大鹏澳养殖水域溶解氧的变化及其与生态结构的关系

Variation characteristics of DO levels in cage-culture waters of Dapengao Cove,South China Sea

根据2001年6月至2002年6月大鹏澳网箱养殖水域周年的溶解氧(DO)水平监测数据,阐述网箱养殖区水体DO的水平、季节的变化、垂直变化和网箱养殖水体DO质量评价以及DO与水环境因子的相关性。结果表明,大鹏湾网箱养殖水域DO周年水平为3 86～8 01mg/L,氧饱和度为51 6%～103 6%,养殖水域DO水平低于非养殖水域的;冬、春季DO水平较高,均符合我国渔业水质标准要求。夏季DO水平普遍较低,超标率为95%;表层水DO水平略高于底层水,DO水平超标率分别为46%和66 7%;DO水平(全年)与pH值、盐度、叶绿素水平均呈显著性正相关(P<0 02,n=32),与水温、无机磷和无机氮水平呈显著性负相关(P<0 02,n=32)。其中,在春季相关最为明显。

According to the annual survey data of dissolved oxygen (DO) in the cage-culturing waters in Dapengao Cove of Daya Bay,DO content,seasonal and vertical variations,water quality evaluation,as well as the correlation with the water environmental factors were analyzed.The results showed that DO content in culturing waters was lower than that in non-culturing waters with the annual content ranging from 3.86 to 8.01mg/L and the oxygen saturation from 51.6% to 103.6%.In winter and spring, DO content was relatively high,but can meet the requirement of national fishery water quality standard of China,while in summer it was generally lower with 95% falling short of the standard. DO content in surface water were slightly higher than that in bottom water,46% and 66.7% of which fell short of the standard. The DO content was in notable positive correlation with pH value,salinity and chlorophyll-a (P<0.02,n=32),and in notable negative correlation with water temperature,inorganic phosphate and inorganic nitrate (P<0.02,n=32) all the year,especially in spring.