象山港紫菜区和网箱区沉积物异养细菌的生态分布

Ecological distribution of bacteria in the sediment of the laver culture area and cage culture area in Xiangshangang Bay

摘要:

为探讨紫菜和网箱两类海水养殖活动对沉积物异养细菌生态分布的影响,于2006年1月和2006年10月对象山港紫菜养殖区、网箱养殖区沉积物细菌数量和群落结构进行了研究,并与周边非养殖海域对照点进行了比较。结果显示,沉积物异养细菌数量呈现10月份>1月份,网箱养殖区>网箱对照区>紫菜养殖区和紫菜对照区的分布特点,各区异养细菌数量平均值依次为(9.6×10⁴±2.0×10⁵)、(1.5×10⁴±2.4×10⁴)、(4.3×10³±1.6×10³)和(4.7×10³±3.0×10³)cfu/g。紫菜养殖区分离细菌109株,归属于17个属,其中芽孢杆菌属(Bacillus)、棒状杆菌属(Coryneforms)为优势菌属;紫菜对照区分离细菌95株,归属于18个属,其中芽孢杆菌属、棒状杆菌属为优势菌群;网箱养殖区分离细菌136株,归属于11个属,其中假单胞菌属(Pseudomonas)、弧菌属(Vibrio)、芽孢杆菌属、不动杆菌属(Acinetobacter)为优势菌群;网箱对照区分离细菌110株,归属于11个属,芽孢杆菌属、棒状杆菌属、假单胞菌属、不动杆菌属、弧菌属为优势菌属。紫菜区和紫菜对照区沉积物检出菌属大多为海洋沉积物中的常见菌属,细菌群落多样性较网箱区和网箱对照区高,而网箱区沉积物长期受到高有机质等外界条件的选择作用,系统中细菌群落多样性下降,菌属组成与污浊海域相似,并且这种影响可能已波及至周边海域。可见,两类养殖区沉积物细菌分布特征存在明显差异,细菌数量和菌属组成与养殖自身污染密切相关。

Abstract:

Microbiological investigation was performed to determine the mariculture impact on the ecological distribution of bacteria in the sediment of the laver culture area and cage culture area of Xiangshangang Bay in January and October,2006,and the results were compared with those in adjacent non-cultured area of cage and laver culture.Bacterial quantity presents a series of characters in sediment:Higher bacterial number was observed in Oct.than that in Jan.,and the horizontal distribution of bacterial quantity displayed that Cage culture area［average of(9.6×10⁴±2.0×10⁵) cfu/g］>Reference site near cage［average of(1.5×10⁴±2.4×10⁴) cfu/g］>Laver culture area［average of(4.3×10³±1.6×10³) cfu/g］and Reference site near laver culture［average of(4.7×10³±3.0×10³) cfu/g］.109 strains of heterotrophic bacteria isolated from laver culture area mainly belonged to 17 genera,and Bacillus and Coryneforms were the dominant genera.95 strains isolated from reference site near laver culture mainly belonged to 18 genera,andBacillus and Coryneforms were the dominant genera.136 strains isolated from cage culture area mainly belonged to 11 genera,andBacillus,Coryneforms,Pseudomonas,Acinetobacter and Vibrio were the dominant genera.Bacteria in sediment under laver culture and reference site near laver culture were mostly common ones that appeared in marine sediment,and the microbial densities in these two areas were higher than that in cage culture area and reference site near cage.Because of longterm drainage of organic matters,cage culture sediment’s microbial density had reduced,its bacterial composition was similar to that in muddy sea areas,and the effect on bacterial community induced by culture has spread to its adjacent area.It is clear that there exist differences in the characters of bacterial ecological distribution in laver and cage culture areas,and bacterial quantitative distribution and community structures were closely related to self-pollution status of mariculture.