Abstract The values of δ13C and δ15N in POM and nutrient concentrations were investigated in the surface water of Jiaozhou Bay during spring, summer and autumn. Results showed that eutrophic conditions were generally the highest in the northeastern bay during the three seasons. It suggested the sewage from urban rivers were the major pollution source in the northeastern Jiaozhou Bay. The δ13C value of POM was significantly higher in the inner bay in spring, but lower in summer. Seasonal distribution of δ13C in POM seems depended on the balance between terrigenous organic matter input and in situ phytoplankton biomass. In contrast, δ15NPOM showed a consistent distribution pattern during the three seasons, where it was higher in the northwest and lower in the northeast. It suggests that a different source or intensity of anthropogenic nutrient loading may have an opposite effect on the δ15N value of POM. The significantly depleted 15N in POM indicated the strong influence of urban sewage in northeastern Jiaozhou Bay. This study suggested the δ13C and δ15N of POM can effectively indicate the influence of anthropogenic nutrients loading in coastal bays. However, the effects may vary depending on the source and strength of nutrients loading.

中文翻译：

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人为养分输入对胶州湾悬浮颗粒有机物稳定碳氮同位素的影响

摘要 对胶州湾地表水春、夏、秋季水体中POM中δ13C、δ15N含量及养分浓度进行了调查。结果表明，东北湾三个季节的富营养化条件普遍最高。说明城市河流污水是胶州湾东北部的主要污染源。内湾POM的δ13C值春季显着较高，夏季较低。POM 中 δ13C 的季节性分布似乎取决于陆源有机质输入和原位浮游植物生物量之间的平衡。相比之下，δ15NPOM在三个季节表现出一致的分布格局，即西北偏高、东北偏低。这表明不同来源或强度的人为营养负荷可能对 POM 的 δ15N 值产生相反的影响。POM中15N的显着消耗表明胶州湾东北部城市污水的影响很大。本研究表明 POM 的 δ13C 和 δ15N 可以有效地指示沿海海湾人为营养物质负荷的影响。然而，效果可能会因营养负荷的来源和强度而异。