Trophic Structure of Abyssal Macrobenthos

Food web structure of the benthic community at the Porcupine Abyssal Plain (NE Atlantic): a stable isotope analysis

“…Clean or size fractionated POM samples are even more difficult to obtain close to the seafloor than from the surface layer. POM arriving at the seabed is a mixture of various components such as phytoplankton, associated microorganisms, amorphous aggregates (marine snow), faecal pellets and moults (Sokolova, 1997;Lampitt, Hillier, & Challenor, 1993).…”

“…Trophic relations within the PAP community may further be complicated by a possible tendency towards vertical extension of trophic niches in various taxa and feeding types, which is currently being being discussed as a typical feature of strongly food limited systems (e.g. Gage & Tyler, 1991;JarreTeichmann et al, 1997;Sokolova, 1997).…”

“…The meiofauna consists of both metazoans and larger protozoan organisms, are often dominant numerically and in terms of biomass in benthic deep-sea environments and so play a highly important role in energy flow (Gooday et al, 1992;Tietjen, 1992). As components of the food web, they are not only important consumers, but also may serve as an important food source either for non-selective deposit feeders (see review in Sokolova, 1997) or for selective consumers of foraminifers (Gooday et al, 1992;Lipps, 1983).…”

“…Competition for food is generally thought to exert strong evolutionary pressure that drives trophic niche separation, either by specialization (Roberts & Moore, 1997;Billett, Llewellyn, & Watson, 1988) and/or by vertical expansion of trophic niches, i.e. omnivory (Gage & Tyler, 1991;Jarre-Teichmann et al, 1997;Sokolova, 1997).…”

Temporal variations in fatty acid composition of deep-sea holothurians: evidence of bentho-pelagic coupling

“…Some bacteria are also capable of de novo synthesis of 20:4 (n-6), particularly free-living and some endosymbiotic strains (Nichols et al 1993, Russell & Nichols 1999, perhaps accounting for some of the increased levels found in all species with high PUFA amounts during periods of low OM flux. A role for bacteria in supplementing nutrition has been suggested for deep-sea holothurians (Manship 1995, Roberts et al 2000, and other depositfeeding megafauna (Sokolova 2000). The pathways for de novo synthesis of PUFA by piezophilic bacteria that dominate abyssal sediments (Nichols 2003) and accumulate within the intestine of deep-sea holothurians could allow the addition of useful fatty acids 20:5 (n-3) and 20:4 (n-6) to their diets and reproductive needs (Nichols 2003) which, in turn, might also account for the lack of fully season-dependent reproduction (Tyler 1988).…”