Deep-Sea Biodiversity

Dr. Rosa León Zayas’ Study of Life in the Least-explored Regions of Our Planet

Last Friday’s installment of the Biology Department seminar series had the pleasure of hosting Willamette University’s Dr. Rosa León Zayas. Dr. Zayas, an expert in marine cell biology and a native of Puerto Rico, has spent the most recent years of her career studying the genomics and physiology of deep-ocean organisms called archaebacteria.

Archaebacteria are believed to be an intermediate between bacteria and eukaryotes, and may have been the first organisms to absorb other entities inside themselves to form mitochondria, the infamous “powerhouse of the cell.” These organisms persist especially well under extreme conditions, such as the depths of the ocean, and according to Dr. Zayas’ study and others like it, are much more numerous in the seemingly lifeless deep plains of the ocean than we would have ever thought.

Dr. Zayas has now undertaken the difficult task of obtaining water and sediment samples from the two deepest places in the world, the Pacific’s Marianas Trench and the Atlantic’s Puerto Rico Trench, twice. This is a lengthy and expensive process requiring highly advanced and finicky equipment, and it doesn’t always work as planned. Given the extreme pressure of deep-ocean environments, it is frustratingly easy to lose all of one’s sample and data through the simplest of equipment failures. Usually, the collection process is automated, but this is not always the case: one of her samples, from the Marianas Trench, was collected in a miniature submersible by James Cameron himself, the filmmaker behind the 2009 science fiction movie Avatar.

The Puerto Rico Trench reaches a depth of over five miles at its most extreme point, and the Marianas Trench exceeds that, coming in at a whopping seven miles deep. Many of the organisms at this depth are chemotrophs, scavengers, or both, persisting on nutrients drifting down from lighter environments above or manufacturing their own sustenance from chemical energy.

Preliminary research by Dr. Zayas and others suggests that these microbial communities of the seafloor are constantly in flux, with these archaebacteria in particular abundance. Dr. Zayas’ goal is to understand the composition of organisms in these communities and how their metabolisms have adapted to fit such demanding environments.