Earth’s Future Ocean: Acidic or Basic?

Miriam Sutton, M.A., NBCTCarteret County Schools

Beaufort, North Carolina

Research Question

How do changes in the chemistry of the ocean affect marine organisms?

Experimental Phase I

1 - Add 3mL of each liquid to the corresponding cup.

Make your Prediction

4 - Predict the level of pH that will create a chemical reaction with calcified shell fragments.

2 - Use pH test strips to determine the pH of each liquid.

3 - Record the pH for each liquid on your data table.

Test Your Prediction

1 - Add 1/2 teaspoon of shell fragments to each

cup of liquid.

2 - Record your observations on your data

table.

Experimental Phase II

Analyze Your Results

1 - Which liquid(s) resulted in a chemical reaction with the calcified shell fragments?

2 - What was the pH of the liquid(s) that resulted in a chemical reaction with the calcified shell fragments?

Chemically Speaking

What happened to the seashells?

What’s going on chemically?

Acetic acid + Calcium carbonate => Calcium acetate + Carbon dioxide

Vinegar + Seashells => Crystals* + Bubbles

*Crystals will form in a few days.

(A double displacement chemical reaction)

Analysis with pH scalepH Analysis

Trends & Predictions in Ocean pH

By 2100, the pH of seawater is predicted to drop another 0.1 - 0.35, which would

result in a Seawater pH = 8.0 - 7.65

Since the Industrial Revolution, the pH of seawater has dropped about 0.1, bringing

the average seawater pH to 8.1.

Vinegar pH = 2.9 Seawater pH = 8.2

Questions to Ponder

Will the predicted drop in seawater pH have a detrimental effect on all marine

organisms? Why or Why not?

Will the change in seawater pH occur at a rate at which marine organisms can adapt?

Other thoughts or questions?

Additional Resources• NOAA/PMEL Carbon Group, National Oceanic and Atmospheric Administration.

Ocean Acidification, What is Ocean Acidification? Seattle, WA. http://www.pmel.noaa.gov/co2/OA/background.html

• NOAA: United States Department of Commerce. State of the Science FACT SHEET. Ocean Acidification. May 2008. http://www.ocean-acidification.net/OAdocs/FactSheet_en.pdf

• Effects of Climate Change and Ocean Acidification on Living Marine Resources. (Scott Doney, Senior Scientist, Marine Chemistry & Geochemistry Department, Woods Hole Oceanographic Institution.) Written testimony presented to the U.S. Senate Committee on Commerce, Science and Transportation’s Subcommittee on Oceans, Atmosphere, Fisheries, and Coast Guard, May 10, 2007. http://www.whoi.edu/page.do?pid=8916&tid=282&cid=27206

• Jewett, Libby. NCCOS: Center for Sponsored Coastal Ocean Research: Proposed Initiatives – Ocean Acidification. NOAA. February 11, 2010. http://www.cop.noaa.gov/stressors/climatechange/current/ProposedInitiatives/ocean_acid.aspx

Earth’s Future Ocean: Acidic or Basic?

Miriam Sutton, M.A., NBCTCarteret County Schools

Beaufort, North Carolina miriam.sutton@carteretk12.org

252.223.3482