Influence of soil frost on the character and degradability of dissolved organic carbon in boreal forest soils

Recent studies suggest that increases in extent and duration of winter soil frost increases dissolved organic carbon (DOC) concentrations in boreal riparian soils and connected aquatic systems during the subsequent spring and summer. However, little is known about the impact of frost on DOC characte...

Full description

Saved in:
Bibliographic Details
Published in:Journal of geophysical research. Biogeosciences 2016-03, Vol.121 (3), p.829-840
Main Authors: Panneer Selvam, B., Laudon, H., Guillemette, F., Berggren, M.
Format: Article
Language:English
Subjects:
Aquatic environment
Bacteria
bioavailability
Biodegradation
Biological
Boreal forests
Carbon
Carbon dioxide
Climate change
Degradation
Dissolution
Dissolved organic carbon
DOC composition
Earth and Related Environmental Sciences
Environmental Sciences
Factor analysis
Fluorescence
Forest Science
Forest soils
Frost
Geovetenskap och miljövetenskap
Global warming
Miljövetenskap
Natural Sciences
Naturvetenskap
Photochemicals
Photodegradation
Pore water
Skogsvetenskap
Soil (material)
soil frost
Water analysis
Water sampling
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Recent studies suggest that increases in extent and duration of winter soil frost increases dissolved organic carbon (DOC) concentrations in boreal riparian soils and connected aquatic systems during the subsequent spring and summer. However, little is known about the impact of frost on DOC character and its degradability. We applied three experimental treatments to riparian soils in northern Sweden—shallow soil frost (insulated), deep soil frost (snow removed) and control plots—to test the effect of different soil frost regimes on the chemical characteristics and degradability of soil DOC. Soil pore water samples were analyzed using excitation‐emission fluorescence (parallel factor analysis) combined with biological and photochemical degradation experiments. We found that the absolute bacterial metabolic rates were significantly lower in samples from the shallow soil frost treatments, compared with the other treatments. Explorative multivariate analyses indicate that increasing soil frost is contributing to increased protein‐like fluorescence and to increased biological degradability of the DOC. Our study shows that decreases in riparian soil frost due to climate warming may not only contribute to decreased riparian DOC concentrations but also lead to shifts in the DOC composition, resulting in decreased biodegradability (yet similar photodegradability) of the DOC that is exported from riparian soils to streams. Key Points Soil frost positively affects DOC quantity and biodegradability in soil waters A constant DOC fraction across frost regimes has a photodegradation potential Warming of soils can reduce CO2 release from DOC degradation in aquatic systems
ISSN:2169-8953
2169-8961
2169-8961
DOI:10.1002/2015JG003228