Kathi
Guelland (WSL Birmensdorf, Switzerland)
"Initial development of carbon fluxes along a soil chronosequence of a glacier
forefield – a labelled litter experiment"
Abstract
In Swiss Alps, 90% of the glaciers have a negative mass balance leading to exposure of fresh rocks
on unvegetated land surfaces. Young soils developing in glacier forefields
are accumulating C. The goal of this study is to investigate the influence
of initial soil development on the C cycling in a glacier forefield. To
identify fate, turnover and transformation of new litter C and old SOM in
different soil ages we added isotopic labelled litter along a chronosequence
at Damma Glacier forefield, Switzerland. Results show an exponential
increase in soil C within each soil age and a gap between the different soil
ages. Annual rates of soil respiration, compared to net C accumulation,
indicate that the latter is an order of magnitude lower than the annual flux
of C through the system. At the younger sites, the contribution of litter to
soil CO2-efflux was 3 times higher. Leaching of DOC increased similar to
respiration. Only a small fraction of the plant C inputs is accumulating in
soils.