钦州湾内湾茅尾海营养状况分析与评价研究

根据2011年-2012年茅尾海水质监测调查资料分析其营养特征,结果显示:茅尾海总体处于中度富营养状态,时空差异较为明显,以夏季最为严重,从湾顶河口往南部湾口减轻.有机污染等级为轻至中度,空间分布与富营养状况相似.水体盐度以湾顶河口区域向中南部呈梯度递增,与富营养化指数(EI)、有机污染指数(AI)、化学需氧量(COD)、亚硝酸盐(NH2-N)、硝酸盐(NO3-N)、铵盐(NH4-N)、溶解态无机氮(DIN)呈显著负相关,表明湾顶钦江、茅岭江的入海污染是茅尾海富营养和有机污染的主要物质来源,其径流输入与外湾潮流运动综合作用对茅尾海营养分布特征具有控制作用.茅尾海丰、枯水期氮磷比分别为60、18,丰、平水期均以磷营养限制为主,茅岭江是该海湾溶解态无机磷(DIP)的主要贡献者.DIP与盐度、EI、AI相关性不显著,对富营养和有机污染程度的贡献相比COD、DIN较为有限.

Analysis and Assessment of Nutrient status in Maowei Sea of Inner Qinzhou Bay

Based on the water quality data of Maowei Sea collected in 2011 to 2012, the nutrition and eutrophication character-istics are analyzed. Results show that the water quality of the Maowei Sea is at medium-eutrophication situation, which is severe in summer, and dropped off from north to south as a whole. The organic pollution level is at light to medium, and its spatial distribu-tion is similar to eutrophication. The gradient distributions of partial nutrient concentration at the estuary to the south central area are basically consistent with that of salinity. It is revealed that there is a significant negative correlation between salinity and some fac-tors, such as eutrophication index(EI), organic pollution index(AI), chemical oxygen demand(COD), nitrite nitrogen(NH2 -N), nitrate nitrogen(NO3 -N), ammonia nitrogen(NH4 -N)and dissolved inorganic nitrogen(DIN), which indicated the main source of pollution was the north rivers, the Qin River and the Maoling River, whose flow combined with tidal movement control the distribution of the nutrients. The N/P-ratio is 60 in wet season, while 18 in dry season. Results also show Phosphorus was the nu-trient limiting the eutrophication of the Maowei Sea in wet season and normal season, and the Maoling River brings the major contri-bution of dissolved inorganic phosphorus( DIP) . The correlations between DIP and salinity, EI, AI is not significant, which indicate the contribution of DIP to eutrophication and organic pollution is relative finite compared to COD and DIN.