This site visit would determine whether the funding for the center where I worked would be renewed. It was critical that we do well—for the center and for my job as education director. But as the panelists asked their questions, all I could think was, “I have multiple sclerosis.” I had been diagnosed a couple weeks prior and was in a state of shock. For months I had noticed my body behaving strangely, for example when my ankle stopped working after I walked a few kilometers. I had known what the symptoms might mean—my mother was diagnosed with multiple sclerosis (MS) in the ’90s. But I had ignored them. I was not prepared to deal with my own battle.
The discovery of life in the deep biosphere has raised a conundrum for scientists: how in the world can anything persist buried far below the surface of the Earth for thousands, and even millions, of years? What adaptations allow organisms to flourish in this ecosystem poised at the edge of starvation and extinction? This is the topic of C-DEBI theme 4, Evolution and Survival: Adaptation, Enrichment, and Repair.
The third theme of deep biosphere research is the Limits of Life: Extremes and Norms of Carbon, Energy, Nutrient, Temperature, Pressure, and pH. There are many different ways that animal and plant life are tested to their limits. The marine realm has long been fertile ground for research into the extremes at which life can thrive and survive. A classic example was the 1977 discovery of life at hydrothermal vents where organisms were found to be thriving in water well above the conventional boiling point. That discovery changed our understanding of the limits of life, especially with regard to temperature.
C-DEBI’s second theme, or avenue of investigation, is Extent of Life: Biomes and the Degree of Connectivity. Given the fundamental role of microbes in life as we know it, one might expect scientists to have some idea of where different types of microbes are found and maybe even why they’re there. Yet specialists in the field of microbiology struggle to understand why, in some cases, nearly identical organisms live a world apart. How can identical bacteria exist thousands of miles away from each other, even when we know the width of a human hair is enough to divide entire microbial populations?
The first C-DEBI theme, or avenue of investigation, is Microbial Activity in the Deep Subseafloor Biosphere. The deep subseafloor biosphere refers to all the life underneath the ocean; not deep in the ocean or living on the bottom of the ocean, like fish, but many feet and even miles below that. In the past decade, researchers have discovered that these distant subseafloor environments contain a substantial amount of biomass, as measured by carbon content. One of the big questions for scientists is how many of those cells are actually alive and active, as opposed to inert. It may sound as though this is veering off into the domain of philosophy, but there is great scientific significance to the answer to this question.