The phytoplankton (left) and zooplankton (right) shown here have been magnified. Otherwise, they would be too small for you to see.
NektonNekton are living things that swim through the water (Figure below). They may live at any depth, in the photic or aphotic zone. Most nekton are fish, although some are mammals. Fish have fins and streamlined bodies to help them swim. Fish also have gills to take oxygen from the water.
Nekton swim through ocean water.
BenthosBenthos are living organisms on the ocean floor. Many benthic organisms attach themselves torocks and stay in one place. This protects them from crashing waves and other water movements. Some benthic organisms burrow into sediments for food or protection. Benthic animals may crawl over the ocean floor. Examples of benthos include clams and worms. Pictured below are two other examples (Figure below).
These animals live on the ocean floor.
Some benthos live near vents on the deep ocean floor. Tubeworms are an example (Figurebelow). Scalding hot water pours out of the vents. The hot water contains chemicals that some specialized bacteria can use to make food. Tubeworms have the bacteria living inside them. The bacteria get protection and the tubeworms get some of the food.
Tubeworms live near hot water vents on the deep ocean floor.
SummaryPlankton are tiny organisms that are swept along on currents. Phytoplankton are tiny plant-like organisms. Zooplankton are tiny animals.Nekton are organisms that go through the water under their own power. Fish and marine mammals are nekton.Benthos bury in the sediment, attach to rocks, or crawl over the seafloor.ReviewCompare and contrast phytoplankton.
