Methanogenes in permafrost

Prepared by Anatoli Brouchkov

2005

Area of permafrost

Ancient ice, about 22000 years old; Arctic coast

Aldan river exposure, about 40 m above water level (left) and Sirdah lake exposure, about 10 m above water level (right). Ice wedges do not contain as much methane as frozen

grounds, but the average content is high. Icewedges are different: Sirdah site dosn’t contain methane, but carbon dioxide; Neleger site contain much methane.

Ice wedges, about 40000 years old

Microorganisms in Arctic permafrost

Microorganisms from marine ice saturated deposits of Ugorsky peninsula, Cara sea coast. Age of permafrost of about 20000 years.

3 μm

Diversity of permafrost

microorganisms

Methane content in permafrost: first section

0 20 40 60 80 100 120 140 160 1801

10

100

1000

10000

Methane content, ppmv

Forest Slope Alas

Distance, m

Methane content and depth

1.000

1.500

2.000

2.500

3.000

3.500

4.000

4.500

5.000

5.500

1 10 100 1000 10000 100000 1000000

Methane content, pppmD

epth

, m

Methane content in permafrost on Alaska (Fairbanks)

778.8

485.9

4890.5

1244.9

45023.7

122244.0

Methane content in permafrost on Alaska (Barrow)

1381.7 772.4

2113.0

362.9

84.2213.1

soil iceice

High greenhouse gas load observed in debris-rich basal ice from the GRIP ice cores from the Greenland ice sheet: 130,000 ppmv of CO2 and 6,000 ppmv of CH4 (Souchez et al., 1995)

Methane content in permafrost

It is suggested that permafrost contains 40 ml/kg CH4 in average (Pearce, 1989). The estimation of gashydrate content in permafrost has not been done

yet.

Methane in ice of Arctic coast of Siberia (Moriizumi, Iida and Fukuda, 1994)

Vertical profiles of total bacteria and methanogens in West Siberia wetland (Utsumi et al., 2000)

WSB-16 (122)

WSB-5 (2)WSB-9

WSB-3

83

78

WSB-1 (3)

67

WSB-4

88

Methanosarcina barkeriWSB-10

WSB-14 (8)94

Methanosarcina mazeii

83

Methanohalobium evestigatumMethanolobus oregonensis

Methanohalophilus mahii

59

Methylcoccoides methylutens

64

99

72

50

98

WSB-19 (5)Methanosaeta concilii

WSB-21 (5)

65

85

100

Methanospirillum hungateiMethanocalculus halotolerans

Uncultured archaeon WCHD3-07WSB-13

Methanoculleus olentangyiMethanoculleus marisnigriMethanogenium cariaciMethanoplanus limicola

Methanomicrobium mobile87

100

55

Methanofollis liminatans

64

99

33

54

25

28

100

WSB-18 (2)Uncultured archaeon WCHD3-34

57

100

Methanococcus vannieliiMethanococcus voltae

Methanosphaera stadtmaniiMethanobacterium formicicum

100

100

69

60

Halococcus morrhua

9

Thermoplasma acidophilumUnidentified archaeon pMC2A203

WSB-1258

27

86

WSB-8WSB-15

89

100

WSB-17Unidentified crenarchaeon pGrfC2

Unidentified archaeon vadinDC69

WSB-11WSB-2

57

37

100

47

97

Cenarchaeum symbiosumWSB-6

Unid-archaeonSCA1170WSB-7

66

62

30

100

Unidentified crenarchaeon pGrfB286WSB-20

21

39

Pyrobaculum islandicum

0.05

West Siberia Bog

Methanococcales

Methanobacteriales

Methanomicrobiales

Methanosarcinales

Utsumi et al., 2000

All organisms in the sample are marked in blue by using DAPI (4',6-Diamidino-2-phenylindole),  a fluorescent dye which bounds to all DNA. 

Methane producing microorganisms of the order Methanomicrobiales are marked in red by hybridisation with a specific oligonucleotide probe (MG1200) 

By overlaying the pictures the fraction of Methanomicrobiales cells per DAPI-detected cells can be visualised. 

Methanogen’s detection by DAPI (Eastern Siberia soils, Alfred Wegener Institute, Potsdam, Germany)

Concentrations of headspace gases generated during 12 months of incubation at 4°C by 1997 thawed ice samples amended with 0.25×

R2A medium

SampleCO2 CH4

Basal ice (debris rich) 58,000 ± 2,700 16,000 ± 100 Glacier ice (debris poor) 5,500 ± 150 1.7 ± 0.1 Uninoculated medium 8,600 ± 300 1.4 ± 0.2

a Values are means ± standard deviations based on the results of duplicate analyses.

