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Controls of δ 13 C‐DIC in lakes: Geochemistry, lake metabolism, and morphometry
Author(s) -
Bade Darren L.,
Carpenter Stephen R.,
Cole Jonathan J.,
Hanson Paul C.,
Hesslein Raymond H.
Publication year - 2004
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.2004.49.4.1160
Subject(s) - dissolved organic carbon , alkalinity , autotroph , environmental chemistry , respiration , total inorganic carbon , environmental science , primary production , chlorophyll a , carbon cycle , photosynthesis , hydrology (agriculture) , ecosystem , ecology , chemistry , carbon dioxide , geology , biology , botany , paleontology , geotechnical engineering , organic chemistry , bacteria
We investigated δ 13 carbon (C)‐dissolved inorganic carbon (DIC) values in 72 lakes from diverse regions using literature data as well as new measurements for 32 lakes. δ 13 C‐DIC varied broadly among lakes from ~31 to +2.6‰. This variation of surface‐water δ 13 C‐DIC among lakes is greater than the seasonal variation within most lakes. Several statistical models account for a large portion of the interlake variation and indicate that geochemical (e.g., DIC, pH, alkalinity) and morphometric (area) variables are important, whereas biological (e.g., gross primary productivity [GPP], respiration [R], chlorophyll a) variables are generally not significant. A process‐based model including gas exchange with the atmosphere, inorganic carbon speciation, and ecosystem metabolism was also constructed. The model provides a reasonable fit to the data for lakes, in which respiration exceeded GPP (heterotrophic lakes; 75% of lakes sampled). Lakes for which GPP exceeded respiration (autotrophic) were not fit well by the process‐based model. The data and models indicate that metabolism creates substantial variation in δ 13 C‐DIC around the potential δ 13 C‐DIC that is set by geochemical factors of the watershed.