[CH Emissions Characteristics and Its Influencing Factors in an Eutrophic Lake].

In order to identify methane (CH) diffusion emissions characteristics and their impact factors in an eutrophic lake, CH flux across the lake-air interface was observed in Meiliang Bay and the central zone of Lake Taihu over one year. The relationships between CH flux and environmental factors and water quality indices were analyzed. The results indicated that the annual mean CH diffusion flux in the eutrophic zone was significantly higher than that in the central zone, which were 0.140 mmol·(m·d) and 0.024 mmol·(m·d), respectively. Additionally, the highest CH flux appeared in the eutrophic littoral zone. The CH flux varied seasonally, which was consistent with water temperature that peaked in summer. Furthermore, the difference in CH flux between seasons was an order of magnitude. The temporal variation in CH flux was mostly driven by wind speed and water temperature. The spatial correlation between CH flux and dissolved organic carbon concentration was highly significant (=0.62, <0.01). Observing temporal and spatial patterns of CH flux was necessary to accurately estimate whole-lake CH emissions due to large variability across time and space.