title: Sea-ice eukaryotes of the Gulf of Finland, Baltic Sea, and evidence for herbivory on weakly shade-adapted ice algae.
abstract: To determine community composition and physiological status of early spring sea-ice organisms, we collected sea-ice, slush and under-ice water samples from the Baltic Sea. We combined light microscopy, HPLC pigment analysis and pyrosequencing, and related the biomass and physiological status of sea-ice algae with the protistan community composition in a new way in the area. In terms of biomass, centric diatoms including a distinct Melosira arctica bloom in the upper intermediate section of the fast ice, dinoflagellates, euglenoids and the cyanobacterium Aphanizomenon sp. predominated in the sea-ice sections and unidentified flagellates in the slush. Based on pigment analyses, the ice-algal communities showed no adjusted photosynthetic pigment pools throughout the sea ice, and the bottom-ice communities were not shade-adapted. The sea ice included more characteristic phototrophic taxa (49%) than did slush (18%) and under-ice water (37%). Cercozoans and ciliates were the richest taxon groups, and the differences among the communities arose mainly from the various phagotrophic protistan taxa inhabiting the communities. The presence of pheophytin a coincided with an elevated ciliate biomass and read abundance in the drift ice and with a high Eurytemora affinis read abundance in the pack ice, indicating that ciliates and Eurytemora affinis were grazing on algae.
authors.affiliation: Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, 10900 Hanko, Finland; Department of Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland; Marine Research Centre, Finnish Environment Institute, P.O. Box 140, 00251 Helsinki, Finland. Electronic address: markus.majaneva@gmail.com.
authors.forename: Markus
authors.initials: M
authors.lastname: Majaneva
authors.affiliation: Department of Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland.
authors.forename: Jaanika
authors.initials: J
authors.lastname: Blomster
authors.affiliation: Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, 10900 Hanko, Finland; Department of Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland.
authors.forename: Susann
authors.initials: S
authors.lastname: Müller
authors.affiliation: Marine Research Centre, Finnish Environment Institute, P.O. Box 140, 00251 Helsinki, Finland.
authors.forename: Riitta
authors.initials: R
authors.lastname: Autio
authors.affiliation: Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, 10900 Hanko, Finland; Department of Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland; Marine Research Centre, Finnish Environment Institute, P.O. Box 140, 00251 Helsinki, Finland.
authors.forename: Sanna
authors.initials: S
authors.lastname: Majaneva
authors.affiliation: Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, 10900 Hanko, Finland; Department of Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland.
authors.forename: Kirsi
authors.initials: K
authors.lastname: Hyytiäinen
authors.affiliation: Research Center for Aquatic Genomics, National Research Institute of Fisheries Science, Kanazawa-ku 236-8648, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nagai
authors.affiliation: Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, 10900 Hanko, Finland; Department of Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland; Marine Research Centre, Finnish Environment Institute, P.O. Box 140, 00251 Helsinki, Finland.
authors.forename: Janne-Markus
authors.initials: JM
authors.lastname: Rintala
mesh_terms: D044822:Biodiversity; D018533:Biomass; D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology; D017377:Diatoms / Q000502:physiology; D056890:Eukaryota / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D005387:Finland; D060434:Herbivory; D046448:Ice Cover / Q000469:parasitology*; D008853:Microscopy; D009792:Oceans and Seas; D010860:Pigments, Biological / Q000032:analysis* / Q000737:chemistry; D013472:Sunlight
chemical_list: D010860:Pigments, Biological
keywords: 18S rRNA gene; Accessory pigments; Herbivory; Photoacclimation; Sea ice