. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 0 10 20 300 10 20 300 DAY OF EXPOSURE 10 20 30 Figure 1. LG,, values or the oxygen tension causing 50% mortality (TorrOi ± 95% fiducial limits), as a function of exposure time of Calli- nectes sapidus. Penaeus azlecus, and Crassostrea virginica- Values were obtained over 28 days, at 10. 20, and 30%oS, and at 20 (D) and 30°C (D). level that was unchanged during 12 h of exposure to an- oxic water. Upon the return to normoxic seawater, the heat dissipation rates of the oysters increased dramati- cally for the first three hours,
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 0 10 20 300 10 20 300 DAY OF EXPOSURE 10 20 30 Figure 1. LG,, values or the oxygen tension causing 50% mortality (TorrOi ± 95% fiducial limits), as a function of exposure time of Calli- nectes sapidus. Penaeus azlecus, and Crassostrea virginica- Values were obtained over 28 days, at 10. 20, and 30%oS, and at 20 (D) and 30°C (D). level that was unchanged during 12 h of exposure to an- oxic water. Upon the return to normoxic seawater, the heat dissipation rates of the oysters increased dramati- cally for the first three hours, and then declined to the initial normoxic steady state level. In contrast, the heat dissipation rate of the two apparently fed T. haemastoma exhibited an oxygen debt upon reexposure to normoxic water after 12 h of anoxia and then returned to the initial normoxic metabolic rate (Fig. 6B). 140 _ 120 O t 100 £ O 80 " 60 40 20 R puqio R. harrisn. E. depressus 10 20 30 0 10 20 30 0 DAY OF EXPOSURE 10 20 30 Figure 2. LCs,, values (Torr O: ± 95% fiducial limits) as a function of exposure time ofPalaemonetespugio, Rhithropanopeus harrisii, and Eurypanopeus depressus: 28 days at 30°C and 10%oS. UJ o o: o P aztecus R horrisu T haemastoma 20 40 60 80 PERCENT SATURATION 100 Figure 3. LC50 values, expressed in percent saturation, for seven species after 7 days (cross hatched portion of bars) and 28 days (total bar lengths) of exposure at 30°C and 10%oS. As expected, the magnitude of metabolic rate depres- sion of these crustaceans and molluscs is directly related to their LT5(I—their mortality upon exposure to anoxia. Callinectes sapidus, E. depressus, and Pa/aemonetes pugio have LT50 values of one day or less at 20 and 30°C (Table I). Two individuals from each of these species were examined for evidence of metabolic rate depres- sion: none was found, and all the specimens died during the 12-h exposure to anoxia. The metabolic rate of Cras- sostrea virginica exposed to anoxic
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
