Premium
Dissolved organic carbon export and internal cycling in small, headwater lakes
Author(s) -
Stets Edward G.,
Striegl Robert G.,
Aiken George R.
Publication year - 2010
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2010gb003815
Subject(s) - dissolved organic carbon , watershed , cycling , hydrology (agriculture) , carbon cycle , structural basin , drainage basin , environmental science , context (archaeology) , total organic carbon , geology , oceanography , ecology , environmental chemistry , ecosystem , geomorphology , chemistry , geography , forestry , cartography , biology , paleontology , geotechnical engineering , machine learning , computer science
Carbon (C) cycling in freshwater lakes is intense but poorly integrated into our current understanding of overall C transport from the land to the oceans. We quantified dissolved organic carbon export (DOC X ) and compared it with modeled gross DOC mineralization (DOC R ) to determine whether hydrologic or within‐lake processes dominated DOC cycling in a small headwaters watershed in Minnesota, USA. We also used DOC optical properties to gather information about DOC sources. We then compared our results to a data set of approximately 1500 lakes in the Eastern USA (Eastern Lake Survey, ELS, data set) to place our results in context of lakes more broadly. In the open‐basin lakes in our watershed ( n = 5), DOC X ranged from 60 to 183 g C m −2 lake area yr −1 , whereas DOC R ranged from 15 to 21 g C m −2 lake area yr −1 , emphasizing that lateral DOC fluxes dominated. DOC X calculated in our study watershed clustered near the 75th percentile of open‐basin lakes in the ELS data set, suggesting that these results were not unusual. In contrast, DOC X in closed‐basin lakes ( n = 2) was approximately 5 g C m −2 lake area yr −1 , whereas DOC R was 37 to 42 g C m −2 lake area yr −1 , suggesting that internal C cycling dominated. In the ELS data set, median DOC X was 32 and 12 g C m −2 yr −1 in open‐basin and closed‐basin lakes, respectively. Although not as high as what was observed in our study watershed, DOC X is an important component of lake C flux more generally, particularly in open‐basin lakes.