Based on the data of phytoplankton surveys made in 1959, 1981-1982, 1985 -1986 and 1991-1992 in Dianshan lake, the main ecological changes in the phytoplankton association is discussed and the main results are as foll...Based on the data of phytoplankton surveys made in 1959, 1981-1982, 1985 -1986 and 1991-1992 in Dianshan lake, the main ecological changes in the phytoplankton association is discussed and the main results are as follows:1. The average annual increase of phytoplankton density generally decreased from the 1959’s to 1985, and exhibited a increasing trend after the 1990’s. The species composition tended to become simple, and there were some changes in the proportions of relative number of phytoplankton.2. The primary productivity of phytoplanktpn showed an increasing trend, and the diversity index of community showed a decreasing trend.3. The average caloric value and standing crop of energy of phytoplankton were 11.61 KJ.g-1 DM and 139.82 KJ.m-2, respectively: their seasonal change laws were somewhat different. The energy conversion efficiency of total radiation by phytoplankton averaged 0. 68%.展开更多
Biomarkers have been widely used to reconstruct phytoplankton productivity and community structure changes, and this method has been applied for the first time in the middle Okinawa Trough during the transition from t...Biomarkers have been widely used to reconstruct phytoplankton productivity and community structure changes, and this method has been applied for the first time in the middle Okinawa Trough during the transition from the last deglaciation to the Holocene. The total content of all marine phytoplankton biomarkers, used as a total productivity indicator, reveals higher productivity during the deglaciation. The ratios of the biomarkers are used as community structure indicators which show that, compared with the Holocene, the contribution from haptophytes decreased while the contributions from diatoms and dinoflagellates increased during the deglaciation. The increased productivity during the deglacia- tion was likely caused by the stronger winter monsoon. Also increased nutrient supply from terrestrial sources contributes to the higher productivity due to lower sea-level, which is consistent with higher terrestrial biomarker (long-chain n-alkanols) content. These changes in the nutrient supply also con- tributed to the community structure changes in the Okinawa Trough.展开更多
附着藻类是湖泊中主要的生产者,尤其是草型湖泊。但与浮游藻类相比,针对附着藻类初级生产的研究还相对较少。采用原位调查与实验模拟相结合的方法测定2014—2015年间白洋淀附植藻类和附泥藻类的现存量和初级生产力,并对附着藻类初级生...附着藻类是湖泊中主要的生产者,尤其是草型湖泊。但与浮游藻类相比,针对附着藻类初级生产的研究还相对较少。采用原位调查与实验模拟相结合的方法测定2014—2015年间白洋淀附植藻类和附泥藻类的现存量和初级生产力,并对附着藻类初级生产与白洋淀水体理化参数的关系进行分析。结果表明,不同采样季节的附植藻类和附泥藻类的叶绿素a分别为34.83—245.22μg/cm^2和26.08—297.40μg/cm^2,无灰干重分别为0.46—5.21g/m^2和0.61—5.81g/m^2。两种附着藻类的生物量都在8月最高,4月和11月最低。空间分布上,南刘庄、府河入口的附着藻类生物量显著高于采蒲台和枣林庄。白洋淀附植藻类和附泥藻类的年均总初级生产分别为494.20mg C m^(-2)d^(-1)和474.45mg C m^(-2)d^(-1),呼吸速率为522.63mg C m^(-2)d^(-1)和508.98mg C m^(-2)d^(-1),净初级生产为-28.44mg C m^(-2)d^(-1)和-34.52mg C m^(-2)d^(-1)。白洋淀附着藻类初级生产力具有明显的时空分布规律,8月最高,6月次之,4月和11月最低,空间分布呈自西向东递减的趋势,在府河入淀口和南刘庄处最高,枣林庄和采蒲台最低。水质较好的区域的净初级生产力为正值,表明这些区域附着藻类以自养型群落为主,水质较差区域的净初级生产力为负值,则该区域以异养型群落为主。运用冗余分析法(RDA)探讨附着藻类与水质因子之间的关系,并采用向前引入法对水质因子进行逐步筛选,Monte Carlo置换检验结果显示,总磷、浮游植物叶绿素a、高锰酸盐指数、氨氮、水温、透明度、溶解氧和氮磷比是影响附着藻类生物量和初级生产的关键水质因子。附着藻类的总初级生产与水体富营养化程度呈正相关关系。展开更多
文摘Based on the data of phytoplankton surveys made in 1959, 1981-1982, 1985 -1986 and 1991-1992 in Dianshan lake, the main ecological changes in the phytoplankton association is discussed and the main results are as follows:1. The average annual increase of phytoplankton density generally decreased from the 1959’s to 1985, and exhibited a increasing trend after the 1990’s. The species composition tended to become simple, and there were some changes in the proportions of relative number of phytoplankton.2. The primary productivity of phytoplanktpn showed an increasing trend, and the diversity index of community showed a decreasing trend.3. The average caloric value and standing crop of energy of phytoplankton were 11.61 KJ.g-1 DM and 139.82 KJ.m-2, respectively: their seasonal change laws were somewhat different. The energy conversion efficiency of total radiation by phytoplankton averaged 0. 68%.
