CO₂ in the Water

In the waters between 250 metres (273.40 yards) and 450 metres (492.13 yards) deep, CO₂CO₂ Rise CO₂ levels are rising at nearly twice the rate as in the surface waters.

~ Daniel Glick National Geographic 2004-09.

This should not be a surprise. A cold soft drink can hold more fizz than a warm one.