What do marine plants provide marine life?

Answer 1

Food

There are many marine plants in the ocean supporting like but the most important of them all is phytoplankton. Phytoplankton (tiny single celled plants that live in the water) are alone responsible for 50% of the oxygen in the atmosphere and the majority of the food in the ocean.

Plankton (tiny animals living in the water) feeds on phytoplankton and in turn, much of the marine life in the ocean, from tiny fish to giant shark and whales, feeds on Plankton.

The annual bloom of the phytoplankton determines the breeding cycles for most marine life. Fish, mammals and crustaceons travel vast distances across the oceans in search of the blooms.

Without phytoplankton, the oceans would be a great marine desert as many of its inhabitants would starve.

Oxygen

The plant life in the oceans releases huge amounts of oxygen into the water, allowing marine life to breath.

It is beacuase if the lack of plant life in the great ocean depths (they can't photosynthesize without sunlight) that marine life there is so sparse.

Shelter

The ocean is a vast empty space. There isn't much to hide behind to avoid predators but floating seaweed or other plant life provides a great escape for small fish and crustaceons that would otherwise be quickly devoured.

The kelp forest of the oceans are a sanctuary for marine life. Kelp can grow to be several metres tall and houses many fish, crustaceons nd even some mamals in the relative safety of it's leaves and stems.