24 Cold-Water Corals in Fluid Venting Submarine Structures

Abstract

A relationship between scleractinian cold-water corals and fluid venting submarine structures has been observed in Mediterranean and adjacent areas. Mud volcanoes and mud diapirs promote different substrate types for biological colonisation: from muddy bottoms with chemosynthesis-based communities and typical bathyal soft bottom fauna to hard bottoms with sessile solitary and colonial scleractinian cold-water corals, sponges, octocorals and antipatharians. Fluid venting submarine structures provide an elevated position for the development of sessile suspension feeders, including scleractinian cold-water corals, where an interaction of the currents with the local topography generally accelerates the water flow. This facilitates the supply of suspended food particles and the development of carbonate mounds mainly built by scleractinian cold-water corals. Methane-derived authigenic carbonates provide hard substrates, which represent a prerequisite for larvae settlement of some scleractinian cold-water corals and further development of polyps and colonies in those elevated areas. These factors make FVSS an appropriate place for the development of habitats conformed by scleractinian cold-water corals as well as genuine and singular biodiversity hotspots.