Cristin-resultat-ID: 1724964
Sist endret: 16. september 2019 10:23
Resultat
Poster
2019

Trophic interactions between filter-feeding mesozooplankton and the Emiliania huxleyi virus

Bidragsytere:
  • Kyle Mayers
  • Janice Lawrence
  • Joachim Paul Töpper
  • Katrine Sandnes Skaar
  • Elzbieta Anna Petelenz-Kurdziel
  • Aud Larsen
  • mfl.

Konferanse

Tittel: 2019 IMBeR Open Science Conference

Sted:

Brest
Frankrike
Utbredelsesområde: Internasjonalt
Årstall: 2019
Dato fra: 17. juni 2019
Dato til: 21. juni 2019

Arrangør:

IMBeR

Om resultatet

Poster
Publiseringsår: 2019
Fagfellevurdert

Finansiering

  • Norges forskningsråd
    Prosjektkode: 275710

Beskrivelse Beskrivelse

Tittel

Trophic interactions between filter-feeding mesozooplankton and the Emiliania huxleyi virus

Sammendrag

Marine viruses are the most abundant entity in the oceans, regulating microbial populations and biogeochemical cycles through infection and lysis of cells. There is a paucity of information, however, about factors that regulate the abundance and diversity of viral populations. One group of planktonic marine tunicates, appendicularians, live inside filtering structures (“houses”) that can efficiently trap and concentrate food particles as small as 0.2 µm (Bedo et al., 1993). Our group has previously demonstrated that the globally distributed appendicularian Oikopleura dioica is able to remove the Emiliania huxleyi virus (EhV) from seawater (Lawrence et al., 2018). Furthermore, we detected EhV DNA in O. dioica houses, gut and faecal pellets. These results suggest an important, yet under-explored, loss mechanism for viruses from the upper water column. However, they also raise questions regarding the net impact of O. dioica feeding on the abundance and diversity of marine virus assemblages, and the ultimate fate of captured viruses. To address these questions, we conducted feeding experiments by incubating O. dioica in seawater collected from a mesocosm experiment in which a bloom of the coccolithophore E. huxleyi was induced by nutrient manipulation. Phytoplankton assemblages were near E. huxleyi bloom peak when water was collected for O. dioica incubations, although Prasinophytes (Micromonas sp.) and other Haptophytes (Phaeocystis spp.) were also observed, increasing the likelihood of rich marine virus diversity. Incubation water was filtered to remove all potential host cells but to retain viruses. Cell-free mesocosm virus assemblages were incubated in triplicate in the presence or absence of mature (Day 5 at 15°C incubation) O. dioica (20 animals L-1) for 8 hours as described previously (Lawrence et al. 2018). Water samples were collected hourly for flow cytometric enumeration of bacteria and viruses. At the beginning and end of incubations, 50-ml water samples from all incubations were pelleted by ultracentrifugation, and pellet DNA was quantified using droplet digital PCR targeting the major capsid protein (mcp) gene of EhV, to determine net differences in EhV genome equivalents after 8h incubations in the presence or absence of O. dioica. In order to assess the potential of O. dioica faecal pellets to disperse infectious viruses, we also incubated individual faecal pellets from both treatments in E. huxleyi 374 cultures to determine if infectious particles are shed from pellets. Clearance rates by O. dioica for an EhV-like virus population varied from approximately 20 - 75 mL individual-1 d-1. Flow cytometry results are compared with droplet digital PCR quantification of EhV in the same samples. Results from virulence assays demonstrate unequivocally that faecal pellets from O. dioica incubated in the presence of EhV contain and shed infectious particles, causing lysis of E. huxleyi. This raises speculation about the importance of this interaction as a loss mechanism for EhV from the water column, but also about the impact of this on the fate of virus particles in the marine environment. Alterations in virus-host dynamics will influence the virus-mediated turnover of carbon within the pelagic realm.

Bidragsytere

Kyle Mayers

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

Janice Lawrence

  • Tilknyttet:
    Forfatter

Joachim Paul Töpper

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

Katrine Sandnes Skaar

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

Elzbieta Anna Petelenz-Kurdziel

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