Hg对锦州湾表层沉积物异养细菌代谢酶活性的影响研究

为了解重金属Hg对锦州湾海域表层沉积物中异养细菌的主要代谢酶的影响,采用Hakanson潜在生态危害指数法对锦州湾表层沉积物中重金属Hg开展潜在生态风险评价,利用平板扩散法测定了9个站位沉积物中异养细菌四种水解酶活性。结果显示:锦州湾海域表层沉积物中重金属污染严重,Hg的含量和潜在生态危害河口最为严重,向外逐步递减,表明本海域表层沉积物中的Hg主要由陆源输入;表层沉积物中异养细菌水解酶活性与抗性异养菌比例均表现为西南部河口区高于东北部外海海域,与重金属Hg的含量分布及Hakanson潜在生态危害指数基本相似,这表明长期高浓度的重金属污染,改变了锦州湾海域表层沉积物中的异养菌的生理代谢过程,在生理或遗传物质上对重金属产生了一定的抗性;磷酸酶、蛋白酶、脂肪酶与沉积物中Hg的含量具有显著正相关性,说明其对重金属Hg较为敏感,在一定程度上可作为反映锦州湾海域沉积物中重金属Hg污染状况的生物学指标。

Research on effects of Hg on the metabolic enzymes of heterotrophic bacteria in surface sediments of Jinzhou Bay

To understand the effects of Hg on the major metabolic enzymes of heterotrophic bacteria in the surface sediments of Jinzhou Bay, in this study, we conducted field investigations and collected surface sediment samples from Jinzhou Bay in August 2012. We evaluated the potential ecological risk of Hg using the Hakanson method and performed diffusion plate assays to measure the activity of four kinds of metabolic enzymes of heterotrophic bacteria. The results showed that the content and potential ecological risk of Hg were highest and most serious in the estuary and this situation gradually weakened from the estuary to the ocean, which indicated that most Hg in the surface sediments of Jinzhou Bay originated from land sources. The metabolic enzyme activity of heterotrophic bacteria and the ratio of resistant heterotrophic bacteria were both higher in the southwest coastal waters than in the northeast offshore waters, which were also similar to the distribution of the heavy metal Hg content and the Hakanson potential ecological risk. This indicates that the metabolism of heterotrophic bacteria changed under long-term high concentrations of heavy metals pollution and produced a certain physiological resistance to heavy metals. The contents of phosphatase, protease, and lipase showed a significant positive correlation with the content of the heavy metal Hg, respectively, which indicates that they can be used as sensitivity indexes to reflect heavy metal Hg pollution in the surface sediments of Jinzhou Bay.