Cold Seep Macrofauna

In deep-sea chemosynthetic ecosystems, macrofaunal diversity and distribution are determined by geochemical environments generated by fluid seepage. The South China Sea is located in the northwestern Pacific Ocean with a passive continental shelf, containing over 40 seep sites. In this chapter, we provide a summary of the macrofaunal diversity and distribution at two active hydrocarbon seeps, Haima cold seep and Site F, with updated information based on samples collected from recent cruises. There are at least 81 macrofaunal species from eight phyla, 14 classes, and 34 orders, highlighting their high diversity of the South China Sea. The two active seep regions share ten species, but their communities present different structures represented by mussel beds, clam beds, and clusters of two siboglinid tubeworms. The four community types all occur at Haima cold seep. The seep community at Site F, characterized by the co-dominance of the bathymodioline mussel Gigantidas platifrons and the squat lobster Shinkaia crosnieri, resembles the vent communities in the Okinawa Trough.