WIPP’s underground isn’t just suited for physics experiments aiming to unlock the mysteries of the universe. It is also a perfect “dig site” for biologists who want to chronicle the history of life.
Some 250 million years ago, the area around WIPP was all part of the Permian Sea. Today, the salt beds that make up the WIPP underground provide a time capsule, of sorts, from this ancient era. Researchers have uncovered ancient bacteria, cellulose and evidence of DNA from intrusions in the salt crystals of the WIPP underground.
Life on Earth has been bathed in background radiation since the dawn of time. This ionizing radiation comes from cosmic rays, terrestrial radioactivity, and internally-deposited, naturally-occurring radioactive material in organisms themselves. While other experiments in the WIPP underground have taken advantage of the location’s low levels of background radiation, one biology experiment actually conducts tests related to this phenomenon.
Ancient Salt Beds
The key to the search for life on other planets may go through WIPP’s ancient salt beds.
In 2008, a team of scientists led by Jack Griffith, from the University of North Carolina, Chapel Hill, retrieved salt samples from the WIPP underground and studied them with a transmission electron microscopy lab at the Lineberger Comprehensive Cancer Center of the University of North Carolina School of Medicine. In examining fluid inclusions in the salt and solid halite crystals, scientists found abundant cellulose microfibers, estimated to be 250 million years old. Evidence of ancient DNA was also observed, but in much smaller amounts than cellulose.
Cellulose is the tough, resilient substance known as the major structural component of plant matter. The source of the cellulose is undetermined. In addition to plant sources of cellulose, cyanobacteria (which have been present for the last 2.8 billion years of earth history) also produce cellulose. The age of the cellulose microfibers is estimated to be 253 million years old, making them the oldest native macromolecules to have been directly isolated, visualized and examined biochemically.
An examination of the salt samples revealed that the cellulose was very much like modern-day cellulose. Researchers noticed microfibers as small as 5 nanometers in diameter, as well as composite ropes and mats. Because cellulose appears to be extremely stable and highly resistant to ionizing radiation, scientists believe that the search for life on other planets may begin with looking for cellulose in salt deposits.
Scientists also have managed to cultivate bacteria from 250-million-year-old spores found in WIPP salt crystals – it’s all similar to the plot of the movie “Jurassic Park”!
In 2000, researchers cultivated a colony of a previously unknown species of halophilic bacillus from spores inside salt deposited at the end of the late Permian period (some 220-250 million years ago). This discovery has pushed the envelope for resurrecting living things back in time by a factor of about 10 and allows the previously unknown bacteria (Bacillus species, designated 2-9-3) to lay claim to the title of “oldest known organism.”
Some micro-organisms form resistant structures called spores when exposed to adverse conditions. These spores have been found to survive for hundreds, and even thousands, of years under the proper conditions.
How did scientists “uncover” this bacteria? Intact salt crystals were carefully collected from the walls of WIPP’s air intake shaft at a depth of 569 meters (1867 feet) below the surface. The nearly pure salt crystals contained fluid inclusions. After thoroughly sterilizing the surface of the crystals, researchers drilled into and removed fluid from a tiny inclusion. The fluid was then inoculated into a growth medium under carefully controlled conditions. The new bacteria then grew from these spores.
Drs. Russell Vreeland and William Rosenzweig of West Chester University, Pennsylvania, and Dr. Dennis Powers, a Consulting Geologist in Anthony, TX, continue to conduct research by studying the new organism and comparing it with its present-day relatives.
Low Background Radiation Experiment
We’re all bathing in it. It’s in the food we eat, the water we drink, the soil we tread and even the air we breathe. It’s background radiation. It’s everywhere, and we can’t get away from it.
But what would happen if you somehow “pulled the plug” on natural background radiation? Would organisms suffer or thrive if they grew up without constant exposure to background radiation? That’s what a consortium of scientists conducting an experiment at WIPP sought to find out.
Dr. Raymond Guilmette, director of the Center for Countermeasures Against Radiation with the Lovelace Respiratory Research Institute, was one of the scientists who first conceived the idea of a biology experiment at WIPP.
The experiment at WIPP involved using two different types of bacteria, one of which is very sensitive to radiation and the other which is very resistant.
The bacteria strains were grown in both simple and complex growth media, and future experiments will involve growing the bacteria with and without manganese, which is connected with the second strain’s ability to resist radiation.
One-third of the experiment took place in the WIPP underground, next to the EXO project in the northern end of the repository. The idea was to let the two strains of bacteria grow side-by-side in an environment where they would receive virtually no background radiation. In fact, the bacteria incubator was placed in a pre-World War II steel chamber to eliminate even the slightest amount of background radiation. The bacteria underground received close to zero radiation doses for hundreds of generations.
The rest of the experiment took place inside of a room near the waste handling bay at WIPP’s above-ground facility. There, for comparison, the two strains of bacteria grew at natural background radiation levels, and another part of the experiment exposed both types of bacteria to significantly higher levels of radiation above normal background. Potassium chloride, a naturally occurring radioactive material normally used as a dietary salt substitute, was used to provide these higher levels. Researchers compared how well the bacteria did at zero, natural and above-natural levels of background radiation.
Biological effects measured included growth rate, growth yield and protein production. Incubators were used to control temperature, light, humidity and air quality.
The experiment at WIPP sought to better understand the effects of low-dose radiation by providing more insight into the role of background radiation in maintaining the fitness of living organisms.
Following the February 2014 events, the Low Background Radiation Experiment needed approximately two years to recover. The experiment resumed in the summer of 2016, with different organisms and media planned for the future.