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Scientific Basis for Ocean Acidification Video Contest

by February 11, 2011

When we set out to launch our first video contest, our goal was to test how well creative storytellers could run with a few key science points and create an engaging video about a science topic. As a small start-up effort, we couldn’t imagine having such great storytellers on staff, so we chose to present our challenge to the crowd via Tongal, a company that runs creative contests.

While the details of the contest will be covered elsewhere, this post focuses on the key science points for our pilot topic, ocean acidification

Your first reaction might be, “ocean what?” If so, you’re with about 75% of Americans who also haven’t heard of ocean acidification, as reported in this study by Yale’s Project on Climate Change Communication. This suggested to us that potential storytellers probably wouldn’t know much about the issue, making it a good test topic. Conveniently, it is an issue that I had a good deal of familiarity, given that my Ph.D. research was in biological oceanography. However, my familiarity with the topic did not prevent me from letting an erroneous statement slip through the creative process—more on that below.

The story of ocean acidification is quite simple. More carbon dioxide in the atmosphere leads to more carbon dioxide dissolving in the ocean (see graphic below from NOAA showing the steady rise in atmospheric carbon dioxide as measured atop Hawaii’s Mauna Loa volcano).

co2_data_mlo

This in turn causes the ocean to become slightly more acidic over time—meaning the pH is decreasing little by little (see the light blue line in the figure below). This increasing acidity is a concern because all sorts of chemical reactions in the ocean depend on the acid-base chemistry of the ocean. A slight shift in pH, and a chemical reaction might proceed more slowly, or not at all. There are tiny organisms who rely on such chemical reactions to create shells and other structures. Corals depend on ocean chemistry to create their structures.

feely_co2_ph_trend

Used with permission by Richard A. Feely. Data from R.A. Feely, Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, USA, with atmospheric data from Pieter Tans and seawater data from David Karl. Adapted from Feely (2008) in Levinson and Lawrimore (eds), Bull. Am. Meteorol. Soc, 89(7): S58.

The tricky part of explaining the issue is, however, that the ocean is not acidic. Solutions with a pH less than 7 are considered acidic, those above 7 are alkaline. The ocean’s pH is about 8. So, while it is okay to say the ocean’s acidity is increasing, it is not okay to state that that the ocean is acidic. One of the winning videos in our contest did just that, but thankfully comments posted on the European Project on Ocean Acidification blog illuminated our slip up. The video has been fixed, yet this underscores our need to have a robust vetting process in place as we gear up to create content on an ongoing basis (I’ll soon be expanding upon the discussion of this in our About Us section).

This post is not meant to be a treatise on the science behind the issue of ocean acidification, however, below are the points we presented to the entrants in the Tongal contest:

  • Carbon dioxide has been increasing in atmosphere over the past ~60 years and it is at levels not seen in nearly one million years.
  • There’s a “fingerprint” from human activity on this increase, that is, the chemical nature of carbon dioxide emitted upon burning fossil fuels is distinct and can be shown to be the main contributor to the increased amount of carbon dioxide in the atmosphere.
  • As noted before, more carbon dioxide in the atmosphere means more carbon dioxide dissolved in the ocean. This happens through well-understood equilibration processes.
  • More carbon dioxide dissolved in ocean means the oceans become more acidic. This is occurring very gradually, yet measurably.
    • Ocean acidity has increased by 30% since the beginning of the Industrial Revolution.
    • This increase is 100 times faster than any change in acidity experienced by marine organisms for at least the last 20 million years.
    • Today’s human-induced acidification represents a rare event in the geological history our planet.
  • The acidity of the ocean drives many chemical reactions in the ocean.
  • Lots of marine life, including tiny plant-like creatures, such as coccolithophores, and corals, depend on these chemical reactions to exist. Typically they rely on this chemistry to build their shells, or in the case of corals, their entire structure.
    • If the concentration of atmospheric carbon dioxide continues to increase at the current rate, scientists expect the ocean will become corrosive to the shells of many marine organisms by the end of this century.
    • How, or if, marine organisms may adapt to the increasing acidity is not known.
  • It is unclear how humans will be affected by ocean acidification, however, it is possible that increasingly acidic oceans will threaten food security, tourism, shoreline protection, and biodiversity.

For more information, here are a couple of good resources: The Ocean in a High‐CO2 World, a site maintained by the Scientific Committee on Ocean Research, and EPOC, mentioned above.


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