A study on chemical and biological oxygen consumption of the seabed sediment under the hypoxic condition

了解影响沉积物耗氧的各种因素对改善封闭近岸海域海底缺氧状况具有重要意义。本研究的目的是分离生物因素从沉积物耗氧（SOC）通过检查溶解氧消耗和CO2的产生与有机质分解。研制了一种防水透气管式水中CO2测量仪，并进行了实验室实验，验证了该方法的有效性。首先，我们测量了通过控制pH值、曝气和加碱改变水中CO2浓度的时间变化，并检验了该测量方法的测量精度和响应度。其次，通过同时测定沉积物上方水体中CO2和DO浓度的时间变化，从CO2产生和DO消耗的关系来认识SOC的生物反应。

It is important to understand each factors of sediment oxygen consumption in order to improve hypoxia at sea bottom in enclosed coastal seas. The purpose of this study was to separate biological factor from sediment oxygen consumption (SOC) by examining DO consumption and CO2 production associated with organic matter decomposition. A CO2 meter in water using water-resistant breathable tube was developed and laboratory experiments were conducted for verification of the effective of this method. First, we measured the time variations of CO2 concentration in water altered by controlling pH, by aerating and by adding soda, and checked the measuring precision and responsivity of this measuring method. Next, we recognized the biological reaction of SOC from relation between CO2 production and DO consumption by measuring the time variations of CO2 and DO concentrations in water above sediment at the same time.