. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 10 15 20 HOURS 25 30 35 05 03 CVJ O =*, B. 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 P02(Torr) FIGURE 4. The effect of a 5 h period of anoxia on the weight-specific oxygen consumption rate [VO- in n\ O2/(mg dry tissue wt-h) at STP] of Melampus bidentatus in 100% seawater at 20°C. A, The effect of anoxia on VO: in fully air-saturated seawater. The horizontal axis is time in hours and the vertical axis VO2 as above. The solid circles represent VO2 before 5 h of anoxia; and the open circles, VO: for
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 10 15 20 HOURS 25 30 35 05 03 CVJ O =*, B. 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 P02(Torr) FIGURE 4. The effect of a 5 h period of anoxia on the weight-specific oxygen consumption rate [VO- in n\ O2/(mg dry tissue wt-h) at STP] of Melampus bidentatus in 100% seawater at 20°C. A, The effect of anoxia on VO: in fully air-saturated seawater. The horizontal axis is time in hours and the vertical axis VO2 as above. The solid circles represent VO2 before 5 h of anoxia; and the open circles, VO: for up to 25 h after return to fully air-saturated seawater (PO2 = 159 torr) from the 5 h of anoxia. B, Effect of five hours of anoxia on VO2 with decreasing oxygen concentration from full air saturation (PO2 = 159 torr). Horizontal axis, partial pressure of oxygen in torr; vertical axis, VO2 as above. Open circles connected by solid lines represent VO2 with declining oxygen concentrations before anoxia. Open triangles, squares, and diamonds connected by solid lines represent VO2 immediately after, 5 h after and 10 h after return to fully air-saturated seawater from anoxia, respectively. Solid triangles, squares and diamonds connected by dashed lines represent VO2 15 h, 20 h, and 25 h after anoxia, respectively. allows Melampus to maintain oxygen uptake rates at or near prehypoxic rates at full air saturation, down to PO2s as low as 30 torr for 5 to 20 h after 5 h of hypoxia (Fig. 4b). In untreated snails at 30 torr, there is no regulation, and uptake rates run at about 20-40% of poststress rates. By 25 h posthypoxia, the ability of Me- lampus to regulate oxygen consumption appears to be lost (b2 X 103 = ), but VO2 remains elevated over the full range of oxygen tensions tested, allowing continued maintenance of uptake rates close to prestress full air saturation levels at PO2s as low as 65 torr. In the first subsample, b2 X 103 values remained low and uptake rates elevated
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
