Characteristics of a microbial community are important as they indicate the status of aquatic ecosystems. In the present study, the metabolic and phylogenetic profile of the bacterioplankton community in Guishan coastal water(Pearl River Estuary), South China Sea, at 12 sites(S1–S12) were explored by community-level physiological profiling(CLPP) with BIOLOG Eco-plate and denaturing gradient gel electrophoresis(DGGE). Our results showed that the core mariculture area(S6, S7 and S8) and the sites associating with human activity and sewage discharge(S11 and S12) had higher microbial metabolic capability and bacterial community diversity than others(S1–5, S9–10). Especially, the diversity index of S11 and S12 calculated from both CLPP and DGGE data(H >3.2) was higher than that of others as sewage discharge may increase water nitrogen and phosphorus nutrient. The bacterial community structure of S6, S8, S11 and S12 was greatly influenced by total phosphorous, salinity and total nitrogen. Based on DGGE fingerprinting, proteobacteria, especially γ- and α-proteobacteria, were found dominant at all sites. In conclusion, the aquaculture area and wharf had high microbial metabolic capability. The structure and composition of bacterial community were closely related to the level of phosphorus, salinity and nitrogen.
HU XiaojuanLIU QingLI ZhuojiaHE ZhiliGONG YingxueCAO YuchengYANG Yufeng
采用欧洲标准局连续提取法(Sequential extraction procedure of European Community Bureau of Reference)测定了汕头南澳白沙湾4种不同类型养殖区(鱼类、贝类、龙须菜和贝藻混养区)表层和柱状沉积物中4种重金属(Pb、Ni、Cu和Zn)不同形态的含量,初步评估了4种重金属的生物可利用性。结果表明,白沙湾表层沉积物中Pb和Zn主要以可还原态存在,而Ni和Cu均以残渣态存在。鱼类养殖区表层沉积物中4种重金属的生物可利用性较其他养殖区要高。4个养殖区柱状沉积物中4种重金属的生物可利用态总体上均随深度增加而减少;其中鱼类养殖区减小幅度较其余三种养殖区要大。形态风险准则评价表明,Zn对白沙湾水环境危害最重,已达到中等程度危害;Ni和Cu在各养殖区均为低危害;Pb在鱼类养殖区无危害,而在其余三个养殖区为低危害。
