亚热带河口区对虾养殖池塘浮游植物初级生产力变化

Variations in phytoplankton primary productivity in aquaculture ponds with Litopenaeus vannamei from subtropical estuary in southeast China

浮游植物初级生产力是评估水产养殖系统结构与功能的基础环节,对渔业资源的开发与管理具有重要意义.于2018年510月,采用黑白瓶法对闽江河口区的3个南美白对虾养殖塘(PondⅠ、PondⅡ和PondⅢ)水体浮游植物初级生产力进行了原位监测,初步研究了初级生产力在池塘间的差异性及其时间变化特征.结果显示,养殖期间养殖塘水体浮游植物总初级生产力(GPP)、呼吸消耗量(R_(P))和净初级生产力(NPP)变化范围分别为619.99~9498.67、1003.16~7063.33和-4179.50~6362.96 mg O_(2)/(m^(2)·d),均值分别为(4386.22±409.72)、(3607.53±150.27)和(778.68±260.16)mg O_(2)/(m^(2)·d),呈现出PondⅡ>PondⅢ>PondⅠ的特征.时间变化上,养殖塘水体浮游植物GPP和NPP呈现出随养殖阶段推移而增加的特征.多元逐步回归分析结果显示,N营养盐和叶绿素a浓度是影响养殖塘水体浮游植物初级生产力时空变化的主要因子.GPP/R_(P)系数在养殖初期小于1,而在养殖中后期大于1,表明养殖塘水体在养殖初期以异养生产为主,而中后期以自养生产为主.本文研究结果表明,今后在开展大尺度滨海水产养殖塘初级生产力精确评估及其相关模型参数构建时,需考虑池塘间水体初级生产力的时间变化特征.

The phytoplankton primary productivity is a great basis to evaluate the structure and function of aquaculture ecosystem,which qualify important significance for fishery resources exploitation.In this study,we measured the phytoplankton primary productivity among shrimp(Litopenaeus vannamei)ponds during the aquaculture periods in the Minjiang River estuary,Southeast China.The results showed that the gross primary production(GPP),respiration(R_(P))and net primary production(NPP)of phytoplankton among ponds over the shrimp aquaculture period varied from 619.99 to 9498.67,1003.16 to 7063.33,and-4179.50 to 6362.96 mg O_(2)/(m^(2)·d)respectively,with mean values of(4386.22±409.72),(3607.53±150.27)and(778.68±260.16)mg O_(2)/(m^(2)·d)respectively.Overall,the mean GPP,R_(P) and NPP decreased significantly among the three ponds in the order:PondⅡ>PondⅢ>PondⅠ.The phytoplankton primary productivity demonstrated a clear seasonal pattern,with an increasing trend with time.Multiple stepwise regression analysis showed that nitrogen nutrient and chlorophyll-a were the major impact factors of the spatiotemporal variations of phytoplankton primary productivity in shrimp ponds.Our results highlighted that the importance of considering the spatiotemporal variations in primary productivity in improving the accuracy of large-scale estimation of phytoplankton primary productivity in coastal aquaculture pond.