黄河三角洲南部潮间带底栖异样细菌的分布特征研究

DISTRIBUTION OF HETEROTROPHIC BACTERIA IN SEDIMENTS IN THE SOUTHERN INTERTIDAL AREA OF YELLOW RIVER DELTA

2008年4月和7月于黄河三角洲南部潮间带进行了大面站调查,采用DAPI荧光染色荧光显微镜计数法测定了沉积物中异养细菌数量,研究其分布特征,探讨满足其生长繁殖需要的物质来源。结果表明,春季和夏季潮间带沉积物中异养细菌丰度的变化范围分别为4.0~31.9×105cells/g dw（平均值为11.81×105cells/g dw）和5.9~53.5×105cells/g dw（平均值为17.80×105cells/g dw）。与世界其它地区相比,本调查区域沉积物中异养细菌丰度处于较低水平,这可能与该区域沉积物中POC含量较低有关（春季平均为0.10%,夏季平均为0.57%）。春季和夏季沉积物中BB∶PB（Bacteria Biomass,BB;Phytoplankton Biomass,PB）值的变化范围分别为0.02~0.89%（平均为0.26%）和0.09~3.38%（平均为0.55%）,都处于较低水平（〈5%）;该较低水平表明底栖藻类现存量远远超过了异养细菌生长的需求。春季和夏季潮间带沉积物中异养细菌丰度和叶绿素浓度的相关系数均为0.24,显示出不显著相关,说明藻类有机物不是异养细菌食物的主要来源。本研究区域有多条河流输入,沉积物中的异养细菌生长繁殖所需的溶解有机物可能有相当一部分来自陆源径流。

In order to study on the distribution of heterotrophic bacteria in sediments in the southern intertidal area of Yellow River Delta,explore the material supplying for their growth and production,heterotrophic bacteria in sediments were analyzed in April and July 2008,stained with DAPI and counted with fluorescence microscopy.The results showed that the heterotrophic bacteria abundance in sediments ranged at 4.0~31.9× 105 cells/g dw（averaged at 11.81×105 cells/g dw） and 5.9~53.5×105 cells/g dw（averaged at 17.80×105 cells/g dw） in spring and summer,respectively.Compared to other similar areas all over the world,the heterotrophic bacteria abundance in this area was at a relatively low level.This may be due to the comparatively low content of POC in sediments（spring averaged at 0.10 %,summer averaged at 0.57 %）.The ratios of BB∶PB（Bacteria Biomass,BB;Phytoplankton Biomass,PB） in sediments ranged at 0.02~0.89%（averaged at 0.26%） and 0.09~3.38%（averaged at 0.55%） in spring and summer,respectively,both values were at a low level（5%）.This suggested that the algae in sediments far exceeded the growth demand of heterotrophic bacteria.The insignificant correlations between heterotrophic bacteria abundance and chl-a content in sediments implied that algae was not the primary food source for heterotrophic bacteria.Meanwhile,there are some rivers input into this studying area,which might support the organic matter to the reproduction of heterotrophic bacteria.