DataSheet_2_Trophic diversity of chemosymbiont hosts in deep-sea hydrothermal vents using amino acid nitrogen isotopes.xlsx

Chemosymbiotic species inhabiting deep-sea hydrothermal vents are known to rely on microbial symbionts for nutrition. However, the relative contributions of heterotrophic energy sources to their diets remain poorly understood. In this study, we investigate the trophic positions (TP) of symbiont-bearing taxa, including vent mussels, snails, and shrimps, and examine the contribution of copepods and detrital organic matter (OM) to the food chain. Amino acid nitrogen isotopic compositions (δ15NAA) were used to investigate the TP of vent mussels (Bathymodiolus septemdierum and Gigantidas vrijenhoeki), snails (Alviniconcha spp.), and shrimps (Alvinocaris sp. and Rimicaris kairei) from two different vent environments. δ15NAA values in copepods and OM were also measured. Microbial resynthesis index (ΣV) was calculated to predict the contribution of reworked OM as an energy source to the hydrothermal vent ecosystem. Variations in TP were observed among vent mussels and snails from different vent environments, with higher TP in species from diffusing vents than in those from black smoker vents. Shrimps dwelling in a single diffusing vent exhibited distinct TP, suggesting that microhabitat and phylogeny may influence their energy acquisition. Notably, copepods occupied higher TPs than expected, possibly owing to the consumption of detrital OM. Our findings provide new insights into the trophic diversity of chemosymbiotic species in deep-sea hydrothermal vents and demonstrate the utility of δ15NAA analysis as a tool for unraveling food web dynamics and ecosystem functioning in these unique environments.

栖息于深海热液喷口的化能共生物种，众所周知，它们依赖微生物共生体以获取营养。然而，异养能量来源在它们饮食中的相对贡献仍然理解不足。在本研究中，我们调查了携带共生体的类群（包括喷口贻贝、蜗牛和虾）的生态位（TP），并检验了桡足类和碎屑有机物质（OM）对食物链的贡献。通过氨基酸氮同位素组成（δ15NAA）研究了来自两个不同喷口环境的喷口贻贝（Bathymodiolus septemdierum 和 Gigantidas vrijenhoeki）、蜗牛（Alviniconcha spp.）和虾（Alvinocaris sp. 和 Rimicaris kairei）的TP。桡足类和OM中的δ15NAA值也进行了测量。计算微生物重合成指数（ΣV）以预测重加工OM作为能量来源对热液喷口生态系统的贡献。观察到来自不同喷口环境的喷口贻贝和蜗牛的TP存在差异，扩散喷口物种的TP高于黑烟囱喷口物种。居住在单一扩散喷口的虾表现出独特的TP，这表明微生境和系统发育可能影响它们的能量获取。值得注意的是，桡足类的TP高于预期，这可能是由于消费碎屑OM。我们的发现为深海热液喷口中的化能共生物种的摄食多样性提供了新的见解，并证明了δ15NAA分析作为揭示这些独特环境中食物网动态和生态系统功能的有用工具。