Thursday, July 4, 2019

Dr. Godin’s TEPS Internship or How I learned to stop Physicsing and Love Micro-Biology

PVL PDF Paul Godin recently returned from his TEPS internship at the Kennedy Space Center in Cape Canaveral, Florida. It was a productive trip and he made many friends along the way, including the character over his shoulder to the right in the picture above.

By Dr. Paul Godin

Many members of the PVL receive funding from the Technologies for Exo-planetary Science (TEPS) NSERC CREATE program (http://teps.science.yorku.ca/). TEPS is more than just funding for the group, it also provides opportunities for go on international research internships. This past spring, I was accepted for an internship at the Space Life Sciences Lab (SLSL) at Kennedy Space Center in Cape Canaveral, Florida.

The SLSL was originally built as a collaboration between NASA and the University of Florida to conduct biology-based experiments relevant to the space program. However, about 10 years ago NASA sold off their portion of the building to Space Florida, a state government agency responsible for promoting the space sector in Florida; the University of Florida portion remains. My internship was under one of these University of Florida professors, Dr. Andrew C. Schuerger. 

Andy’s lab focuses on planetary protection, which is insuring that missions to other planets don’t accidentally contaminate those worlds with terrestrial microbes. As such Andy’s lab conducts experiments testing the limits of bacterial survivability in extreme environments. The centerpiece of his lab is a state-of-the-art Mars simulation chamber, capable of recreating the temperature, atmosphere, and UV light conditions on Mars.



The Mars simulation chamber at the SLSL.

At this point you might be asking why did I, a physicist, go on an internship to a microbiology lab? It starts with a question about the habitability of the Martian surface. The atmosphere of Mars lacks an ozone layer; on Earth the ozone layer absorbs harmful UV rays from the sun, protecting life on the surface. The surface of Mars has no such protection and is one of the reasons why its surface is apparently devoid of life. However, there may be another way to protect life at the surface that doesn’t require ozone: Martian brines.

There’s plenty of geological evidence to suggest that the surface of Mars once had large bodies of water. It’s reasonable to expect that minerals in the rock/soil would leach into the surrounding bodies of water and form brines. It’s been theorized that these Martian brines could absorb UV radiation, protecting life just below the surface for either liquid water on ancient Mars, or ice deposits in the present day.

At the PVL at York University, we investigated the possibility that brines could absorb UV radiation. Nine different salts were investigated. We passed UV light through a cuvette filled with a salt solution and measured the absorption. What we found, is that yes, some Martian brines could absorb significant amounts of UV radiation, particularly those that contain iron ions.


The experimental set-up at York University to detect UV absorption by Marian brines.

Now that we know that brines can protect life from UV radiation, the next question is can life handle the brines themselves? It’s possible that the salt could kill bacteria directly, and the question of UV radiation is rendered moot. It was to answer this second question that I went to Florida.

During my time at the SLSL, I placed bacteria samples in different salt solutions at different concentrations. These bacteria/salt solutions were placed in a simplified Mars simulation chamber, one that only provided temperature and pressure control. Samples were exposed to Mars conditions for a period of time and the number of surviving bacteria was compared to the initial population. What we found was that spore forming bacteria can survive exposure to Martian brines. However, non-spore forming bacteria are sensitive to the pH of the solution and die off quickly in acidic environments.







Simple Mars simulation chamber containing bacteria+salt samples.

My time in Florida wasn’t only spent in the lab, I also enjoyed uniquely Floridian experiences, such as paddling in the mangrove-forests of the everglades (gators included) and got to witness three different rocket launches.

I’m back in Canada now, but I’ll be returning to Florida in September to finish off the last part of the experiment: putting bacteria in Martian brines and exposing them to UV radiation. While the first part of this study suggested that bacteria will survive, it’s still important to experimentally verify this. Furthermore, since bacteria are uniformly distributed in a liquid sample, the bacteria at the top will be exposed to more radiation than the bacteria at the bottom, so some die off of bacteria is still expected.



SpaceX Falcon 9 Rocket Launch.


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