基金the National Natural Science Foundation of China (Grant Nos. 40676032, 40706021, 40621063 and 40431002)
文摘Biomarkers have been widely used to reconstruct phytoplankton productivity and community structure changes, and this method has been applied for the first time in the middle Okinawa Trough during the transition from the last deglaciation to the Holocene. The total content of all marine phytoplankton biomarkers, used as a total productivity indicator, reveals higher productivity during the deglaciation. The ratios of the biomarkers are used as community structure indicators which show that, compared with the Holocene, the contribution from haptophytes decreased while the contributions from diatoms and dinoflagellates increased during the deglaciation. The increased productivity during the deglacia- tion was likely caused by the stronger winter monsoon. Also increased nutrient supply from terrestrial sources contributes to the higher productivity due to lower sea-level, which is consistent with higher terrestrial biomarker (long-chain n-alkanols) content. These changes in the nutrient supply also con- tributed to the community structure changes in the Okinawa Trough.
文摘附着藻类是湖泊中主要的生产者,尤其是草型湖泊。但与浮游藻类相比,针对附着藻类初级生产的研究还相对较少。采用原位调查与实验模拟相结合的方法测定2014—2015年间白洋淀附植藻类和附泥藻类的现存量和初级生产力,并对附着藻类初级生产与白洋淀水体理化参数的关系进行分析。结果表明,不同采样季节的附植藻类和附泥藻类的叶绿素a分别为34.83—245.22μg/cm^2和26.08—297.40μg/cm^2,无灰干重分别为0.46—5.21g/m^2和0.61—5.81g/m^2。两种附着藻类的生物量都在8月最高,4月和11月最低。空间分布上,南刘庄、府河入口的附着藻类生物量显著高于采蒲台和枣林庄。白洋淀附植藻类和附泥藻类的年均总初级生产分别为494.20mg C m^(-2)d^(-1)和474.45mg C m^(-2)d^(-1),呼吸速率为522.63mg C m^(-2)d^(-1)和508.98mg C m^(-2)d^(-1),净初级生产为-28.44mg C m^(-2)d^(-1)和-34.52mg C m^(-2)d^(-1)。白洋淀附着藻类初级生产力具有明显的时空分布规律,8月最高,6月次之,4月和11月最低,空间分布呈自西向东递减的趋势,在府河入淀口和南刘庄处最高,枣林庄和采蒲台最低。水质较好的区域的净初级生产力为正值,表明这些区域附着藻类以自养型群落为主,水质较差区域的净初级生产力为负值,则该区域以异养型群落为主。运用冗余分析法(RDA)探讨附着藻类与水质因子之间的关系,并采用向前引入法对水质因子进行逐步筛选,Monte Carlo置换检验结果显示,总磷、浮游植物叶绿素a、高锰酸盐指数、氨氮、水温、透明度、溶解氧和氮磷比是影响附着藻类生物量和初级生产的关键水质因子。附着藻类的总初级生产与水体富营养化程度呈正相关关系。
