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Dissolved organic carbon dynamics in the peat-streamwater interface

Bengtsson, Göran LU and Törneman, Niklas LU (2004) In Biogeochemistry 70(1). p.93-116
Abstract
A series of experiments were conducted to address the fate of dissolved organic carbon (DOC) in the peat - stream interface zone linking a minerotrophic poor fen and an ombrotrophic mire with surrounding stream water in the drainage area of Lake Ortrasket in northern Sweden. Transport and mineralisation of DOC were quantified in peat - stream interface cores in response to variations in pore water velocity, DOC concentration and the molecular size and source of DOC. Mineralisation and CH4 production were positively correlated with pore water velocity at rates between 0.08 and 0.20 cm h(-1) and negatively correlated at rates between 0.20 and 0.40 cm h(-1). The DOC concentration of the effluent from the peat cores was independent of the pore... (More)
A series of experiments were conducted to address the fate of dissolved organic carbon (DOC) in the peat - stream interface zone linking a minerotrophic poor fen and an ombrotrophic mire with surrounding stream water in the drainage area of Lake Ortrasket in northern Sweden. Transport and mineralisation of DOC were quantified in peat - stream interface cores in response to variations in pore water velocity, DOC concentration and the molecular size and source of DOC. Mineralisation and CH4 production were positively correlated with pore water velocity at rates between 0.08 and 0.20 cm h(-1) and negatively correlated at rates between 0.20 and 0.40 cm h(-1). The DOC concentration of the effluent from the peat cores was independent of the pore water velocity but proportional to the DOC concentration of the source water. Higher concentrations of DOC were exported from than imported to the peat cores, and the cores exported DOC molecules of smaller average molecular size than received. Carbon mineralisation in the peat, assessed in a static system, was independent of the concentration of DOC. DOC with a nominal cutoff at 100 Da was mineralised faster by streamwater bacteria than DOC dialysed with a cutoff at 3500 Da, and their mineralisation rate was positively correlated with the DOC concentration. Streamwater bacteria mineralised streamwater DOC at a lower rate than the peat - stream interface zone pore water DOC. The pattern of velocity dependence of mineralisation was the same for both sources of peat DOC but the mineralisation rates, average molecular size, and bioavailability of DOC were different, emphasising the importance of the compositional heterogeneity of the peat - stream interface zone for the DOC budget of streamwater. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biogeochemistry
volume
70
issue
1
pages
93 - 116
publisher
Springer
external identifiers
  • wos:000225323600005
  • scopus:9644255720
ISSN
1573-515X
DOI
10.1023/B:BIOG.0000049338.81809.7c
language
English
LU publication?
yes
id
4e8f8300-8157-4547-b32b-e67405e88515 (old id 135787)
date added to LUP
2007-06-27 08:17:49
date last changed
2017-01-01 04:23:57
@article{4e8f8300-8157-4547-b32b-e67405e88515,
  abstract     = {A series of experiments were conducted to address the fate of dissolved organic carbon (DOC) in the peat - stream interface zone linking a minerotrophic poor fen and an ombrotrophic mire with surrounding stream water in the drainage area of Lake Ortrasket in northern Sweden. Transport and mineralisation of DOC were quantified in peat - stream interface cores in response to variations in pore water velocity, DOC concentration and the molecular size and source of DOC. Mineralisation and CH4 production were positively correlated with pore water velocity at rates between 0.08 and 0.20 cm h(-1) and negatively correlated at rates between 0.20 and 0.40 cm h(-1). The DOC concentration of the effluent from the peat cores was independent of the pore water velocity but proportional to the DOC concentration of the source water. Higher concentrations of DOC were exported from than imported to the peat cores, and the cores exported DOC molecules of smaller average molecular size than received. Carbon mineralisation in the peat, assessed in a static system, was independent of the concentration of DOC. DOC with a nominal cutoff at 100 Da was mineralised faster by streamwater bacteria than DOC dialysed with a cutoff at 3500 Da, and their mineralisation rate was positively correlated with the DOC concentration. Streamwater bacteria mineralised streamwater DOC at a lower rate than the peat - stream interface zone pore water DOC. The pattern of velocity dependence of mineralisation was the same for both sources of peat DOC but the mineralisation rates, average molecular size, and bioavailability of DOC were different, emphasising the importance of the compositional heterogeneity of the peat - stream interface zone for the DOC budget of streamwater.},
  author       = {Bengtsson, Göran and Törneman, Niklas},
  issn         = {1573-515X},
  language     = {eng},
  number       = {1},
  pages        = {93--116},
  publisher    = {Springer},
  series       = {Biogeochemistry},
  title        = {Dissolved organic carbon dynamics in the peat-streamwater interface},
  url          = {http://dx.doi.org/10.1023/B:BIOG.0000049338.81809.7c},
  volume       = {70},
  year         = {2004},
}