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General Session 1: Physical oceanic processes: Dynamics and physical-biological-biogeochemical interactions |
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Nitrogen fixation within an anticyclonic eddy in the northeastern South China Sea
GS1-23-S
Jiaxing Liu* , South China Sea Institute of Oceanology, Chinese Academy of Sciences
Presenter Email: ljx2ljx@126.com
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| Mesoscale eddies play a key role in ocean biogeochemistry. Nevertheless, the effects of mesoscale eddies on the nitrogen fixation are not well understood. Using quantitative polymerase chain reaction (qPCR) and 15nitrogen (15N) tracer methods, we for the first time examined the abundance of nitrogen-fixing cyanobacteria and nitrogen fixation in the upper water column (0¨C100 m) within an anticyclonic eddy in the northeastern South China Sea (SCS). Relatively higher nitrogen fixation rates and nifH abundances of nitrogen-fixing cyanobacteria (Trichodesmium spp., unicellular groups A and B) were observed within the anticyclonic eddy. The nitrogen fixation was estimated to be able to meet 9.2% ¡À 4.7% of the nitrogen demand by primary production within the anticyclonic eddy. Our results indicate that anticyclonic eddy can play a crucial role in regulating nitrogen fixation in the oligotrophic SCS. |
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