环莱州湾主要河口氮磷组成特征及其输送贡献

Composition and transport of nitrogen and phosphorus in the main estuaries around Laizhou Bay

  • 摘要: 本研究于2018年10月、2019年5月和8月,调查环莱州湾主要河口、直排口和黄河口不同形态氮、磷组成和结构及其对莱州湾营养盐的相对输送贡献。环莱州湾河口水体氮、磷浓度较高,分布差异显著,东部河口总氮和总磷浓度总体高于西部和西南部河口,溶解无机氮/磷和溶解有机氮/磷达到较高水平。溶解有机氮和硝酸氮平均占总氮的59%和29%,成为莱州湾近岸氮的主要存在形式;不同形态磷的占比差异大,西部和西南部河口颗粒磷平均占比超过50%,可能限制磷的再生利用。环莱州湾河口水体的氮、磷组成和结构现状,将进一步扩大莱州湾“高氮、少磷”和高氮磷比特征。虽然环湾东部河口水体总氮和总磷浓度总体高于西部和西南部河口,但是径流量较高的黄河和小清河输送氮、磷的总体贡献超过90%。

     

    Abstract: Carried out in October 2018, May and August 2019, this study investigated the composition of nitrogen and phosphorus and their relative transport contribution in the main estuaries and discharge outlets around Laizhou Bay and Yellow River. The results show that both nitrogen and phosphorus were in high concentrations with significantly different spatial distribution. The concentrations of total nitrogen and phosphorus in eastern estuaries were generally higher than those in western and southwestern estuaries, and both dissolved inorganic and organic nitrogen to phosphorus ratios were in high levels. As the main forms of nitrogen, the dissolved organic nitrogen and nitrate accounted for 59% and 29%, respectively, of the total nitrogen in Laizhou Bay. The proportion of different phosphorus forms varied greatly, and the average proportion of particulate phosphorus exceeded 50% in the western and southwestern estuaries, which may limit the recycling of phosphorus. The composition and structure of nitrogen and phosphorus in the estuaries would further expand the characteristics of "high nitrogen, low phosphorus" and high nitrogen/phosphorus ratio in Laizhou Bay. Although the total nitrogen and phosphorus concentrations in the eastern estuaries were generally higher than those in the western and southwestern estuaries, the overall contribution of nitrogen and phosphorus from Yellow River and Xiaoqing River with high runoff was over 90%.

     

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