A new study has revealed the under-appreciation that exists for the role dams play in climate change; how the reservoirs behind them can cause surges of greenhouse gases as the water levels go up and down.  In a study of the water column at such a reservoir, marine scientists found an astonishing 20-fold increase in methane emissions as water levels were drawn down.  Bubbles coming out of the mud and sediment at the bottom were chock full of this potent greenhouse gas.

The role of lakes, reservoirs, and streams often go unnoticed when calculating carbon emissions.  Most of the time we think about fossil fuel vehicles, factories, power plants, and landfills.

The truth is that there is a lot of biological activity going on behind the dam.  This is where the natural flow of sediment and living things stop and therefore accumulate.  Through the decomposition of such creatures and organic material comes methane gas that builds up in the lake bed.

Read more… (Environmental News Network)