Trophic structure of deep-sea macrobenthos

Abstract

The effect of the trophic factor on large-scale distributional patterns of deep-sea macrobenthos inhabiting the floor of the World Ocean has been studied. Two hundred and twenty-eight bottom trawl samples collected by Soviet research vessels in the Pacific and Indian Oceans at depths ranging from 3000 to 6000 m were analyzed. For each sample, the weight of animals with a similar mode of feeding was determined to find the weight ratio of representatives of three main trophic groups, i.e., deposit-feeders, suspension-feeders and carnivores. These data, indicating predominance of alternate groups as well as data on their geographic distribution, were related to feeding conditions which depend on: (1) rates of sedimentation, (2) nature of sediments, (3) content of organic carbon, (4) degree of transformation of organic matter on and within sediments, and, when available, (5} data on redox potential, biochemical oxygen consumption, and state of heterotrophic microflora in the sediments. In dealing with the feeding conditions of deep-sea maerobenthos in the Atlantic Ocean, biological characteristics were deduced from literature data on the composition of sediments, their redox potential and organic carbon content. As a result of this research, eutrophic and oligotrophic regions on the floor of the World Ocean have been distinguished and their boundaries defined. Eutrophic regions lie within areas with high biological productivity of surface-water layers, and cover the peripheral and equatorial parts of the oceans; they are characterized by quantities of labile (digestible) organic matter within sediments which are sufficient for deposit-feeders to predominate in eutrophic regions everywhere, except on considerable bottom elevations. Oligotrophic regions are confined to open areas of the oceans lying beyond the equatorial belt; ~hey are characterized by very low rates of sedimentation and, consequently, by scarce quantities of deposited organic matter. Here, suspensionfeeders predominate, although their population density is very low.

Comparative feeding habits of polychelid lobsters in the Western Mediterranean deep-sea communities

“…S. sculpta exhibits quite similar trophic preferences, and seems to be better adapted to environments with lower prey densities (Jumars & Gallagher 1982, Rowe 1983, Thiel 1983, Peres 1985 or with less nutritional food resources (pteropod remains or foraminiferans). The tendency of species that inhabit relatively unproductive (oligotrophic) zones like deep-sea bottoms to be more omnivorous and microphagous has been reported for a variety of invertebrate groups (Carey 1972, Sokolova 1972) and appears to be part of a general pattern of trophic adaptation to conditions in which resources are scarce. Thus, S. sculpta appears to match the definition of cropper species put forward by Dayton & Hessler (1972) for deep-water predators.…”

Colonisation of hard substrata along a channel system in the deep Greenland Sea

“…This morphotype, although larger in size, resembles foraminiferal mudballs, which are common in the north Atlantic and GreenlandIceland-Norwegian Seas (Linke 1989;Gooday et al 1997). Gooday et al (1997) suggested that mudball-like komokiaceans might be deposit-feeders, which will profit from an enhanced deposition of organic matter caused by smallscale flow patterns surrounding large structures (Sokolova 2000). So far, it could be neither confirmed nor disproved that Morphotype I contains komokiaceans (Gooday, pers.…”

The reproductive ecology of deep-sea ophiuroids around the Crozet plateau, Southern Indian ocean, under contrasting productivity regimes

“…et al 2009;Billett et al 2010;Glover et al 2010;Wei et al 2010). Large-scale patterns in deep-sea communities (Sokolova, 2000;Ebbe et al 2010) mirror surface water biogeochemical provinces (Longhurst, 2007) indicating that productivity is important in regulating the distributions of species. However, the relative importance of food supply, and whether all taxa respond in the same way, has been difficult to determine because environmental drivers change at different rates across regions and oceans.…”