An upper slope “cold” seep community: Northern California.

Piston coring and trawling on the northern California continental slope (450–600 m) recovered shells and live organisms typical of a “cold” seep community. The presence of gas‐charged sediments, hydrates, and nearby oil seepage suggests that this habitat is like the hydrocarbon seeps of the Louisiana slope. Carbon, sulfur, and nitrogen isotopic compositions of organism tissues confirm the presence of bacterial chemosynthesis at these locations. This dicovery and previous reports suggest that the general occurrence of animals dependent on chemosynthesis is widespread.