茅尾海沉积物营养物质空间分布特征研究

Spatial Distribution of Nutrients in Sediments of the Maowei Sea

弄清沉积物中营养物质(如氮和磷)的迁移富集规律,对于海域的渔业资源保护和利用、疏浚沉积物综合利用与生态环境功能恢复都非常重要。2010年1月在茅尾海设置7个采样点,分层采集0~30 cm的沉积物样品,研究了茅尾海沉积物中有机质、总氮、无机氮、总磷和溶解性磷酸盐等营养物质的空间分布特征,并利用有机指数法对其营养水平进行了评价。结果表明,有机质、总氮与无机氮含量自茅尾海湾内至湾外呈显著下降的空间变化趋势,有机质在垂向分布上变化不明显,总氮与无机氮含量呈现逐渐增大的趋势,但不显著,3种营养物质之间均有极显著的正相关关系(P【0.01);而总磷与溶解性磷酸盐在水平与垂向分布上总体均呈现'低-高-低'波浪型的变化趋势,两项指标在湾内与湾外、各层次间未出现显著性差异,而两者间有极显著的正相关关系(P【0.01),且相关系数高达0.96,表明有机质、总氮与无机氮,总磷与溶解性磷酸盐两组营养物质各有同源性。调查海域的有机指数平均值为0.06,属高营养,且位于湾内的3个站点均超过0.08,处于严重污染的高营养状态;C/N值表明,调查海域的营养物质除少量来源于藻类和浮游生物外,多数来源于周边的陆生环境。

Understanding environmental processes of nutrients(e.g., nitrogen and phosphorus)in sediments is crucial for fishery, environmental protection and management. Spatial distribution patterns of organic matter(OM), total nitrogen(TN), inorganic nitrogen(IN), total phosphorus(TP)and soluble reactive phosphate(SRP)were investigated in surface sediments(0~30 cm)sampled at seven sites of the Maowei Sea in January 2010. Concentrations of OM, TN and IN decreased from the inner bay to the outer parts. Organic matter did not change at different depths, but concentrations of TN and IN tended to decrease with depths. Significant positive relationships were found amongst OM, TN and IN. Total phosphorus and SRP had low-high-low patterns from the inner to the outer and along depths, and were significantly correlated(r=0.96, P<0.01). The nutrient index was averagely 0.06 across the sampling sites, with greater than 0.08 at three sites located in the inner bay, indicating high pollution of these sites. High C/N ratio suggested that nutrients in the sediments mainly came from terrestrial ecosystems.