Controls on the stable isotope composition of seasonal growth bands in aragonitic fresh-water bivalves (unionidae)
Controls on the stable isotope composition of seasonal growth bands in aragonitic fresh-water bivalves (unionidae)
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DOI：
10.1016/s0016-7037(99)00020-4
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发表时间：
1999-04-01
影响因子：
5
通讯作者：
Lohmann, KC
中科院分区：
文献类型：
--
作者：
Dettman, DL;Reische, AK;Lohmann, KC
1990年9月下旬至1992年6月，对密歇根州南部的休伦河和弗莱明河两条河流的水温、氧同位素组成和溶解无机碳的增量(13)C进行了测量。对1992年采集的3条河流的贝壳类进行了30微米分辨率的稳定同位素分析。根据生物成因文石的分馏关系，准确地预测了贝壳珍珠层和棱柱层的~(18)O。3个物种的高分辨率采样和3个其他物种的批量采样表明，所有的球藻都符合这一氧同位素分馏关系。这一关系被用来表明贝壳的生长在大约12摄氏度以下停止。在这两种情况下，贝壳的平均增量(18)O值(PDB标度)在河水平均三角洲(18)O(SMOW标度)的千分之0.5以内。因此，Unonids可用于基于氧同位素的古气候和古水文重建。相反，已发表的DIC和碳酸盐分馏系数并不能准确地预测壳层的碳同位素比值。壳层三角洲(13)C比预测值更负，偏移量变化很大，表明代谢碳显著和可变地并入壳层碳酸盐中。版权所有(C)1999爱思唯尔科学有限公司。
Water temperature, oxygen isotope composition and the delta(13)C of dissolved inorganic carbon were measured in 2 southern Michigan rivers, the Huron River and Fleming Creek, between late September 1990 and June 1992. The final full year of shell growth in 3 unionids collected in 1992 from these rivers was sampled for stable isotope analysis with a resolution of 30 mu m The delta(18)O of both shell nacre and the prismatic layer is accurately predicted by a fractionation relationship developed for biogenic aragonite. High resolution sampling of 3 species and bulk sampling of 3 other species suggest that all unionids adhere to this oxygen isotope fractionation relationship. This relationship is used to show that shell growth ceases below approximately 12 degrees C. In these 2 settings the average delta(18)O value of shell (PDB scale) is within 0.5 parts per thousand of the average delta(18)O of river water (SMOW scale). Unionids can therefore be used in oxygen-isotope-based paleoclimatic and paleohydrologic reconstructions. In contrast, the carbon isotope ratio of shell is not accurately predicted by published fractionation factors between D.I.C. and carbonate. Shell delta(13)C is more negative than predicted values and the offset is highly variable suggesting a significant and variable incorporation of metabolic carbon into the shell carbonate. Copyright (C) 1999 Elsevier Science Ltd.