Increased surface seawater pCO(2) in the eastern Bering Sea shelf: An effect of blooms of coccolithophorid Emiliania huxleyi?

摘要

Increased surface seawater pCO(2) observed in the eastern Bering Sea shelf ( long 168 degrees W - 160 degrees W+ADs- lat 54 degrees N - 68 degrees N) were examined in relation to blooms of the coccolithophorid Emiliania huxleyi, using data obtained from R/ V Mirai cruises once or twice annually ( August - October 1998 - 2002). A principal component analysis demonstrated that there are two spatial scales of pCO(2) variability associated with E. huxleyi blooms. One is a small- scale variation ( similar to 0.2 degrees in latitude), which shows a decrease of pCO(2) by 18 mu atm relative to surrounding waters. The other is a large- scale variation (similar to 10.0 degrees in latitude), with spatial gradient in pCO(2) of up to 250 mu atm. Detailed analyses show that the large- scale variation is associated with diatom blooms, while the small- scale variation is associated with coccolithophorid blooms with a calcification: photosynthesis +AD0- 1.0, and thus that seawater pCO(2) is affected by the composition of marine ecosystems and its response to climate variability. SST rise also contributed to increased pCO(2).