We present Raman spectroscopy analysis on laboratory and field sample analysis on several expeditions.
Our measurements in mineral and organic composition have demonstrated that both mineral and organic
species in low concentrations can be identified with Raman spectroscopy with no sample preparations
and without instrument probe contact to the samples. Our laboratory studies on cyanobacterial biomat,
and Mojave Desert rocks have demonstrated the promising potential for Raman spectroscopy as a nondestructive,
in situ, high throughput detection technique, as well as a desirable active remote sensing tool
for future planetary and space missions.
The High-Lakes Project is funded by the NAI and explores the highest perennial volcanic lakes on Earth in the Bolivian
and Chilean Andes, including several lakes ~6,000 m elevation. These lakes represent an opportunity to study the
evolution of microbial organisms in relatively shallow waters not providing substantial protection against UV radiation.
Aguas Calientes (5,870 m) was investigated (November 2006) and samples of water and sediment collected at 1, 3, 5,
and 10 cm depth. An Eldonet UV dosimeter positioned on the shore records UV radiation and temperature, and is
logging data year round. A UV SolarLight sensor allowed acquisition of point measurements in all channels at the time
of the sampling. UVA, UVB, and PAR peaks between 11:00 am and 1:00 pm reached 7.7 mW/cm2, 48.5 μW/cm2, and
511 W/m2, respectively. The chemical composition of the water sample was analyzed. DNA was extracted and DGGE
analyses with bacterial and archaeal 16S fragments were performed to describe microbial diversity. Antibiotic
resistances were established previously in similar environments in Argentine Andean wetlands. In order to determine
these resistances in our samples, they were inoculated onto LB and R2A media and onto R2A medium containing either
chloramphenicol, ampicillin or tetracycline. Bacterial was higher than archeal cell number determined by RT-PCR in all
the samples, reaching maximum total values of 5x105 cell mL-1. DGGE results from these samples and Licancabur
summit lake (5,916 m) samples were also compared. Eight antibiotic-resistant Gram negative strains have been isolated
with distinct resistance patterns.
The impact of individual extremes on life, such as UV radiation (UVR), temperatures, and salinity is well
documented. However, their combined effect in nature is not well-understood while it is a fundamental issue controlling
the evolution of habitat sustainability within individual bodies of water. Environmental variables combine in the
Bolivian Altiplano to produce some of the highest, least explored and most poorly understood lakes on Earth. Their
physical environment of thin atmosphere, high ultraviolet radiation, high daily temperature amplitude, ice, sulfur-rich
volcanism, and hydrothermal springs, combined with the changing climate in the Andes and the rapid loss of aqueous
habitat provide parallels to ancient Martian lakes at the Noachian/Hesperian transition 3.7-3.5 Ga ago. Documenting this
analogy is one of the focuses of the High-Lakes Project (HLP). The geophysical data we collected on three of them
located up to 5,916 m elevation suggests that a combination of extreme factors does not necessarily translate into a
harsher environment for life. Large and diverse ecosystems adapt to UVR reaching 200%-216% that of sea level in
bodies of water sometimes no deeper than 50 cm, massive seasonal freeze-over, and unpredictable daily evolution of
UVR and temperature. The HLP project has undertaken the first complete geophysical and biological characterization of
these lakes and documents how habitability is sustained and prolonged in declining lakes despite a highly dynamical
environment. The same process may have helped life transition through climate crises over time on both Earth and Mars.
We present design, integration and test results for a field Raman spectrometer science payload, integrated into the Mars
Analog Research and Technology (MARTE) drilling platform. During the drilling operation, the subsurface Raman
spectroscopy inspection system has obtained signatures of organic and mineral compositions. We also performed ground
truth studies using both this field unit and a laboratory micro Raman spectrometer equipped with multiple laser
excitation wavelengths on series of field samples including Mojave rocks, Laguna Verde salty sediment and Rio Tinto
topsoil. We have evaluated laser excitation conditions and optical probe designs for further improvement. We have
demonstrated promising potential for Raman spectroscopy as a non-destructive in situ, high throughput, subsurface
detection technique, as well as a desirable active remote sensing tool for future planetary and space missions.
Conference Committee Involvement (7)
Instruments, Methods, and Missions for Astrobiology XVII
9 August 2015 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology XVI
27 August 2013 | 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
Instruments, Methods, and Missions for Astrobiology X
28 August 2007 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology IX
14 August 2006 | San Diego, California, United States
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