[CH₄ Emissions Characteristics and Its Influencing Factors in an Eutrophic Lake]

In order to identify methane (CH₄) diffusion emissions characteristics and their impact factors in an eutrophic lake, CH₄ flux across the lake-air interface was observed in Meiliang Bay and the central zone of Lake Taihu over one year. The relationships between CH₄ flux and environmental factors and water quality indices were analyzed. The results indicated that the annual mean CH₄ diffusion flux in the eutrophic zone was significantly higher than that in the central zone, which were 0.140 mmol·(m²·d)^-1 and 0.024 mmol·(m²·d)^-1, respectively. Additionally, the highest CH₄ flux appeared in the eutrophic littoral zone. The CH₄ flux varied seasonally, which was consistent with water temperature that peaked in summer. Furthermore, the difference in CH₄ flux between seasons was an order of magnitude. The temporal variation in CH₄ flux was mostly driven by wind speed and water temperature. The spatial correlation between CH₄ flux and dissolved organic carbon concentration was highly significant (R²=0.62, P<0.01). Observing temporal and spatial patterns of CH₄ flux was necessary to accurately estimate whole-lake CH₄ emissions due to large variability across time and space.