Upwelling, species, and depth effects on coral skeletal cadmium-to-calcium ratios (Cd/Ca)
Upwelling, species, and depth effects on coral skeletal cadmium-to-calcium ratios (Cd/Ca)
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DOI：
10.1016/j.gca.2008.05.064
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发表时间：
2008-09
影响因子：
5
通讯作者：
K. Matthews;A. Grottoli;W. McDonough;James E. Palardy
中科院分区：
文献类型：
--
作者：
K. Matthews;A. Grottoli;W. McDonough;James E. Palardy
skeleton镉钙（Cd/Ca）的比例在造礁石石珊瑚已被用来重建上升流随着时间的推移的变化，但还没有一个系统的评价，这种示踪剂的自然变异性内和珊瑚物种之间，深度和跨环境条件。在这里，在巴拿马湾（太平洋）的上升流和非上升流间隔期间，测量了在两个深度（1 m和7 m）饲养的多个孔雀藻、大孔雀藻和叶滨珊瑚群落中珊瑚骨骼的镉/钙比。总体而言，骨骼镉/钙比值显着高于在上升流期间比非上升流，在浅比深珊瑚，并在这两个物种的孔雀比P.裂叶珊瑚。与其他物种相比，裂叶松骨骼Cd/Ca比值均较低，上升流和非上升流值之间无显著差异。在同一物种的殖民地，骨骼Cd/Ca比值始终较高，在所有浅的P. lactea殖民地在上升流相比，nonupwelling，虽然增加的幅度各不相同的殖民地。对于P. lobata，P. clavus和深P. lobtea，骨骼Cd/Ca比值的变化是不一致的，在所有的殖民地，与一些殖民地有较低的比例在上升流期间比在nonupwelling。骨骼Cd/Ca比值与最大线性骨骼延伸δ 13 C或δ 18 O之间没有统计学显著关系，表明在季节分辨率下，Cd/Ca信号分别与生长速率、珊瑚代谢以及海洋温度和盐度解耦。结果表明：（1）珊瑚骨骼Cd/Ca比值与骨骼伸展、珊瑚代谢和环境温度/盐度无关;（2）浅水珊瑚是重建古涌的最可靠物种;（3）重建古涌事件需要多个珊瑚群体的平均Cd/Ca记录，而不是单个珊瑚的平均Cd/Ca记录。
Skeletal cadmium-to-calcium (Cd/Ca) ratios in hermatypic stony corals have been used to reconstruct changes in upwelling over time, yet there has not been a systematic evaluation of this tracer’s natural variability within and among coral species, between depths and across environmental conditions. Here, coral skeletal Cd/Ca ratios were measured in multiple colonies of Pavona clavus, Pavona gigantea and Porites lobata reared at two depths (1 and 7m) during both upwelling and nonupwelling intervals in the Gulf of Panama (Pacific). Overall, skeletal Cd/Ca ratios were significantly higher during upwelling than during nonupwelling, in shallow than in deep corals, and in both species of Pavona than in P. lobata. P. lobata skeletal Cd/Ca ratios were uniformly low compared to those in the other species, with no significant differences between upwelling and nonupwelling values. Among colonies of the same species, skeletal Cd/Ca ratios were always higher in all shallow P. gigantea colonies during upwelling compared to nonupwelling, though the magnitude of the increase varied among colonies. For P. lobata, P. clavus and deep P. gigantea, changes in skeletal Cd/Ca ratios were not consistent among all colonies, with some colonies having lower ratios during upwelling than during nonupwelling. No statistically significant relationships were found between skeletal Cd/Ca ratios and maximum linear skeletal extension, δ13C or δ18O, suggesting that at seasonal resolution the Cd/Ca signal was decoupled from growth rate, coral metabolism, and ocean temperature and salinity, respectively. These results led to the following conclusions, (1) coral skeletal Cd/Ca ratios are independent of skeletal extension, coral metabolism and ambient temperature/salinity, (2) shallow P. gigantea is the most reliable species for paleoupwelling reconstruction and (3) the average Cd/Ca record of several colonies, rather than of a single coral, is needed to reliably reconstruct paleoupwelling events.