Adaptive processes linked to overall metabolism were studied in terms of oxygen consumption and ammonia excretion in each of three self-contained krill populations along a climatic gradient. In the Danish Kattegat, krill were exposed to temperatures which ranged from 4degreesC to 16degreesC between seasons and a vertical temperature gradient of up to 10degreesC during summer. In the Scottish Clyde Sea, water temperatures varied less between seasons and the vertical temperature gradient in summer was only 3degreesC. Temperatures in the Ligurian Sea, off Nice, were relatively constant around 12-13degreesC throughout the year, with a thin surface layer (20-30 m) of warm water developing during summer. The trophic conditions were rich in the Kattegat and, particularly, in the Clyde, but comparatively poor in the Ligurian Sea. Oxygen consumption increased exponentially with increasing experimental temperature, which ranged from 4degreesC to 16degreesC. Overall respiration rates were between 19.9 and 89.9 mumol O-2 g(-1) dry wt h(-1). Krill from the Kattegat, the Clyde Sea, and the Ligurian Sea all exhibited approximately the same level of oxygen consumption (30-35 mumol O-2 g(-1) dry wt h-1) when incubated at the arribient temperatures found in their respective environments (9degreesC, 5degreesC, and 12degreesC). This indicates that krill adjust their overall metabolic rates to the prevailing thermal conditions. The exception to this were the respiration rates of Ligurian krill from winter/spring, which were about twice as high as the rates from summer krill despite the fact that the thermal conditions were the same. This effect appears to result from enhanced somatic activity during a short period of increased food availability and reproduction. Accordingly, krill appears to be capable of adapting to both changing thermal and trophic conditions, especially when nutrition is a limiting factor in physiological processes.
- VERTICAL MIGRATION BEHAVIOR
- Marine & Freshwater Biology
- LIGURIAN SEA
Sabrowski, R., Brohl, S., Tarling, G. A., & Buchholz, F. (2002). Metabolic properties of northern krill, Meganyctiphanes norvegica, from different climatic zones. I. Resperation and excretion. MAR BIOL, (0), 547-556. https://doi.org/10.1007/s00227-001-0730-4