Biochemical ecology of deep-sea animals

Abstract

Deep-sea ecosystems contain unique endemic species whose distributions show strong vertical patterning in the case of pelagic animals and sharp horizontal patterning in the case of benthic animals living in or near the deep-sea hydothermal vents. This review discusses the biochemical adaptations that enable deep-sea animals to exploit diverse deep-sea habitats and that help establish biogeographic patterning in the deep-sea. The abilities of deep-sea animals to tolerate the pressure and temperature conditions of deep-sea habitats are due to pervasive adaptations at the biochemical level: enzymes exhibit reduced perturbation of function by pressure, membranes have fluidities adapted to deep-sea pressures and temperatures, and proteins show enhanced structural stability relative to homologous proteins from cold-adapted shallow-living species. Animals from the warmest habitable regions of hydrothermal vent ecosystems have enzymes and mitochondria adapted to high pressure and relatively high temperatures. The low metabolic rates of bathypelagic fishes correlate with greatly reduced capacities for ATP turnover in locomotory muscle. Reduced light and food availability in bathypelagic regions select for low rates of energy expenditure in locomotory activity. Deep-sea animals thus reflect the importance of biochemical adaptations in establishing species distribution patterns and appropriate rates of metabolic turnover in different ecosystems.

Aggregations of Arctic deep-sea scavengers at large food falls: temporal distribution, consumption rates and population structure

“…For a long time the seafloor of the deep sea was considered to be a monotonous, desert-like environment colonised by only a few organisms because of the high hydrostatic pressure, low temperature, absence of light and limited food supply (Svedrup et al 1942, Dayton & Hessler 1972, Somero et al 1983. Scientific results obtained during the second half of the last century led to a shift in the understanding of the deep-sea ecosystem (Sanders 1968).…”

Deep-sea echinoderm oxygen consumption rates and an interclass comparison of metabolic rates in Asteroidea, Crinoidea, Echinoidea, Holothuroidea and Ophiuroidea

“…2) s. and temperature changes (Somero, 1998). Temperature influences the weak chemical bonds that maintain protein formation, functioning and subunit aggregation, enzyme-ligand complex integrity and lipidbased physical structures (Somero et al, 1983). Pressure influences the volume of both gas-and water-filled spaces, with alterations in pressure having consequences to biological functioning ranging from the molecular level to that of the whole organism (Somero, 1991).…”

Duration and timing of reproduction in decapod crustaceans of the NW Mediterranean continental margin: is there a general pattern?

“…total length over 1 cm) species dwelling at these intermediate depths have been mainly addressed in terms of growth, biochemical and physiological adaptation to the midwater realm (Childress et al 1980, and see review by Childress 1995), and even fewer studies are available regarding the benthic realm (Childress et al 1990. These intermediate depths have strong physical and biochemical gradients: the pressure increases progressively and a physiological boundary has been established at ~1000 m (Somero et al 1983); the temperature usually decreases by more than 10°C, although this decrease is not found in the Mediterranean (Hopkins 1985); the trophic resources decrease dramatically; and the light decreases progressively up to 1000 m before completely disappearing below this depth (Margalef 1986). In this sense, the biological study of congeneric species dwelling across the upper and middle slope habitats should be highly enlightening and may supply valuable knowledge of the biological characteristics present in deeper waters, since these environments act as a physical and biochemical transitional environment between the shallow (< 200 m) and the deep-sea (>1000 m) domains, to which life cycles of individual species are adapted.…”