厦门海域浮游植物和细菌对溶解有机磷的利用

应用（３２）Ｐｉ同位素稀释法，测定了外加溶解有机磷化合物（ＤＯＰ）对浮游植物和细菌吸收（３２）Ｐｉ的影响．结果表明：厦门海域浮游植物和细菌均能不同程度地利用ＤＯＰ，从抑制程度（百分率）来看，浮游植物对ＤＯＰ的利用能力大于细菌；在多数情况下，随ＤＯＰ浓度升高，抑制程度增大，表明浮游植物吸收ＤＯＰ增加．     

Spatio.temporal variations of the bacterioplankton community composition in Chaohu Lake,China

Despite considerable attention paid to Chaohu Lake in China,the dynamics of bacterioplankton community composition(BCC) on spatial and seasonal scales are poorly understood.In this study.water samples were collected from autumn 2006 to summer 2007 at five positions in Chaohu Lake with different trophic status.BCC of these samples was determined by both the PCR amplifieation of the 16S rDNA gene and the denaturing gradient gel electrophoresis (DGGE).The abundance and diversity of bacterioplankton communities at different sampling positions showed similar seasonal pattems.The BCCs in the samples varied substantially,and the pattern of changes indicated that the seasonal difiefence might have a significant impact on the BCC'S structure iU the lake.Canonical correspondence anal-ysis(CCA)on the DGGE patterns and physicochemical parameters indicated that the temperature and the levels of 5-d biochemical O2 demand(BODs),NH3-N,CODMn,total nitrogen,total phosphorous,and dissolved oxygen significantly influenced the BCC,and four of the seven variables were related to the level of eutrophication.Our results indicate that eutrophic status and season are the most inttu-ential factors in determining BCC in Chaohu Lake.     

Spatio-temperial variations of the bacterioplankton community composition in Chaohu Lake, China

Despite considerable attention paid to Chaohu Lake in China, the dynamics of bacterioplankton community composition （BCC） on spatial and seasonal scales are poorly understood. In this study, water samples were collected from autumn 2006 to summer 2007 at five positions in Chaohu Lake with different trophic status. BCC of these samples was determined by both the PCR amplification of the 16S rDNA gene and the denaturing gradient gel electrophoresis （DGGE）. The abundance and diversity of bacterioplankton communities at different sampling positions showed similar seasonal patterns. The BCCs in the samples varied substantially, and the pattern of changes indicated that the seasonal difference might have a significant impact on the BCC＇s structure in the lake. Canonical correspondence analysis （CCA） on the DGGE patterns and physicochemical parameters indicated that the temperature and the levels of 5-d biochemical 02 demand （BODs）, NH3-N, CODMn, total nitrogen, total phosphorous, and dissolved oxygen significantly influenced the BCC, and four of the seven variables were related to the level of eutrophication. Our results indicate that eutrophic status and season are the most influ- ential factors in determining BCC in Chaohu Lake.