As the water becomes deeper, the food source for the bacteria starts to disappear.The new discovery adds some nuances to this conception:The Mariana Trench and other deep parts of the world???s oceans are ???hotspots??? for bacterial activity in the deep sea.Ronnie Glud???Fifty percent of the seabed lies in what we call the abyssal plain, which is found at depths between 4,000 and 6,000 metres.