Table S1. Nearest neighbours from the database to clone sequences.

Clone / Nearest neighbour (Accession no.) / % IDa / Origin / CF/Totb
LP1 / Uncultured archaeon clone kaa15 ( FJ936578) / 95 / Volcano mud at Avachinsky (Kamtchatka), Russia / 18/40
LP2 / Uncultured Thermoprotei archaeon clone NRA16 (HM041917) / 99 / High-temperature petroleum reservoir / 1/40
LP3 / Methanobacterium aarhusense strain 5-4 (DQ649334) / 99 / - / 4/40
LP4 / Uncultured archaeon clone:OHKA5.23 (AB094546) / 96 / Sediments from the sea of Okhotsk, / 1/40
LP5 / Uncultured archaeon clone HWA1012-2-58 (HM244058) / 98 / Honghu Lake sediments, China / 3/40
LP6 / Uncultured archaeon clone: HDBW-WA17 (AB237750) / 82 / Fault-bordered aquifers in the Miocene formation, Japan / 1/40
LP7 / Methanothermobacter marburgensis str. Marburg (CP001710) / 99 / - / 4/40
LP8 / Methanobacterium aarhusense strain 5-4 (DQ649334) / 99 / - / 1/40
LP9 / Methanobacterium aarhusense strain 5-4 (DQ649334) / 99 / - / 2/40
LP10 / Uncultured Candidatus Nitrosocaldus sp. fosmid clone: No.45-H-12 (AB201308) / 98 / Uncultivated thermophilic crenarchaeotes from a subsurface gold mine / 1/40
LP11 / Methanobacterium aarhusense strain 5-4 (DQ649334) / 98 / - / 1/40
LP12 / Uncultured archaeon clone AS-E (HM749818) / 94 / Anaerobic bioreactor / 1/40
LP13 / Uncultured archaeon clone: HDBW-WA17 (AB237750) / 83 / Fault-bordered aquifers in the Miocene formation, Japan / 2/40
LP14 / Uncultured bacterium clone SZT-B28 (GU363557) / 99 / Lion Head Hot Spring, Rehai National Geothermal Park, China / 2/34
LP15 / Leptolyngbya sp. O-77 (AB668059) / 99 / Thermophilic cyanobacteria / 2/34
LP16 / Uncultured bacterium clone BB-B51 (GQ844340) / 97 / Waste water treatment plant (anaerobic tank) / 2/34
LP17 / Uncultured bacterium isolate CMW-169 (FR828744) / 91 / Sludge, Ontario, Canada / 1/34
LP18 / Uncultured bacterium clone Mio58 (EU644970) / 93 / Meromictic soda lake, Washington State, USA / 1/34
LP19 / Uncultured Bacteroidetes bacterium clone A1-00YK9 (EU376409) / 99 / Hot spring mats, Western Thailand / 1/34
LP20 / Uncultured bacterium clone SZT-B28 (GU363557) / 98 / Lion Head Hot Spring, Rehai National Geothermal Park, China / 2/34
LP21 / Uncultured bacterium clone 87 (EF632320) / 99 / Dagejia hot spring, Tibet / 1/34
LP22 / Uncultured bacterium clone F7-B68 (FJ206963) / 98 / Red Layer Microbial Observatory Sites / 2/34
LP23 / Uncultured bacterium clone FL0428B_PF35 (FJ716450) / 97 / Sulfate-reducing cave biofilm / 1/34
LP24 / Uncultured Chloroflexales bacterium clone E7-00YK9 (EU376435) / 93 / Hot spring mats, Western Thailand / 1/34
LP25 / Uncultured bacterium clone TX4CB_86 (FJ152955) / 98 / Alkaline saline soil, Lake Texcoco, Mexico / 1/34
LP26 / Uncultured bacterium clone BB-B40 (GQ844335) / 88 / Anaerobic tank, water treatment plant / 1/34
LP28 / Uncultured bacterium clone BE325FW032701CTS_hole1-69 (DQ088759) / 95 / Fracture derived groundwater in a deep gold mine of South Africa / 2/34
LP29 / Uncultured bacterium clone CVCloAm1Ph47 (AM777992) / 96 / Nonsaline alkaline environment / 1/34
