太湖藻型湖区CH4冒泡通量

冒泡是甲烷排放的主要途径之一，为量化太湖藻型湖区CH₄冒泡通量及其占总通量的比例，本研究采用静态箱-便携式温室气体自动分析仪方法对春、夏季太湖梅梁湾进行了多日连续观测.结果表明，太湖藻型湖区春、夏季CH₄冒泡通量均存在白天高于夜间的日变化特征.春、夏季CH₄冒泡通量分别为1.843、104.497nmol/（m²·s），占总通量的比例分别为31.2%和68.6%，即冒泡是夏季CH₄排放的主要方式，而春季CH₄排放则以扩散为主.在小时及日尺度上，CH₄冒泡通量与温度（气温、表面水温和底泥温度）和气压显著相关，且随着温度升高、气压降低，CH₄冒泡排放分别呈指数增加和线性增加趋势.本研究可为准确估算太湖流域CH₄总排放量及明确我国湖泊对全球碳循环的贡献提供重要的基础数据.

The methane ebullition flux over algae zone of Lake Taihu

Ebullition is one of the main pathways for CH₄ emission. To quantify CH₄ ebullition flux and its ratio to total CH₄ emission flux over algae zone of Lake Taihu, floating chamber method was utilized in this study in the Meiliang Bay of Lake Taihu during spring and summer time. The results showed that daytime CH₄ ebullition flux was obviously higher than that of nighttime in both spring and summer seasons. The mean CH₄ ebullition flux and its ratio to total CH₄ flux in spring were 1.843nmol/(m²·s) and 31.2% respectively and that in summer were 104.497nmol/(m²·s) and 68.6%. The results indicated that the dominant CH₄ emission pathway was diffusion in spring and different from spring, ebullition played important role in summer. Temperature (air temperature, surface water temperature, and sediment temperature) and air pressure were significantly correlated to CH₄ ebullition emission at hourly and daily scale. The CH₄ ebullition emission increased exponentially with increasing temperature and increased linearly as air pressure decreased. This study can provide important basic data for accurately estimating total CH₄ emission in Lake Taihu basin and clarifying the contribution of CH₄ emission from lakes in China to the global carbon cycle.