. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PHOTOSYNTHESIS IN TRIDACNA GIGAS 235 500 100 o I 5° 10. 50 10 c 3 CT re ~t N O O X Oi CJ (V ^x r: 3 001 10 Wet weight (g) 100 1000 10,000 FIGURE 1. Number of zooxanthellae and amount of chlorophyl a per gram (wet weight) of T. gigas as a function of the wet weight of the clam (without shell). Squares represent the number of zooxanthellae per Mg clam (y = ~00966, n = 11, r = , P < ). Circles represent the ^g Chi. a per gram clam (y = 127x °l035, n = 14, r = , P < ). synthetic oxygen producti
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PHOTOSYNTHESIS IN TRIDACNA GIGAS 235 500 100 o I 5° 10. 50 10 c 3 CT re ~t N O O X Oi CJ (V ^x r: 3 001 10 Wet weight (g) 100 1000 10,000 FIGURE 1. Number of zooxanthellae and amount of chlorophyl a per gram (wet weight) of T. gigas as a function of the wet weight of the clam (without shell). Squares represent the number of zooxanthellae per Mg clam (y = ~00966, n = 11, r = , P < ). Circles represent the ^g Chi. a per gram clam (y = 127x °l035, n = 14, r = , P < ). synthetic oxygen production rates of the zooxanthellae in situ were inversely related to the size of the clam (Fig. 2). The decrease in number of zooxanthellae per gram of clam (Fig. 1) and in in situ productivity of those zooxanthellae with increasing size of the clam (Fig. 2) results in a strong inverse relation between oxygen production rate and size of the clams (Fig. 3). The rate of respiratory oxygen consumption is also inversely related to the size of the clams (Fig. 3). The relation between photosynthetic oxygen evolution and irradiance (P-I) was determined for 7 clams ranging from 1. 15 to cm in shell length ( g wet weight). Four representative curves are presented in Figure 5. Both alpha/g (the slope of the initial light limited portion of the P-I curve) and "Pmax" (assumed maximum photosynthetic rate) decrease with increasing size of the clam. The smallest clams showed light saturation of photosynthesis by 600 AtE-m^-s"1, but the larger clams were not saturated even at 2000 jE • m~2 • s '. P-I relations were also determined for zooxanthellae isolated from the mantles of three different clams. One of these curves, together with the P-I curve for the intact clam from which the zooxanthellae were isolated, is shown in Figure 6. The freshly isolated zooxanthellae did not show any evidence of photoinhibition up to maximum ambient illumination (2000 ^E • m~2 •
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
