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Photochemical mineralization of dissolved organic carbon in lakes of differing pH and humic content

Anesio, Alexandre Magno LU and Granéli, Wilhelm LU (2004) In Archiv für Hydrobiologie 160(1). p.105-116
Abstract
Photochemical mineralization of dissolved organic carbon (DOC) to dissolved inorganic carbon (DIC) was studied in surface water from 10 oligotrophic lakes in Southern Sweden differing in DOC, pH, and iron content. In addition, we studied the effects of acidification on the DOC photoreactivity. Samples from each lake were filtered through 0.2 mum-filters, acidified by one pH unit or kept under ambient pH conditions, and incubated in quartz tubes, in situ and in the laboratory. We found a positive relationship between photochemical DIC production at the surface and DOC concentration or absorbed dose of UV radiation. On average, lake water treated with acid showed higher rates of photooxidation than lake water with ambient pH. However, the... (More)
Photochemical mineralization of dissolved organic carbon (DOC) to dissolved inorganic carbon (DIC) was studied in surface water from 10 oligotrophic lakes in Southern Sweden differing in DOC, pH, and iron content. In addition, we studied the effects of acidification on the DOC photoreactivity. Samples from each lake were filtered through 0.2 mum-filters, acidified by one pH unit or kept under ambient pH conditions, and incubated in quartz tubes, in situ and in the laboratory. We found a positive relationship between photochemical DIC production at the surface and DOC concentration or absorbed dose of UV radiation. On average, lake water treated with acid showed higher rates of photooxidation than lake water with ambient pH. However, the difference in rates of photooxidation between acidified and non-acidified treatments was only evident for lake water with high DOC and iron content (i.e. lakes with DOC concentration > 10 mg C/l, and iron concentration > 400 mug/l). Results from this study indicate that acidification may increase photochemical mineralization, especially in humic lakes. Finally, we showed that a substantial increase in UV-B radiation (e. g. a doubling) would influence the rates of photochemical mineralization of DOC in humic lakes (DOC > 10 mg C/l) substantially less than a rather moderate decrease in pH of one unit. In clear lakes an increased UV-B radiation would have a stronger impact on areal DIC-production than a decrease in pH. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Archiv für Hydrobiologie
volume
160
issue
1
pages
105 - 116
publisher
E. Schweizerbart Science Publishers
external identifiers
  • wos:000221450000007
  • scopus:2442700527
ISSN
0003-9136
DOI
10.1127/0003-9136/2004/0160-0105
language
English
LU publication?
yes
id
14cad1d2-3d73-49c7-89d2-c420e214fa51 (old id 136671)
date added to LUP
2007-06-28 12:10:29
date last changed
2017-12-10 04:39:43
@article{14cad1d2-3d73-49c7-89d2-c420e214fa51,
  abstract     = {Photochemical mineralization of dissolved organic carbon (DOC) to dissolved inorganic carbon (DIC) was studied in surface water from 10 oligotrophic lakes in Southern Sweden differing in DOC, pH, and iron content. In addition, we studied the effects of acidification on the DOC photoreactivity. Samples from each lake were filtered through 0.2 mum-filters, acidified by one pH unit or kept under ambient pH conditions, and incubated in quartz tubes, in situ and in the laboratory. We found a positive relationship between photochemical DIC production at the surface and DOC concentration or absorbed dose of UV radiation. On average, lake water treated with acid showed higher rates of photooxidation than lake water with ambient pH. However, the difference in rates of photooxidation between acidified and non-acidified treatments was only evident for lake water with high DOC and iron content (i.e. lakes with DOC concentration > 10 mg C/l, and iron concentration > 400 mug/l). Results from this study indicate that acidification may increase photochemical mineralization, especially in humic lakes. Finally, we showed that a substantial increase in UV-B radiation (e. g. a doubling) would influence the rates of photochemical mineralization of DOC in humic lakes (DOC > 10 mg C/l) substantially less than a rather moderate decrease in pH of one unit. In clear lakes an increased UV-B radiation would have a stronger impact on areal DIC-production than a decrease in pH.},
  author       = {Anesio, Alexandre Magno and Granéli, Wilhelm},
  issn         = {0003-9136},
  language     = {eng},
  number       = {1},
  pages        = {105--116},
  publisher    = {E. Schweizerbart Science Publishers},
  series       = {Archiv für Hydrobiologie},
  title        = {Photochemical mineralization of dissolved organic carbon in lakes of differing pH and humic content},
  url          = {http://dx.doi.org/10.1127/0003-9136/2004/0160-0105},
  volume       = {160},
  year         = {2004},
}