Gtf. Wong et al., The Kuroshio edge exchange processes (KEEP) study - an introduction to hypotheses and highlights, CONT SHELF, 20(4-5), 2000, pp. 335-347
The Kuroshio edge exchange processes (KEEP) study is a multidisciplinary st
udy on the internal cycling of material, especially carbon, within the East
China Sea Shelf and the exchange of material between this Shelf and its ad
joining Kuroshio. The project has been ongoing since 1989. The East China S
ea Shelf is a net sink of atmospheric carbon dioxide. Rich supplies of nutr
ients. mostly from the upwelling of the Kuroshio Subsurface Water and, to a
lesser extent, from the riverine discharges, notably from the Changjiang,
sustain a high primary production (550 mg C m(-2) d(-1)) on the Shelf and h
elp the draw down of carbon dioxide. The sum of the demands for organic car
bon for sustaining the observed bacterial production in the water column an
d the rate of sulfate reduction in the sediments of this Shelf appears to e
xceed its primary production. This suggests that a large fraction of the ph
otosynthetically fixed carbon is recycled effectively within the Shelf. How
ever, a comprehensive and definitive carbon budget for the Shelf cannot yet
be constructed. Organic particles that survive oxidation within the Shelf
and reach the Okinawa Trough are deposited in a belt along the upper northw
estern slope of the Trough. A particle-rich mid-depth layer and the very hi
gh fluxes of sinking particles off the shelf break northeast of Taiwan sugg
est active cross shelf transport of particles from the Shelf to the Okinawa
Trough. The cyclonic eddy at the shelf edge northeast of Taiwan is an impo
rtant pathway for the exchange of dissolved and particulate materials betwe
en the Shelf and the Kuroshio. Nitrogen fixation may be a significant contr
ibutor of combined nitrogen to the oligotrophic Kuroshio Surface Water and
the Taiwan Strait Warm Water so that it may support up to 25% of the new pr
oduction in the Kuroshio Surface Water. (C) 2000 Elsevier Science Ltd. All
rights reserved.