Role of karstic dissolution in global carbon cycle

The balance of the world carbon exchanges shows a 1.3 GtC/year unknown sink in the continental biosphere. The aim of this article is to determine the contribution of the karstic dissolution processes to this sink. To calculate the karstic dissolution in every part of the world, a new parameter has been created, called «maximal potential dissolution» (MPD). It calculates the theoretical dissolution rate in an idealized karstic system reduced to a simple, pure carbonated block crossed by a flux of CO2-enriched water. MPD is as efficient as other methods in calculating the karstic dissolution. MPD can be calculated everywhere with the mean annual temperature and precipitation values. In this paper, climatic data from 266 meteorological stations all over the world have been treated. They gave a mean MPD value for each main climatic type. The calculation has been made from 10° square grids, each grid assigned to a climatic type, i.e. to a mean value of MPD. The total consumed carbon mass all around the world is thus around 0.3 GtC/year, which represents 23% of the unknown carbon sink. More precise calculations are in progress based on a thousand climatic values.