In order to clarify the
role of biological activity in determining seasonal variations in carbonate
system in the western North Pacific, we have estimated the net community
production (NCP) at 10˚N, 20˚N, and 30˚N along 137˚E based on measurements of
dissolved inorganic carbon (DIC), 13C/12C of DIC, and
auxiliary hydrographic parameters. Sample seawaters in the surface/subsurface
layers were taken during five cruises conducted between July 2003 and July
2004. From November 2003 to February 2004, the calculated NCP was -21.2±13.1 mmol
m-2 d-1 at 30ºN and -1.7±15.2 mmol m-2 d-1
at 10ºN, where the negative value represents that the respiration exceeds the
biological production. From February 2004 to May 2004, the NCP was calculated
to be 25.8±19.2 mmol m-2 d-1 at 30˚N and 10.7±3.9 mmol m-2
d-1 at 10˚N. The present results showed a fairly good agreement with
those estimated earlier (13-54 mmol m-2 d-1 in 24-30˚N in
winter-spring, Ishii et al., 2001). The NCP was large as compared with the
other processes controlling surface carbonate system, although the
concentrations of macronutrients remained the lower levels during the annual
cycle.
Author: T. Takamura, M. Ishii, T. Midorikawa, A. Nakadate, et al (takamura at ees dot hokudai dot ac dot jp)
Filesize: 155.62 Kb