0000000000177605
AUTHOR
Marc Ruppenthal
Isotope ratios of nonexchangeable hydrogen in soils from different climate zones
Abstract The fractionation of H isotopes in global precipitation leads to a continuous decrease in 2 H concentrations of precipitation with increasing latitude, altitude and continentality. Thus, the local precipitation, soil and ground water used by plants for photosynthesis or consumed during neoformation of pedogenic clay minerals often have a spatially diagnostic δ 2 H value. We hypothesize that the δ 2 H value of isotopically nonexchangeable H in bulk soil (composed of C-bonded H in soil organic matter (SOM) and the nonexchangeable fraction of O-bonded H in pedogenic clay minerals) is correlated with the mean δ 2 H value of local precipitation water at the place and time of biomass pro…
Contributions of terrestrial organic carbon to northern lake sediments
Abstract Sediments of northern lakes sequester large amounts of organic carbon (OC), but direct evidence of the relative importance of their sources is lacking. We used stable isotope ratios of nonexchangeable hydrogen (δ2Hn) in topsoil, algae, and surface sediments in order to measure the relative contribution of terrestrial OC in surface sediments of 14 mountainous arctic and lowland boreal lakes in Sweden. The terrestrial contribution to the sediment OC pool was on average 66% (range 46–80) and similar between arctic and boreal lakes. Proxies for the supply of terrestrial and algal OC explained trends in the relative contribution of terrestrial OC across lakes. However, the data suggest …