Zooplankton play a key role in the marine ecosystem. They feed on phytoplankton and are a major food source for fish and other higher trophic levels, typically those exploitable by humans. Because of their relatively short life span, they respond quickly to their environment. We conduct research on zooplankton response to seasonal and inter-annual phytoplankton dynamics, zooplankton physiological response to ocean acidification and warming, the role zooplankton play in microplastic consumption and fate, and the contribution of zooplankton to nutrient cycling and the biological pump.