The hidden unknowns are always terrifying. Usually shedding light on the unknowns make them less frightening, sometimes more so.

Understanding our global ocean, which contains about 97% of Earth’s water, has long been the desired goal of marine researchers worldwide. Some of the research efforts have shed a negative light on human impacts on the ocean. Charles Keeling’s counterpart (who measured atmospheric carbon concentrations), Andrew Dickson has been documenting carbon concentrations in the ocean. Since March 1958 at the Mauna Loa Observatory in Hawaii, atmospheric carbon dioxide concentrations have increased from ~310ppm to ~410ppm the past few years. Dickson found that about 25% of atmospheric carbon dioxide dissolves into the ocean yearly, some of which is used for oceanic photosynthesis.

There are two governing (somewhat simplified) equations involved in the ocean-carbon dioxide relationship. Carbon dioxide and water combine to form carbonic acid, which dissociates (or breaks down) to release a proton (H⁺) and a bicarbonate. Bicarbonate further breaks down to release another proton (H⁺) and a carbonate. Increasing carbon dioxide in the atmosphere increases the carbon dioxide dissolved into the ocean, which means increasing carbonic acid levels and therefore, more protons and bicarbonates are released. As more bicarbonate breaks down to form yet another proton and carbonate, something else happens. In pure water, these protons (H⁺), would turn the water acidic by decreasing the pH. The pH is a log scale of proton concentrations (pH=-log[H⁺]); but with a buffer in place, this change in pH is resisted. The buffer capacity indicates how well or poorly a solution is able to resist the increase (solution becomes more basic) or decrease (solution becomes more acidic) in pH. The ocean has a buffer system in place: carbonate. So as more protons and carbonate are formed as bicarbonate breaks down, the buffer resists the increasing acidity of increasing proton concentrations by using the carbonate to combine with the proton to form bicarbonate.

As we just established, as carbon dioxide dissolves into the ocean, a proton is released, bicarbonate increases and carbonate decreases. Focusing on the decreasing carbonate concentrations, it is important to note that shelled organisms in the ocean such as coral, some plankton, and oyster larvae rely on carbonate to form their shells. Many of these shelled plankton species form the base of marine food webs. With decreasing carbonate concentrations, organisms will divert more energy to forming shells, causing stress to the organisms at the base of most marine food webs. Therefore, it is expected that growth rates will slow for these organisms as more carbon dioxide is dissolved from the atmosphere to the ocean.

In the U.S. alone, one in six jobs is linked to marine resources, be it fishing, ocean transportation, recreation, or tourism. In 2015, the U.S. fishing industry generated just over $200 billion in sales. Compromising the health of the base of the ocean food web will be felt economically; consequently, a solution must be found to mitigate increasing carbon dioxide concentrations in our atmosphere.

Dajana Gaube-Ogle is a third-year transfer student studying environmental sciences