On Earth, the ice of the lakes, glaciers, and caves of the cryosphere (from the ancient Greek word cryos, meaning
"cold" or "ice") harbors rich, complex biotic communities. Ice cave habitats have been posited for the Mars
cryosphere. Ice in such caves would protect microbes from UV, X-rays, and heavy particle radiation and might be
accessible during robotic or astronaut missions. Detection of putative biota-rich ice will require in situ detection of
biosignatures in cave walls, floor, and ceiling a few centimeters to tens of meters distant from the investigating rover
or astronaut. We describe the development of a prototype for a non-destructive, non-contact device that rapidly
generates reflectance and fluorescence images and a midline target profile of 960 reflectance and fluorescence
spectra. Spectral Profiling and Imaging (SPI) requires no irreplaceable consumables and can be sufficiently
miniaturized to be used by a single astronaut or a small robotic explorer. The current laboratory instrument is
designated SPI2 since it generates data sets for two optical phenomena: reflectance and fluorescence. In final form
SPI4 will be integrated with an autonomous rover and generate data for four optical phenomena: reflectance,
fluorescence, Raman scattering, and circular polarization. SPI4 will be useful for the Remote Evaluation of Life in
Ice Caves (R.E.L.I.C.) on planetary bodies whose distance from Earth prohibits real-time mission control.
Extreme conditions such as low temperature, dryness, and constant UV-radiation in terrestrial Antarctica are limiting
factors to the survival of microbial populations. The objective of this study was to investigate the microbial diversity and
enumeration between the open water lakes of Schirmacher Oasis and the permanently ice-covered Lake Untersee. The
lakes in Schirmacher Oasis possessed an abundant and diverse group of microorganisms compared to Lake Untersee.
Furthermore, the microbial diversity between two lakes in Schirmacher Oasis (Lake L27C and L47) was compared by
culture-based molecular approach. It was determined that L27C had a richer microbial diversity representing 4 different
phyla and 7 different genera. In contrast L47 consisted of 3 different phyla and 6 different genera. The difference in
microbial community could be due to the wide range of pH between L27C (pH 9.1) and L47 (pH 5.7). Most of the
microbes isolated from these lakes consisted of adaptive biological pigmentation. Characterization of the microbial
community found in the freshwater lakes of East Antarctica is important because it gives a further glimpse into the
adaptation and survival strategies found in extreme conditions.
Extreme conditions such as low temperature, aridness, low availability of organic matter, high salinity and UV-radiation
in terrestrial Antarctica are key factors limiting the habitation of biotic communities and ecosystem dynamics. In recent
studies, it has been discovered that the bacterial communities are highly diverse and distributed widely in the extreme
ecosystem of Antarctica. Besides available morphometric data, geology, and thermal profile, limited study on the
microbial identification, phylogenetic analysis, diversity and distribution of microorganisms in different lakes of
Schirmacher Oasis in East Antarctica has been reported. The objective of this study was to assess the microbial
biodiversity and distribution using culture-independent and culture-dependent methodologies based upon bacterial 16S
rRNA gene analysis in three categories of lakes, i.e., the land-locked (L), epi-shelf (E), and pro-glacial (P) lakes in
Schirmacher Oasis. The water and ice samples were collected during the 2008 Tawani International Scientific
Expedition. Direct culturing of the samples on R2A agar media exhibited a wide variety of pigmented bacteria. Two of
the pigmented bacteria that were cultured belong to the genera, Hymenobacter, and Flavobacterium. Cultureindependent
methodology of one of the land-locked lakes L27C identified a rich microbial diversity consisting of six
different phyla of bacteria. The majority of bacteria (56%) belong to the Class γ-proteobacteria within the phylum
Proteobacteria. Within the Class γ-proteobacteria, Acinetobacter dominated (48%) the total microbial load.
Characterization of the microbial diversity within the three different types of Antarctic lakes is important because it will
help give us a better understanding of the survival mechanisms and the functionality of these bacteria in extremely cold
and harsh Antarctic ecosystems.
