Well! We don't really see bacteria using hydrogen and producing hydrogen, but it's actually happening all around us because there's some bacteria that release hydrogen as a waste product to get rid of excess electrons from their cells. And there are other bacteria that use that hydrogen as a very high energy food source and that's happening inside our stomachs, so we have as we ferment foods that we ate we have bacteria that are able to produce hydrogen as a waste product. And we have other bacteria in our stomachs like E coli very common bacteria that we've heard of that can cause stomach upsets. E coli is one of the bacteria that is able to use hydrogen as an energy source. And, hydrogen is also recycled in a same sort of ways in the soil and in water but we never ever see bubbles of hydrogen escaping because it's such a good energy source that there's always some organism ready to take out that hydrogen before it can escape to the atmosphere. I am Kylie kensent. I run a research group in the chemistry department at the university of Oxford. And I'm in the area of inorganic chemistry, but particularly interested in biological inorganic chemistry where we're learning from how nature does chemistry.