Ph Levels in the Oceans

Today, as we were travelling along the Brazilian coast, we were visited by a pod of playful dolphins.  They reminded me of the delicacy of Earth’s ocean biome, and how small changes can result in large consequences.

Time for a brief chemistry lesson! When carbon dioxide from the atmosphere dissolves in the ocean, it forms carbonic acid. However, it quickly breaks down into bicarbonate (HCO₃) and hydrogen ions (H+).

H₂O + CO₂ → HCO₃ + H

Since acidity is the measure of hydrogen ions in a fluid, as the number of ions increases, the acidity of the oceans rises as well.

The pH levels of the oceans are regulated by a process called “buffering”, where hydrogen atoms react with calcium carbonate to produce carbon dioxide and water. This is the opposite of the process that previously occurred:

HCO₃ + H → H₂O + CO₂

However, there must be enough calcium carbonate in the oceans to increase carbon dioxide levels, and currently, the ocean’s buffering system is not effective enough to counter the rapid increase in the water’s acidity.

 The Earth’s oceans are normally slightly basic, but with an increase in greenhouse gases, the seawater will likely slide down the Ph scale. Since the Ph scale’s intervals are by powers of 10 (each level is to the 10^th power more acidic then the level below), this represents a drastic increase in the water’s acidity.

Dolphins are considered a symbol of protection in many cultures around the world. The health of these dolphins relies on the health of the ocean’s ecosystems, and hopefully we can all make an effort to ensure that these lovely creatures survive.

References

 Adam-Carr, Christine, Douglas Fraser, et al. Science Perspectives 10. Toronto: Nelson Education Ltd, 2010. Print.

Findlay, Helen. "Ocean Acidification." Catlin Arctic Survey Blog. Catlin Arctic Survey, 12 Apr 2011. Web. 21 April 2012. <http://www.catlinarcticsurvey.com/2011/04/12/ocean-acidification/>.

Gerad Bandos. Ph Scale. 2007. Graphic. Chemical Education Digital Library. Web. 6 May 2012. <http://chemteacher.chemeddl.org/services/chemteacher/images/stories/pH_Scale.jpg>.

Kim Martineau. Ocean Chemistry. 2009. Photograph. Ocean Acidification. Web. 27 April 2012. <http://theotherco2problem.files.wordpress.com/2009/11/ocean-chemistry.gif>.