Cold Seep Communities
I. Introduction

The biology, geology, chemistry, and ecology of cold seep habitats in the Monterey Bay region have been the subject of study since the discovery of seeps in the axial valley of the Monterey Canyon at 3200 m depth in the late 1980s (Embley et al. 1990). Cold seeps are sites of fluid release from the sea floor, derived from various sources including artesian flow and processes producing sediment compaction. Specialized chemosynthetic communities are often associated with seepage of sulfide or methane-rich fluids from hydrocarbon seeps (Kennicutt et al. 1985, 1988, 1989), groundwater seeps (Paull et al. 1984; Hecker, 1985), methane seeps (Kennicutt et al, 1985; Dando et al. 1991), accretionary prisms associated with subduction zones or other sites of tectonically-compressed sediment (Suess et al. 1985; Laubier et al. 1986; Boulegue et al. 1987; Cadet et al. 1987; Le Pichon et al. 1987; Ohta and Laubier 1987; Hashimoto et al. 1987, 1989; Jollivet et al. 1990), and relict organic material buried in debris flow deposits (Embley et al., 1990). Recent discoveries of three new cold seep sites from 600 to 1000 m depth broaden our knowledge of cold seeps (Barry et al. in review), and demonstrate the general similarity in community structure among seeps with differing geologic settings and fluid sources.