In recent decades, global aquaculture has expanded rapidly, raising concerns about coastal environmental degradation due to unregulated or poorly regulated discharge of aquaculture tailwater. Despite the crucial role of dissolved organic matter (DOM) in biogeochemical processes and aquatic biodiversity, the influence of aquaculture type on the molecular characteristics of DOM remains largely unexplored. Herein, this study investigated the variations in chemical and spectroscopic properties as well as molecular characteristics and composition of DOM across different aquaculture types including crustacean, fish and shellfish. Our findings revealed notable differences in DOM quantities among different aquaculture types, with crustacean and fish aquaculture water containing higher DOM amount compared to shellfish aquaculture water. This disparity can be attributed to the more frequent formulated feeds of crustacean and fish in contrast to shellfish aquaculture. Furthermore, distinct differences were also observed in the characteristics and composition of DOM among the different aquaculture waters. Specifically, DOM in shellfish aquaculture water exhibited a higher abundance of unsaturated and reduced molecules as well as increased aromaticity compared to the other two aquaculture waters. Conversely, DOM from fish aquaculture water showed a greater contribution from terrestrial origin characterized by elevated levels of plant-based components such as lignin-like and tannin-like compounds. Interestingly, DOM from shellfish aquaculture water contained lower levels of microbial-derived components such as lipid-like and protein-like compounds, likely due to reduced microorganism populations resulting from lower nutrients availability and higher salinity. Overall, these significant variations in characteristics and composition of DOM underscore the potential impacts of aquaculture type on the DOM biogeochemical cycle and the environmental quality in aquatic ecosystems.

中文翻译：

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探索水产养殖类型驱动的溶解有机物分子特征的变化


近几十年来，全球水产养殖迅速扩张，引发了人们对水产养殖尾水排放不受监管或监管不力导致沿海环境退化的担忧。尽管可溶性有机物 （DOM） 在生物地球化学过程和水生生物多样性中起着至关重要的作用，但水产养殖类型对 DOM 分子特性的影响在很大程度上仍未得到探索。在此，本研究调查了包括甲壳类、鱼类和贝类在内的不同水产养殖类型中 DOM 的化学和光谱特性以及分子特征和组成的变化。我们的研究结果揭示了不同水产养殖类型之间 DOM 数量的显着差异，与贝类水产养殖水相比，甲壳类和鱼类养殖水的 DOM 含量更高。这种差异可归因于与贝类养殖相比，甲壳类和鱼类的配方饲料更频繁。此外，在不同水产养殖水域中，DOM 的特性和组成也存在明显差异。具体来说，与其他两种水产养殖水域相比，贝类养殖水中 DOM 表现出更高的不饱和分子和还原分子丰度以及更高的芳香性。相反，来自鱼类养殖水的 DOM 显示出来自陆地来源的更大贡献，其特征是植物成分（如木质素样和单宁样化合物）水平升高。有趣的是，来自贝类养殖水的 DOM 含有较低水平的微生物衍生成分，例如脂质样和蛋白质样化合物，这可能是由于营养物质可用性较低和盐度较高导致微生物种群减少。 总体而言，DOM 特征和组成的这些显着变化强调了水产养殖类型对 DOM 生物地球化学循环和水生生态系统环境质量的潜在影响。