By Bryan Carter
Over 700 million gallons of oil end up in the ocean each year! While immediate physical impacts of oil on ecosystems are obvious, chemical components of oil spills receive less publicity than they deserve (3). About a quarter of the oil that is spilled vaporizes into the atmosphere in the form of volatile organic carbons (3).
Volatile organic carbons (VOCs) are a wide variety of chemical compounds that vaporize into gas easily due to low boiling points. VOCs are naturally released by plants, deposited into soils, and eventually carried by rivers into the oceans. This is part of the global carbon cycle, a circuit of inputs and outputs of carbon into different regions of the biosphere.
Human-caused sources of VOCs can disrupt the carbon cycle. They are responsible for human health concerns as well as negative biological influences (3). A major source of these VOCs is from oil spills (3). Oil is composed primarily of carbon that has been stored deep in rocks out of the carbon cycle for millions of years. Re-introducing oil into the environment alters the carbon cycle, which is crucial to understanding climate change.
Once in the atmosphere, VOCs can disrupt traditional chemical reactions, directly affecting ozone concentrations (2) (5). This can lead to increased amounts of dangerous UV rays reaching the earth’s surface, making VOCs directly responsible for changes in global climate.
Oceans hold the key to our planet’s natural defense against human inputs of VOCs. Carbon naturally fluxes between the ocean and atmosphere. This transference represents an attempt to balance the concentrations between each medium, or achieve equilibrium (1). Human inputs of VOCs result in an over abundance in the atmosphere, compared to the ocean. This leaves the potential for VOCs to flux into the ocean.
Studies have shown that the infamous chlorofluorocarbons, a non-natural VOC used as a refrigerant up until the 1970s is now currently fluxing into the ocean (2). Chlorofluorocarbons destroy ozone in the atmosphere but are harmless in the ocean (2). Acetone, a commonly used household-cleaning agent has been found to be fluxing into the ocean as well (4) (5).
VOCs released from oil spills will eventually flux into the ocean. Bryan Carter, a graduate student at the University of North Carolina Wilmington was recently interviewed on the subject of oil spill impacts on climate change.
“VOCs will naturally flux into the ocean. The key is will this process be able to keep up with the amount of oil we release into the environment? The ocean will do its part to contest climate change, but it’s important that humans do ours as well,” said Carter.
Oil spills dramatically and quickly damage ocean environments. However, the ability of the ocean to remove VOCs from the atmosphere where they directly promote climate change, to the ocean where they are harmless is critical to the long-term health of the environment.
(1) Cen-Lin, HE, May-Tzung, FU. Air-Sea Exchange of Volatile Organic Compounds: A New Model with
Microlayer Effects, Atmospheric and Ocean Science Letters. 6: 97-102 (2013).
(2) Fine, Rana A. Observations of CFCs and SF6 as Ocean Tracers, The Annual Review of Marine
Science. 3: 173-195 (2011).
(3) Hanna, Steven R., Drivas, Peter J. Modeling VOC Emissions and Air Concentrations from the Exxon
Valdez Oil Spill, Air & Waste. 43:6 298-309 (1993, 2012).
(4) Marandino, C.A., De Bruyn, W.J., Miller, S.D., Prather, M.J., Saltzman, E.S. Oceanic Uptake and the
Global Atmospheric Acetone Budget, Geophysical Research Letters. 32: 5806 (2005).
(5) Sinha, V., Williams, J., Meyerhöfer, M., Riebesell, U., Paulino, A.I., Larsen, A. Air-sea Fluxes of methanol, acetone, acetaldehyde, isoprene, and DMS from a Norwegian fjord following a phytoplankton bloom in a mesocosm experiment, Atmospheric Chemistry and Physics. 7: 739-755 (2007).