title: Benthic eukaryotic diversity in the Guaymas Basin hydrothermal vent environment.
abstract: Molecular microbial ecology studies have revealed remarkable prokaryotic diversity in extreme hydrothermal marine environments. There are no comparable reports of culture-independent surveys of eukaryotic life in warm, anoxic marine sediments. By using sequence comparisons of PCR-amplified small subunit ribosomal RNAs, we characterized eukaryotic diversity in hydrothermal vent environments of Guaymas Basin in the Gulf of California. Many sequences from these anoxic sediments and the overlaying seawater represent previously uncharacterized protists, including early branching eukaryotic lineages or extended diversity within described taxa. At least two mechanisms, with overlapping consequences, account for the eukaryotic community structure of this environment. The adaptation to anoxic environments is evidenced by specific affinity of environmental sequences to aerotolerant anaerobic species in molecular trees. This pattern is superimposed against a background of widely distributed aerophilic and aerotolerant protists, some of which may migrate into and survive in the sediment whereas others (e.g., phototrophs) are simply deposited by sedimentary processes. In contrast, bacterial populations in these sediments are primarily characteristic of anoxic, reduced, hydrocarbon-rich sedimentary habitats.
authors.affiliation: The Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
authors.forename: Virginia P
authors.initials: VP
authors.lastname: Edgcomb
authors.forename: David T
authors.initials: DT
authors.lastname: Kysela
authors.forename: Andreas
authors.initials: A
authors.lastname: Teske
authors.forename: Alvin
authors.initials: A
authors.lastname: de Vera Gomez
authors.forename: Mitchell L
authors.initials: ML
authors.lastname: Sogin
mesh_terms: D000818:Animals; D016798:Ciliophora / Q000145:classification / Q000235:genetics; D017931:DNA Primers; D017753:Ecosystem; D005658:Fungi / Q000145:classification / Q000235:genetics; D014644:Genetic Variation; D019015:Geologic Sediments / Q000032:analysis* / Q000382:microbiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D010944:Plants / Q000145:classification / Q000235:genetics; D016133:Polymerase Chain Reaction; D012335:RNA, Ribosomal / Q000737:chemistry / Q000235:genetics*
chemical_list: D017931:DNA Primers; D012335:RNA, Ribosomal