title: Protistan diversity in the Arctic: a case of paleoclimate shaping modern biodiversity?
abstract: BACKGROUND
  The impact of climate on biodiversity is indisputable. Climate changes over geological time must have significantly influenced the evolution of biodiversity, ultimately leading to its present pattern. Here we consider the paleoclimate data record, inferring that present-day hot and cold environments should contain, respectively, the largest and the smallest diversity of ancestral lineages of microbial eukaryotes.
  
  
  RESULTS
  We investigate this hypothesis by analyzing an original dataset of 18S rRNA gene sequences from Western Greenland in the Arctic, and data from the existing literature on 18S rRNA gene diversity in hydrothermal vent, temperate sediments, and anoxic water column communities. Unexpectedly, the community from the cold environment emerged as one of the richest observed to date in protistan species, and most diverse in ancestral lineages.
  
  
  CONCLUSIONS
  This pattern is consistent with natural selection sweeps on aerobic non-psychrophilic microbial eukaryotes repeatedly caused by low temperatures and global anoxia of snowball Earth conditions. It implies that cold refuges persisted through the periods of greenhouse conditions, which agrees with some, although not all, current views on the extent of the past global cooling and warming events. We therefore identify cold environments as promising targets for microbial discovery.
authors: Department of Ecology, University of Kaiserslautern, Kaiserslautern, Germany.
authors: Thorsten
authors: T
authors: Stoeck
authors: Jennifer
authors: J
authors: Kasper
authors: John
authors: J
authors: Bunge
authors: Chesley
authors: C
authors: Leslin
authors: Valya
authors: V
authors: Ilyin
authors: Slava
authors: S
authors: Epstein
mesh_terms: D000818:Animals; D001110:Arctic Regions; D044822:Biodiversity; D005075:Biological Evolution; D002980:Climate; D057231:Climate Change; D056890:Eukaryota / Q000145:classification / Q000235:genetics; D006116:Greenland; D009792:Oceans and Seas; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000145:classification / Q000235:genetics; D013696:Temperature; D014871:Water Microbiology
chemical_list: D012337:RNA, Ribosomal, 18S
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