There are fungi in the genera Lindra and Lulworthia, bacteria like Vibrio furnissii, shipworms, nematodes, and amoebas that break down dead things in the ocean. Decomposers are an important part of the marine ecosystem because they break down dead organisms and release nutrients back into the ocean.
In estuarine areas of the ocean, fungi from the genera Lindra and Lulworthia break down dead seaweed. Vibrio furnissii is a type of bacteria that breaks down the chitin found in the shells of lobsters, crabs, and other arthropods. Shipworms are a kind of mollusk that breaks down wood and leaves calcium deposits behind. Nematodes eat seaweed that has washed up on the beach. Amoebas are a kind of microbe that breaks down dead marine plants and animals.
Most decomposition happens on the ocean floor because most organisms sink when they die.
Phosphorus, nitrogen, and potassium are a few of the nutrients that decomposers help put back into the ocean. Organisms in a different group of marine life, called producers, use these inorganic nutrients to make organic matter. Most of the food in the sea comes from phytoplankton. Seaweeds also grow in the ocean. The marine organisms that eat the producers include copepods, larvaceans, and protozoans.