sentence: Gases trapped in clathrates are enclosed in ice, they look like packed snow.
sentences_before: The weight of the ice on top of lake Vostok is believed to add to the high concentration of oxygen. Oxygen from the ice gets dissolved into the water of the lake. Deposits of oxygen and other gases are trapped in the lake as well. The structure that traps them is called a clathrate.
concept_name: gas
headings: Lake Vostok Pressure and oxygen
categories: Lakes Geography of Antarctica