Effect of Hydrographic Variability on the Distribution of Microbial Communities in Taiwan Strait in Winter

Abstract

This study investigated the spatial variation in the components of a microbial food web (viruses, picoplankton, nanoflagellates, and ciliates) in different hydrographic environments in the Taiwan Strait during winter. Water temperature and salinity varied spatially, with lower temperatures (15.3–22.8 °C) and salinities (32.2–33.4 psu) in the northern part of the Taiwan Strait, largely affected by runoff from the coast of China. Concentrations of nutrients and Chl a were significantly higher in the northern part than that in the southern part of the study area. Synechococcus spp., nanoflagellate, and ciliate abundance also varied significantly, with the northern strait having higher abundances of these communities. In contrast, a higher abundance of bacteria was found in the southern part of the Taiwan Strait. The results of this study, which describes two different ecosystems in the Taiwan Strait, suggest that during winter, a “viral loop” might play an important role in controlling bacterial production in the southern part of the Taiwan Strait, while nanofalgellate grazing of picophytoplankton may contribute mainly to the flux of energy in the northern part.