This video was shot under the lake ice in April 2008 (by Dennis Witmer). It shows the ice-free cavern generated by a violent bubbling plume that is active year-round. The milk jug frozen in place is a buoy, anchored to the lake bottom for seep location identification in summertime. Here it gives an idea of the scale of the cavern.
So the methane isn't all coming from cows farting in the Amazon rainforest causing globe warming? No answer required.
toechesse 4 weeks ago