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Linking allochthonous dissolved organic matter and boreal lake sediment carbon sequestration: The role of light‐mediated flocculation
Author(s) -
von Wachenfeldt Eddie,
Sobek Sebastian,
Bastviken David,
Tranvik Lars J.
Publication year - 2008
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2008.53.6.2416
Subject(s) - dissolved organic carbon , flocculation , environmental chemistry , organic matter , sediment , sedimentation , total organic carbon , water column , phytoplankton , environmental science , lake ecosystem , chemistry , geology , oceanography , ecology , environmental engineering , ecosystem , nutrient , geomorphology , biology , organic chemistry
We measured flocculation of dissolved organic carbon (DOC) in the water from a humic lake (DOC = 14.9 mg C L ‐1 ) and from an adjacent mire (DOC = 25.7 mg C L ‐1 ), in in situ enclosure experiments with different light regimes. Light stimulated the formation of organic particles in both waters, and organic particle formation was observed at all incubation depths, even in the dark controls. Production of phytoplankton biomass was negligible, and allochthonous DOC was the most important precursor of the sinking particles. 8‐22% and 25‐ 60% of the loss of DOC in lake and mire water, respectively, could be accounted for by flocculation. Depthintegrated flocculation based on the enclosure experiments was 14.7 mg C m ‐2 d ‐1 . Lake‐water DOC concentration and water color has been increasing during the last decade, and sediment trap studies show that gross sedimentation of organic carbon also increased. Thus flocculation of allochthonous DOC, stimulated by light, constitutes a pathway for the sequestration of carbon in lake sediments.