Epsilon Archive for Student Projects

Abstract

Boreal headwaters potentially represent important conduits for the exchange of gaseous carbon between the terrestrial ecosystem and the atmosphere. Even if the loss is small in absolute terms compared to the uptake and release directly from forested terrestrial systems, it is a persistent term that is important when discussing the landscape carbon budget. Earlier studies in Sweden by Algesten et al. (2004) estimate the flux of gaseous carbon between boreal streams and the atmosphere to 0.5 g C/m2 &year. Similar studies in Brocky Burn, Scotland by Hope et al. (2001) show a flux up to 14 g C/m2 &year.

The aim of this study is to determine the flux of carbon dioxide between streams in a typical Swedish boreal headwater catchment and the atmosphere. This was done by using the same method as in Brocky Burn. A comparison with other methods calculating the evasion was done in an attempt to get appropriate results. The study was performed within the headwater catchment of Krycklan in Västerbotten during 2003-2005. Totally around 570 water samples were taken during the period at different sites within the catchment and at different times of the year.

The results from this study show that the loss of carbon from a boreal headwater catchment is somewhere between 2 and 13 g C/m2 &year. The wide range depends on the annual variation and what measurements are used in the calculations. Earlier Swedish studies seem to have underestimated the evasion flux of carbon dioxide from headwater streams. The study also shows that the evasion is to a great extent regulated by the spring flood.