. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. HEMOCYANIN AND SALINITY IN LIMULUS 463 effects of low salinity on oxygen uptake and transport are not obscured. The lower blood PO- in dilute media induces greater deoxygenation of hemocyanin at the tissues (Table II). The predicted effect of low blood salt is in fact more than compensated, and the net result is an increase rather than a decrease in the volume of oxygen carried by hemocyanin. These calculations also suggest a decrease in blood flow at low salinity, which is consistent with recordings of heartbeat (Fig. 2). T
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. HEMOCYANIN AND SALINITY IN LIMULUS 463 effects of low salinity on oxygen uptake and transport are not obscured. The lower blood PO- in dilute media induces greater deoxygenation of hemocyanin at the tissues (Table II). The predicted effect of low blood salt is in fact more than compensated, and the net result is an increase rather than a decrease in the volume of oxygen carried by hemocyanin. These calculations also suggest a decrease in blood flow at low salinity, which is consistent with recordings of heartbeat (Fig. 2). The measured decrease of heartbeat in different animals ranged from 13-33% (P 140 torr and 32'/V in comparison with those for small animals at POu — 98-105 torr at £f, which more closely simulates the events occurring in natural estuarine migrations. Oxygen uptake is maintained at a nearly constant level, regardless of salinity and water PO^, by decreases in blood flow and blood Thus the mechanisms of respiratory adaptation at low salinity are in part passive, the increase in efficiency of oxygen transport by hemocyanin, and in part active, the bradycardia. ~ .03 E ^s 3 .02 c o ra .01 c 0) o 0 0 .03 .02 .01 low salinity high salinity prebranchial postbranchial f. VO 20 40 PO2 (torr) 60 0 50 100 Q (ml/kg-min) FIGURE 3. The changes in oxygen transport by the blood of Liinnhts polyphemus induced by adaptation to low salinity. The volume of oxygen delivered to tissue is represented by the height of the stippled or hatched boxes, and cardiac output (Q) by the width. Thus, according to the Pick principle the area of the boxes represents oxygen consumption (/il/ kg-min). Curves are calculated from oxygen equilibrium data for Linuilus hemocyanin (Redfield and Ingalls, 1933; Sullivan et al, 1974), and from data in Tables I and Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and a
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
