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Molecular size of riverine dissolved organic matter influences coastal phytoplankton communities

Fagerberg, Tony LU ; Jephson, Therese LU and Carlsson, Per LU (2010) In Marine Ecology - Progress Series 409. p.17-25
Abstract
Dissolved organic matter (DOM) concentrations in many northern European freshwater systems have been increasing during the past decades. DOM affects the marine plankton community where rivers discharge into the sea. Large DOM molecules have been suggested to be more available to aquatic plankton than smaller ones due to their more recent origin in the degradation process. In this study, we investigated the effect of riverine DOM molecular size on coastal plankton with the hypothesis that nitrogen associated with large molecules stimulates the plankton more than nitrogen in smaller molecules. Three size fractions of riverine DOM were isolated with tangential ultrafiltration and introduced at similar nitrogen concentrations to mesocosms with... (More)
Dissolved organic matter (DOM) concentrations in many northern European freshwater systems have been increasing during the past decades. DOM affects the marine plankton community where rivers discharge into the sea. Large DOM molecules have been suggested to be more available to aquatic plankton than smaller ones due to their more recent origin in the degradation process. In this study, we investigated the effect of riverine DOM molecular size on coastal plankton with the hypothesis that nitrogen associated with large molecules stimulates the plankton more than nitrogen in smaller molecules. Three size fractions of riverine DOM were isolated with tangential ultrafiltration and introduced at similar nitrogen concentrations to mesocosms with a natural coastal marine plankton community under nitrogen limiting conditions. The results show that growth of bacteria and dinoflagellates, but not diatoms, was stimulated by addition of large DOM molecules. Even though organic nitrogen concentrations tended to decrease more in large DOM treatments compared to smaller DOM treatments, no significant differences were detected. However, proteolytic enzyme activities were elevated in treatments with the largest DOM molecules, suggesting that more organic nitrogen was utilized in this treatment. We suggest that input of larger river DOM molecules to nitrogen limited coastal systems may influence the composition of the coastal phytoplankton community in favour of dinoflagellates. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Molecular size, DON, River, Dissolved organic matter, DOM, Marine, phytoplankton
in
Marine Ecology - Progress Series
volume
409
pages
17 - 25
publisher
Inter-Research
external identifiers
  • wos:000279054000002
  • scopus:77954090507
ISSN
1616-1599
DOI
10.3354/meps08616
language
English
LU publication?
yes
id
4a8cb6f6-5e2c-4c9f-94ff-a3c3eb07a75c (old id 1630010)
date added to LUP
2010-07-23 12:15:59
date last changed
2018-05-29 10:51:54
@article{4a8cb6f6-5e2c-4c9f-94ff-a3c3eb07a75c,
  abstract     = {Dissolved organic matter (DOM) concentrations in many northern European freshwater systems have been increasing during the past decades. DOM affects the marine plankton community where rivers discharge into the sea. Large DOM molecules have been suggested to be more available to aquatic plankton than smaller ones due to their more recent origin in the degradation process. In this study, we investigated the effect of riverine DOM molecular size on coastal plankton with the hypothesis that nitrogen associated with large molecules stimulates the plankton more than nitrogen in smaller molecules. Three size fractions of riverine DOM were isolated with tangential ultrafiltration and introduced at similar nitrogen concentrations to mesocosms with a natural coastal marine plankton community under nitrogen limiting conditions. The results show that growth of bacteria and dinoflagellates, but not diatoms, was stimulated by addition of large DOM molecules. Even though organic nitrogen concentrations tended to decrease more in large DOM treatments compared to smaller DOM treatments, no significant differences were detected. However, proteolytic enzyme activities were elevated in treatments with the largest DOM molecules, suggesting that more organic nitrogen was utilized in this treatment. We suggest that input of larger river DOM molecules to nitrogen limited coastal systems may influence the composition of the coastal phytoplankton community in favour of dinoflagellates.},
  author       = {Fagerberg, Tony and Jephson, Therese and Carlsson, Per},
  issn         = {1616-1599},
  keyword      = {Molecular size,DON,River,Dissolved organic matter,DOM,Marine,phytoplankton},
  language     = {eng},
  pages        = {17--25},
  publisher    = {Inter-Research},
  series       = {Marine Ecology - Progress Series},
  title        = {Molecular size of riverine dissolved organic matter influences coastal phytoplankton communities},
  url          = {http://dx.doi.org/10.3354/meps08616},
  volume       = {409},
  year         = {2010},
}