Analysis of the scaphognathite ventilatory pump in the shore crab Carcinus maenas. II: Pumping efficiency and metabolic cost
The water pumping efficiency and the metabolic costs of the scaphog-nathites (SC), the gill ventilating water pumps, of shore crabs have been measured. The ratio of dynamic stroke volume to static pumping chamber volume, measured over the range of ventilation frequencies (fr) of 60−300 beats min-1,...
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Veröffentlicht in: | Journal of experimental biology 1984-11, Vol.113 (1), p.69-81 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The water pumping efficiency and the metabolic costs of the scaphog-nathites (SC), the gill ventilating water pumps, of shore crabs have been measured. The ratio of dynamic stroke volume to static pumping chamber volume, measured over the range of ventilation frequencies (fr) of 60−300 beats min-1, shows the water pumping efficiency to be 85%. Despite this high efficiency, the pump appears to become leaky at low FR. Reflux of water back through the pumping chamber was demonstrated by artificially increasing the pressure gradient across the SC chamber at normal fR.
The oxygen requirements of actively beating SCs, the ventilatory fraction of total metabolism, was measured by comparing oxygen consumption before and after SC ablation. The cost of ventilation for resting crabs is 30% of total . The oxygen requirement for a single SC beat is 0·032μmolO2 kg-1. The high ventilatory fraction of total may be one factor contributing to the low metabolic scope of most crustaceans. |
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ISSN: | 0022-0949 1477-9145 |
DOI: | 10.1242/jeb.113.1.69 |