Details
| Original language | English |
|---|---|
| Qualification | Doctor rerum naturalium |
| Awarding Institution | |
| Supervised by |
|
| Date of Award | 23 Mar 2018 |
| Place of Publication | Hannover |
| Publication status | Published - 2018 |
Abstract
Sustainable Development Goals
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Hannover, 2018. 144 p.
Research output: Thesis › Doctoral thesis
}
TY - BOOK
T1 - Origin and fate of dissolved organic matter in the subsoil
AU - Leinemann, Timo
N1 - Doctoral thesis
PY - 2018
Y1 - 2018
N2 - Dissolved organic matter (DOM) is the most mobile fraction of organic matter in soil and thus is important for the dynamic of soil organic carbon (OC), which represents the largest terrestrial OC pool. DOM produced from plant litter in the forest floor is transported down into the mineral soil with the soil solution. During this transport interactions with soil minerals and microorganisms lead to a decreased DOC concentration in the subsoil and distinct DOM composition. To assess the changing characteristics of DOM from topsoil to subsoil three studies were conducted in a Dystric Cambisol in the Grinderwald beech forest, challenging the influence of different hydrological conditions on the DOM transport and the distribution of leaf litter derived DOC over the soil profile, as well as the importance of mineral sorption for the demobilization of DOC. In study I a monitoring of the soil solution with segmented plate lysimeters was conducted. This enabled to investigate the spatial and temporal variability of water flux, DOC concentration and DOM composition in 10, 50 and 150 cm depth on the same spatial and temporal resolution over 15 month. The water flux was found to have an influence on the DOC concentration and DOM composition as a negative relationship between water flux and DOC concentration and a positive relationship between water flux and DOC flux was found. The aromaticity of the DOM, as assessed by specific UV absorbance at 280 nm, was positively correlated with the water flux in 50 cm and 150 cm depth indicating a bypassing of possible binding sites at higher water fluxes. In the topsoil the variability of the measured parameters was dominated by seasonal variations and in the subsoil for the most part by variations on the centimeter scale, highlighting the importance of hotspots for the OC dynamic. In study II the leaf litter at the monitoring site of study I was replace by highly 13C enriched beech leafs to follow the fate of litter derived DOC in the subsoil. Over 18 month after the label addition the overall contribution to DOC was found to be low (
AB - Dissolved organic matter (DOM) is the most mobile fraction of organic matter in soil and thus is important for the dynamic of soil organic carbon (OC), which represents the largest terrestrial OC pool. DOM produced from plant litter in the forest floor is transported down into the mineral soil with the soil solution. During this transport interactions with soil minerals and microorganisms lead to a decreased DOC concentration in the subsoil and distinct DOM composition. To assess the changing characteristics of DOM from topsoil to subsoil three studies were conducted in a Dystric Cambisol in the Grinderwald beech forest, challenging the influence of different hydrological conditions on the DOM transport and the distribution of leaf litter derived DOC over the soil profile, as well as the importance of mineral sorption for the demobilization of DOC. In study I a monitoring of the soil solution with segmented plate lysimeters was conducted. This enabled to investigate the spatial and temporal variability of water flux, DOC concentration and DOM composition in 10, 50 and 150 cm depth on the same spatial and temporal resolution over 15 month. The water flux was found to have an influence on the DOC concentration and DOM composition as a negative relationship between water flux and DOC concentration and a positive relationship between water flux and DOC flux was found. The aromaticity of the DOM, as assessed by specific UV absorbance at 280 nm, was positively correlated with the water flux in 50 cm and 150 cm depth indicating a bypassing of possible binding sites at higher water fluxes. In the topsoil the variability of the measured parameters was dominated by seasonal variations and in the subsoil for the most part by variations on the centimeter scale, highlighting the importance of hotspots for the OC dynamic. In study II the leaf litter at the monitoring site of study I was replace by highly 13C enriched beech leafs to follow the fate of litter derived DOC in the subsoil. Over 18 month after the label addition the overall contribution to DOC was found to be low (
U2 - 10.15488/4282
DO - 10.15488/4282
M3 - Doctoral thesis
CY - Hannover
ER -