Arctic glacier, eastern Ellesmere Island, Canada

Interannual variations in Alaskan tundra methane emission (Whalen and Reeburg, 1992)

Methane emission in frozen soils

Methane producing in permafrost?

Methanogenic bacteria and metane both present in permafrost (Rivkina et al., 1993; Jansen, Bock, 1994). The most ancient bacteria (up to 3 mln years) found in permafrost is a methane producing archeobacteria. Methane could be more easy lost in common deposits, but not in ice-saturated permafrost. Origin of known fields of gashydrates in permafrost (Pradho Bay and others) is not explained yet. It has shown that upper layer of permafrost (about 10 m) of eastern Siberia is enriched by methane (up to 1%) in the air bubbles and the methane is younger then 5000 years (Fukuda, 1994). Methane content in active layer is much less at the beginning of winter than at the end. Methane collection in active layer in the winter period is about 100 ml/kg, and could be from 4 to 9 times more then in summer (Glotov, 1991).

Relationship between soil temperature at 5 cm depth and the cumulative methane flux, g/sq.m a day in Alaska (Ota et al., 2000)

Experimental methane emission below freezing point (Mountfort et al., 2003)

Plots of decrease in the log specific radioactivity of acetate after addition of [2-14C]acetate to sediments

which were incubated at 4°C (a) and below freezing (b).

Plots of log ratio of methane production rate: sulfate reduction rate versus

temperature for low-sulfate pond systems.

Days of experiment Samples/Methane content, ppmv

Tomakomai Alaska Yakutsk

1 1.43 0.90 1.23

2 1.18 1.54 -

23 2.06 1.98 -

70 2.05 2.12 1.98

209 2.07 2.02 2.29*)

230 2.01 2.02 -

*)148 days

Methane emission in frozen soils: experiments

Methane producing in frozen soils: experiments

0.500

1.000

1.500

2.000

2.500

3.000

1 10 100

Days

Met

hane

con

tent

, ppm

v

Tomakomai 1

Tomakomai 2

Alaska 1

Alaska 2

0.000

0.500

1.000

1.500

2.000

2.500

3.000

1 10 100

Days

Met

hane

con

tent

, ppm

v

Yakutsk 3

Yakutsk 4

Yakutsk 5

Methane producing at low temperatures (-5 deg. C):

effect of thawing

-500

0

500

1000

1500

2000

0 200 400 600 800

Time, days

Met

hane

con

tent

, ppm

v

Tomakomai

Tomakomai sterile

Tomakomai 2

Tomakomai double

Technique of sampling is important

Technique of permafrost sampling

Sample washing in 70% ethanol

Thermoplasma acidophilumclone

freshwater clone VAL2 (AJ131264)Methanocorpusculum labreanum

Methanospirillum hungateiMethanoculleus marisigriMethanogenium frigidum

clone

cloneclonecloneclone

100

71

Methanosaeta thermoacetophilaMethanosaeta concilii

cloneclone

cloneclone

97

100

Methanosarcina lacustris

93

100

100

85

0.02

Methanosaeta

Methanomicrobiales

aquatic group III

Phylogenic analysis of archaeal clones retrieved from a Siberian permafrost sample, showing unknown methanogenic communities may be present in the environment.

