Seasonal discharge of estuarine freshwater to the western Chukchi Sea shelf identified in stable isotope profiles of mollusk shells
Seasonal discharge of estuarine freshwater to the western Chukchi Sea shelf identified in stable isotope profiles of mollusk shells
复制标题
软体动物壳稳定同位素剖面鉴定出河口淡水季节性排放到楚科奇海西部陆架
DOI：
10.1029/2003jc001816
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发表时间：
2003
影响因子：
--
通讯作者：
J. Grebmeier
中科院分区：
文献类型：
--
作者：
B. Khim;D. Krantz;L. Cooper;J. Grebmeier
[1]双壳类软体动物（Serripes groenlandicus和Macoma calcarea）的氧和碳同位素剖面记录了白令海峡地区与河口淡水从Kolyuchin湾到楚科奇海西部的季节性排放相关的水团性质的明显变化。δ 18 O剖面中的周期与贝壳生长带相关，并解释为年度;最大δ 18 O值对应于最冷的水温，与标志着冬季生长较慢的贝壳中的黑暗内部带相吻合。两个样本（HX 68和HX 65）冬季基线δ 18 O值之间0.5 ‰的偏移，在不同的距离河口排放，归因于海水δ 18 O的差异，这两个网站之间，并表明河口水的影响持续通过一年中的大部分时间。采集于楚科奇海白令海峡以北的标本AK 55的同位素剖面反映了来自白令海峡以南的白令海峡-阿纳德尔水。δ 13 C剖面的比较表明，HX 68，收集更接近Kolyuchin湾，具有高幅度的负δ 13 C偏移与溶解的无机碳，同位素贫化13 C，可能来自陆地径流的结合。δ 18 O和δ 13 C值之间存在显著的正相关关系，表明稳定同位素剖面反映了环境水团的性质。这些结果表明，软体动物壳的稳定同位素配置文件可以作为水团特性的代理指标，特别是在北极沿海地区的径流事件，物流难以直接采样。
[1] Oxygen and carbon isotope profiles of bivalve mollusks (Serripes groenlandicus and Macoma calcarea) record distinct changes of water mass properties in the Bering Strait region associated with the seasonal discharge of estuarine freshwater from Kolyuchin Bay into the western Chukchi Sea. Cycles in the δ18O profiles are correlated with shell growth bands and interpreted as annual; maximum δ18O values corresponding to coldest water temperatures coincide with dark internal bands in the shell that mark slower growth during winter. A 0.5 ‰ offset between the baseline winter δ18O values of two specimens (HX68 and HX65), at different distances from the estuarine discharge, is attributed to a difference in seawater δ18O between the two sites and indicates that the influence of the estuarine water persists through much of the year. The isotope profiles of specimen AK55, collected north of Bering Strait in the Chukchi Sea, reflect the Bering Shelf-Anadyr Water flowing from south of Bering Strait. Comparison of the δ13C profiles shows that HX68, collected closer to Kolyuchin Bay, has high-amplitude negative δ13C excursions associated with incorporation of dissolved inorganic carbon that is isotopically depleted in 13C, probably from terrestrial runoff. The significant positive correlation between δ18O and δ13C values in these specimens suggests that the properties of the ambient water masses are reflected in the stable isotope profiles. These results show that the stable isotope profiles of mollusk shells can serve as proxy indicators of water mass properties, particularly during runoff events in Arctic coastal regions that are logistically difficult to sample directly.