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Estimated net community production during the summertime at the SEATS time‐series study site, northern South China Sea: Implications for nitrogen fixation
Author(s) -
Chou WenChen,
Chen YuhLing Lee,
Sheu David D.,
Shih YungYen,
Han ChiaAn,
Cho Chung Lung,
Tseng ChunMao,
Yang YiingJang
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl025365
Subject(s) - trichodesmium , environmental science , diazotroph , nitrogen fixation , nitrogenase , new production , drawdown (hydrology) , primary production , plankton , nitrogen , cyanobacteria , oceanography , environmental chemistry , nutrient , ecology , biology , geology , phytoplankton , chemistry , ecosystem , genetics , geotechnical engineering , organic chemistry , bacteria , aquifer , groundwater
The continuous summertime drawdown of normalized dissolved inorganic carbon has been observed repeatedly in the mixed‐layer at the South East Asia Time‐series Study (SEATS) site, northern South China Sea (SCS) between March 2002 and November 2004. Mass balance calculation reveals that a net community production (NCP) of −4.47 mmolC m −2 day −1 is responsible for this drawdown. Nonetheless, bioavailable nitrogen (N bio ) from atmospheric deposition, vertical diffusion, and N 2 ‐fixation by Trichodesmium and Richelia together could only account for ∼55% of N bio required for the calculated NCP. Unicellular cyanobacteria, which are identified unambiguously by the presence of nitrogenase genes ( nifH ) in 1–10 μ m fraction of planktons collected at SEATS, may account for the N bio deficit. Our results, thus, support the potential importance of unicellular cyanobacteria in providing an additional N bio source in oligotrophic waters such as the SCS.