Environmental impacts of nitrate-accumulating sulfur oxidizing bacteria on coastal ecosystems : Population dynamics and nitrogen metabolism

为了阐明沿海海洋环境富营养化与积累硝酸盐的硫氧化细菌（NA-SOB）之间的关系，本文开展了以下研究：1. a - b种群时空动态的野外调查；[3]环境因子对NA-SOB种群动态的影响。4. NA-SOB氮代谢的实验室研究；NA-SOB对底底生物呼吸和沉积物-水界面氮循环定量影响的现场（实验室）研究。NA-SOB所在的沿海海洋沉积物底栖生物呼吸和氮循环数学模型的建立。为了研究NA-SOB种群的时空动态，研究了枚举每个NA-SOB种群的生物量和估算单丝中细胞内no_3 -浓度的方法。基于克隆文库和FISH分析的定量PCR技术也得到了发展。为了研究控制NA-SOB种群动态的环境因素，开发了一种带有微传感器的原位微剖面系统，用于测量沉积物-水界面的微环境。为了定量研究NA-SOB对底底生物呼吸和沉积物-水界面氮循环的影响，构建了原位通量室。利用这些方法和仪器，在东京湾的两个站点进行了为期两年的季节性田野调查，每隔一两个月进行一次。对于NA-SOB的氮代谢，将^<15>N技术应用于实验室条件下建立的NA-SOB实验沉积物岩心，结果表明，细胞内80%以上的no_3 -被NH_4+还原。利用NA-SOB建立了沿海海洋沉积物中底栖生物呼吸和氮循环的数学模型，该模型基于两个并行计算程序（模块）；1 .生物地球化学模块；描述NA-SOB及其细胞内NO_3-池运动的生物学模块。因此，将生物地球化学模块与生物模块耦合，构建na - sob模型。在生物NA-SOB模块中，NA-SOB灯丝被描述为响应外部微环境的“自我操作粒子”（自动机）。该模型定量表明，NA-SOB与泥沙内部氮负荷的增加和泥沙反硝化作用的减少密切相关。少

The following studies have been conducted to clarify the relationships between eutrophication in coastal marine environments and nitrate-accumulating sulfur oxidizing bacteria (NA-SOB); 1. Field investigation of spatial and temporal dynamics of NA-SOB populations, 2. Field investigation of environmental factors controlling the population dynamics of NA-SOB, 3. Laboratory investigation of nitrogen-metabolism of NA-SOB, 4. Field (laboratory) investigation of quantitative effects of NA-SOB on benthic respiration and nitrogen cycling at sediment-water interface and 5. Development of mathematical model of benthic respiration and nitrogen cycling in coastal marine sediments where NA-SOB dwells on or in. To investigate the spatial and temporal dynamics of NA-SOB populations, methods to enumerate biomass of each NA-SOB population and to estimate intracellular-NO_3- concentration in a single filament had been developed. Quantitative PCR based on clone library and FISH analysis had also been dev … More eloped for biomass enumeration. To investigate the environmental factors controlling the population dynamics of NA-SOB, an in situ micro-profiling system with micro-sensors had been developed to measure micro-environments at sediment-water interface. To investigate the quantitative effects of NA-SOB on benthic respiration and nitrogen cycling at sediment-water interface, an in situ flux chamber was constructed. With those methods and instruments, seasonal filed investigation had been performed at one or two months intervals for two years at two stations in Tokyo Bay. Regarding the nitrogen -metabolism of NA-SOB, ^<15>N technique was applied to the experimental sediment core with NA-SOB established under laboratory conditions and showed that more than 80% of the intracellular-NO_3- is reduced NH_4+. The mathematical model of benthic respiration and nitrogen cycling in coastal marine sediments with NA-SOB was based on two parallel calculation procedures (modules); i. a biogeochemical module and ii. A biological module describing the movement of NA-SOB and their intracellular pools of NO_3- in particular. Thus, the NA-SOB-model was built by coupling the biogeochemical module to the biological module. In the biological NA-SOB module a NA-SOB filament was described as a "self-operating particle" (automaton) responding to external micro-environments. It has been quantitatively shown with the model that NA-SOB is deeply concerned in the increase in the internal nitrogen loading from the sediment and in the decrease in the sediment denitrification. Less