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Indirect link between riverine dissolved organic matter and bacterioplankton respiration in a boreal estuary

Soares, Ana LU and Berggren, Martin LU (2019) In Marine Environmental Research 148. p.39-45
Abstract
Increasing loading of terrestrially derived dissolved organic matter tends to enhance bacterioplankton respiration (BR) in boreal estuaries, but knowledge on the mechanisms behind this effect is not complete. We determined the stable isotopic signature of the reactive estuarine dissolved organic carbon (DOC) in the Öre estuary (Baltic Sea) by using the Keeling plot method. The δ13C ratio of the estuarine labile DOC varied from −26.0‰ to −18.7‰ with most values resembling those typical for DOC of coastal phytoplanktonic origin (−18 to −24‰), while being distinctly higher than those of DOC from ter­res­trial sources (−28‰ to −27‰). Furthermore, the δ13C of the respired carbon was positively correlated to DOC concentrations, indicating that... (More)
Increasing loading of terrestrially derived dissolved organic matter tends to enhance bacterioplankton respiration (BR) in boreal estuaries, but knowledge on the mechanisms behind this effect is not complete. We determined the stable isotopic signature of the reactive estuarine dissolved organic carbon (DOC) in the Öre estuary (Baltic Sea) by using the Keeling plot method. The δ13C ratio of the estuarine labile DOC varied from −26.0‰ to −18.7‰ with most values resembling those typical for DOC of coastal phytoplanktonic origin (−18 to −24‰), while being distinctly higher than those of DOC from ter­res­trial sources (−28‰ to −27‰). Furthermore, the δ13C of the respired carbon was positively correlated to DOC concentrations, indicating that carbon of marine origin increasingly dominated the reactive substrates when input of organic matter into the estuary became higher. This suggests that riverine organic matter mainly affects BR indirectly, by providing nutrients that stimulate the production of phytoplankton-derived reactive DOC in the estuary. Thus, riverine derived DOC per se may not be as important for coastal CO2 emissions as previously thought. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Riverine dissolved organic matter, Dissolved organic carbon, Bacterial respiration, Baltic sea, Carbon isotopes, Bacterioplankton, Primary production, Carbon cycling
in
Marine Environmental Research
volume
148
pages
39 - 45
publisher
Elsevier
external identifiers
  • scopus:85065249380
ISSN
0141-1136
DOI
10.1016/j.marenvres.2019.04.009
language
English
LU publication?
yes
id
17787138-2428-4121-90ca-da1f5ed5032d
date added to LUP
2019-05-16 11:37:42
date last changed
2019-06-11 04:04:42
@article{17787138-2428-4121-90ca-da1f5ed5032d,
  abstract     = {Increasing loading of terrestrially derived dissolved organic matter tends to enhance bacterioplankton respiration (BR) in boreal estuaries, but knowledge on the mechanisms behind this effect is not complete. We determined the stable isotopic signature of the reactive estuarine dissolved organic carbon (DOC) in the Öre estuary (Baltic Sea) by using the Keeling plot method. The δ13C ratio of the estuarine labile DOC varied from −26.0‰ to −18.7‰ with most values resembling those typical for DOC of coastal phytoplanktonic origin (−18 to −24‰), while being distinctly higher than those of DOC from ter­res­trial sources (−28‰ to −27‰). Furthermore, the δ13C of the respired carbon was positively correlated to DOC concentrations, indicating that carbon of marine origin increasingly dominated the reactive substrates when input of organic matter into the estuary became higher. This suggests that riverine organic matter mainly affects BR indirectly, by providing nutrients that stimulate the production of phytoplankton-derived reactive DOC in the estuary. Thus, riverine derived DOC per se may not be as important for coastal CO2 emissions as previously thought.},
  author       = {Soares, Ana and Berggren, Martin},
  issn         = {0141-1136},
  language     = {eng},
  pages        = {39--45},
  publisher    = {Elsevier},
  series       = {Marine Environmental Research},
  title        = {Indirect link between riverine dissolved organic matter and bacterioplankton respiration in a boreal estuary},
  url          = {http://dx.doi.org/10.1016/j.marenvres.2019.04.009},
  doi          = {10.1016/j.marenvres.2019.04.009},
  volume       = {148},
  year         = {2019},
}