niederdorfer Robert,
Gernand Anna,
Veuger Bart,
Prommer Judith,
Mooshammer Maria,
Wanek Wolfgang,
Battin Tom J
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl067719
Subject(s) - mineralization (soil science) , environmental chemistry , biogeochemical cycle , organic matter , biofilm , dissolved organic carbon , ecosystem , chemistry , fluvial , microbial metabolism , aquatic ecosystem , total organic carbon , sorption , ecology , nitrogen , bacteria , geology , biology , organic chemistry , adsorption , paleontology , structural basin
In fluvial ecosystems mineral erosion, carbon (C), and nitrogen (N) fluxes are linked via organomineral complexation, where dissolved organic molecules bind to mineral surfaces. Biofilms and suspended aggregates represent major aquatic microbial lifestyles whose relative importance changes predictably through fluvial networks. We tested how organomineral sorption affects aquatic microbial metabolism, using organomineral particles containing a mix of 13 C, 15 N‐labeled amino acids. We traced 13 C and 15 N retention within biofilm and suspended aggregate biomass and its mineralization. Organomineral complexation restricted C and N retention within biofilms and aggregates and also their mineralization. This reduced the efficiency with which biofilms mineralize C and N by 30% and 6%. By contrast, organominerals reduced the C and N mineralization efficiency of suspended aggregates by 41% and 93%. Our findings show how organomineral complexation affects microbial C:N stoichiometry, potentially altering the biogeochemical fate of C and N within fluvial ecosystems.