title: [Distribution and activity of marine bacterioplankton at frequent HAB area of East China Sea].
abstract: The distribution, activity and community structure of bacterioplankton in surface water were investigated at frequent harmful algae blooms (HABs) area in East China Sea (28 degrees-30.7 degrees N) from April to May, 2006. The abundance of bacterioplankton was determined by using the DAPI (4, 6-diamidino-2-phenylindole) direct count (DDC) method. The beta-glucosidase and aminopeptidase activity were measured with fluorogenic model substrates. And the bacterial community structure was analyzed by PCR-DGGE. Results showed that bacterial abundance in northern of the sampling area was much more than that in southern of the sampling area. It ranged from 5.85 x 10(4) cells x mL(-1) to 9.26 x 10(5) cells x mL(-1). And there was the highest value area outer the costal of Zhou Shan Island. The average aminopeptidase activity was 3.6 times of beta-glucosidase activity which was 0. 023 micromol x (L x h) (-1) in this area. The beta-glucosidase activity in >5 microm fraction contributed 47.4% of the total, and that of the aminopeptidase activity was 44.24% of the total. Bacterial extracellular enzyme activity had a higher average value in southern of the sampling area. This indicated that the bacterial activity had no direct relationship with bacterial abundance. Bacterial diversity and community structure differed from each sampling station. There were more divers in northern sampling area. The results suggested that the human being activity and continental inputting organic matters played a key role on the distribution of bacterial abundance. The distribution of bacterial extracellular enzyme activity was mainly affected by the Taiwan warm current. And it was the complicated unknown factors that caused the difference of the bacterial community structure and diversity from each sampling station. Obviously, it needed further work to enhance the knowledge of the ecological function of the bacterioplankton at frequent HABs area of the coastal water in East China Sea.
authors.affiliation: Key Laboratory of Ministry of Education for Coast and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361005, China. wxxmu@163.com
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Zhi-jiang
authors.initials: ZJ
authors.lastname: Li
authors.forename: Tian-ling
authors.initials: TL
authors.lastname: Zheng
mesh_terms: D001419:Bacteria / Q000254:growth & development*; D002681:China; D017753:Ecosystem; D004784:Environmental Monitoring; D005068:Eutrophication / Q000502:physiology*; D009792:Oceans and Seas; D010933:Plankton / Q000254:growth & development* / Q000502:physiology; D012623:Seawater; D014871:Water Microbiology; D014877:Water Pollution, Chemical / Q000032:analysis