青岛潮间带趋磁细菌的垂直分布特征及与环境因子的关系

Vertical distribution characteristics of magnetotactic bacteria and the relationship with environmental factors in intertidal zone of Qingdao

趋磁细菌是一类能够沿着磁力线运动的革兰氏阴性细菌,主要生活在淡水和海洋的有氧-无氧过渡区。本调查通过对青岛汇泉湾潮间带沉积物柱状样分层样品中趋磁细菌的计数和沉积物理化因子的分析,研究了趋磁细菌的垂直分布特征及其与环境因子的关系。结果显示趋磁细菌以趋北型的趋磁球菌占优势,主要分布环境的氧化还原电位为179.7--107.0 mV,为弱还原-还原性质,最大丰度（94-169个/cm3）出现在氧化还原跃层（表层下5-9 cm黄-黑沙界面处）,暗示有氧-无氧过渡区；趋磁细菌的垂直变化趋势与粒径、含水率、硫酸盐的变化趋势基本一致。

Magnetotactic bacteria （MTB） are Gram-negative, motile prokaryotes that can orient and migrate along the geomagnetic lines of force. MTB are ubiquitous in sediments and stratified water column and distribute pre-dominantly in the oxic-anoxic transition zone （OATZ）. To study the vertical distribution of MTB and their rela-tionships with environmental factors, sediment cores were collected from intertidal sites in the Huiquan Bay, Qing-dao. The redox potential and temperature were measured in situ, and other geochemical parameters of the sediments and count of MTB were analyzed in laboratory. Results showed that the most abundant MTB are coccoid-shaped ones which swim toward the north pole. MTB were concentrated in the reduced environments with a redox potential ranging from 179.7 mV to-107.0 mV. The maximum abundance （94-169 ind./cm3） of MTB was observed at redox cline which was located at the yellow-black layers transition with a depth of 5-9 cm, implying it’s a OATZ. The MTB exhibited a similar vertical distribution manner with those of the grain size, water content and sulfate concen-tration in the sediment.