title: Biogeography and phylogenetic position of a warm-stenotherm centric diatom, Skeletonema potamos (C.I. Weber) hasle and its long-term dynamics in the River Danube.
abstract: Skeletonema potamos is a poorly known freshwater species in the ancestrally and predominantly marine genus Skeletonema. With phylogenetic analysis of two nuclear {partial SSU (18S) and partial LSU (28S) rDNA)} and two chloroplast (rbcL and psbC) genes, we verified its placement within the genus Skeletonema and identified the mostly brackish species, Skeletonema subsalsum, as its closest known relative. Comparisons of SSU and LSU rRNA genes from S. potamos populations from Europe and North America revealed no intraspecific variation. Skeletonema potamos can be a dominant element of the phytoplankton community in various ecosystems, including the River Danube. We tracked phytoplankton composition in the River Danube weekly from 1979 to 2 012, and throughout this period, S. potamos exhibited a strong increase in proportion of total phytoplankton abundance and biomass - an increase that was correlated with increasing water temperature over the same time period. Current records indicate a temperate distribution of S. potamos, but ecological data predict possible expansion of its geographic range and increase in seasonal duration within existing habitats in response to the warming of surface waters.
authors.affiliation: Danube Research Institute, MTA Centre for Ecological Research, Karolina út 29, H-1113 Budapest, Hungary.
authors.forename: Mónika
authors.initials: M
authors.lastname: Duleba
authors.affiliation: Department of Environment and Agro-biotechnologies (EVA), Public Research Centre- Gabriel Lippmann, 41 rue du Brill, L-4422 Belvaux, Luxembourg.
authors.forename: Luc
authors.initials: L
authors.lastname: Ector
authors.affiliation: WasserCluster Lunz, Dr. Carl Kupelwieser Promenade 5, A-3293 Lunz am See, Austria.
authors.forename: Zsófia
authors.initials: Z
authors.lastname: Horváth
authors.affiliation: Danube Research Institute, MTA Centre for Ecological Research, Karolina út 29, H-1113 Budapest, Hungary.
authors.forename: Keve Tihamér
authors.initials: KT
authors.lastname: Kiss
authors.affiliation: Doctoral School of Environmental Sciences, Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary.
authors.forename: Levente Farkas
authors.initials: LF
authors.lastname: Molnár
authors.affiliation: Department of Microbiology, Institute of Biology, Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary.
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Pohner
authors.affiliation: Doctoral School of Environmental Sciences, Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary.
authors.forename: Zsuzsa
authors.initials: Z
authors.lastname: Szilágyi
authors.affiliation: Danube Research Institute, MTA Centre for Ecological Research, Karolina út 29, H-1113 Budapest, Hungary.
authors.forename: Bence
authors.initials: B
authors.lastname: Tóth
authors.affiliation: Doctoral School of Environmental Sciences, Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary.
authors.forename: Csaba Ferenc
authors.initials: CF
authors.lastname: Vad
authors.affiliation: Danube Research Institute, MTA Centre for Ecological Research, Karolina út 29, H-1113 Budapest, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Várbíró
authors.affiliation: Danube Research Institute, MTA Centre for Ecological Research, Karolina út 29, H-1113 Budapest, Hungary. Electronic address: acs.eva@okologia.mta.hu.
authors.forename: Éva
authors.initials: É
authors.lastname: Acs
mesh_terms: D016000:Cluster Analysis; D048028:DNA, Algal / Q000737:chemistry / Q000235:genetics; D018742:DNA, Chloroplast; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D017377:Diatoms / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D005060:Europe; D008969:Molecular Sequence Data; D058974:Phylogeography; D012335:RNA, Ribosomal / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D045483:Rivers / Q000469:parasitology*; D012621:Seasons; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D048028:DNA, Algal; D018742:DNA, Chloroplast; D004275:DNA, Ribosomal; D012335:RNA, Ribosomal; D012337:RNA, Ribosomal, 18S; C065096:RNA, ribosomal, 26S
keywords: Biogeography; Skeletonema potamos.; ecology; global warming; phylogeny