The variation features of the cross-equatorial flow and its impact on the ridge position of the subtropical high have been analyzed in this paper. It is shown as follows. (1) The intensity of the Somali cross-equatori...The variation features of the cross-equatorial flow and its impact on the ridge position of the subtropical high have been analyzed in this paper. It is shown as follows. (1) The intensity of the Somali cross-equatorial flow is increasing in winter and summer in the past 44 years and the airflow of Northern Hemisphere exchanges more and more intensively with that of Southern Hemisphere. (2) The Somali cross-equatorial flow in May has the most impact on the ridge position of the subtropical high in the typhoon season, presenting a positive correlation. (3) The diagnosis is consistent with the real situation in 2005.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
基金Open Research Fund for Meteorological Science in Fujian Meteorological Bureau (2006K01)
文摘The variation features of the cross-equatorial flow and its impact on the ridge position of the subtropical high have been analyzed in this paper. It is shown as follows. (1) The intensity of the Somali cross-equatorial flow is increasing in winter and summer in the past 44 years and the airflow of Northern Hemisphere exchanges more and more intensively with that of Southern Hemisphere. (2) The Somali cross-equatorial flow in May has the most impact on the ridge position of the subtropical high in the typhoon season, presenting a positive correlation. (3) The diagnosis is consistent with the real situation in 2005.
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.
