There's a lake that's a 'dead sea' in a sense that nothing lives in it, but it's not because of salt or chemicals. - Apparently.
Lake Vida in Antarctica is a saline lake that has been frozen for over 2,800 years. Despite its high salt content, the lake's water is so low in oxygen that no living organisms can survive in it. This is due to the fact that the lake's water is trapped beneath a thick ice sheet, preventing any oxygen from reaching it. In 2013, a team of scientists discovered that the lake's water is home to a type of extremophilic microbe that can survive in the lake's oxygen-free environment.