Publication Date:
2022-04-27
Description:
1. In experiments of one hour's duration the pressure resistance of marine invertebrates and fish was examined by determining the number of surviving specimens. The results (LD50-data) show great (probably specific) differences in resistance to pressure. Young Pleuronectes platessa and Platichthys flesus, Neomysis vulgaris and decapod crustaceans (Eupagurus bernhardus, Crangon crangon, Carcinus maenas) are relatively sensible to pressure. The highest levels of pressure resistance can be observed on echinoderms (Asterias rubens, Psammechinus miliaris), molluscs (Mytilus edulis, Modiolus modiolus, Mya arenaria, Cyprina islanica, Littorina littorea), Jaera albifrons and Nereis diversicolor.
2. Gammarus oceanicus, G. duebeni and Crangon crangon are more sensible to pressure at 15° and 20° C than at 5° C.
3. The resistance to pressure of G. oceanicus becomes greater with increase of salinity as well as of osmotic concentration in the external medium.
4. The pressure resistance of G. oceanicus changes with the seasons, being obviously influenced by the stage of maturity of the gonades and the size of the animals. Crangon crangon is more sensitive to pressure at higher temperatures in summer than at lower ones in winter.
5. Asterias rubens and Littorina littorea decrease in weight at increasing sublethal pressures.
6. The frequency of cardiac beat of G. oceanicus, G. duebeni and young Zoarces viviparus was studied under pressure. Relatively little increase of pressure temporarily stimulates the heart-beat, whereas a decrease of pressure stops the beat or can slow it down for a short time. The heart-beat of Gammarus is accelerated after decompression. These effects of pressure also depend on the temperature.
7. Under pressure in short- and long-termed experiments the O2-consumption of diverse species wasmeasured in steadily running sea-water. Increasing pressure by steps (100-300 atm) Asterias rubens, Henricia sanguinolenta, Ophiura texturata and Psammechinus miliaris react every time with initial "shock-like" reduction of O2-consumption. At 100-200 atm Carcinus maenas, Hyas araneus, Nereis diversicolor and Platichthys flesus initially accelerate their metabolism. Constant pressures of 200 and 300 atm lower the O2-consumption below the normal rates.
8. The slight changes in metabolism of some eurybathic echinoderms under a step by step increase of pressure (100-300 atm) and a gradual recovery of O2-consumption during long-termed exposure to pressure may be looked upon as an adaptation to pressure.
Type:
Article
,
NonPeerReviewed
Format:
text
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