The isotopic composition (δ¹³C and δ¹⁵N), organic carbon and nitrogen contents and C/N ratios of suspended particulate organic matter (POM) collected from the Pearl River Estuary and the adjacent shelf during spring and summer of 2017 were determined to understand the main controlling factors of spatiotemporal distribution and to elucidate the sources of particulate organic matter. Our study revealed considerable spatial variability of these parameters. In summer, δ¹³C in the Pearl River Estuary generally increased seawards, reflecting the increasing contribution of marine organic matter. Domestic sewage and industrial wastewater were responsible for relatively high δ¹⁵N in the Pearl River Estuary. In spring, δ¹³C on the adjacent shelf generally decreased from land to sea, with elevated δ¹³C occurred at the nearshore stations, suggesting that the eutrophic level, phytoplankton biomass and microbial activity played an important role in determining the sources of POM. Compared with δ¹³C, δ¹⁵N values displayed a complicated spatial distribution. Especially in the bottom water, enriched δ¹⁵N would be influenced by the degradation and mineralization of suspended matter. Given that isotopic values in summer can be applied in source apportionment, a Bayesian isotope mixing model was used to estimate that in summer the marine and terrestrial organic matter contributed 47% and 38% in the Pearl River Estuary, respectively. The greatest contribution from marine-derived POM (73%) was observed on the adjacent shelf.

同位素组合物（δ ¹³ C和δ ¹⁵ N），弹簧和2017夏季有机碳和氮含量和从珠江口和相邻的架子收集悬浮粒状有机物（POM）C / N比被确定为了解时空分布的主要控制因素，并阐明有机颗粒物的来源。我们的研究表明这些参数的空间变异性很大。在夏季，δ ¹³下在珠江口普遍增加向海，反映的海洋有机物的越来越大的贡献。生活污水和工业废水负责相对高的δ ¹⁵在珠江口ñ。在弹簧，δ ¹³C中的相邻的货架上通常从陆地下降到海中，与升高的δ ¹³ Ç发生在近岸站，这表明富营养化水平，浮游植物生物质和微生物活性在确定POM的源发挥了重要作用。与δ相比较¹³ C，δ ¹⁵的N个值中显示的复杂的空间分布。尤其是在底部的水，富集的δ ¹⁵氮会受到悬浮物的降解和矿化的影响。考虑到夏季的同位素值可用于源解析，贝叶斯同位素混合模型用于估算夏季，珠江口的海洋和陆地有机物分别占47％和38％。在邻近的架子上观察到了来自海洋的POM的最大贡献（73％）。