Overview of Defensive Mutualism in the Marine Environment
The marine environment abounds with microbial symbiosis. Eukaryotic, bacterial, and archaeal microbes form an enormous variety of associations with marine animals, with seaweeds, and with one another. Although those marine microbial symbioses that have received the most widespread attention are of a nutritional nature (e.g., photosynthetic symbiosis, thiotrophic symbiosis, and methanotrophic symbiosis), a variety of microbial symbioses are defensive, while others probably serve mixed functions of nutrition and defense. It is probably unnecessary to state that we have barely begun to study these associations, and that countless symbioses have yet to reveal themselves. What is covered in this chapter is only a small number of defensive microbial symbiosis in the marine environment. Certain topics will be dealt with in greater detail in other chapters. So, although the coverage here
will be broader than in other chapters, it might (unfortunately) be shallower, because of the diversity of topics, and with admittedly disproportionate detail given to the best-studied systems.