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Organic Carbon Processing During Transport Through Boreal Inland Waters: Particles as Important Sites
Author(s) -
Attermeyer Katrin,
Catalán Núria,
Einarsdottir Karolina,
Freixa Anna,
Groeneveld Marloes,
Hawkes Jeffrey A.,
Bergquist Jonas,
Tranvik Lars J.
Publication year - 2018
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2018jg004500
Subject(s) - dissolved organic carbon , environmental chemistry , aquatic ecosystem , environmental science , particulates , total organic carbon , organic matter , ecosystem , particulate organic carbon , carbon cycle , peat , degradation (telecommunications) , chemistry , ecology , phytoplankton , nutrient , biology , telecommunications , computer science
The degradation and transformation of organic carbon (C) in inland waters result in significant CO 2 emissions from inland waters. Even though most of the C in inland waters occurs as dissolved organic carbon (DOC), studies on particulate organic carbon (POC) and how it influences the overall reactivity of organic C in transport are still scarce. We sampled 30 aquatic ecosystems following an aquatic continuum including peat surface waters, streams, rivers, and lakes. We report DOC and POC degradation rates, relate degradation patterns to environmental data across these systems, and present qualitative changes in dissolved organic matter and particulate organic matter during degradation. Microbial degradation rates of POC were approximately 15 times higher compared to degradation of DOC, with POC half‐lives of only 17 ± 3 (mean ± SE) days across all sampled aquatic ecosystems. Rapid POC decay was accompanied by a shift in particulate C:N ratios, whereas dissolved organic matter composition did not change at the time scale of incubations. The faster degradation of the POC implies a constant replenishment to sustain natural POC concentrations. We suggest that degradation of organic matter transported through the inland water continuum might occur to a large extent via transition of DOC into more rapidly cycling POC in nature, for example, triggered by light. In this way, particles would be a dominant pool of organic C processing across the boreal aquatic continuum, partially sustained by replenishment via flocculation of DOC.