河口区中国对虾池水化学状况

THE HYDROCHEMICAL STATE OF WATER IN PENAEUS CHINENSIS PONDS ALONGSHORE ESTUARY

本文报道了杭州湾畔对虾养殖池水的化学状况。1990年6—10月和1991年7—8月内所观测的虾池水化学成分平均值分别为:总含盐量9.5g/l,碱度1.79m mol/l,pH8.98,阴阳离子含量最高者分别为Cl^-(5.5g/l)与Na^++K^+(3.1g/l),为典型河口水质特点,但仍属海水水质体系,即系氯化水,钠组,Ⅲ型(Cl_Ⅲ^(Na))。有效氮含量丰富,总量平均为1.65mg/l,其中总氨氮占56%,硝酸氮占39%,亚硝酸氮占5%,可溶性有效磷含量较低,仅为0.012,N/P=304(原子比)化学耗氧量(COD_(Mn))17.4mg/l,可溶性有机物与悬浮颗粒有机物含量近为相等。据观测结果与多年生产状况,认为河口区虾池每59小时排换水量约40%,3—4cm虾苗放养密度为18.0±3.

The paper investigated the hydrochemical state in Penaeus chinensisponds from June to October 1990 and from July to August 1991. Averaged contents ofdifferent chemical compositions of the pond water are as follows: 1. The pH is 8.98, and alkalinity, 1.79 m mol/l. Total contents of salts are 9.50g/l.Contents of Cl and Na^++K^+ are the highest among ions in the pond water: they are5.50g/l and 3.10g/l, respectively. The contents of the above materials are greatly less thanthat of oceanwater. The natural seawater in Cao Jin area has the characters of typicalestuarine water, but it still belongs to normal oceanwater type, i.e. chloride water,natrium group, type Ⅲ(Cl_Ⅲ^(Na)). 2. Contents of nutrient elements in the water are rich, but phosphorus contents areinadequate. The effective nitrogen averages 1.65 mg/l, among which NH_3-N_T accounts for56%; NO_3^--N,39%;No_2^--N,5%. The reactive soluble phosphorus is 0.012 mg/l. The ratio ofN to P is 304. The chemical oxygen consumption (COD_(Mn)) is 17.4 mg/l. 3. According to hydrochemical determination in 1990 and 1991 and the productivestates for these two years it is more reasonable that 40% of water in a pond should bechanged for 59 hours in a culture density of 180.0-30.0 10~3 Penaeus chinensis juveniles (3-4cm) per ha.