不同鲍养殖模式下浮游植物群落结构与水质特征的比较

Comparison of phytoplankton community structure and water quality in different modes of abalone mariculture

为研究不同鲍养殖模式对浮游植物群落结构和水环境的影响,于2016年5月至6月初大型海藻龙须菜(Gracilaria lemaneiformis)收获前后,选取汕头市南澳县深澳湾海域鲍单养区(A)、鲍与龙须菜混养区(GA)、过渡海区(M)和对照海区(C),对浮游植物群落及水体理化因子进行了6次高频调查。结果表明,调查海区共记录浮游植物4门45属84种,其中硅藻为优势类群,共37属71种。时间上比较,龙须菜收获后所有调查海区浮游植物细胞密度都显著高于龙须菜收获前(P<0.05);各养殖区域间比较,龙须菜收获前鲍单养区浮游植物细胞密度显著高于鲍-龙须菜混养区(P<0.05)。龙须菜收获前,鲍-龙须菜混养区总氮(TN)、总磷(TP)、氨氮(NH_4^+-N)和叶绿素a(Chl-a)浓度最低,多样性指数(H')及均匀度指数(J')最高;龙须菜收获后各区无显著差异(P>0.05)。影响浮游植物群落结构特征的理化因子为TN、TP、水温和叶绿素a。该研究表明,鲍-大型海藻复合养殖模式可降低鲍养殖水体中氮、磷的浓度,并维持浮游植物群落结构相对的稳定。

To study the effects of different modes of abalone mariculture on phytoplankton community structure and water environment, we carried out six surveys on the phytoplankton community and environmental factors in four mariculture areas （ abalone culture area, Gracilaria lernaneiformis-abalone polyculture area, transition area and control area） in Shen＇ao Bay, Nan＇ao Island of Shantou City, from May to June, 2016. Altogether 84 species belonging to 45 genera of 4 phyla were recorded. The diatoms were the most dominant population with 37 genera and 71 species. For all culture areas, the average density of phytoplankton in after-harvest-period was higher than that in before-seaweed-harvest-period significantly （P 〈 0. 05）. The average density of phytoplankton in abalone culture area in before-harvest-period was higher than that in G. lemaneiformis-abalone polyculture area in after-harvest-period significantly （ P 〈 0. 05 ）. In before-harvest-period, the concentrations of total nitrogen （TN）, total phosphorus （TP）, ammonia nitrogen （NH4 -N） and chlo- rophyll-a （Chl-a） in G. lemaneiformis-abalone polyculture area were the lowest, while the values of Shannon-Wiener index and Pielou＇s were the highest. No significant difference was found in different culture areas in after-harvest-period. The phytoplankton community structure was affected by TN, TP, water temperature （T） and chlorophyll a significantly. It is indicated that G. lemaneiformis- ablone polycuhure system can reduce the concentrations of nitrogen and phosphorus, maintaining relative stable community structure of phytoplankton.