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Photo-reactivity of dissolved organic carbon in the freshwater continuum

Panneer Selvam, Balathandayuthabani LU ; Lapierre, Jean-François ; Soares, Ana LU ; Bastviken, David ; Karlsson, Jan and Berggren, Martin LU (2019) In Aquatic Sciences 81(4).
Abstract
The patterns in dissolved organic carbon (DOC) photo-mineralization along the freshwater continuum from land to sea are poorly known. Specifically, it has not been resolved how the photo-degradation of DOC into CO2 (PD) depends on the combination of intrinsic properties of DOC and extrinsic variables that affect the photo-reactions. We measured PD per unit of absorbed ultraviolet light energy (PD-Ew) in headwater streams, lakes, intermediate rivers and river mouths in Sweden. Surprisingly, no trend of decreasing PD-Ew was found with decreases in colored DOC. However, there was a relationship between PD-Ew and pH, best described by a quadratic (U-shaped) curve, indicating environmental control of photo-reactivity. Interestingly, the highest... (More)
The patterns in dissolved organic carbon (DOC) photo-mineralization along the freshwater continuum from land to sea are poorly known. Specifically, it has not been resolved how the photo-degradation of DOC into CO2 (PD) depends on the combination of intrinsic properties of DOC and extrinsic variables that affect the photo-reactions. We measured PD per unit of absorbed ultraviolet light energy (PD-Ew) in headwater streams, lakes, intermediate rivers and river mouths in Sweden. Surprisingly, no trend of decreasing PD-Ew was found with decreases in colored DOC. However, there was a relationship between PD-Ew and pH, best described by a quadratic (U-shaped) curve, indicating environmental control of photo-reactivity. Interestingly, the highest values for both of these variables were recorded for river mouths. Moreover, PD-Ew increased with proxy variables for the amount of autochthonous DOC in the water. Thus, changes in pH and autochthonous DOC input along the continuum may sustain high DOC photo-mineralization throughout continental aquatic networks. (Less)
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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Photo-reactivity, Dissolved organic carbon, Freshwater systems, Colored dissolved organic matter, pH
in
Aquatic Sciences
volume
81
issue
4
article number
57
publisher
Springer
external identifiers
  • scopus:85069150114
ISSN
1420-9055
DOI
10.1007/s00027-019-0653-0
project
Terrestrial export of labile dissolved organic carbon in a changing environment
language
English
LU publication?
yes
id
7e925d28-0356-4094-a695-b77366d0ec2b
date added to LUP
2019-07-22 10:14:11
date last changed
2020-12-29 04:11:10
@article{7e925d28-0356-4094-a695-b77366d0ec2b,
  abstract     = {The patterns in dissolved organic carbon (DOC) photo-mineralization along the freshwater continuum from land to sea are poorly known. Specifically, it has not been resolved how the photo-degradation of DOC into CO2 (PD) depends on the combination of intrinsic properties of DOC and extrinsic variables that affect the photo-reactions. We measured PD per unit of absorbed ultraviolet light energy (PD-Ew) in headwater streams, lakes, intermediate rivers and river mouths in Sweden. Surprisingly, no trend of decreasing PD-Ew was found with decreases in colored DOC. However, there was a relationship between PD-Ew and pH, best described by a quadratic (U-shaped) curve, indicating environmental control of photo-reactivity. Interestingly, the highest values for both of these variables were recorded for river mouths. Moreover, PD-Ew increased with proxy variables for the amount of autochthonous DOC in the water. Thus, changes in pH and autochthonous DOC input along the continuum may sustain high DOC photo-mineralization throughout continental aquatic networks.},
  author       = {Panneer Selvam, Balathandayuthabani and Lapierre, Jean-François and Soares, Ana and Bastviken, David and Karlsson, Jan and Berggren, Martin},
  issn         = {1420-9055},
  language     = {eng},
  number       = {4},
  publisher    = {Springer},
  series       = {Aquatic Sciences},
  title        = {Photo-reactivity of dissolved organic carbon in the freshwater continuum},
  url          = {https://lup.lub.lu.se/search/ws/files/77107071/PanneerSelvam2019_Article_Photo_reactivityOfDissolvedOrg_correction.pdf},
  doi          = {10.1007/s00027-019-0653-0},
  volume       = {81},
  year         = {2019},
}