Ocean Acidification Activity Source: Adapted with permission by National Oceanic and Atmospheric Administration. The ocean is a “carbon sink,” which means that it removes CO2 (carbon dioxide) from the atmosphere. The ocean currently absorbs about one-third of the CO2 released by the burning of fossil fuels. However, beyond a certain level of atmospheric CO2, the ocean can no longer act as a carbon sink without it having a negative impact on marine life. [Read More]