MEPS 261:41-49 (2003)  -  doi:10.3354/meps261041

Response of the Banda Sea to the southeast monsoon

Thomas Surman Moore II1,2,*, John Marra2, Ali Alkatiri3

1CSIRO DMR, GPO Box 1538, Hobart, Tasmania, 7000 Australia
2Lamont-Doherty Earth Observatory (LDEO) of Columbia University, Palisades, New York 10964-8000, USA
3Agency for the Assessment and Application of Technology (BPPT), Jakarta 10340, Indonesia

ABSTRACT: Three mechanisms are suggested to describe the physical response in the Banda Sea to the seasonal winds of the southeast monsoon: basin-wide wind-induced mixing, upwelling primarily on the eastern side, and a more complex basin circulation. We use the distribution of chl a in the Banda Sea, from both shipboard and satellite data, as an indicator of the dominant mechanism. An east-west transect of stations through the central Banda Sea in September 1998 shows higher phytoplankton biomass to the east, suggesting a remnant upwelling signal from the southeast monsoon in the previous months. Phytoplankton pigment data indicate a community dominated by diatoms to the east, and a more oligotrophic community (e.g. cyanobacteria) to the west. Furthermore, satellite images reveal a strong seasonal signal, an east-west gradient in chl a, and coincidentally, the related impact of the 1997-1998 El Niño. Overall, the bio-optical data support the idea that the Banda Sea responds to the southeast monsoon through upwelling in the eastern part of the basin.

KEY WORDS: Monsoons · Upwelling · Indonesian Seas · ENSO · Ocean Color

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