Table 1 shows more detailed information on 8 sampling sites and 4 transects.

Figure 2 and 3 are the photographs of sampling site on Wusong River.

Here are the photographs of unmanned surface vehicles, which helps us collect water sample and detect water quality indicator (e.g., EC, DO, pH etc.,).

We collected 24 water samples and stored them at 4℃ environment (Figure 5.). All water samples were analysed within seven days.

The calculation process of dissolved methane concentration (dCH4) are shown in Figure 6 and 7.

Here are some photos of our field work.

Here are some photos of floating chamber technique.

ANOVA results are shown in Figure 14 and 15.