Marine microorganism Marine microorganism Marine microorganisms are defined by their habitat as the microorganisms living in a marine environment, that is, in the saltwater of a sea or ocean or the brackish water of a coastal estuary. A microorganism (or microbe) is any microscopic living organism, that is, any life form too small for the naked human eye to see, needing a microscope. Microorganisms are very diverse. They can be single-celled or multicellular and include all bacteria and archaea and most protozoa, as well as some species of fungi, algae, and certain microscopic animals, such as rotifers. Many macroscopic animals and plants
Marine biogenic calcification Marine biogenic calcification Marine biogenic calcification is the process by which marine organisms such as oysters and clams form calcium carbonate. Seawater is full of dissolved compounds, ions and nutrients that organisms can utilize for energy and, in the case of calcification, to build shells and outer structures. Calcifying organisms in the ocean include molluscs, foraminifera, coccolithophores, crustaceans, echinoderms such as sea urchins, and corals. The shells and skeletons produced from calcification have important functions for the physiology and ecology of the organisms that create them. The ocean is the largest sink or reservoir of atmospheric carbon dioxide (CO), continually