Please enable JavaScript.
Coggle requires JavaScript to display documents.
DOC Composition (SUVA254) - Coggle Diagram
DOC Composition (SUVA254)
Residence time
Long in permafrost dominated wetlands
Hydrology
Soil water becomes hydrologically connected to streams at different hydrograph stages
Seasonality
Lower aromaticity and higher lability of DOC during spring freshet
Disturbances
Permafrost thaw
Lower SUVA
Increased thermokarst formation
Contribution of recalcitrant DOM to streams will likely increase
isolated thermokarst bogs become connected, and connected to stream = increasing peatland = delivery of highly labile DOC during spring freshet
Shifts in vegetation compostion
Wildfire
Increased aromaticity and decreased lability
char: leaches hydrophobic and highly aromatic DIC
Landscape characteristics
Wetlands
More aromatic C from peat than forests
Higher molecular weight
Permafrost dominated
Cold, wet environments = reduction in plant activity & slower OM decomposition rates
Recalcitrant DOM due to long hydrologic residence and time for microbial processing
Coniferous dominated = high aromatic C content
High concentration of hydrophobic compounds. High C:N than hydrophilic compounds - contain humic substances and are highly aromatic
Permafrost absent
Drier, warmer environments = higher decomposition rates
Deciduous dominated = low aromatic C content
Major source of DOC in winter
Forests
Plant litter chemistry
High N content & lower aromatic C content = higher decomposition rates in deciduous than coniferous forest litter
Soil
Selective sorption of hydrophobic compounds in mineral soil = hydrophilic compounds in solution
lower SUVA in the presence of hydrophilic organic matter (HPIOM) - partly microbially synthesized and partly plant-derived = small molecules.
Water-soluble OC in forest soils is more leachable and aliphatic near the soil surface
Snow cover reduces heat loss from soil, which has control over soil temperatures and frost develpment = influences biogeochemical processes during the winter, with consequences for DOC formation and export.
Temperature
Freezing soils damage belowground biomass = release of simple sugars and amino acids = decreased SUVA post frost (Haei et al., 2012)
Lower aromaticity (spring)