The world's oceans occupy the major portion of this planet, and the stability of all ecosystems is influenced by biological processes in the sea. Algae capture carbon dioxide from the atmosphere and convert it into cell mass.
Microorganisms transform mineral nutrients and degrade dead organisms and detritus.
Animals, including important fish stocks, depend upon the growth of algae, through a complex web of carnivore and herbivore interactions. Microorganisms are key players in the maintenance of these marine communities, as they channel critical nutrients from the atmosphere and terrestrial environments into the marine ecosystem and release nutrients from dead organisms. Describing and understanding the identities, physiologies, and behavior of marine organisms is difficult because of the inaccessibily of much of the world's oceans. The development of new molecular tools and approaches, however, is enabling the study of marine organisms on an unprecedented scale. Microorganisms that cannot be cultured in the laboratory can now be characterized directly with molecular probes.