浮游植物的碳生物量和叶绿素a浓度比值(简记为C∶Chl-a)是海洋生物地球化学过程中的关键基础参数,在自然环境下有极大的变化.通过收集和整理近年来南海的东南亚时间序列观测(the South East Asian Time-series Study,SEATS)站的现场调...浮游植物的碳生物量和叶绿素a浓度比值(简记为C∶Chl-a)是海洋生物地球化学过程中的关键基础参数,在自然环境下有极大的变化.通过收集和整理近年来南海的东南亚时间序列观测(the South East Asian Time-series Study,SEATS)站的现场调查资料,对比分析了超微型浮游植物中三大类群的变化及其总C∶Chl-a的垂直分布.叶绿素a浓度通过高效液相色谱分析获得,碳生物量依据文献报道的同纬度海区的C∶Chl-a计算或基于流式细胞技术分析细胞丰度与体积后经换算得到.结果显示基于这两种方法计算得到的超微型浮游植物三大类群的碳生物量之间均存在极显著正相关(n=41,p<0.001),其中聚球藻(Synechococcus)基于高效液相色谱分析获得的碳生物量有一定的高估,而原绿球藻(Prochlorocoecus)和超微型真核藻类(pico-eukaryotes)的数据结果则基本一致,这种差异可能与聚球藻的光适应机制有关.通过计算南海SEATS站全粒径浮游植物的C∶Chl-a,发现其呈现随深度递减的变化趋势,但相对于同纬度海区整体上偏小,进而讨论了南海SEATS站浮游植物时空分布模式和C∶Chl-a变化的原因.展开更多
The importance of phytoplankton cell death is being increasingly recognized, however, there are still no published reports on this in Xiamen Bay. In this study, the proportion of dead phytoplankton cells associated wi...The importance of phytoplankton cell death is being increasingly recognized, however, there are still no published reports on this in Xiamen Bay. In this study, the proportion of dead phytoplankton cells associated with environmental factors was assessed at a station in Xiamen Bay from December 2012 to December 2013, using a cell digestion assay, which is an effective method to analyze dead/ living ceils in complex natural phytoplankton communities. The percentages of dead cells （% DC） in the total phytoplankton in summer （16%＋6%） were lower than those in winter （27%q-16%）. Six groups of phytoplankton （G1-G6） were categorized by flow cytometry. These phytoplankton communities with diverse seasonal variations in % DC had different responses to environmental constraints. The main factors affecting mortality were temperature and salinity, while nutrient concentration showed little influence on phytoplankton death. Additio^aally, our results provide evidence that chlorophyll a concentrations had an inverse relationship with total phytoplankton % DC and viable cell abundance was more meaningful than total cells to explain variations in environmental parameters （such as Chl a）. Moreover, the lowest mean % DC in total phytoplankton was 16%q-6% at our sample site, which is in a subtropical area with high water temperatures, full solar radiation, and rich nutrients. This indicates that phytoplankton cell death is a process that cannot be ignored. In summary, phytoplankton cell death is important in understanding the dynamics of phytoplankton communities and the fimctioning of subtropical ecosystems.展开更多
文摘浮游植物的碳生物量和叶绿素a浓度比值(简记为C∶Chl-a)是海洋生物地球化学过程中的关键基础参数,在自然环境下有极大的变化.通过收集和整理近年来南海的东南亚时间序列观测(the South East Asian Time-series Study,SEATS)站的现场调查资料,对比分析了超微型浮游植物中三大类群的变化及其总C∶Chl-a的垂直分布.叶绿素a浓度通过高效液相色谱分析获得,碳生物量依据文献报道的同纬度海区的C∶Chl-a计算或基于流式细胞技术分析细胞丰度与体积后经换算得到.结果显示基于这两种方法计算得到的超微型浮游植物三大类群的碳生物量之间均存在极显著正相关(n=41,p<0.001),其中聚球藻(Synechococcus)基于高效液相色谱分析获得的碳生物量有一定的高估,而原绿球藻(Prochlorocoecus)和超微型真核藻类(pico-eukaryotes)的数据结果则基本一致,这种差异可能与聚球藻的光适应机制有关.通过计算南海SEATS站全粒径浮游植物的C∶Chl-a,发现其呈现随深度递减的变化趋势,但相对于同纬度海区整体上偏小,进而讨论了南海SEATS站浮游植物时空分布模式和C∶Chl-a变化的原因.
基金Supported by the National Natural Science Foundation of China(Nos.41330961,41406143)the Chinese Academy of Sciences Special Pilot Program(No.XDA10020103)+1 种基金the SOA Ocean Research Project,China(No.201105021-03)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20130121110031)
文摘The importance of phytoplankton cell death is being increasingly recognized, however, there are still no published reports on this in Xiamen Bay. In this study, the proportion of dead phytoplankton cells associated with environmental factors was assessed at a station in Xiamen Bay from December 2012 to December 2013, using a cell digestion assay, which is an effective method to analyze dead/ living ceils in complex natural phytoplankton communities. The percentages of dead cells （% DC） in the total phytoplankton in summer （16%＋6%） were lower than those in winter （27%q-16%）. Six groups of phytoplankton （G1-G6） were categorized by flow cytometry. These phytoplankton communities with diverse seasonal variations in % DC had different responses to environmental constraints. The main factors affecting mortality were temperature and salinity, while nutrient concentration showed little influence on phytoplankton death. Additio^aally, our results provide evidence that chlorophyll a concentrations had an inverse relationship with total phytoplankton % DC and viable cell abundance was more meaningful than total cells to explain variations in environmental parameters （such as Chl a）. Moreover, the lowest mean % DC in total phytoplankton was 16%q-6% at our sample site, which is in a subtropical area with high water temperatures, full solar radiation, and rich nutrients. This indicates that phytoplankton cell death is a process that cannot be ignored. In summary, phytoplankton cell death is important in understanding the dynamics of phytoplankton communities and the fimctioning of subtropical ecosystems.
