tunities to evaluate ecosystem responses to the slowest, but most pervasive, effects of human activities, such as global warming, increased ultraviolet radiation, and the gradual accumulation of pollutants. In order to recognize, and ultimately to predict, such responses, it will be necessary to identify the functionally significant organisms in the pelagic ecosystems and to establish their responses to the anticipated anthropogenic agents. Therefore the open ocean should provide excellent opportunities to relate biodiversity concerns, traditionally the domain of population biologists and taxonomists, to issues of ecosystem organization and function.

Deep Sea

"The frequency with which the deep ocean is popping up as a fanciful solution to waste and resource problems is extremely worrisome. I see four origins for this trend. First, it is the product of our success in defending better known habitats like reefs and bays. Second, it is the persistent belief among nonbiologists that the abyss is the desert proposed by Issacs (seep and vent communities are still referred to as oases). Third, the distant deep ocean is the ultimate 'not in my backyard.' Finally, the vastness of the abyss gives rise to a wasteland management policy which views insults to relatively small areas as fully acceptable."

R. Carney (pers. comm., 1994)

The number of species contained within the deep sea—the least-studied marine habitat—has been a subject of recent, intensive debate (J.F. Grassle and Maciolek, 1992; May, 1992; Poore and Wilson, 1993). There is no question, however, that the previous notion of a global deep-sea bottom that is uniformly featureless has been shattered over the last two decades by countless discoveries of unique, sometimes bizarre, and highly diverse deep-sea communities (e.g., Butman and Carlton, in press). Each major ocean basin has a distinctive fauna, and bottom assemblages vary according to latitudinal gradients (Rex et al., 1993) and topographic features such as basins, canyons, and areas of strong currents (J.F. Grassle, 1989). Discrete, ephemeral patches of food (Billett et al., 1983; Wolff, 1979; Suchanek et al., 1985; Gooday and Turley, 1990) or biogenic structure (C.R. Smith et al., 1986; Thistle and Eckman, 1990), and defaunated patches produced by disturbance (C.R. Smith and Hessler, 1987; Snelgrove et al., 1994), are common and introduce a measure of small-scale spatial heterogeneity. At larger spatial scales, disturbances generated by upwelling regions, episodic strong currents (bottom boundary currents, canyons), slumping (trenches or steep slopes) or heavy sedimentation (e.g., Mississippi plume, or offshore of Cape Hatteras) introduce large-scale patterns (greater than 1,000 square kilometers) that appear to obliterate the patterns of discrete, widely separated, ephemeral patches (J.F.



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