有机海水围塘养殖生态系统氮磷的变化规律及相关性研究

为了解海水围塘养殖区氮磷的变化规律以及围塘养殖对水环境的影响,以沿海滩涂地区的海水围塘养殖池为研究案例,定点监测了虾-鱼-贝混合养殖池和对虾单养池的无机氮(氨氮、亚硝酸盐和硝酸盐)、总氮、磷酸盐、总磷和高锰酸盐指数等指标,并分析了该养殖区各种水化学要素在养殖期间的变化特征以及它们之间的相关性。研究结果表明:两种养殖方式下水环境中无机氮之间的转化是完全的,在高溶解氧时硝酸盐氮含量始终较高,而在混合养殖中,硝酸盐氮是该养殖区水体无机氮的主要存在形态;混养池中总磷和总氮、磷酸盐均正相关,与无机氮之间无相关;而单养区总磷也与总氮显著正相关,但与磷酸盐和无机氮无相关;在混养区对总氮主要作用的是物理过程,单养区则是物理过程和化学过程同时起作用;对NH3+-N的影响虽然同是物理过程起作用,但混养区是盐度,而单养区是pH值和溶解氧;影响磷的各种形态变化的主要是化学过程起作用,但在单养区对PO43--P的影响还有pH值;通过采用有机养殖技术,围塘养殖的水质基本符合养殖要求标准,说明有机养殖、混合养殖等可以减少环境污染,应加强对这方面养殖技术的推广和应用。

VARIATION AND CORRELATION OF N AND P OF ORGANIC AQUACULTURE ECOSYSTEM IN SEAWATER ENCLOSURE POND

In order to understand the change rule of N and P and the influence of aquaculture on aquatic environment in seawater enclosure area, the indexes of inorganic nitrogen (NH₄⁺-N, NO₂^-N, NO₃^--N), TN, PO₄³-P, TP and COD_Mn, were fixed-point monitored; and variation characteristics of various hydro-chemical elements in the aquaculture area during the period of cultivation and their correlation were analyzed. The results showed that the transformation was complete in inorganic nitrogen, and nitrate nitrogen content was always high in higher dissolved oxygen, while nitrate nitrogen was the main form of inorganic nitrogen in polyculture pond; TP, TN and phosphate in polyculture pond were positively correlated, but not with inorganic nitrogen; and TP in monoculture pond was also correlated with TN, and no correlation with phosphate and inorganic nitrogen. The physical process played a major role to TN in polyculture pond, while the physical process and chemical process played a simultaneous role in monoculture pond; although the physical process played a role in NH₃⁺-N, the salinity was in polyculture pond, while the pH and DO were in monoculture zone; the chemical process played a major role in influencing the morphological changes of phosphorus, however, the effect of PO₄^3--P in monoculture pond is pH value. By adopting organic culture technology, the water quality of pond basically meets the requirements of aquaculture, which shows that organic culture and polyculture can reduce environmental pollution, and the popularization and application of aquaculture technology in this area should be strengthened.