Microbial processes in a high-latitude fjord (Kongsfjorden, Svalbard): II. Ciliates and dinoflagellates

Type : ACL
Nature : Production scientifique
Au bénéfice du Laboratoire : Oui
Statut de publication : Publié
Année de publication : 2011
Auteurs (3) : SEUTHE Lena IVERSEN Kriss,rokkan NARCY Fanny
Revue scientifique : Polar Biology
Volume : 34
Fascicule : 5
Pages : 751-766
DOI : 10.1007/s00300-010-0930-9
URL : <go to isi>://wos:000289481400012
Abstract : The composition and ecological role of ciliates and dinoflagellates were investigated at one station in Kongsfjorden, Svalbard, during six consecutive field campaigns between March and December 2006. Total ciliate and dinoflagellate abundance mirrored the seasonal progression of phytoplankton, peaking with 5.8 x 10(4) cells l(-1) in April at an average chlorophyll a concentration of 10 mu g l(-1). Dinoflagellates were more abundant than ciliates, dominated by small athecates. Among ciliates, aloricate oligotrichs dominated the assemblage. A large fraction (> 60%) of ciliates and dinoflagellates contained chloroplasts in spring and summer. The biomass of the purely heterotrophic fraction of the ciliate and dinoflagellate community (protozooplankton) was with 14 mu g C l(-1) highest in conjunction with the phytoplankton spring bloom in April. Growth experiments revealed similar specific growth rates for heterotrophic ciliates and dinoflagellates (< 0-0.8 d(-1)). Food availability may have controlled the protozooplankton assemblage in winter, while copepods may have exerted a strong control during the post-bloom period. Calculations of the potential grazing rates of the protozooplankton indicated its ability to control or heavily impact the phytoplankton stocks at most times. The results show that ciliates and dinoflagellates were an important component of the pelagic food web in Kongsfjorden and need to be taken into account when discussing the fate of phytoplankton and biogeochemical cycling in Arctic marine ecosystems.
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Commentaire : Times Cited: 21 Narcy, Fanny/A-7448-2013 22
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Citation :
Seuthe L, Iversen KR, Narcy F (2011) Microbial processes in a high-latitude fjord (Kongsfjorden, Svalbard): II. Ciliates and dinoflagellates. Polar Biol 34: 751-766 | doi: 10.1007/s00300-010-0930-9