An overview of physical and biogeochemical processes and ecosystem dynamics in the Taiwan Strait

The Taiwan Strait is an important channel in the west Pacific Ocean transporting water and chemical constituents between the East China Sea and the South China Sea. Due to its complex bottom topography, alternating monsoon forcing and conjunction of several current systems [such as the Zhejiang–Fujian (Zhe–Min) Coastal Current, the Kuroshio intrusion and the extension of the South China Sea Warm Current], the physical and biogeochemical processes and ecosystem dynamics in the Taiwan Strait vary significantly both in space and in time. Our recent interdisciplinary studies, combining in situ and remote sensing observations with numerical modeling, allow us to address several important issues concerning the Taiwan Strait. The temporal and spatial variation of circulation in the Taiwan Strait is modulated by strong monsoon forcing, complex topography and circulation in the northern South China Sea as well as coastal water input and the Kuroshio intrusion. The biogeochemical processes of carbon and nutrients in the Taiwan Strait depend largely on the physical forcing (external input) and the community structure (internal cycling). The primary producers in the Taiwan Strait are dominated by nano- and pico-phytoplankton, and the contribution of the microbial food web to the traditional food web is estimated to be about 30%, implying the fundamental significance of the microbial food web in this subtropical region. Upwelling is a predominant feature in the Taiwan Strait and shows dynamic short-term, seasonal and interannual variations. Combined hydrographic and satellite-derived information provides evidence on the teleconnection between the Taiwan Strait upwelling variation and the El Nino-Southern Oscillation (ENSO) climate variability. Upwelling has a tremendous impact on biogeochemical processes, biological productivity and ecosystem structure. Not only the biological productivity, but also dramatic changes in the phytoplankton community structure reveal the dynamic ecosystem responses to the variations in upwelling, which should have significant impact on the fishery resources. In this overview, we summarize the hydrographical features with an emphasis on upwelling, which is the key driver of biogeochemical processes and ecosystem dynamics in the Taiwan Strait.

► This overview summarizes the key hydrographical features in the Taiwan Strait.
► Upwelling is a predominant feature due to wind-driven and topographic forcing
► Upwelling has a tremendous impact on biogeochemical processes and productivity
► The interannual variations of upwelling show teleconnection with ENSO events.