乳山湾邻近海域沉积物中好氧氨氧化微生物分布特征

氮素循环是海洋生态系统物质循环的重要组成部分,对维持海洋生态平衡具有重要意义.由好氧氨氧化微生物(aerobic ammonia-oxidizing microorganism,AOM)推动的氨氧化过程是硝化作用的限速步骤.本研究通过荧光定量PCR技术,并结合潜在硝化速率(potential nitrification rates,PNR)的测定,研究了2014年8月乳山湾邻近海域沉积物中好氧氨氧化微生物种群分布特征.结果表明,3个采样站位中氨氧化细菌(ammonia-oxidizing bacteria,AOB)amo A拷贝数均高于氨氧化古菌(ammonia-oxidizing archaea,AOA);活性AOB占总AOB的比值低于1%,而活性AOA未检出;添加可抑制AOB活性的氨苄青霉素后,潜在硝化速率显著降低(P0.05).由此可知,AOB在8月乳山湾邻近海域沉积物氨氧化过程中发挥了重要作用.溶解氧浓度、温度及铵盐浓度对乳山湾邻近海域沉积物中好氧氨氧化微生物的种群丰度起着重要的调控作用.

Distribution of Aerobic Ammonia-Oxidizing Microorganisms in Sediments from Adjacent Waters of Rushan Bay

Nitrogen cycle is a key process in material circulation of marine ecosystem, which plays an important role in maintaining ecological balance. The ammonia oxidation process promoted by aerobic ammonia-oxidizing microorganism (AOM) is a rate-limiting step of nitrification. Real-time quantitative polymerase chain reaction (qPCR), along with the determination of potential nitrification rates (PNR) was carried out in this study to understand the distribution of AOM in sediments of adjacent waters of Rushan Bay in August, 2014. The results indicated that the abundance of total ammonia-oxidizing bacteria (AOB) was always greater than that of total ammonia-oxidizing archaea (AOA) in the three sampling stations; the ratio of active AOB to total AOB was less than 1%, while no active AOA was detected in this study; the PNR significantly decreased after adding ampicillin which could inhibit the activity of AOB (P<0.05). It was speculated that AOB might play a more important role in the ammonia oxidation in sediments of adjacent waters of Rushan Bay in August, 2014. Dissolved oxygen concentrations, temperature and ammonium concentrations played a significant role in distribution of AOM in sediments of adjacent waters of Rushan Bay.