Among the most interesting targets for Astrobiology research are the polar ice caps and the permafrost of Mars and
the ice and liquid water bodies that may lie beneath the frozen crusts of comets, the icy moons of Jupiter (Europa, Io
and Ganymede) and Saturn (Titan and Enceladus). The permanently ice-covered lakes of Antarctica, such as Lake
Vostok and Lake Untersee, provide some of the best terrestrial analogues for these targets. The 2008 International
Tawani Schirmacher Oasis/Lake Untersee Expeditions have been organized to conduct studies of novel microbial
extremophiles and investigate the biodiversity of the glaciers and ice-covered lakes of Dronning Maud Land, East
Antarctica.
This paper describes the preliminary analysis of the anaerobic microbial extremophiles isolated from samples
collected during the 2008 International Schirmacher Oasis Antarctica Reconnaissance Expedition. These samples
showed great diversity of psychrophlic and psychrotolerant bacteria. Six new anaerobic strains have been isolated in
pure cultures and partially characterized. Two of them (strains ARHSd-7G and ARHSd-9G) were isolated from a
small tidal pool near the colony of African Penguins Spheniscus demersus. Strain ARHSd-7G was isolated on
mineral anaerobic medium with 3 % NaCl, pH 7 and D-glucose, it has motile, vibrion shape cells, and is Gram
variable. Strain ARHSd-9G grew on anaerobic, alkaline medium with pH 9 and 1 % NaCl at 3°C. The substrate was
D-glucose supplemented with yeast extract (0.05 %). Cells of strain ARHSd-9G had morphology of straight or
slightly curved elongated rods and demonstrated unusual optical effects under dark-field visible light microscopy.
The cells were spore-forming and Gram positive. From the mat sample collected near Lake Zub, the new strain LZ-3
was isolated in pure culture at 3°C. Strain LZ-3 was anaerobic and grew on 0.5 % NaCl mineral medium with Dglucose
as a substrate. The gram positive cells were spore-forming. They exhibited a distinctive morphology of large
rods with rounded ends and size 1x10 μm. From the sample of ice sculpted by wind and melting by solar heating,
containing many entrained black rocks collected near Lake Podprudnoye the new strain ISLP-22 was isolated in
pure culture. The cells of this strain had vibrion shape and were spore-forming and had "baseball bat" shapes). This
culture preferred 0.1 % NaCl mineral anaerobic medium and grew rapidly at 3 °C. Currently, all strains are under
physiological study and phylogenetic analysis.
We have investigated the feasibility of the PCR amplification of the 16S rRNA genes from eubacteria and
Archea on samples collected on Whatman FTA filters from Schirmacher Oasis for the study of culture-independent
analysis of the microbial diversity. Both conventional PCR and real-time TaqmaTM PCR successfully amplified the
targeted genes. A number of diverse groups of psychrotolerant microorganisms with various pigments have been isolated
when cultured on agar medium. 16S rRNA gene analysis of these isolates helped us to identify closest taxonomic genus
Pseudomonas, Frigoribacterium, Arthrobacter, Flavobacterium, and Janthinobacterium. It is possible that the pigments
play protective role from solar UV radiation, which is prevalent in Antarctic continent especially during Austral summer
months. Study of the expression of cold adaptive protein CapB and ice-binding protein IBP using western blots showed
positive detection of both or either of these proteins in 6 out of 8 isolates. Since the CapB and IBP protein structure
greatly varies in microorganisms, it is possible that the 2 isolates with negative results could have a different class of
these proteins. The expression of the CapB and the IBP in these isolates suggest that these proteins are essential for the
survival in the Antarctic cold and subzero temperatures and protect themselves from freeze-damage. The current study
provided sufficient data to further investigate the rich and diverse biota of psychrotolerant extremophiles in the Antarctic
Schirmacher Oasis using both culture-independent and culture-based approaches; and understand the mechanisms of
cold tolerance.
Conference Committee Involvement (5)
Instruments, Methods, and Missions for Astrobiology XVI
27 August 2013 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology XIV
23 August 2011 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology XIII
3 August 2010 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology XII
4 August 2009 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology XI
12 August 2008 | San Diego, California, United States
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