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Importance of Considered Organic Versus Inorganic Source of Carbon to Lakes for Calculating Net Effect on Landscape C Budgets
Author(s) -
Lu Weiqi,
Wang Shilu,
Yeager Kevin M.,
Liu Fang,
Huang Qiangsheng,
Yang Yuxue,
Xiang Peng,
Lü Yingchun,
Liu Congqiang
Publication year - 2018
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2017jg004159
Subject(s) - carbon cycle , terrestrial ecosystem , total inorganic carbon , total organic carbon , environmental science , carbon fibers , context (archaeology) , ecosystem , dissolved organic carbon , soil carbon , environmental chemistry , primary production , drainage basin , carbon dioxide , hydrology (agriculture) , ecology , chemistry , soil science , soil water , geology , geography , biology , composite number , paleontology , materials science , cartography , geotechnical engineering , composite material
Lakes and reservoirs transform, emit, and bury carbon that is exported from land and are thus significant components of terrestrial carbon budgets. Their significance is often assessed by integrating these water bodies into terrestrial primary production. However, the transfer of inorganic carbon (IC) is likely a sticking point for these integrations because IC is not part of net ecosystem production. Here we integrated carbon evasion and organic carbon (OC) burial in a lake in the context of inorganic and OC cycling in a karst catchment from a system perspective. The lake emitted carbon dioxide (CO 2 ) and buried OC at rates of 1.0 ± 0.2 and 0.9 ± 0.2 g C m −2 a −1 , respectively, approximately equaling 13% and 11% of catchment net ecosystem production, respectively. These proportions represent significant influences on terrestrial carbon budgets, given an organic origin. However, catchment carbon export is dominated by IC that is derived from carbonates dissolved by soil CO 2 . Lake CO 2 evasion accounts for less than 0.1% of soil CO 2 efflux, suggesting little potential in significantly altering terrestrial carbon budgets. This comparison indicates the significance of aquatic CO 2 evasion, requiring an adjustment of terrestrial carbon budgets to recognize their dependence on carbon origins. The significance may be overstated if inorganic origin is ignored. Our study suggests that a careful reassessment of the significance of CO 2 evasion and OC burial in freshwater ecosystems to local and global carbon budgets, with full consideration of their sources, is necessary and pressing.