| dc.description.abstract | Bogs are important sinks of atmospheric carbon (C) due to their unique ability to
accumulate vast amounts of partially decomposed litter as peat, containing up to 25% of the
world’s soil carbon. Climate change and increases in nitrogen (N) deposition as a result of
human activities is expected to affect the dynamics of carbon accumulation and the fate of
the carbon sink capacity of peatlands is therefore uncertain. Increased N deposition may
alter decomposition dynamics and decrease the carbon sink ability if the layer of peatforming Sphagnum moss becomes N saturated. This study builds on a study by Ohlson and
Økland (1998a) who measured peat accumulation variables in an ombrotrophic bog, SE
Norway, in 1995. The aim of this study was to collect samples and model peat accumulation
in peat that had accumulated since 1995, and compare rates of peat accumulation to those
recorded in the previous study. Here I used the exact same location and estimated vertical
peat growth, carbon accumulation rate and peat bulk density in Sphagnum dominated
hummocks. Peat samples were gathered from the top peat layer and dated using small
pines. A subset of samples from hummocks and within the same age-range was then
derived from Ohlson and Økland (1998a) to acquire a comparable set of samples. Mean
vertical peat growth recorded in 2012 (the current study) was 64% higher compared to the
previous measurements, while the mean carbon accumulation rate and bulk density was
85% and 11% higher, respectively. Atmospheric N deposition in the region has decreased
the last three decades. Despite this, the mean peat N concentration increased from 1.06% in
the previous study, to 1.22% in the samples recorded in 2012. This indicates that the
Sphagnum layer is not currently N saturated, and that beneficial climatic conditions might
explain the increase in peat growth rates. | no_NO |
