Response of Response of methanogensmethanogensfrom Siberian permafrost to extreme conditions of from Siberian permafrost to extreme conditions of terrestrial and extraterrestrial permafrostterrestrial and extraterrestrial permafrost

???

> 3.8 Ga Biosphere

oceans, rivers, lakes oceans

Hydrosphere

≈0°C

≥0°C Temperature

≈1atm

≥1 atm Pressure

water vapour, CO2, N2 water vapour, CO2, N2

Primitive atmosphere

Mars Mars Early

EarlyEarth Earth

Response of

Response of methanogens methanogens from Siberian permafrost to extreme conditions of from Siberian permafrost to extreme conditions of terrestrial and extraterrestrial permafrost

terrestrial and extraterrestrial permafrost Daria

Daria Morozova Morozova and Dirk Wagner and Dirk Wagner

I I

Since ESA mission Mars Express determined water on Mars, fundamental requirement for life, and presence of CH₄ in the Martian atmosphere, which could be originated only from active volcanism or from biological sources, it is obviously that microbial life could still exist on Mars, for example in form of subsurface lithoautotrophic ecosystems, which are also exist in permafrost regions on Earth. In the scope of a DFG project we use methanogenic archaea from Siberian permafrost as a model for comparative system studies regarding the resistance of methanogens to different extreme conditions.

(WA 1554/1-2)

Methanogenic archaea were isolated from permafrost soils of the Lena Delta (Siberia). The study site represents a typical low-centred ice- wedge polygon. The organisms were grown on bicarbonate-buffered, oxygen-free OCM culture medium under an atmosphere of H₂/CO₂ (80:20, v:v) or N₂/CO₂ (80:20, v:v) with methanol at 10°C and 28°C.

M M

A A

Phase contrast and fluorescence micrographs of methanogenic strain SMA-23 (A), SMA-16 (B), MethanosarcinaSMA-21 (C) from parmafrost and Methobacterium MC-20 (D) from non-permafrost habitats.

Methanosarcina MethanosarcinaSMASMA--2121

0,000 0,002 0,004 8 16 24 32 40

CH₄[nmol h ^-1ml ^-1] M. barkeri

MC-20

SMA-21

0,00048 ± 0,0008 nmol CH₄ 37,6 ± 3,1 nmol CH4

0,0008 ± 0,001 nmol CH₄ 20,1 ± 1,7 nmol CH4 5,24 ± 1,38 nmol CH₄ 10,98 ±1,5 nmol CH4

Before After

0,00 0,02 5 10 15 20 25

4°C 28°C no NaCl 28°C

CH₄[nmol h^-1ml^-1] NaClNaClSaturatedSaturated

solution solution

3M NaCl

1M NaCl

Control

0,00 0,05 0,10 0,15 0,20 0,25 10 20 30 SMA-21

MC-20 M. barkeri

CH4[nmol h^-1ml^-1] 0,02±0,009 nmol CH4 35,8±2,9 nmol CH₄ 0,21±0,078 nmol CH₄ 19,12±1,59 nmol CH4

10,87±1,22 nmol CH4 5,57±0,67 nmol CH4

Before After

CH4[nmol ml-1]

0 50 100 150 200 250

0 200 400 600 800 1000 1200 1400 1600

time [h]

control 50 J m^-2 150 J m^-2 400 J m^-2 800 J m^-2

CH4[nmol g-1]

0 50 100 150 200 250

0 100 200 300 400 500

time [h]

control 1000 J m^-2 2000 J m^-2 3000 J m^-2 4000 J m^-2 5000 J m^-2

0 20 40 60 80 100 0 20 40 60 80 100

0 500 1000 1500 2000 2500

CH4[nmol ml-1]

Time [h]

control 0.1M NaCl 0.2M NaCl 0.3M NaCl 0.4M NaCl

SMA-21 MC-20

Methanosarcina spec.

500 nm

4 H₂+ CO₂

Climate

Climatehistoryhistoryof of earlyearlyEarth and MarsEarth and Mars

???

> 3.8 Ga Biosphere

oceans, rivers, lakes oceans Hydrosphere

≈0°C Temperature

≥1 atm water vapour, CO2, N2

Mars Mars Early Early Earth Earth

McKay and Davis, 1991

Martian surface and terrestrial permafrost areas show similar morphological structures.

Northern Martian hemisphere (NASA) Lena Delta, Siberia (AWI)

CH₄+ H₂O

Pressure

≥0°C

≈1atm water vapour, CO₂, N₂ Primitive

atmosphere

M M

E E

C C

C C

CH₄production of methanogenic archaea as pure cultures and in natural environments after exposure to different intensities of UV-C radiation

Methanogenesis of methanogenic archaea from permafrost and non-permafrost habitats before and after freezing at – 80°C

CH₄production rates of permafrost strain under high salinity and different temperatures

Differences of CH₄ production of permafrost and non-

permafrost isolates under different salinities Methanogenesis of permafrost and non- permafrost isolates before and after exposure to 3 weeks of desiccation

The presented results show that methanogenic archaea from permafrost environments are highly resistant to different stress conditions comparably to methanogens from non-permafrost habitats. Permafrost isolates could be suitable keystone organisms for further studies about adaptation strategies and long-term survival in extreme environments. Investigation of the survival potential of these high specialized organisms can provide a unique insight to explore the putative life on the extraterrestrial planets.

Daria Morozova Forschungsstelle Potsdam Telegrafenberg A 43 14473 Potsdam dmorozova@awi-potsdam.de

Alfred-Wegener-Institut für Polar- und Meeresforschung in der Helmholtz-Gemeinschaft www.awi-potsdam.de

C B A

5 2 4 1

3

2 3 1

4 5 Evidence of

water on Mars

Evidence of CH₄on Mars

SMA-21 Permafrost samples

Fumisano, 2004

Methanobacterium MethanobacteriumMC-MC-2020 D