The size dependent phytoplankton growth and mortality rate, according to Metabolic Theory in Ecology, together shape its size structure, which would critically regulate the nutrient and energy transfer efficiency. This study aims to identifying the detailed size specific growth and mortality of microphytoplankton, on which studies are scarce. We first hypothesize that the mass-specific growth rate and mortality scales with the body size with an exponent of -1/4 after temperature correction in natural microphytoplankton assemblage. We simultaneously measure the high resolution size specific growth and mortality rate of microzooplankton by incorporating the FlowCAM into dilution technique, which were conducted in the southern East China Sea from 2010 to 2011. Our results first illustrate that the mass-specific growth rates are independent to body mass, while the mortality rates show a slightly positive (0.12) regression. We further suggest that grazing impact also exhibit non-significant regression with body size. The higher correlation between size-specific growth and mortality rate, on the other hand, implies that the microzooplankton community would selectively feed on those fast growers.

Keywords: Dilution experiment，Microzooplankton grazing，East China Sea，Size specific growth rate，Size specific mortality rate