桑沟湾不同养殖区水体微生物群落结构特征

采用PCR-DGGE分子指纹图谱技术研究了2007年夏季桑沟湾不同养殖区水体微生物群落结构特征。DGGE指纹图谱分析表明, 不同站位之间既存在共同图谱, 又具有各自的特征谱带, 总体上可分为4个区, 湾外区、湾口区, 湾中区和湾底区, 分别与非养殖区、海带养殖区、综合养殖区、贝类单养与网箱养殖区行相对应; 扇贝养殖区和牡蛎养殖区微生物相似性最高为94%, 贝类单养与网箱养殖区和非养殖区相似性最低为41%, 仅在网箱区发现对含氮污染物有去除作用的玫瑰杆菌属(Roseobacter)。17个站位表层水样共获得30个优势菌群, 选择比较明显的12条带进行回收、扩增和测序, 与GenBank中已经登录的细菌种群的同源性进行比较(相似性92%~98%), 结果表明, 这12条序列所代表的细菌分属于变形菌亚门(α-proteobacteria和γ-proteobacteria)、放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)。研究结果说明贝类单养和网箱养殖对环境的改变较大, 海带养殖对环境的改变较小, 综合养殖能减少贝类和网箱养殖对环境的污染程度, 是一种值得大力推广的养殖模式。

Effect of mariculture activities on bacterial community structure in the water of Sanggou Bay

We evaluated the bacterial community structure in water collected from several mariculture zones in Sanggou Bay in summer 2007 using PCR-DGGE. Some of the bands were shared by two or more stations, while others were unique to a particular location. Based on the DGGE profiles, we distinguished four areas, including a no-culture area (outer bay), kelp farming area (bay-mouth), integrated mariculture area (majority of the area in the middle of the bay), and a mollusk monoculture or fish farming area (bottom of the bay). The highest similarity in the bacterial community structure was between the scallop and oyster culture areas (94%), while the lowest was between the no-culture and mollusk monoculture or fish farming area (41%). Sequence analysis of twelve major bands from the DGGE profiles revealed that these sequences were highly similar to those of Actinobacteria, Firmicutes, and Proteobacteria, including class Alpha and Gamma proteobacteria. The similarity of the nucleotide sequences ranged from 92% to 98%. Roseobacter, which can remove nitrogen-containing pollutants, was only present in the fish farming area. Our results suggest that seaweed culture had a lower impact on the environment then shellfish monoculture and fish culture. Thus practicing IMTA can reduce the degree of pollution from shellfish and fish monoculture.