中文摘要：

2011年4月期间,对北部湾北部海域水柱中颗粒有机碳（POC）、颗粒氮（PN）浓度及其同位素组成开展了研究,结果表明,研究海域水柱中的颗粒有机物主要受陆源输入和生物生产过程的影响.根据POC、PN、C/N比（摩尔比）、δ18C和δ15N的空间分布规律,可将研究海域区分为具有不同特征的3个区域,其中钦州湾外围海域的δ13C最低,反映出该区域颗粒有机物受陆源输入的影响较大;铁山港外围海域具有高的POC、PN和δ15N特征,C/N比也接近于Redfield比值,说明其颗粒有机物主要受控于生物初级生产过程;琼州海峡西侧海域呈现低POC和PN特征,与南海外海水的特征较为接近,而该区域同时具有低C/N比和低δ15N的特征,表明其受生物固氮作用的影响明显.

英文摘要：

Suspended particles in the northern Beibu Gulf were collected for measurements of particulate organic carbon （POC） and particulate nitrogen （PN） and their isotopic composition during April 2011.Our results showed that particulate organic matter in the northern Beibu Gulf was influenced by terrestrial input and biological production,and this influence could be divided into three sub- regions with different geochemical and isotopic characteristics. Particulate organic matter was mostly depleted in 813C around the Qinzhou Gulf,indicating the terrestrial influence. However, high POC, PN and 815N values were observed around the Tieshan Gulf with the C/N ratios closed to the Redfield ratio,suggesting the major contribution from the local biological production.In contrast, contents of POC and PN were low in the western Qiongzhou Strait,implying the intrusion of the South China Sea offshore waters. The most depleted in 81SN and the lowest C/N ratios suggested a significant contribution from the biological nitrogen fixation in ,he western Qiongzhou Strait.