珠江口海域无机氮和活性磷酸盐含量的时空变化特征

主要利用1998年在珠江口海域连续同步观测资料，研究该海域无机氮、活性磷酸盐含量和富营养化状况。结果表明，无机氮主要来自四个口门的径流，但深圳湾附近的陆源亦有一定贡献；无机氮的形态主要以硝酸氮为主，而在深圳湾附近海域则以氨氮为主；无机氮含量普遍超过0．30mg/dm^3的我国海水水质标准二类标准值，大部分海域已超过0．50mg/dm^3的四类水质标准值，径流对活性磷酸盐含量的贡献不显著，而深圳湾附近的陆源则有明显的贡献，从珠江口附近由沿岸流和涨潮流带来的活性磷酸盐亦有明显的影响；除深圳湾附近海域活性磷酸盐含量超过0．030mg/dm^3的二类海水水质标准值外，其他海域基本符合0.015mg/dm^3的一类海水水质标准值要求。该海域的N／P值普遍较高，而且北部海域的高于南部海域；最高值超过300，最小值也大小30；该水域的营养盐主要为磷限制。

Temporal and spatial variation characteristics of inorganic nitrogen and active phosphorus in Zhujiang Estuary

Continuous and synchronous vertical profiles of NO 3-N, NO 2-N, NH 3-N, PO 4-P, Chl-a, salinity, temperature and other chemical parameters were taken at 10 stations in March, 1998 in the Zhujiang Estuary in order to analyze the status and characteristics of eutrophication. The results confirmed that inorganic nitrogen mainly comes from the runoff of four river channels, and also the terrigenous sources from the area near Shenzhen Bay. NO 3-N is the main form of inorganic nitrogen in most area, and NH 3-N is the main form near Shenzhen Bay. The concentrations of inorganic nitrogen are generally above 0.30mg/dm 3 (the second grade of seawater quality standard in China) in the estuary, and more than 0.50 mg/dm 3 (the forth grade of seawater quality standard of China) in most part. Active phosphorus from four river channels is not main sources, but terrigenous sources from the area near Shenzhen Bay are obvious, and active phosphorus near the estuary brought by coastal current and flood current also shows obvious influence. The concentrations of active phosphorus are generally lower than 0.015mg/dm 3 (the first grade of seawater quality standard) except the area near Shenzhen Bay. The ratios of N/P are generally high, and it is higher in the north than in the south. The highest ratio is higher than 300, and the lowest one is more 30. This indicates that active phosphorus was a limiting nutrient in the estuary.