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Disruption of the microbial food web and inhibition of metazooplankton development in the presence of iron- and DOM-stimulated Baltic Sea cyanobacteria

Kozlowsky-Suzuki, Betina LU ; Karjalainen, Miina; Koski, Marja; Carlsson, Per LU ; Stolte, Willem; Balode, Maija and Graneli, Edna (2007) In Marine Ecology - Progress Series 337. p.15-26
Abstract
Summer N-2-fixing cyanobacterial blooms are a common feature in the Baltic Sea, and the occurrence of Nodularia spumigena toxic blooms is of particular concern. Cyanobacterial blooms can be favoured by certain conditions including high concentrations of dissolved organic matter, which may increase the availability of iron critical for N-2 fixation. Cyanobacteria may negatively affect grazers because many species produce toxins and generally lack fatty acids essential for zooplankton reproduction. In this study we investigated the effect of riverine high-molecular weight dissolved organic matter (DOM-)/iron-stimulated cyanobacteria on the development of proto- and metazooplankton, and evaluated the role of DOM in stimulating the zooplankton... (More)
Summer N-2-fixing cyanobacterial blooms are a common feature in the Baltic Sea, and the occurrence of Nodularia spumigena toxic blooms is of particular concern. Cyanobacterial blooms can be favoured by certain conditions including high concentrations of dissolved organic matter, which may increase the availability of iron critical for N-2 fixation. Cyanobacteria may negatively affect grazers because many species produce toxins and generally lack fatty acids essential for zooplankton reproduction. In this study we investigated the effect of riverine high-molecular weight dissolved organic matter (DOM-)/iron-stimulated cyanobacteria on the development of proto- and metazooplankton, and evaluated the role of DOM in stimulating the zooplankton part of the microbial food web. A plankton community was incubated in cylinders with either nitrate (NO3) or DOM alone or combined with iron (Fe) or zooplankton >100 mu m (G). The development of proto- and metazooplankton was followed for 10 d. Trophic relationships between metazooplankton taxa and their potential food items were assessed by ordination analysis and by feeding and reproduction bottle incubations with the calanoid copepod Acartia bifflosa. Contrary to our expectations, DOM did not stimulate the microbial food web, and proto- and metazooplankton developed similarly in all treatments until the middle of the experiment. However, by the end of the experiment, the biomass of proto- and metazooplankton as well as the biomass of diatoms and dinoflagellates was greatly depressed in all DOM and NO3Fe treatments. In these treatments, cyanobacterial and bacterial biomasses were highest leading up to phosphate depletion. Plankton development seemed to be bottom-up controlled and to be affected by extracellular compound(s) produced by the dominant cyanobacteria, possibly triggered by phosphate limitation. Diatoms, dinoflagellates, protozoans and metazooplankton were instead stimulated in the NO3 and NO(3)G treatments, where cyanobacterial biomass was low. Accordingly, A. bifilosa reproduction and survival were sustained in NO3 bottles. Deleterious effects of cyanobacteria on metazooplankton were diminished in NO3 and NO(3)G tanks where other food resources were available. Overall, the results suggest that increases in the input of DOM to the Baltic Sea can potentially stimulate cyanobacterial blooms that may disrupt the microbial food web and inhibit metazooplankton development. (Less)
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organization
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Contribution to journal
publication status
published
subject
keywords
Acartia bifilosa, zooplankton, riverine high-molecular weight dissolved organic matter (DOM) iron, microbial food web, cyanobacteria, extracellular compounds
in
Marine Ecology - Progress Series
volume
337
pages
15 - 26
publisher
Inter-Research
external identifiers
  • wos:000247105100002
  • scopus:34548278316
ISSN
1616-1599
language
English
LU publication?
yes
id
c6869871-a851-4964-aa49-4fde046b5df4 (old id 650733)
alternative location
http://www.int-res.com/articles/meps2007/337/m337p015.pdf
date added to LUP
2007-12-12 14:59:27
date last changed
2017-02-05 04:14:43
@article{c6869871-a851-4964-aa49-4fde046b5df4,
  abstract     = {Summer N-2-fixing cyanobacterial blooms are a common feature in the Baltic Sea, and the occurrence of Nodularia spumigena toxic blooms is of particular concern. Cyanobacterial blooms can be favoured by certain conditions including high concentrations of dissolved organic matter, which may increase the availability of iron critical for N-2 fixation. Cyanobacteria may negatively affect grazers because many species produce toxins and generally lack fatty acids essential for zooplankton reproduction. In this study we investigated the effect of riverine high-molecular weight dissolved organic matter (DOM-)/iron-stimulated cyanobacteria on the development of proto- and metazooplankton, and evaluated the role of DOM in stimulating the zooplankton part of the microbial food web. A plankton community was incubated in cylinders with either nitrate (NO3) or DOM alone or combined with iron (Fe) or zooplankton >100 mu m (G). The development of proto- and metazooplankton was followed for 10 d. Trophic relationships between metazooplankton taxa and their potential food items were assessed by ordination analysis and by feeding and reproduction bottle incubations with the calanoid copepod Acartia bifflosa. Contrary to our expectations, DOM did not stimulate the microbial food web, and proto- and metazooplankton developed similarly in all treatments until the middle of the experiment. However, by the end of the experiment, the biomass of proto- and metazooplankton as well as the biomass of diatoms and dinoflagellates was greatly depressed in all DOM and NO3Fe treatments. In these treatments, cyanobacterial and bacterial biomasses were highest leading up to phosphate depletion. Plankton development seemed to be bottom-up controlled and to be affected by extracellular compound(s) produced by the dominant cyanobacteria, possibly triggered by phosphate limitation. Diatoms, dinoflagellates, protozoans and metazooplankton were instead stimulated in the NO3 and NO(3)G treatments, where cyanobacterial biomass was low. Accordingly, A. bifilosa reproduction and survival were sustained in NO3 bottles. Deleterious effects of cyanobacteria on metazooplankton were diminished in NO3 and NO(3)G tanks where other food resources were available. Overall, the results suggest that increases in the input of DOM to the Baltic Sea can potentially stimulate cyanobacterial blooms that may disrupt the microbial food web and inhibit metazooplankton development.},
  author       = {Kozlowsky-Suzuki, Betina and Karjalainen, Miina and Koski, Marja and Carlsson, Per and Stolte, Willem and Balode, Maija and Graneli, Edna},
  issn         = {1616-1599},
  keyword      = {Acartia bifilosa,zooplankton,riverine high-molecular weight dissolved organic matter (DOM) iron,microbial food web,cyanobacteria,extracellular compounds},
  language     = {eng},
  pages        = {15--26},
  publisher    = {Inter-Research},
  series       = {Marine Ecology - Progress Series},
  title        = {Disruption of the microbial food web and inhibition of metazooplankton development in the presence of iron- and DOM-stimulated Baltic Sea cyanobacteria},
  volume       = {337},
  year         = {2007},
}