BIOLOGICAL COLONIZATION OF NEW HYDROTHERMAL VENTS FOLLOWING AN ERUPTION ON JUAN-DE-FUCA RIDGE

A recent eruption on CoAxial Segment of Juan de Fuca Ridge initiated h ydrothermal conditions with rapid changes in water chemistry and growt h of microbial communities. Vent animals recruited from distal sources within a year. One site with newly erupted lava attracted no animals to high-iron and low-sulphide conditions. However, sustained release o f flocculent material at a second site suggests extensive subterranean microbial production; here, the dissolved sulphide/heat ratio peaked during the first year. The first larval recruits included vestimentife rans, alvinellid polychaetes and nemerteans; despite the small areal e xtent of venting, one-third of the regional vent species pool had arri ved by 2 years. Near-optimal growth conditions and recruitment by many species continued in the centre of the system but several habitats we nt extinct within 2 years. Rapid response and exploitation by vent ani mals must be an important adaptation to such ephemeral conditions. (C) 1997 Elsevier Science Ltd.