A temperature-tolerant interstitial worm with associated epibiotic bacteria from the shallow water fumaroles of Deception Island, Antarctica

A prominent not previously identified species of Monocelidae (Platyhelminthes, Proseriata) was found in the vicinity of fumarole activity at Fumarole Bay. The distribution of this animal and the metazoan meiobenthos in the vicinity of this area suggests that this species constitutes the most abundant species and the bulk of the biomass at these shallow water fumaroles. In contrast to the other metazoan meiofauna, the distribution of this species is positively correlated with the water temperature and gas emissions, indicating a preference for the areas around fumaroles. The range of temperature tolerated by this animal was determined in in vivo experiments to be at least 30-40degreesC. The outer surface the animals is colonized by apparently symbiotic bacteria, which are usually rod-like and approximately 0.68 mum wide and 2.07 mum long. The results of this study revealed a remarkable difference between shallow-water and deep-sea hydrothermal vent meiobenthic communities. Generalists capable of tolerating extreme abiotic conditions appear to dominate shallow-water vents, whereas endemism seems to be the rule in the deep-sea vents. (C) 2003 Elsevier Science Ltd. All rights reserved.