If zooplankton fail to reproduce, it disrupts the food chain, threatening fish populations and, in turn, seals and other large animals. "If we still have some sea ice, but it's melting more ...

The diagram shows how mercury can accumulate in the food chain. In the sea, tiny animals and plants called plankton absorb the mercury compounds. When the plankton are eaten by small fish ...

Almost all food chains begin with a green plant. Here in the sea, seaweed and plankton do the job. A plant that converts the Sun's rays into energy is called a producer. They are the start of a ...