Narrative Index

Alissa J. Arp, Ph.D., Director and Professor, Romberg Tiburon Center for Environmental Studies, San Francisco State University presents aspects of physiology in marine invertebrates exposed to energy rich, but highly toxic, hydrogen sulfide in three different environments. Various sulfide detoxification strategies are employed by marine animals in these sulfide environments. Some organisms contain symbiotic, chemosynthetic bacteria. These symbionts detoxify the sulfide and provide nutrition for their hosts. Others do not contain symbionts, and detoxify sulfide through physiological pathways.

In the deep-sea hydrothermal vents, chemoautotrophic endosymbiont-harboring worms, Riftia pachyptila , clams and mussels utilize sulfide to fuel bacterial metabolism while protecting their tissues from toxicity by the sulfide detoxification process of binding the sulfide to blood-borne components.

In cold seeps, chemosynthetic communities congregate around naturally seeping pools of sulfide, methane and hypersaline brine. Chemosynthetic mussels utilize methane as their inorganic energy supply. Newly discovered polychaete worms colonize mounds of frozen methane.

In estuarine mudflats at low tides, the non-chemosynthetic, echiuran worm, Urechis caupo, is exposed to toxic sulfide. The animal tolerates moderate sulfide levels through physiological adaptations that protect the body tissues and internal fluids.

• Meet the presenter
• Acknowledgements