九龙江河口区营养盐分布特征及其影响因素分析

根据2009、2010年"丰水期"和"枯水期"四航次九龙江河口混合区的调查资料,且结合历史资料对营养盐含量及分布特征、周日变化特征进行了统计和相关分析,研究了九龙江流域营养盐输入海洋的变化过程,探讨九龙江河口营养盐伴随潮汐变化,以及河口混合过程中的生物地球化学行为。调查期间溶解无机氮、硅和磷含量的平面分布呈现出由径流冲淡水高值向河口外海端递减的变化趋势;在涨潮时,河口区感潮段高溶解无机氮、硅、磷营养盐的陆源冲淡水与低溶解无机氮、硅、磷营养盐外海水相遇,随着外海水的侵入,外海水的作用逐渐加强,在稀释混合过程中呈现出无机营养盐逐步降低的变化趋势,退潮时则相反;营养盐在这复杂的河口过程中往往表现出在水动力的作用下稀释混合是主要过程,无机氮和活性硅酸盐在河口稀释混合过程中呈现保守性特征,活性磷酸盐在河口转移(补充)过程的行为复杂化,呈现缓冲作用为主。

Analysis of the nutrient distribution features and affecting factors in the Jiulongjiang estuary

Based on historical data and the four surveys in the wet season and dry season of 2009 and 2010 in Jiulongjiang estuary, the concentration and distribution of nutrient were discussed during the mixing process. Furthermore, the daily variation of nutrient concentration with the tide was also discussed. The results showed that: (1) the concentration of total dissolved inorganic nitrogen, silicate and phosphate all gradually decreased from the river runoff to seawater; (2) in high tide, during the mixing process of the runoff with high nutrient concentration and the seawater with low concentration of nutrient, the concentration of nutrient decreased due to seawater. On the contrary, in ebb, the concentration of nutrient increased due to the runoff; (3) during the mixing process in Jiulongjiang estuary, nitrogen and silicate were both conservatively diluted, but phosphate was buffered because of the complicated transfer and complement of phosphate.