Advanced

Reactivity of dissolved organic matter in response to acid deposition

Ekström, Sara M. LU ; Sandahl, Margareta LU ; Nilsson, Anders LU ; Kleja, Dan B. and Kritzberg, Emma S. LU (2016) In Aquatic Sciences 78(3). p.463-475
Abstract

Fluvial export of organic matter from the terrestrial catchment to the aquatic system is a large and increasing carbon flux. The successful reduction in sulfuric acid deposition since the 1980s has been shown to enhance the mobility of organic matter in the soil, with more terrestrially derived dissolved organic matter (DOM) reaching aquatic systems. Changes in soil acidity also affect the quality of the DOM. In this study we explore the consequences this may have on the reactivity and turnover of the terrestrially derived DOM as it reaches the aquatic system. DOM of different quality (estimated by absorbance, fluorescence and size exclusion chromatography) was produced through extraction of boreal forest O-horizon soils from podzol at... (More)

Fluvial export of organic matter from the terrestrial catchment to the aquatic system is a large and increasing carbon flux. The successful reduction in sulfuric acid deposition since the 1980s has been shown to enhance the mobility of organic matter in the soil, with more terrestrially derived dissolved organic matter (DOM) reaching aquatic systems. Changes in soil acidity also affect the quality of the DOM. In this study we explore the consequences this may have on the reactivity and turnover of the terrestrially derived DOM as it reaches the aquatic system. DOM of different quality (estimated by absorbance, fluorescence and size exclusion chromatography) was produced through extraction of boreal forest O-horizon soils from podzol at two sulfuric acid concentrations corresponding to natural throughfall in spruce forest in Southern Sweden around 1980 and today. Extraction was done using two different methods, i.e. field leaching and laboratory extraction. The DOM extracts were used to assess if differences in acidity generate DOM of different reactivity. Three reactivity experiments were performed: photodegradation by UV exposure, biodegradation by bacteria, and biodegradation after UV exposure. Reactivity was assessed by measuring loss of dissolved organic carbon and absorbance, change in fluorescence and molecular weight, and bacterial production. DOM extracted at lower sulfuric acid concentration was more susceptible to photooxidation, and less susceptible to bacterial degradation, than DOM extracted at a higher sulfuric acid concentration. Thus the relative importance of these two turnover processes may be altered with changes in acid deposition.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Biodegradation, Carbon cycling, Decreasing acidification, DOM quality, Photooxidation
in
Aquatic Sciences
volume
78
issue
3
pages
13 pages
publisher
Birkhaüser
external identifiers
  • scopus:84949495447
  • wos:000377360200005
ISSN
1015-1621
DOI
10.1007/s00027-015-0453-0
language
English
LU publication?
yes
id
57c598ca-6113-49c1-aa2a-9da5d450f138
date added to LUP
2017-01-23 14:54:21
date last changed
2017-09-24 05:06:13
@article{57c598ca-6113-49c1-aa2a-9da5d450f138,
  abstract     = {<p>Fluvial export of organic matter from the terrestrial catchment to the aquatic system is a large and increasing carbon flux. The successful reduction in sulfuric acid deposition since the 1980s has been shown to enhance the mobility of organic matter in the soil, with more terrestrially derived dissolved organic matter (DOM) reaching aquatic systems. Changes in soil acidity also affect the quality of the DOM. In this study we explore the consequences this may have on the reactivity and turnover of the terrestrially derived DOM as it reaches the aquatic system. DOM of different quality (estimated by absorbance, fluorescence and size exclusion chromatography) was produced through extraction of boreal forest O-horizon soils from podzol at two sulfuric acid concentrations corresponding to natural throughfall in spruce forest in Southern Sweden around 1980 and today. Extraction was done using two different methods, i.e. field leaching and laboratory extraction. The DOM extracts were used to assess if differences in acidity generate DOM of different reactivity. Three reactivity experiments were performed: photodegradation by UV exposure, biodegradation by bacteria, and biodegradation after UV exposure. Reactivity was assessed by measuring loss of dissolved organic carbon and absorbance, change in fluorescence and molecular weight, and bacterial production. DOM extracted at lower sulfuric acid concentration was more susceptible to photooxidation, and less susceptible to bacterial degradation, than DOM extracted at a higher sulfuric acid concentration. Thus the relative importance of these two turnover processes may be altered with changes in acid deposition.</p>},
  author       = {Ekström, Sara M. and Sandahl, Margareta and Nilsson, Anders and Kleja, Dan B. and Kritzberg, Emma S.},
  issn         = {1015-1621},
  keyword      = {Biodegradation,Carbon cycling,Decreasing acidification,DOM quality,Photooxidation},
  language     = {eng},
  month        = {07},
  number       = {3},
  pages        = {463--475},
  publisher    = {Birkhaüser},
  series       = {Aquatic Sciences},
  title        = {Reactivity of dissolved organic matter in response to acid deposition},
  url          = {http://dx.doi.org/10.1007/s00027-015-0453-0},
  volume       = {78},
  year         = {2016},
}