ABSTRACT Benthic invertebrates are a crucial trophic link in Arctic marine food webs. However, estimates of the contribution of different primary production sources sustaining these organisms are not well characterised. We measured the stable carbon isotope values (δ13C) of essential amino acids (EAAs) in muscle tissue from two common bivalve genera (Macoma spp. and Astarte spp.) collected in Hanna Shoal in the northeastern Chukchi Sea. Mixing models comparing the δ13CEAA fingerprints of the bivalves to a suite of primary production endmembers revealed relatively high contributions of EAAs from phytoplankton and bacteria in both species. We also examined whether δ13CEAA fingerprints could be produced from the EAAs preserved in bivalve shells, which could allow primary production sources to be estimated from ancient bivalve shells. The δ13CEAA fingerprints from a suite of paired modern bivalve shells and muscle from Macoma calcarea from across the Chukchi Sea revealed a correspondence between the estimates of the dominant primary production source of EAAs derived from analyses of these two tissue types. Our findings indicate that δ13CEAA fingerprinting of marine bivalves can be used to examine dominant organic matter sources in the Arctic marine benthos in recent years as well as in deeper time.

中文翻译：

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使用氨基酸稳定碳同位素指纹识别北极双壳类初级生产的来源

摘要底栖无脊椎动物是北极海洋食物网中重要的营养环节。然而，对维持这些生物体的不同初级生产来源的贡献的估计并没有得到很好的表征。我们测量了在楚科奇海东北部汉纳浅滩收集的两种常见双壳类动物属（Macoma 属和 Astarte 属）肌肉组织中必需氨基酸 (EAA) 的稳定碳同位素值 (δ13C)。将双壳类动物的 δ13CEAA 指纹与一组初级生产端成员进行比较的混合模型显示，这两种物种中浮游植物和细菌的 EAA 贡献相对较高。我们还检查了 δ13CEAA 指纹是否可以从保存在双壳贝壳中的 EAA 中产生，这可以允许从古代双壳贝壳中估计主要生产来源。来自楚科奇海对面 Macoma calcarea 的一组现代双壳类贝壳和肌肉的 δ13CEAA 指纹揭示了对这两种组织类型的分析得出的 EAA 主要初级生产来源的估计值之间的对应关系。我们的研究结果表明，海洋双壳类动物的 δ13CEAA 指纹图谱可用于检查近年来以及更深层次的北极海洋底栖动物中的主要有机物质来源。