Cristin-resultat-ID: 1424840
Sist endret: 10. august 2017 16:38
NVI-rapporteringsår: 2016
Resultat
Vitenskapelig artikkel
2017

Dampened copepod-mediated trophic cascades in a microzooplankton-dominated microbial food web: A mesocosm study

Bidragsytere:
  • Bernadette Pree
  • Aud Larsen
  • Jorun Karin Egge
  • Paolo Simonelli
  • Rakhesh Madhusoodhanan
  • Tatiana Tsagaraki
  • mfl.

Tidsskrift

Limnology and Oceanography
ISSN 0024-3590
e-ISSN 1939-5590
NVI-nivå 1

Om resultatet

Vitenskapelig artikkel
Publiseringsår: 2017
Volum: 62
Hefte: 3
Sider: 1031 - 1044

Importkilder

Scopus-ID: 2-s2.0-85005932163

Beskrivelse Beskrivelse

Tittel

Dampened copepod-mediated trophic cascades in a microzooplankton-dominated microbial food web: A mesocosm study

Sammendrag

Interactions of bottom-up factors such as the availability of mineral and organic nutrients, and top-down factors like predation and viral infection affect microbial communities of the pelagic food web. Hypothesis derived from previous experimental and modeling work suggest some general mechanisms on how these factors may be linked and call for an experiment to test interactions between (1) nitrogen source and diatom cell size, (2) bacterial growth rate limitation by mineral nutrients versus organic carbon, and (3) enhanced versus decreased predation pressure by copepods (Calanus finmarchicus). We performed a mesocosm experiment using a replicated three factor––two level full factorial design (NH1 4 /NO2 3 , 1/2 glucose, and 1/2 copepods). Diatoms, pico- and nano-sized autotrophs, prokaryotes, heterotrophic nanoflagellates, micro- and mesozooplankton abundances were monitored for 19 days. The main finding was a system that responded remarkably little to these manipulations with no effects of nitrogen source and only moderate effects of carbon treatments. Zooplankton manipulations had the strongest impact on microbial communities, but, opposite to our hypothesis based on previous studies, microzooplankton and diatoms increased during the first 7–10 days when mesozooplankton abundances were experimentally enhanced. We suggest that high abundances of dinoflagellates and ciliates and occurrence of rotifers, which dominated microzooplankton community in the first half of the experiment complicated trophic linkages between copepods, microzooplankton and diatoms. Apart from this dampened copepod mediated trophic cascade, we found tight couplings between communities of the microbial food web, with maxima of predator communities coinciding with low abundances of prey communities.

Bidragsytere

Bernadette Pree

  • Tilknyttet:
    Forfatter
    ved Institutt for biovitenskap ved Universitetet i Bergen

Aud Larsen

  • Tilknyttet:
    Forfatter
    ved NORCE Miljø ved NORCE Norwegian Research Centre AS

Jorun Karin Egge

  • Tilknyttet:
    Forfatter
    ved Institutt for biovitenskap ved Universitetet i Bergen

Paolo Simonelli

  • Tilknyttet:
    Forfatter
    ved Institutt for biovitenskap ved Universitetet i Bergen
  • Tilknyttet:
    Forfatter
    ved Institutt for geovitenskap ved Universitetet i Bergen

Rakhesh Madhusoodhanan

  • Tilknyttet:
    Forfatter
    ved Institutt for biovitenskap ved Universitetet i Bergen
  • Tilknyttet:
    Forfatter
    ved Kuwait
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