During the past two centuries, the oceans have absorbed one-quarter of the carbon dioxide emitted into the atmosphere by human activities, according to the United Nations' Intergovernmental Panel on Climate Change (IPCC). While that has helped to lessen the impact of carbon dioxide emissions on the climate, it has been at a cost. This carbon dioxide - the same gas that makes fizzy beverages corrosive – is altering the oceans' alkaline-acid balance, known as pH.
The average pH levels in the world's oceans have dropped from 8.21 at the start of the Industrial Age (in the late 18th century) to an average 8.1 on the 1-to-14 scale, according to the IPCC. Changes will be more dramatic in coming years, the IPCC warns. Average pH levels are expected to decrease by as much as 0.4 by the end of the century, continuing the move in the acidic direction, the committee says.
Mathis and his fellow researchers are trying to understand how – and when – these changes might affect Alaska. They are making spring and fall voyages into the Bering Sea, Arctic Ocean, and Gulf of Alaska to analyze the contents of water retrieved from capsules plunged into the water column.