The atmosphere is mainly Water and Carbon Dioxide. The water is due to the heat of the planet boiling the water into the atmosphere. There is also trace amounts of CH4, SO2, and NH3.
The ocean is extremely deep, as is common with oceanias. The pressure is so great at the bottom that it has never been explored. It is thought to be a barren floor, however.
It is unknown why life has not developed on Remaria, considering the presence of Carbon Dioxide and Water. It is possible Geothermal vents do not exist at the bottom of the sea, which would prevent life.
In 3576, the planet was discovered by a flyby probe. 2 years later, a colony was established, as terraforming and water were not needed. The colony grew into floating cities, and are now home to 500 million.