Oxygen and carbon isotope records of cultured freshwater pearl mussel Hyriopsis sp. shell from Lake Kasumigaura, Japan
Oxygen and carbon isotope records of cultured freshwater pearl mussel Hyriopsis sp. shell from Lake Kasumigaura, Japan
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养殖淡水珍珠蚌的氧和碳同位素记录。
DOI：
10.1007/s10933-009-9341-8
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
H
中科院分区：
文献类型：
--
作者：
Yoshimura;T.;Nakashima;R.;Suzuki;A.;Tomioka;N.;Kawahata;H
本文介绍了养殖淡水珍珠贻贝（Hyriopsissp.）的氧、碳同位素比值和形态结构。贝壳和珍珠。外壳层δ18O沿最大生长轴的一阶波动次数与养殖年数一致。控制年δ18O波动的主要因素是水温，环境水δ18O变化的贡献较小，尤其是在雨季。δ13C值在贻贝的整个生命周期中几乎是恒定的，表明体型对贝壳δ13C的贡献很小。我们在壳的外表面观察到九个明显的扰动环。5个环与δ18O剖面的5个冬季峰值相吻合，表明冬季生长在约10°C以下停止，可能是由于低水温时生长不活跃或繁殖。所有年份均未观测到夏季扰动环。此外，一些夏季环在内部结构上表现出不连续性。这些发现表明，夏季生长停止可能是由偶发事件引起的，如暴雨，因为溶解氧浓度降低。δ18O剖面和壳结构表明，壳文石的沉淀与周围水体氧同位素组成接近平衡。贝壳可以潜在地用于重建过去的水文条件。珍珠的δ18O值表明，钙化发生在至少13 ~ 23℃的温度范围内。本种珍珠钙化的适宜温度低于海洋珍珠钙化的适宜温度。
We present oxygen and carbon isotope ratios and the morphological structure of the cultured freshwater pearl mussel (Hyriopsissp., Unionidae) shell and pearl. The number of first-order fluctuations of δ18O of the outer shell layer along the maximum growth axis was consistent with the number of cultured years. The dominant factor controlling annual δ18O fluctuations was water temperature with a minor contribution from the variation in δ18O of ambient water, especially during the rainy season. The δ13C values were approximately constant throughout the life of the mussel, suggesting that the contributions of body size to δ13C of the shell were minor. We observed nine distinct disturbance rings on the outer surface of the shell. Five rings coincided with the five winter peaks of the δ18O profile, indicating winter growth cessation below approximately 10°C, probably because of either inactive growth at low water temperatures or reproduction. Summer disturbance rings were not observed in all years. Moreover, some summer rings showed discontinuity in the inner structure. These findings suggest that summer growth cessation may be caused by occasional events such as heavy rains, as the decrease of dissolved oxygen concentration. The δ18O profile and shell structures indicated that shell aragonite was precipitated at close to equilibrium conditions with respect to the oxygen isotope composition of the ambient water.Hyriopsissp. shells can potentially be used for reconstruction of past hydrologic conditions. The δ18O of a pearl indicated that calcification occurred over a temperature range of at least 13–23°C. The optimal temperature for pearl calcification in this species is lower than that for marine pearl calcification.