唐岛湾网箱养殖区底层水营养盐变化及营养状况分析

Analysis on nutrient status and variation in bottom water of cage culture area of Tangdao Bay

根据2004年8月、10月和2005年2月、5月对唐岛湾网箱养殖区现场调查,分析了网箱养殖区底层海水营养盐的季节变化,并对水质营养化状况进行了评价。结果表明,与对照点相比,唐岛湾网箱养殖对底层海水pH、DO影响不明显,对COD、NO2--N、PO34--P、NH4+-N影响相对较大。从无机氮营养结构看,DIN在冬季和春季以NO3--N为主,秋季NO3--N和NH4+-N二者相差不大,占主要比重,而在夏季NH4+-N所占比重最大。从A值和NQI值的统计结果看,在养殖活动较强的夏季和秋季,A值范围为1～2,为开始受污染等级,其他季节为水质处于良好等级,营养状态指数EQI值也呈夏季和秋季较其他季节高的变化趋势。

Based on the field investigation data at cage culture area of Tangdao Bay in August, October 2004 and February, May 2005, the concentration difference and seasonal change of nutrients in bottom water of cage culture area and its nutrient status were analyzed. The results showed that the effects of cage culture on pH, DO in bottom water were not apparent, but COD,NO^- 2-N,PO^3- 4-P and NH^＋ 4-N were obviously influenced by it. The NO^- 3-N was major constituent of DIN in winter and spring, the NO^- 3-N and NH^＋ 4-N occupied major constituent in autumn and NH^＋ 4-N was major constituent in summer. The calculated values of A and EQI showed that the scope of A values was 1-2 when breeding activities was stronger in summer and autumn, the waters had began contaminated, but there was no contamination in other seasons. The EQI value was also higher in summer and autumn than that in other seasons.