The Carbon Ballpark Series

Authors

Christoph Geiss (christoph.geiss@trincoll.edu), Tim Kroeger (tjkroeger@bemidjistate.edu), Colleen Livingston (livingston@bemidjistate.edu)

Introduction

Some marine organisms use calcium carbonate (CaCO3) to make their shells. The deposition of these shells and other organic and inorganic sources of calcium carbonate (limestone) result in carbonate platforms such as that found in the Great Bahama Bank. These platforms provide long term storage of carbon dioxide and thereby form some natural protection from global warming. How significant is this protection? How does the amount of carbon held in the Great Bahama Bank compare to the amount of carbon humans are currently producing each year?

Images

1. Block diagram of the Great Bahama Bank carbonate platform.
2. Simple map of the Great Bahama Bank.
3. Bathymetric map.
4. Borehole data for the Great Bahama Bank.
5. Geologic timescale

Procedure

1. Approximate the volume of the Great Bahama Bank.
2. Calcium carbonate is deposited at a rate of approximately 50 millimeters per 1000 years for the last 25 million years (Miocene and younger). Calculate the amount of carbon held in the Great Bahama Bank. Link to Chemical Information.
3. Currently there is 750 gigatons (Gt) of carbon in the air. Compare this to that held in the Great Bahama Bank. Using the carbon dioxide emissions information, determine how many years it would take to contribute the amount of carbon held in the Great Bahama Bank.  Links to anthropogenic carbon dioxide emissions graph / data.

Bibliography

Instructors Guide