Deep-sea coral geochemistry: Implication for the vital effect
Deep-sea coral geochemistry: Implication for the vital effect
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DOI：
10.1016/j.chemgeo.2005.08.009
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发表时间：
2005-12
期刊：
影响因子：
3.9
通讯作者：
K. Shirai;M. Kusakabe;S. Nakai;T. Ishii;Tsuyoshi Watanabe;H. Hiyagon;Y. Sano
中科院分区：
文献类型：
--
作者：
K. Shirai;M. Kusakabe;S. Nakai;T. Ishii;Tsuyoshi Watanabe;H. Hiyagon;Y. Sano
深海珊瑚作为古海洋学重要方面的关键，至少有两个原因，1）它们提供了深海环境的时间高分辨率记录，因为它们具有生长带结构，2）它们非常适合研究生命效应，因为深海环境不会在短时间内发生变化。然而，深海珊瑚骨骼的化学成分与环境因素之间的关系还不清楚。在这项研究中，深海珊瑚的化学成分是在散装个人和沿着骨骼微结构测量。在个体中，δ 18 O值和Sr/Ca比值与环境温度呈弱负相关。另一方面，Mg/Ca比与温度具有正的弱相关性。在相似温度下采集的样品之间发现了很大的差异。在平均温度1 ℃以内的样品中，δ 18 O、Sr/Ca比值和Mg/Ca比值的变化分别高达3.8‰、0.9mmol/mol和0.78mmol/mol。这种变化可能是由于一个大的生命效应。高钙化率下形成的钙化中心（COCs）与周围纤维束相比，Sr/Ca、U/Ca值较低，Mg/Ca值较高。这种化学分布支持了元素掺入取决于钙化速率的模型。这表明，钙化率是深海珊瑚化学组成的一个非常重要的因素，也是生命效应的最重要机制之一。由于这种巨大的生命效应，必须进行进一步调查，以使用深海珊瑚作为温度代用指标。
Deep-sea corals hold a great potential as a key to important aspects of paleoceanography for at least two reasons, 1) they offer temporal high resolution records of deep-sea environment, because they have growth banding structures, 2) and they are well suited for studying vital effects, because the deep-sea environment does not change over short time scales. However, the relationship between the chemical composition of deep-sea coral skeletons and environmental factors is not well understood. In this study, the chemical composition of deep-sea corals was measured in bulk individuals and along skeletal micro-structures. Among the bulk individuals, δ18O value and Sr/Ca ratio show a negative but weak correlation with ambient temperature. On the other hand, the Mg/Ca ratio has a positive, weak correlation with the temperature. Large variations were found among samples collected from similar temperature. The variation is up to 3.8‰ for δ18O, 0.9 mmol/mol for Sr/Ca ratios, and 0.78 mmol/mol for Mg/Ca ratios among samples with ambient average temperature within 1 °C. This variation may be due to a large vital effect. The centers of calcification (COCs), which were formed at high calcification rate, have lower Sr/Ca, U/Ca and higher Mg/Ca ratios than surrounding fasciculi. This chemical distribution supports the model that elemental incorporation depends on calcification rate. This suggests that calcification rate is a very important factor for the chemical composition in deep-sea corals and is one of the most significant mechanisms of the vital effect. Because of this large vital effect, further investigations are essential to use the deep-sea coral as a temperature proxy.