珠江口伶仃洋海域营养盐的历史变化及影响因素研究

History change and influence factor of nutrient in Lingdinyang sea area of Zhujiang River Eestuary

根据2006年丰水期和枯水期对珠江口伶仃洋海域的调查资料,分析了该海域营养盐的现状,发现丰水期NO3-N和SiO3-Si含量呈自口门向外逐渐降低的变化,NO2-N和PO4-P高值区则集中在深圳附近海域,枯水期各项营养盐均呈自口门向外逐渐降低的变化。结合1990年、1998年、2001年3个年份的资料,分析了珠江口邻近海域5项营养盐(SiO3-Si,NO3-N,NO2-N,NH4-N和PO4-P)近20 a来的变化规律,并对其影响因素进行了探讨和分析。结果发现,NO3-N,NO2-N,NH4-N和PO4-P含量呈现显著上升趋势,DIN/DIP呈下降趋势。NO3-N和SiO3-Si含量丰水期显著高于枯水期,NO2-N和PO4-P则相反,径流携带作用是NO3-N和SiO3-Si的主要来源,而径流对NO2-N和PO4-P则起稀释作用。另外农业施肥的影响、围填海造成的海域面积缩小以及网箱养殖业饵料的不合理投放亦是造成珠江口伶仃洋海域DIN,DIP含量上升的因素。

Based on the data obtained by field survey and experiments of the Zhujiang River Estuary in 2006, the distribution and concentration of nutrients in water mass of the Lingdingyang sea area are studied. It is discovered that there is a large content of nitrite and phosphate nearby Shenzhen sea area, and contents of nitrate and silicate constantly reduced off the Zhujiang River Estuary in wet season. The con tents of five nutrients constantly reduced off the Zhujiang River Estuary in dry season. Based on the historical data obtained in 1990, 1998 and 2000, the variation of nutrients in water mass of the Lingdingyang sea area is studied, and the influence factors are also discussed. The results show that the contents of nitrate, nitrite, and phosphate in water mass increased remarkably, but DIN/DIP reduced constantly. The contents of nitrate and silicate in wet season are higher than dry season, but nitrite and phosphate is oppo site. The runoff is an important source for nitrate and silicate, but it plays dilution function to nitrite and phosphate. In addition, the agriculture fertilizer, the sea area acreage reduction caused by filling the sea, the unreasonable utilization of bait in net cage culture are also the main reasons which bring about the increase of DIN and DIP concentration in water mass of Lingdingyang sea area.