Bingzhang Chen, L. Zheng, B. Huang, S. Song, H. Liu.Biogeosciencesce, 2013. 10, 2775–2785.

We conducted a comprehensive investigation onthe microzooplankton herbivory effect on phytoplankton inthe northern South China Sea (SCS) using the seawater dilutiontechnique at surface and deep chlorophyll maximum(DCM) layers on two cruises (July–August of 2009 and Januaryof 2010).We compared vertical (surface vs. DCM), spatial(onshore vs. offshore), and seasonal (summer vs. winter)differences of phytoplankton growth (μ0) and microzooplanktongrazing rates (m). During summer, both μ0 andm were significantly higher at the surface than at the DCMlayer, which was below the mixed layer. During winter, surfaceμ0 was significantly higher than at the DCM, while mwas not significantly different between the two layers, bothof which were within the mixed layer. Surface μ0 was, onaverage, significantly higher in summer than in winter, whileaverage surface m was not different between the two seasons.There were no cross-shelf gradients of μ0 in summer or wintersurface waters. In surface waters, μ0 was not correlatedwith ambient nitrate concentrations, and the effect of nutrient

enrichment on phytoplankton growth was not pronounced.There was a decreasing trend of m from shelf to basin surfacewaters in summer, but not in winter. Microzooplanktongrazing effect on phytoplankton (m/μ0) was relativelysmall in the summer basin waters, indicating a decoupling ofmicrozooplankton grazing and phytoplankton growth at thistime.On average, microzooplankton grazed 73% and 65%of the daily primary production in summer and winter, respectively.