Mars Astrobiology: Recent Status and Progress - Planetary Exploration and Science: Recent Results and Advances - page 232

Lichens' strange partnership also creates strange morphological forms. In many
circumstances, these organisms resemble exotic corals, sponges, or plants. Addi-
tionally, many lichens are brightly colored. The result is often beautiful miniature
landscapes.
Since it involves both algae and fungi, lichen reproduction can be complicated
and takes many different forms depending on the species and the circumstance.
Some lichens form soredia , small groups of algal cells surrounded by fungal
filaments which are dispersed as a group by wind.
Others produce isidia , elongated outgrowths from the thallus which break away.
During the dry season, certain lichens crumble into dusty flakes which are blown
across the landscape. When the rains come, the flakes burst into full growths. In the
most interesting and complicated pattern of reproduction, the fungal portion of the
lichen produces spores (as a result of sexual exchange and meiosis); these spores
are disseminated across the landscape, and then they must find compatible algae or
cyanobacteria with which to partner.
Lichens are probably long lived, and what is certain is that they are one of life's
most efficient colonizers: in areas such as the Atacama Desert and Antarctica, plants
cannot grow unless lichen lived there previously.
On April 26, 2012, scientists reported that lichen survived and showed remark-
able results on the adaptation capacity of photosynthetic activity within the simula-
tion time of 34 days under Martian conditions in the Mars Simulation Laboratory
(MSL) maintained by the German Aerospace Center (Deutsches Zentrum für Luft-
und Raumfahrt - DLR) (Fig. 8.34 )(Mee“en et al. 2013 ;deVeraetal. 2014 ).
And to better study the possible living conditions of future lichens on Mars, we
need to - besides other organisms - perform simulations on the lichens' growth
taxes under Martian gravity, 0.38 g, on board the International Space Station (ISS),
as stated in this subchapter (de Morais 2004 ). These gravity simulators could be used
for this objective during selected months-period shifts, to conduct the initial exper-
iments using the NASA-Johnson Space Center's Mars Soil Analog (JSC-1), under
6 10 3 atm atmospheric pressure with pure CO 2 ,at0 ı C inside a secure chamber,
during 1 year, or less, under about 800 mol quanta m 2 s 1 (1,370 Wm 2 )of
photosynthetic active radiation for the growing of the abovementioned bacteria,
algae, lichens, and plant seeds, with ultraviolet radiation with wavelengths between
200 and 300 nm and with an energy of about 7 10 4 Jcm 2 s 1 , in a step-by-step

approach, and simulating temperature and light variations of the Martian seasons
(de Morais 2004 ).
These numbers (which can be altered for better simulation parameters) above
are to simulate conditions found by robotic spacecraft on regions of Mars with
good sites for the international manned bio-exploration and Martian terraforming:
the northern hemisphere close to the equator, near to canyons, possible ancient
liquid water quiet-flood valleys, depressions, caves, and volcanic systems are best
places for astronauts to keep a semipermanent simple facility (with controlled closed
growing of vegetables using Martian soil in a hydroponics system) to search for
possible extinct (and hypothetical extant) microbial mats, in the form of Earth's