Calculating the global flux of carbon dioxide into groundwater

In this research, the global annual flux of inorganic carbon into groundwater was calculated to be 4.4 GtC/y, with a lower bound of 1.4 GtC/y and an upper bound of 27.5 GtC/y. Starting with 44 soil PCO2 measurements, the dissolved inorganic carbon (DIC) of the groundwater was determined by equilibrium equations for the carbonate system. The calculated DIC was then multiplied by the groundwater recharge to determine the annual carbon flux per area. These PCO2 estimates were assigned to specific bio-temperatures and precipitations according to the Holdridge life-zone classification system, and regressions between PCO2, biotemperature, and precipitation were used to provide estimates for regions of the world that lacked PCO2 measurements. The fluxes were mapped on a generalized Holdridge life-zone map, and the total flux for each life-zone was found by multiplying the calculated flux by the area in each life-zone. While there was a wide range in the error, the calculations in this study strongly suggest that the flux of carbon into groundwater is comparable to many of the major fluxes that have been tabulated for the carbon cycle. The large flux that was calculated in this study was due to the high PCO2 that is common in soils. The elevated PCO2 levels are due to the decomposition of organic matter in soils, and the absorption of oxygen by plant roots. After the groundwater enters into rivers, it is possible that large amounts of CO2 is released from the surface of rives, as the carbon-rich waters re-equilibrate with the low atmospheric PCO2-

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1999

Author dc:creator

• Kessler, Toby Jonathan, 1974-

Advisor dc:contributor.advisor

• Charles F. Harvey.

• Earth, Atmospheric, and Planetary Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/54439

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/54439