Controls on the greenhouse gas exchange of a high-arctic ecosystem

Abstract

Geografisk Tidsskrift, Danish Journal of Geography 99: 19–26, 1999 The polar regions have during the last decade received increasing attention, due to the potential importance that these areas have on the global greenhouse gas budget. During the period from spring to early autumn of 1997 the exchange of two of the most important greenhouse gases namely carbon dioxide and methane were measured in a high-arctic valley in northeastern Greenland. The results show a significant temporal and spatial variation in the exchange of these gases, as well as a high dependency on the prevailing climatic conditions of this harsh location. From measurements carried out over three dominating vegetation types we found that during the summer season of 1997, the valley was a sink of CO2 in the order of 11.5 g C m−2, with the most densely vegetated areas showing the highest uptake rates. Over the same period the measurements showed that the valley was a source of CH4 with a magnitude of 0.85 g C m −2. Emission rates were mainly related to the soil temperature and to the position of the water table. This paper presents a summary of the most important processes controlling the seasonal dynamics of CO2 and CH4 exchange in high-arctic Greenland.