Characteristics and significance of atmospheric carbon monoxide consumption by soils

Gary M. King, University of Maine


CO consumption by soils is an important but uncertain component of atmospheric CO budgets. Global estimates range from 15 to 640 Tg CO yr-1. A number of such estimates have been used in models of CO dynamics in the atmosphere. Uncertainties in these models and in CO sources readily accommodate a wide range of consumption estimates. A review of empirical evidence suggests that a range of 190-580 Tg yr-1 derived from Seiler (1978) encompasses the likely sink strength, although the lower limit is most probable since CO production in temperate soils and the effects of illumination have not yet been adequately incorporated. Various evidence also indicates that soil water content and organic matter concentrations are major parameters affecting CO exchange, with temperature exerting more modest effects except in arid systems. The microbes active in CO consumption remain unknown, although ammonia- and methane-oxidizing bacteria seem to contribute little. © 1999 Elsevier Science Ltd. All rights reserved.