[1] After our previous study about methane (CH 4 ) emissions from littoral marshes of the Three Gorges Reservoir (TGR), Chinese dams have raised a world-wide concern. Through measurements from the surface of the TGR, a CH 4 emission rate was recorded as 0.26 ± 0.38 mg CH 4 m −2 h −1 (Mean ± SD), relatively low compared with those from other hydropower reservoirs. We also recorded CH 4 emission rate from the surface of downstream water, which was also relatively low (0.24 ± 0.37 mg CH 4 m −2 h −1 ). Such result may indicate that TGR is not a great CH 4 emitter (not "CH 4 menace"). One possible reason for such a low emission rate is that measures to maintain water quality and protect environment and ecosystem decrease the input of organic materials (for methanogenesis), which in turn limits the CH 4 production in the sediment of the TGR. We also found that CH 4 emission from the flooding drawdown area (0.29 ± 0.37 mg CH 4 m −2 h ). Because of annual vegetation re-growth, the drawdown zone is the especially important carbon source for methanogenesis in flooding season. Interestingly, we also observed that mean CH 4 emission was significantly higher in winter than in spring and summer. This was partly due to seasonal dynamics of hydrology. In order to estimate the net CH 4 emissions caused by the reservoir and reservoir operation, the best approach would be Life Cycle Analysis.

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Lignocellulosic biomass, such as cassava residues, rice straw, corn stalks, and corncob, can be directly converted to hydrogen using dark fermentation by newly isolated Clostridium lentocellum strain Cel10.