ranging in size from shrimps to whales. In the Sargasso Sea 

 around Bermuda, Sargasso weed is sometimes stripped of its floats 

 in rough weather and sinks below the surface, eventually reaching 

 the bottom. In the experiments reported here, local enrichments 

 of the sediments were produced by burying clumps of Sargassum in 

 shallow pits in a sand bottom near Bermuda, then sampling the 

 sediments later to compare the numbers and diversity of organisms 

 in the enriched sediments with those from control areas. After 

 37 days, abundances of some of the opportunistic species had 

 increased sharply in the enriched sediment, creating a community 

 composition like those seen in disturbed environments elsewhere. 



Use of submersibles for observation in the water column 

 dates back to Beebe in the 1930 's, but only recently have 

 scientists been able to use more quantitative techniques and 

 bring back specimens. In the last 10 years, the number of known 

 species of midwater plankters, especially gelatinous ones, has 

 been dramatically increased, and in situ observations have 

 changed our perceptions of the kinds of organisms that live in 

 this largest of earthly habitats. Comparable advances in 

 understanding behavioral interactions and trophic structure are 

 now beginning to be seen as manned operations in midwater enter a 

 second decade. Two major efforts in midwater biology, supported 

 in part by NOAA/NURP, are described in this chapter. 



Larson and co-authors report on a series of dives made in 

 1986 and 1987 in the submarine canyons off the New England coast. 

 These are the first submersible explorations of these productive 

 regions, and were carried out by a group of systematic and 

 behavioral specialists led by Richard Harbison. Most of their 

 emphasis is on gelatinous zooplankton and midwater fish, two 

 conspicuous components of the midwater community. The paper 

 summarizes patterns of distribution found for dominant species 

 within these groups, concluding that most were truly mesopelagic 

 in distribution. Ctenophores and siphonophores were common and 

 diverse, although they are rarely seen in net collections because 

 of their fragility. The Sea-Link ' s sophisticated collecting 

 equipment permitted collection of numerous specimens of these 

 delicate organisms, including some probable new species. 



The papers by Madin and Hamner et al . stem from the Beebe 

 Project, a multidisciplinary study of the water column and 

 benthos (Grassle's work was part of this project) at stations 

 near Bermuda. The first field season of this project was in July 

 1987. Due to weather and logistical problems, the number of 

 dives accomplished was fewer than planned, and most of the 

 participants consider the 1987 results as preliminary. 



Madin 's paper discusses the objectives of the pelagic 

 component of the project, and describes a midwater mooring 

 developed for studying behavior of mesopelagic plankton and 

 nekton. From transcripts of the recorded comments of observers, 



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