Ocean Deep
Uploaded by stick_ucsb on Apr 30, 2001
Snelgrove and Grassle in The Deep Sea: Desert and Rainforest published in Oceanus, volume 38 in 1995 argue that the popular belief that the deep sea is little more than an “ocean desert” is a pure fallacy. Contrary to such thinking a multitude of benthic organisms dwell on the ocean bottom; despite the frigid temperatures and high pressure, a large heterogeneity of creatures, rivaling in variety and number those inhabiting tropical rainforests, thrive in this environment.
The “analogy of the ocean desert” arose from the technologically inadvanced photographs and sampling equipment prior to the 1960’s (25). However, it was during that decade that WHOI biologists Sanders and Hessler, employing an epibenthic sled, produced extremely varied samples of organisms from deep-sea communities. The epibenthic sled permitted researchers to observe organisms that had previously gone unnoticed; unknown to the scientific community was a varied population of macrofaunal benthos inhabiting the bottom sediment, in addition to new species of polychaetes, crustaceans, and mollusks. Further sampling in the 1980’s, with the use of a box corer, revealed an astoundingly heterogeneous population of benthic organisms equal, or perhaps more expansive in variety than the number of species residing in the tropical rainforests. Therefore, though the deep-sea may physically resemble a desert with its “large expanses of . . . gently rolling contours of mud or sand with little visible life,” in reality it is an ecosystem teeming with life (27). Such diversity was most noteably evidenced by a sample taken from an area no larger than seven feet by seven feet off the coast of Charleston, South Carolina where a total of 1,597 divergent species were recovered from the ocean bottom in a single sampling.
The heterogeneity among species is also apparent with respect to both “space and time” (28). Observations have revealed that different species dwell in different patches along the ocean bottom; this patchwork of species is what, in effect, provides all species in the deep-sea with adequate sustenance. Phytoplankton blooms, sinking fish carcasses, pieces of wood, pieces of seaweed, disturbances created by fish feeding, and the polychaete fecal mounds all create microhabitats within the larger habitat of the ocean bottom; different species derive sustenance from different patches or microhabitats generated by such activities. In addition, seasonal changes and the passage of time affect these microhabitats and thus, those organisms present in each. Therefore, it is the heterogeneity of the deep-sea habitat with its mosaic...