九龙江河-海系统夏季浮游植物磷胁迫研究

摘要

Phosphorus stress of phytoplankton was determined by using bulk and single-cell alkaline phosphatase activity (APA) assays during summer (June-July 2010) in Jiulongjiang River-Estuary and adjacent waters system. Results showed that Chl.a-normalized APA was significantly higher in the lower Jiulongjiang River [(48.80±14.69)nmol/(h·μgChl.a)] than the estuary and adjacent coastal waters [(10.60±15.58)nmol/(h·μgChl.a) and (23.54±25.41)nmol/(h·μgChl.a), respectively], indicating that phytoplankton phosphorus stress was more serious in the lower Jiulongjiang River than that in the estuary and coastal waters. High soluble APA contribution indicated that phytoplankton suffered long-term phosphorus (P) stress in the river-estuary-coastal water system. Single-cell ELF labeling of phytoplankton showed that there was no significant difference between the estuary (20%±20%) and adjacent coastal waters (38%±20%), which was coincided with the results of bulk APA. However ELF labeling of phytoplankton in estuary-coastal waters was significantly higher than that in the lower Jiulongjiang River (9%±3%) (P<0.05).%采用群落水平和细胞水平碱性磷酸酶活性(APA)相结合的方法,研究了2010年夏季(6-7月)九龙江河-海系统(河流-河口-邻近海域)浮游植物的磷胁迫,结果表明,单位叶绿素a的APA在河流下游区[(48.80±14.69)nmol/(h.μg Chl a)]显著高于河口区[(10.60±15.58)nmol/(h·μg Chl.a)]和邻近海域[(23.54±25.41)nmol/(h·μg Chl.a)],表明河流区的浮游植物磷胁迫显著高于河口区和邻近海域.三个区域高比例的游离态APA表明该水域浮游植物已较长时间处于磷胁迫状态.细胞水平的浮游植物荧光标记结果显示,河口区(20％±20％)与邻近海域(38％±20％)无显著差异(P＞0.05),此结果与群落水平APA结果相一致;但河口-邻近海域浮游植物的标记比例显著高于河流下游区(9％±3％)(P＜0.05).