@Paul B It seems as if slime coat in seaweeds is as important as slime coat in fish.
Microbial Communities Associated with Macroorganisms in the Sea: Antagonism, Neutralism, Synergism in Epibiosis
[From an ecological perspective, most interactions among conspecifics, or host/parasite and predator/pray pairs are linked to and controlled by properties of the organism’s body surface. Finally, most environmental stressors such as, e.g., desalination, hypoxia, UV radiation, and pollution are experienced at this functional interface foremost.]
Microbial Communities Associated with Macroorganisms in the Sea: Antagonism, Neutralism, Synergism in Epibiosis
[From an ecological perspective, most interactions among conspecifics, or host/parasite and predator/pray pairs are linked to and controlled by properties of the organism’s body surface. Finally, most environmental stressors such as, e.g., desalination, hypoxia, UV radiation, and pollution are experienced at this functional interface foremost.]

