. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 250 R. G. STEEN AND L. MUSCATINE 120 - 100 _o ~4> O X o o V .0 e. 0 468 Time (days) 10 20 FIGURE 1. Number of zooxanthellae remaining in Aiptasia pulchella vs. time in dark at 25°C after an initial 4-h incubation at 25°C (•), 14°C (•), and 4°C (A); and time in light at 25°C after an initial 4-h incubation in dark at 4°C (A). Vertical bars indicate standard error of the mean. mined. Figure 1 shows that such individuals lost abundant zooxanthellae immedi- ately and at approximately the same rate as those that were chilled a
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 250 R. G. STEEN AND L. MUSCATINE 120 - 100 _o ~4> O X o o V .0 e. 0 468 Time (days) 10 20 FIGURE 1. Number of zooxanthellae remaining in Aiptasia pulchella vs. time in dark at 25°C after an initial 4-h incubation at 25°C (•), 14°C (•), and 4°C (A); and time in light at 25°C after an initial 4-h incubation in dark at 4°C (A). Vertical bars indicate standard error of the mean. mined. Figure 1 shows that such individuals lost abundant zooxanthellae immedi- ately and at approximately the same rate as those that were chilled and maintained in darkness, but the rate of loss decreased slightly after 2 days until, by day 6, about 91% of the original population had been expelled. Then, over the next 4 days, the population began to increase at a specific growth rate of about d"1. Viability of cold-treated zooxanthellae To determine if low temperature incubation affected the viability of zooxanthel- lae, we tested the ability of freshly isolated and expelled zooxanthellae to photosyn- thetically fix 14C and to exclude dye. The results are given in Table I. Zooxanthellae freshly isolated (FIZ) from control anemones (25°C, dark) fixed 14C at normal rates (cf. Muller-Parker, 1984), and about 98-99% of these zooxanthel- lae were viable as judged from ability to exclude dye. FIZ from cold (4°C) treated anemones assayed immediately or after a 4-h recovery period also fixed 14C but at much lower rates. Of these cells, were judged viable. Extending the recov- ery period at 25°C to 24 h resulted in a modest increase in photosynthetic rates, but the rates were still below control levels and viability was reduced to FIZ customarily release a fraction of their fixed 14C to the external medium (Mus- catine, 1980). Those from A. pulchella (Clone B) normally release less than 10% of. Please note that these images are extracted from scanned page images that may have been digitally
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
