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Anticyclonic Eddy Edge Effects on Phytoplankton Communities and Particle Export in the Northern South China Sea
Author(s) -
Wang Lei,
Huang Bangqin,
Laws Edward A.,
Zhou Kuanbo,
Liu Xin,
Xie Yuyuan,
Dai Minhan
Publication year - 2018
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2017jc013623
Subject(s) - haptophyte , oceanography , phytoplankton , chlorophyll a , environmental science , anticyclone , water column , chlorophyll , prochlorococcus , geology , biology , ecology , botany , cyanobacteria , nutrient , paleontology , synechococcus , bacteria
We examined response of phytoplankton total chlorophyll a (TChl a ) and community composition to three coherent anticyclonic eddies (ACEs) observed during a cruise to the northern South China Sea on 28 July to 7 August 2007. Photosynthetic pigments were measured to estimate the contribution of nine phytoplankton groups to TChl a . Although the water column‐integrated TChl a inventory in the upper 100 m was very similar among the three ACEs (17.6–18.9 mg/m 2 ) we observed during the cruise, there were remarkable enhancements in biomasses at the eddy edges. TChl a inventory was 20.8 ± 3.0 mg/m 2 at the edge, which was 33% or 60% higher than at the center and reference. The greatest enhancement of the TChl a at edge was attributed to haptophyte‐8, which was 1.6 and 2.2 times the analogous concentrations at the center and reference sites. The Prochlorococcus Chl a was ~50% greater at the edge relative to the reference and was intermediate at the center. Diatom Chl a at the edge was ~2.5 times the concentrations at the center and reference sites. The positive correlation between particulate organic carbon flux and haptophyte‐8 Chl a at the edge implied an important role of haptophyte‐8 in particle export productivity. It is interesting to note that there occurred higher fluxes of biogenic Si at the center of the ACEs due likely to lateral transport of diatoms from the edge. The phenomenon of higher TChl a at the edge but higher export at the center may have been the combined result of vertical convection and lateral transport within the eddies.