What is the role of oceans in the carbon cycle? A:they are carbon sources in the geosphere
B:they are carbon reservoirs in the geosphere
C:they are carbon sources in biosphere
D:they are carbon reservoirs in the hydrosphere

The ocean plays a critical role in carbon storage, as it holds about 50 times more carbon than the atmosphere. Two-way carbon exchange can occur quickly between the ocean's surface waters and the atmosphere, but carbon may be stored for centuries at the deepest ocean depths.

Explanation: