astrobiology” an introduction to an obscure field of research · “astrobiology” an...

“Astrobiology”an introduction to an obscure

field of research

Kai Finster

SAC & Bioscience

How is Astrobiology defined?

Astro- or Exo- or Planetary-biology?

= study of the origin, evolution, adaptation

and distribution of past and present life in the universe

including Earth.

= encompasses anthropology, astronomy, astrophysics,

biochemistry, biology, chemistry, cosmology, genetics,

geology, palaeontology, planetary science (philosophy

and theology). Monica. M. Grady, Geology Today 19:99-103. 2003.

Exploration along three lines

• In situ observations and experiments

• Study of Earth analogues

• Simulation experiments

In situ experiments

• Mars classic: The Viking experiments

Viking experiments

ALH84001- rocky bio-signatures?

McKay et al,

1996

ALH84001- rocky bio-signatures?

Remote In situ observations

• Satellite observations: Mars-express

“Follow the water”


Boynton et al, 2002


Phoenix - ice underneath the surface

Trace gases in the atmosphere

• Methane on Mars - Why is that of interest?

Methane on MARS

Methane data Earth Mars

Atmospheric

concentration

1750 ppbv 10 ppbv

Life time in the

atmosphere (years)

10 600

Production pr. year

to keep a constant

atmospheric

concentration (tons)

515 millioner 125

Sources Prokaryotes in

cattle, termits, rice

paddies; abiotic

chemical reactions

Prokaryotes?

Water-rock

reactions

Methane in the Martian atmosphere

Methane in the Martian atmosphere,

and where it could originate from,

and what the implications are.

Study of Earth analogues

Focus on Astro”micro”biology.

Astromicrobiologist search for life in the

universe by studying life/microbes on earth.

How is this justified?

We find environments on Earth that can be

regarded as Analogues to extraterrestrial

habitats. Such as Mars!

What are analogues?

Definition: something that is similar to another thing.

Without being the thing.

What is considered an

Analogue -and to what?

We usually have two extraterrestrial

habitats in mind-

1. Mars

2. Europa

What is considered an

Analogue -and to what- some

examples ?

- Black smokers

- Deep biosphere

- Dry (cold) desserts

- Permafrost Soil

Black Smokers

• High pressure

• High temperature

• Chemolithotrophic

microbes

• Ancient

phylogenetic

lineages

• Cradle of Life

Deep Biosphere

• Survival for long

periods of time

• Low substrate

concentrations

• Chemolithotrophic

microbes

• No/little interference

with the surface

Problems with the AnaloguesAnalogues are embedded in the complex eco-system

Earth

-> protecting atmosphere

-> high temperature

-> a lot of organic matter/oxygenic photosynthesis

-> oxygen

-> complex food webs

-> complex microbial communities everywhere

-> about 4 billion years of evolution and interactions

between the biotic and the abiotic world

-> etc.

Simulation experiments

Biological Marssimulations

0

2

4

6

8

10

12

14

16

18

1950 - 59 1960 - 69 1970 - 79 1980 - 89 1990 - 99 2000 - 07

Time Intervals

Nu

mber

of

Exper

imen

ts

Prokarytic Cultures

Prokaryotic Communities

Organic Molecules

Eukaryotes

Virus

Marssimulation facility at the University of Aarhus

Table 1. Environmental conditions in the Mars simulation chamber and on the surface

of present-day Mars.

Parameter Sim.environment Present-day Marsa

Temperature range

(°C)b

-41 - +40 -123 - +25

Pressure range (mbar) 7.6 - 9.7 6.7 - 9.9c

UV radiation (nm) >200 >200

UV intensity at 239 nm

(W m-2 nm-1)

0.207 0.006d

Gas composition (%)

CO2 91.4 95.3

N2 4.8 2.7

Ar 2.8 1.6

O2 0.24 0.13

H2O 0.14 0.02

CO 0.16 0.07

Other 0.41 0.25

•aFrom Horneck .

•bAt the soil surface.

See Fig. 1.

•cFrom Tillman et al. .

•dAnnual average

intensity at 11.6° N

(Patel, M., Personal

communication).

Our Approach

Simulation experiments

Concentrations of individual amino acids as

function of depth

0.0 0.1 0.2 0.3 0.4 0.5 0.6

0-1.5

1.5-3

3-6

6-9

9-15

15-21

21-27

27-33

Control

Dep

th (

mm

)

[DNA] (µg gdw -1

)

DNA concentrations as a function of depth

Parameter Temperature

(ºC)

Pressure

(mbar)

UV radiation

(nm)

UV intensity dose Lamp Protection of

sample

Mars

half-life

(days)

Reference

DNA -41 - 40 8 200 - 1000 35 times Mars Hg-xenon,

135 W

Soil matrix

0 – 1.5 mm80 Present study

THAA -41 - 40 8 200 - 1000 35 times Mars See above See above 135 Present study

Aspartate in

THAA

-41 - 40 8 200 - 1000 35 times Mars See above See above 70 Present study

Arginine in

THAA


Glycine in

THAA


Cell numbera -41 - 40 8 200 - 1000 35 times Mars See above See above 35 Present study

Viable cellsb -41 - 40 8 200 - 1000 35 times Mars See above See above 46 Present study

CFU’sc 41 - 40 8 200 - 1000 35 times Mars See above See above 22 Present study

Glycine 21 ~10-7 190-325 1/12 of Mars Deuterium None 1.5 ten Kate et

al. 2006

Glycine 21 ~10-7 190-325 1/12 of Mars Deuterium None 1.5 See above

Glycine -63 7 190-325 1/12 of Mars Deuterium None 10 See above

Glycine 21 4 � 10-6 190-325 1/25 of Mars Deuterium None 0.9 ten Kate et

al. 2005

D-alanine 21 4 � 10-6 190-325 1/25 of Mars Deuterium None 0.1 ten Kate et

al. 2005

Conclusions and hypotheses

• UV effect in H1

• Reactive compounds in H1 + H2

• Freeze-thaw cycles H1 - H5

Exo-planets

What do I consider being

“relevant Astro”micro”biological

research topics”?

• Simulation experiments, which include the information on the abiotic conditions obtained from space missions and exploration



research topics”?

• Simulation experiments, which include the information on the abiotic conditions

obtained from space missions and exploration

• De-contamination studies - planetary protection



research topics”?• Simulation experiments, which include the information on the abiotic conditions

obtained from space missions and exploration

• De-contamination studies - planetary protection

• Analogues with respect to exoplanets: Atmosphere composition, processes and signatures.

astrobiology” an introduction to an obscure field of research · “astrobiology” an...

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