In the NGA study area, the biological community is highly productive. The lower levels of the food chain (phytoplankton and zooplankton) support the iconic fish, crabs, seabirds, and marine mammals of Alaska. Large increases in phytoplankton during the spring and sustained production during the summer support zooplankton that transfer energy up the food chain. Substantial amounts of this organic matter also sink to feed animals on the sea bottom.