Chapter 8 RESPONSES OF PELAGIC MARINE ECOSYSTEMS TO CLIMATE CHANGE ­ CAN WE PREDICT THEM?

Marine ecosystems both respond to and influence climate variability. Our interest in planktonic ecosystems in particular and their interaction with climate change is twofold. First, planktonic ecosystems playa role in regulating greenhouse gases, especially in removing carbon dioxide from the surface ocean to the deep ocean via sinking organic particles, the so-called "biological (or biotic) pump." Second , planktonic ecosystems operate as the base ofthe marine foodweb, providing food for fish and other top predators in the ocean. To forecast how marine ecosystems may function in a changing climate, we must understand not only how they respond to climate changes but how these changes in marine ecosystems might themselves affect climate change through possible feedback effects . Inthis chapter, I consider both roles ofthe marine planktonic ecosystem, as a regulator of greenhouse gases and as food for fish, and how they interact with a changing climate.