Effekter av näringstillförsel på CO2-utbytet på Fäjemyr

Sammanfattning: During the last century the carbon dioxide, CO2, concentration in our atmosphere has increased because of anthropogenic emissions, mainly from fossil fuel burning. This release of carbon dioxide has caused an increase of the greenhouse effect. During millennia’s peatlands have acted as a carbon sink, taking up the carbon dioxide from the atmosphere. One third of the world´s total soil carbon is stored in peatlands. In this study I measured, using the closed chamber technique, the Net Ecosystem Exchange, NEE, and ecosystem respiration, R, in a fertilization experiment at an ombrotrophic bog Fäjemyr in southern Sweden to see if fertilization would affect the CO2 exchange in peatlands. The fertilization experiment consisted of four treatments; fertilization with phosphorous, P, nitrogen, N, nitrogen+phosphourus, NP and no fertilization at all, C (control). The study was done in late spring, 28:th of March to 27:th of April in the year 2011. Vegetation during this time consisted mainly of Sphagnum mosses, but some sedges and dwarf shrubs were also present. The results showed a significant increase in gross primary production, GPP (photosynthesis on the ecosystem scale), in the NP and P fertilized plots in comparison to control. If the temperature should increase in the future a greater uptake of carbon by photosynthesis could be offset by an increase in respiration (which releases carbon dioxide to the atmosphere) from decomposition.