“底充式增氧”技术对梭子蟹养殖池塘水质环境及浮游植物群落结构的影响

摘要

于2009年6-9月在浙江省宁海县三门湾海域养殖场,选取2口水文环境相似的梭子蟹Portunus trituberculatus养殖池塘,分别采用“底充式增氧”(实验塘)和传统水车式增氧(对照塘)方式,比较研究了池塘水质环境及其浮游植物群落结构的变化.结果显示:(1)实验塘水质的溶解氧和氨氮指标均优于对照塘,其中实验塘底部溶解氧质量浓度维持在5 mg/L以上,而对照塘则维持在4.28～6.45mg/L;养殖末期,实验塘的氨氮质量浓度为0.140mg/L,低于对照塘(1.360mg/L).(2)实验塘内主要藻类细胞丰度值(3 980×105个/L)远远高于对照塘(234×105个/L).经MDS标序、ANOSIM检验、SIMPER和Bio-Env分析可知,2口池塘浮游植物群落结构存在明显差异,养殖中后期实验塘浮游植物群落结构稳定,而对照塘的浮游植物群落结构较不稳定.实验塘优势种为卵囊藻Oocystis sp.和席藻Phormidiumsp.,对照塘以蓝藻和硅藻为优势种,2口池塘浮游植物群落结构不相似性高达84.44％.浮游植物细胞丰度与含有溶解氧的环境变量组合相关性最强.(3)与水车式增氧方式相比,“底充式增氧”技术对梭子蟹养殖塘的增氧效果明显,且能改善池塘水质,同时对于改善和稳定养殖池塘内的藻相结构起到重要作用.%Two adjacent Portunus trituberculatus culture ponds with similar hydrological environment in Sanmen Bay, Ninghai County, Zhejiang Province were selected to compare the effects of "submerged aeration system" (experimental pond) and traditional waterwheel aeration system (control pond) on water quality and phytoplankton community structure of the aquaculture pond from June to September 2009. The results show that (1) the indices of dissolved oxygen and ammonia nitrogen of the experimental pond with "submerged aeration system" are better than those of the control pond; the mass concentration of dissolved oxygen at the bottom of the experimental pond is kept at above 5 mg/L, while that of the control pond at (4. 28～6. 45) mg/ L; and at the later period of cultivation, the mass concentration of ammonia nitrogen of the experimental pond was 0.140 mg/L, much lower than that of the control pond (1. 360 mg/L). (2) the cell abundance of the algae in the experimental pond is much higher than that of the control pond, and that of green algae is 8. 79 X 108 ind/L; MDS sequencing, ANOSIM test and SIMPER analysis show significant differences of phytoplankton community structure between the two ponds; at the mid and later period of cultivation, the phytoplankton community structure is stable in the experimental pond and unstable in the control ponds; the dissimilarity of the two ponds is as high as 84. 44%, and the dominant species of the former are Oocystis sp. And Phormidium sp. , while that of the latter are diatom and cyanobacteria 5 Bio-Env analysis show that the correlation between the zooplankton abundance and environmental viable combination with dissolved oxygen is the strongest. (3) Compared to the traditional waterwheel aeration system, the effects of "submerged aeration system" to improve the DO mass concentration of the aquaculture pond are obvious, and it can also improve the water quality and stabilize the community structure of the algae in the farming pond during the cultivation.