Anaerobic incubation

Incubation of local (Tomakomai), Yakutsk and Siberian soil

Marked in red cells - increase of methane

Calculated values of CH4 in head space, ppmv

Soil Medium Temperature Sample Comment 11.09.04 04.10.04

Yakutsk H2 20 1 208 17880

Yakutsk H2 0 2 210 502

Yakutsk Butyrate 20 5 329 51493

Yakutsk Butyrate 0 6 351 1757

Yakutsk Butyrate -5 7 turn red once 192 399

Yakutsk Butyrate -5 8 170 215

Yakutsk Acetate 20 9 233 5585

Local - Tomakomai H2 20 13 587 113274

Local - Tomakomai H2 0 14 904 1523

Local - Tomakomai H2 -5 15 934 15261

Local - Tomakomai H2 -5 16 was frozen 702 753

Siberian soil Acetate 20 17 38 518

Siberian soil Acetate -5 20 32 136

Siberian soil Acetate -5 21 34 2681

Siberian soil Glucose 20 22 33 106

Siberian soil Glucose 0 23 153 4971

Tomakomai soil, methane emission experiment at -5°C

Clone Length Homology Organism Environment

LocH-55 285 100 Methanobacterium bryantii

LocH-52 478 99

Oryza sativa rice roots LocH-520 440 99

LocH-512 515 98 Methanobacterium bryantii

LocH-515 351 98 Uncultured archaeon clone

LocH-522 468 98

Methanobacterium bryantii

LocH-531 412 98

LocH-54 463 98

LocH-521 343 97

LocH-525 394 97

LocH-529 477 97

Yakutsk soil, from active layer, methane emission experiment at 20°C

Clone Length Homology Organism Environment

YakH2015 390 98

Uncultured Methanomicrobiaceae archaeon soilYakH202 557 98

YakH203 470 98 Methanobacterium palustre tundra soil

YakH206 431 98

Uncultured Methanomicrobiaceae archaeon soilYakH208 410 98

YakH2031 402 97 Methanobacterium palustre tundra soil

YakH2011 233 96 Uncultured Methanomicrobiaceae archaeon soil

YakH2016 432 96

Methanobacterium palustre tundra soil

YakH2026 432 96

YakH205 428 96

YakH2025 417 95

Yakutsk soil, from active layer, methane emission experiment at -5°C

Clone Length Homology Organism Environment

YakH-511 409 99 Uncultured methanogen contaminated aquifer

YakH-526 402 99 Uncultured archaeon riparian flooding

YakH-528 409 99

YakH-530 499 99

YakH-541 406 99

YakH-546 405 99 Methanobacteriaceae archaeon acidic peat

YakH-56 434 99 Uncultured archaeon riparian flooding

YakH-531 472 98

YakH-533 368 98 Methanobacteriaceae archaeon acidic peat

YakH-54 390 98 Uncultured methanogen contaminated aquifer

YakH-542 394 98 Methanobacteriaceae archaeon acidic peat

YakH-547 547 97 Ruminococcus palustris swamp

YakH-538 391 96 Methanobacteriaceae archaeon acidic peat

Siberian permafrost soil, methane emission experiment at 20°C

Clone Length Homology Organism Environment

SibH201 432 99

Uncultured crenarchaeote cold soil

SibH2012 504 99

SibH2016 503 99

SibH2020 482 99

SibH2022 508 99

SibH2027 358 99

SibH2029 504 99

SibH2032 530 99 Uncultured bacterium clone contaminated soil

SibH208 511 99 Uncultured crenarchaeote cold soil

SibH2013 406 93 Uncultured Chloroflexi bacterium clone pasture soil

Siberian permafrost soil, methane emission experiment at -5°C

Clone Length Homology Organism Environment

SibH-516 475 99

Archaeon

soil

SibH-518 490 99

SibH-513 89 98

SibH-524 498 98

SibH-527 535 98

SibH-529 418 91

Uncultured bacteriumSibH-528 512 88

SibH-57 336 86

Uncultured archaeon

rice soil

SibH-511 363 85 rice soil

SibH-55 363 85 rice soil

SibH-56 518 85

Uncultured bacterium surface coal miningSibH-58 508 85

SibH-514 284 84

Uncultured archaeon rice soil

SibH-521 269 84

SibH-525 405 84

SibH-519 466 82

SibH-53 500 82

SibH-526 539 81 Uncultured archaeon deep sea

SibH-523 468 80

Uncultured archaeon cold sulfidic springs

SibH-54 467 80

SibH-520 510 79

SibH-522 506 79

Methane producing and content in permafrost: consequences

Latitude, degree N

Area of northern

wetland, 10 in 9

degree m2

Measure-ments,

methane flux,

mg/m2 a day

Measured methane emission,Tg a year

Methane produ-cing in active layer,

Tg/year

Addition as a result of 0,5 m increase of active

layer,Tg a year

Addition as a result of

thawing permafrost (Tg), taking

average 1000 ppmv

methane content and

5% air content

Methane produced and stored in

permafrost for 10000 years

75-72.5 30.2 45 0.1 0.1 0.8 0.2 320.7

72.5-70 80.2 100 0.7 0.8 2.0 1.2 1703.2

70-67.5 91.9 170 1.4 1.6 2.3 2.0 2927.4

Total 202.3 2.2 2.5 5.1 3.4 4951.3

Conclusion

Methane concentration is high in permafrost soils and ice in Siberia. Experiments show a production of methane in soils at -5 °C. A large amount of produced methane was trapped in frozen soil and emitted due to thawing only. Methanogenes, which were possibly responsible for the production, were identified in the samples. Finding of a number of methanogenes in permafrost present another evidence of the opportunity. Therefore permafrost might be a source of methane, which could be emitted in case of thawing.