Microbial symbiosis in marine animals was not discovered until 1981. In the time following, symbiotic relationships between marine invertebrates and chemoautotrophic bacteria have been found in a variety of ecosystems, ranging from shallow coastal waters to deep-sea hydrothermal vents. The type of marine animal vary greatly, for example, sponges, sea squirts, corals, worms, and algae all host a variety of unique symbionts. Each symbiotic relationship displays a unique ecological niche, which in turn can lead to entirely new species of host species and symbiont.
It is particularly interesting that it took so long to discover the marine microbial symbiosis because nearly every surface submerged in the oceans becomes covered with biofilm, including a large number of living organisms. Many marine organisms display symbiotic relationships with microbes. Epibiotic bacteria have been found to live on crustacean larvae and protect them from fungal infections. Other microbes in deep-sea vents have been found to prevent the settlement of barnacles and tunicate larvae.
The most notable display of marine symbiotic relationship would be coral. Coral reefs are home to a variety of dinoflagellate symbiont, these symbionts give coral its bright coloring and are vital for the survival of the reef. The symbionts provide the coral with food in exchange for protection. If the waters warm or become too acidic, the symbionts are expelled, the coral bleaches and if conditions persist the coral will die. This in turn leads to the collapse of the entire reef ecosystem.
Microbial biotechnology
Marine invertebrates are the hosts of a wide spectrum of bioactive metabolites, which have vast potential as drugs and research tools. In many cases, microbes aid in or are responsible for marine invertebrates natural products. Certain marine microbes can provide insight into the biosynthesis mechanisms of natural products, which in turn could solve the current limitations on marine drug development.