北部湾夏、冬两季异养细菌的水平分布特征及其影响因子

于2006年7月15日-8月7日和2006年12月25日-2007年1月22日对北部湾夏、冬两季水体中异养细菌丰度进行调查,探讨环境网子对异养细菌丰度的影响.结果表明,北部湾夏、冬两季异养细菌平均丰度分别是8.00×103和3.85× 102 mL-1.夏季北部湾北部海域表、中、底3个水层异养细菌丰度均显著高于中部和南部海域(p＜0.05),而冬季北部海域表层水体反而成为异养细菌丰度的低值区(p＜0.05),中层和底层水体中异养细菌丰度分布差异不大.随着离岸距离的增加,夏季水体中异养细菌丰度呈现逐步降低的趋势,而冬季这种趋势不明显.活性硅酸盐(SiO3 -Si)和叶绿素a(Chl a)浓度是影响北部湾夏、冬季异养细菌丰度水平分布的关键环境因子.除此之外,冬季水体中异养细菌的丰度还与温度、盐度和溶解氧(DO)显著相关.

Horizontal Distribution Characteristics and Influencing Factors of Heterotrophic Bacterial Abundance in Beibu Gulf in Summer and Winter

Based on two cruises which dated from July 15th,2006 to August 7th,2006 and from December 25th,2006 to January 22th,2007,the horizontal distribution patterns of heterotrophic bacteria in Beibu Gulf were studied.Moreover,the relationship between the bacterial abundance and the environmental ecological factors was also analyzed.The results showed that the mean bacterial abundance in Beibu Gulf in summer and winter were 8.00×103 and 3.85×102 mL-1 respectively.In summer,from the surface to the bottom water,the bacterial abundance of the north area of Beibu Gulf was higher than that of the middle and the south area(p<0.05),while in winter it became the lowest(p<0.05) and there was no distinct difference among three sea areas in middle and bottom water.In summer,with the increasing distance from the coast,the abundance of heterotrophic bacteria gradually decreased,while this trend was not obvious in winter.The concentration of reactive silicates(SiO3-Si) and chlorophyll-a(Chl a) were the key environmental factors which could influence the horizontal distribution patterns of heterotrophic bacteria in the two seasons.In addition,in winter the bacterial abundance closely correlated with the level of temperature,salinity and the concentration of dissolved oxygen(DO).