中华绒螯蟹幼蟹养殖池塘溶氧收支平衡状况

为研究中华绒螯蟹幼蟹养殖池塘溶氧收支概况，于2019年7 —10月测定了上海市松江区泖港镇6口幼蟹养殖池塘的光合作用产氧量、喜旱莲子草呼吸耗氧量、幼蟹呼吸耗氧量、底质呼吸耗氧量和水呼吸耗氧量，并通过公式计算出机械增氧量及用差减法计算出大气交换溶氧量。实验期间，幼蟹塘光合作用产氧量始终小于水呼吸耗氧量，仅幼蟹塘表层水体光合作用产氧量显著大于水呼吸耗氧量(P<0.05)，中层和底层水体光合作用产氧量几乎为零。幼蟹塘各层水呼吸耗氧量无显著差异(P>0.05)。机械增氧为池塘溶氧收入的主要因子，占溶氧总收入的72.32%；光合作用产氧仅占3.66%；大气交换溶氧量占溶氧总收入的24.02%，整个实验期间均通过大气溶解获得氧。喜旱莲子草呼吸耗氧量约为光合作用产氧量的21倍，是池塘溶氧支出的主要因子，占溶氧总支出的80.51%；底质呼吸、幼蟹呼吸和水呼吸耗氧量分别占总耗氧量的4.19%、4.81%和10.49%。结果表明，幼蟹养殖池塘定期清理喜旱莲子草和合理掌握增氧机开机时间是有效维持池塘溶氧收支平衡的重要手段。

Balance of dissolved oxygen in culture ponds of juvenile Eriocheir sinensis

The present study investigated the incomings and outgoings budget of dissolved oxygen (DO) in juvenile Chinese mitten crab (Eriocheir sinensis) culture ponds. The research was conducted in six juvenile crab farming ponds in Maogang Town, Songjiang District, Shanghai from July to October in 2019. The DO production from photosynthesis, respiratory oxygen consumption by Alternanthera philoxeroides, juvenile crab, pond sediment, and oxygen consumption of aquatic respiration were measured. The DO incomings from deploying aerators, and oxygen exchanges between water and atmospheric were calculated based on measured values by the subtraction method. The DO production from photosynthesis was less than the water respiratory oxygen consumption during the test period, only the DO production from photosynthesis in the surface water column was significantly greater than the water respiratory oxygen consumption, and the DO production from photosynthesis in the middle and bottom water layers were almost zero. There was no significant difference in the respiratory oxygen consumption by different water layer. Mechanical aeration was the main factor contributing to the DO incomings, accounted for 72.32% of the total DO incomings; this is followed by oxygen exchanges between water and atmosphere 24.02%, and DO production from photosynthesis 3.66%. Alternanthera philoxeroides is the main factor of DO outgoings, accounting for 80.51% of the total DO outgoings. The respiratory oxygen consumption of Alternanthera philoxeroides is about 21 times that of DO production from photosynthesis. Benthic respiration, juvenile crab respiration and aquatic respiration accounted for 4.19%, 4.81% and 10.49% of total oxygen outgoings, respectively. The results show that in the juvenile crab ponds, regular cleaning of Alternanthera philoxeroides and control of the aerators operating time are important means to maintain the balance of DO.