LP30 / Uncultured beta proteobacterium clone: HAuD-LB/2-3 (AB176697) / 96 / Subsurface geothermal water stream in a Japanese gold mine / 1/34
LP31 / Uncultured bacterium clone CVCloAm1Ph47 (AM777992) / 93 / Nonsaline alkaline environment / 1/34
LP32 / Uncultured bacterium clone BSTSG-15 (JN104837) / 93 / Bosten Lake, Northwest China / 1/34
LP33 / Uncultured bacterium clone BB-B51 (GQ844340) / 90 / Anaerobic tank, water treatment plant / 1/34
LP34 / Uncultured bacterium clone BB-B93 (GQ844346) / 97 / Anaerobic tank, water treatment plant / 1/34
TC1 / Uncultured archaeon clone LHC3_L2_F12 (EU924220) / 98 / Little Hot Creek, USA / 1/24
TC2 / Uncultured euryarchaeote clone YLA053 (JF262348) / 99 / Yellowstone Lake, USA / 1/24
TC3 / Methanothermobacter thermautotrophicus strain DM1 (HM228401) / 99 / - / 3/24
TC4 / Uncultured archaeon clone KCL60a_01_12 (FJ638517) / 98 / Sulfate reducing communities in a muddy hot spring in Southwestern Taiwan / 1/24
TC6 / Uncultured archaeon clone LHC1_L5_G08 (EU924235) / 97 / Little Hot Creek, USA / 1/24
TC7 / Uncultured Desulfurococcales archaeon clone YNP_SSp_A51 (DQ243775) / 96 / Hot springs of YNP, USA / 2/24
TC8 / Uncultured euryarchaeote clone ANB-14 (FJ898363) / 98 / High-temperature petroleum reservoir / 2/24
TC9 / Uncultured Thermoproteales archaeon clone YNP_SBC_MS2_A36 (HM448061) / 87 / Lower Geyser Basin, YNP, USA / 1/24
TC10 / Uncultured bacterium clone BJ67 (FM210909) / 99 / Inner Mongolia / 18/33
TC11 / Uncultured bacterium clone bac54 (HM184958) / 99 / 'Eryuan' Hot Spring, Yunnan Province, China / 1/33
TC12 / Uncultured Thermus/Deinococcus group bacterium clone E25 16S (DQ886547) / 99 / Hot Spring Frog Mouth in Tengchong Rehai, Yunnan,China / 1/33
TC13 / Uncultured bacterium clone BJ67 (FM210909) / 99 / Inner Mongolia / 1/33
TC14 / Uncultured bacterium clone BJ67 (FM210909) / 99 / Inner Mongolia / 1/33
TC15 / Uncultured delta proteobacterium clone SM1G01 (AF445695) / 86 / Mammoth Hot Springs, YNP, USA / 1/33
TC16 / Uncultured bacterium clone BJ67 (FM210909) / 99 / Inner Mongolia / 1/33
TC17 / Uncultured bacterium clone ZB_P13_A05 (GQ328611) / 94 / Thermal pools in the Uzon Caldera, Kamchakta, Russia / 1/33
TC18 / Uncultured bacterium clone ZB_P13_A05 (GQ328611) / 95 / Thermal pools in the Uzon Caldera, Kamchakta, Russia / 1/33
TC19 / Unidentified green non-sulfur bacterium OPB11 (AF027032) / 95 / YNP, USA / 1/33
TC20 / Uncultured bacterium clone BJ67 (FM210909) / 99 / Inner Mongolia / 1/33
TC21 / Uncultured bacterium clone AB_P5_B07 (GQ328365) / 93 / Thermal pools in the Uzon Caldera, Kamchakta, Russia / 1/33
TC22 / Uncultured bacterium clone KCLunmb_06_07 (FJ638580) / 97 / Muddy hot spring, Southwestern Taiwan / 1/33
TC23 / Uncultured bacterium clone NKB3-4 (FR691802) / 95 / Microbial mat, Nakabusa hot spring, Japan / 2/33

a Percentage identity (% ID) of the clone sequence compared to its nearest neighbour.

b Clone Frequency (CF) / Total number of clones (Tot); based on RFLP data.