Photoacclimation of Stylophora pistillata to light extremes: metabolism and calcification
Photoacclimation of Stylophora pistillata to light extremes: metabolism and calcification
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DOI：
10.3354/meps334093
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发表时间：
2007-03
影响因子：
2.5
通讯作者：
T. Mass;S. Einbinder;E. Brokovich;N. Shashar;R. Vago;J. Erez;Z. Dubinsky
中科院分区：
文献类型：
--
作者：
T. Mass;S. Einbinder;E. Brokovich;N. Shashar;R. Vago;J. Erez;Z. Dubinsky
造礁珊瑚Stylophora pistillata具有广泛的水深分布（0至70米）。在这个范围内，光强度呈指数下降。深海群体的形态通常是平面的，上部是黑色的，面向底部的部分是浅色的。浅水群体通常是亚球形和象牙色。研究了光驯化对S. pistillata殖民地沿着其水深范围内的珊瑚礁剖面（5至65米）在埃拉特，亚喀巴，红海，在冬季和夏季，使用潜水呼吸计。呼吸速率、光饱和光合速率（Pmax）、补偿光强（Ec）和初始饱和光强（Ek）均随深度的增加而降低。相反，光合效率（α）随深度增加而增加。所有集落在白天显示“轻度钙化”，钙化率随深度增加而降低。这些结果表明，藻类共生体对光环境的捕获和利用进行了调整。在所有的光强度，除了最低的，有一个一致的比率的钙化光合作用，与光增强钙化的概念。在最深处的低光照珊瑚中，没有证据支持光合作用导致的钙化，我们假设这些群体主要靠捕食浮游动物生存。
The hermatypic coral Stylophora pistillata has a wide bathymetric distribution (0 to 70 m). Within this range, light intensity decreases exponentially. Deep-water colonies are generally planar in morphology, with the upper part being dark and the bottom-facing part pale. Shallow-water colonies are generally subspherical and ivory in coloration. We studied the effects of photoacclima- tion on photosynthesis, respiration, and calcification in S. pistillata colonies along its bathymetric range over a reef profile (5 to 65 m) in Eilat, Gulf of Aqaba, Red Sea, during winter and summer, using a submersible respirometer. Respiration rate, light-saturated rate of photosynthesis (Pmax), compensa- tion light intensity (Ec), and light intensity of incipient saturation (Ek), all decreased with depth. In contrast, the efficiency of photosynthesis (α) increased with depth. All colonies displayed 'light- enhanced calcification' during daytime and decreasing calcification rates with depth. These results indicate an adjustment in harvesting and utilization of light by the algal symbionts to the light envi- ronment. At all light intensities except the lowest ones, there was a consistent ratio of calcification to photosynthesis, in agreement with the concept of light-enhanced calcification. In the deepest, low- light corals, there was no evidence for support of calcification by photosynthesis, and we assume that these colonies subsist mainly by preying on zooplankton.