微生物在近海氮循环过程的贡献与驱动机制

Contribution and mechanism of microbe-driving nitrogen cycling processes in coastal ecosystems

人类活动导致海岸带氮超载而富营养化,进而引起更多的生态环境问题。在全球变化背景下,进一步揭示微生物驱动的氮循环过程的驱动机制及贡献,对评价与预测近海生态系统服务功能变化、管理决策等至关重要。本文介绍了固氮、氨化、硝化、反硝化、硝酸盐铵化、厌氧氨氧化过程在近海多种生境沉积物中的生物地球化学(速率、通量、贡献)与微生物生态学(功能类群丰度)特征及时空变化规律,阐述温度、溶氧、盐度、活性溶解有机碳、无机氮、沉水植物、底栖动物活动等因素对各过程速率的影响及对各竞争性类群或过程(氨氧化细菌/氨氧化古菌,反硝化/硝酸盐铵化/厌氧氨氧化)的调控机制,并简析了海岸带微生物氮循环研究所面临的机遇与挑战。

Human activities introduced increased amounts of nitrogen in coastal oceans, caus-ing eutrophication and numerous ecological and environmental problems. It is crucial to better illustrate and understand the function and contribution of the microbe-driving nitrogen cycle within the coastal ecosystems, especially under the global change background. This review focuses on the rates, fluxes, contribution and functional gene quantity of microbes in nitrogen fixation, ammonification, nitrification, denitrification, dissimilatory nitrate reduction to am- monium, and anammox in coastal sediments. The controls of major physiochemical and bio- logical factors （e.g. temperature, dissolved oxygen, salinity, labile dissolved organic carbon, dissolved inorganic nitrogen, submerged macrophytes and benthic animals） on these processes, as well as functionally related microbial groups and pathways （e.g. ammonia-oxidizing bacte- ria and archaea and nitrate reduction）, are summarized.