title: Eukaryotic opportunists dominate the deep-subsurface biosphere in South Africa.
abstract: Following the discovery of the first Eukarya in the deep subsurface, intense interest has developed to understand the diversity of eukaryotes living in these extreme environments. We identified that Platyhelminthes, Rotifera, Annelida and Arthropoda are thriving at 1.4 km depths in palaeometeoric fissure water up to 12,300 yr old in South African mines. Protozoa and Fungi have also been identified; however, they are present in low numbers. Characterization of the different species reveals that many are opportunistic organisms with an origin due to recharge from surface waters rather than soil leaching. This is the first known study to demonstrate the in situ distribution of biofilms on fissure rock faces using video documentation. Calculations suggest that food, not dissolved oxygen is the limiting factor for eukaryal population growth. The discovery of a group of Eukarya underground has important implications for the search for life on other planets in our solar system.
authors.affiliation: Extreme Life Isyensya (ELI), PB 65, 9050 Gentbrugge, Belgium.|Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: G
authors.identifier: http://orcid.org/0000-0003-1196-8159
authors.initials: G
authors.lastname: Borgonie
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: B
authors.initials: B
authors.lastname: Linage-Alvarez
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: A O
authors.initials: AO
authors.lastname: Ojo
authors.affiliation: Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto, Ontario, Canada M5S 3B1.
authors.forename: S O C
authors.initials: SO
authors.lastname: Mundle
authors.affiliation: AngloGold Ashanti Kopanang Mine, Private Bag X5010, Vaal Reef, North West 2621, Republic of South Africa.
authors.forename: L B
authors.initials: LB
authors.lastname: Freese
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: C
authors.initials: C
authors.lastname: Van Rooyen
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: O
authors.initials: O
authors.lastname: Kuloyo
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: J
authors.initials: J
authors.lastname: Albertyn
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: C
authors.initials: C
authors.lastname: Pohl
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: E D
authors.initials: ED
authors.lastname: Cason
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: J
authors.initials: J
authors.lastname: Vermeulen
authors.affiliation: AngloGold Ashanti Kopanang Mine, Private Bag X5010, Vaal Reef, North West 2621, Republic of South Africa.
authors.forename: C
authors.initials: C
authors.lastname: Pienaar
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: D
authors.initials: D
authors.lastname: Litthauer
authors.affiliation: Sibanye Gold Ltd, Driefontein Operations, Farm Leeupoort P111, Goudveld 2507, Republic of South Africa.
authors.forename: H
authors.initials: H
authors.lastname: Van Niekerk
authors.affiliation: Sibanye Gold Ltd, Driefontein Operations, Farm Leeupoort P111, Goudveld 2507, Republic of South Africa.
authors.forename: J
authors.initials: J
authors.lastname: Van Eeden
authors.affiliation: Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto, Ontario, Canada M5S 3B1.
authors.forename: B
authors.initials: B
authors.lastname: Sherwood Lollar
authors.affiliation: Department of Geosciences, Princeton University, B79 Guyot Hall, Princeton, 08544 New Jersey, USA.
authors.forename: T C
authors.initials: TC
authors.lastname: Onstott
authors.affiliation: Department of Microbial, Biochemical and Food Biotechnology, Swot Street 9300 Bloemfontein, Republic of South Africa.
authors.forename: E
authors.initials: E
authors.lastname: Van Heerden
mesh_terms: D000818:Animals; D000845:Annelida / Q000235:genetics; D001181:Arthropods / Q000235:genetics; D001483:Base Sequence; D018441:Biofilms; D017753:Ecosystem; D056890:Eukaryota / Q000235:genetics*; D005658:Fungi / Q000235:genetics; D008906:Mining; D008969:Molecular Sequence Data; D009348:Nematoda / Q000235:genetics; D010986:Platyhelminths / Q000235:genetics; D012403:Rotifera / Q000235:genetics; D012987:Soil; D013019:South Africa; D014741:Video Recording; D014867:Water
chemical_list: D012987:Soil; D014867:Water