Journal of Oceanography

, Volume 63, Issue 4, pp 671–683

Effects of cold eddy on phytoplankton production and assemblages in Luzon strait bordering the South China Sea

  • Yuh-Ling Lee Chen
  • Houng-Yung Chen
  • I. -I. Lin
  • Ming-An Lee
  • Jeng Chang
Original Articles

DOI: 10.1007/s10872-007-0059-9

Cite this article as:
Chen, YL.L., Chen, HY., Lin, I.I. et al. J Oceanogr (2007) 63: 671. doi:10.1007/s10872-007-0059-9

Abstract

The biochemical effects of a cold-core eddy that was shed from the Kuroshio Current at the Luzon Strait bordering the South China Sea (SCS) were studied in late spring, a relatively unproductive season in the SCS. The extent of the eddy was determined by time-series images of SeaWiFS ocean color, AVHRR sea surface temperature, and TOPEX/Jason-1 sea surface height anomaly. Nutrient budgets, nitrate-based new production, primary production, and phytoplankton assemblages were compared between the eddy and its surrounding Kuroshio and SCS waters. The enhanced productivity in the eddy was comparable to wintertime productivity in the SCS basin, which is supported by upwelled subsurface nitrate under the prevailing Northeastern Monsoon. There were more Synechococcus, pico-eucaryotes, and diatoms, but less Trichodesmium in the surface water inside the eddy than outside. Prochlorococcus and Richelia intracellularis showed no spatial differences. Water column-integrated primary production (IPP) inside the eddy was 2–3 times that outside the eddy in the SCS (1.09 vs. 0.59 g C m−2d−1), as was nitrate-based new production (INP) (0.67 vs. 0.25 g C m−2d−1). INP in the eddy was 6 times that in the Kuroshio (0.12 g C m−2d−1). IPP and INP in the eddy were higher than the maximum production values ever measured in the SCS basin. Surface chlorophyll a concentration (0.40 mg m−3) in the eddy equaled the maximum concentration registered for the SCS basin and was higher than the wintertime average (0.29 ± 0.04 mg m−3). INP was 3.5 times as great and IPP was doubled in the eddy compared to the wintertime SCS basin. As cold core eddies form intermittently all year round as the Kuroshio invades the SCS, their effects on phytoplankton productivity and assemblages are likely to have important influences on the biogeochemical cycle of the region.

Keywords

Phytoplankton assemblageprimary productionnew productioneddyLuzon StraitKuroshioSouth China Sea

Copyright information

© The Oceanographic Society of Japan/TERRAPUB/Springer 2007

Authors and Affiliations

  • Yuh-Ling Lee Chen
    • 1
  • Houng-Yung Chen
    • 2
  • I. -I. Lin
    • 3
  • Ming-An Lee
    • 4
  • Jeng Chang
    • 5
  1. 1.Department of Marine Biotechnology and ResourcesNational Sun Yat-sen UniversityKaohsiungTaiwan
  2. 2.Institute of Marine BiologyNational Sun Yat-sen UniversityKaohsiungTaiwan
  3. 3.Department of Atmospheric SciencesNational Taiwan UniversityTaipeiTaiwan
  4. 4.Department of Environmental Biology and Fishery ScienceNational Taiwan Ocean UniversityKeelungTaiwan
  5. 5.Institute of Marine BiologyNational Taiwan Ocean UniversityKeelungTaiwan