Arctic marine food chain

An Arctic marine food chain begins with phytoplankton, tiny organisms that use sunlight to make food in the ocean. Zooplankton consume phytoplankton, Arctic cod consume zooplankton, ringed seals consume fish, and polar bears can prey on seals. The arrows mark the transfer of energy from food to consumer. Marine decomposers break down dead organisms and recycle nutrients in the water. Seasonal sea ice, water temperature, and plankton blooms influence these relationships, so a real Arctic food web is more complex than a single line. This example gives students a clear sequence before they investigate how changes to sea ice can affect multiple trophic levels.