Pioneering Researcher Explores Deep Limits of Life

Off the Pacific coast of Colombia, beneath miles of seawater, lie two holes bored deep into the ocean floor. Over the last three decades, they have helped a generation of scientists make crucial discoveries about the formation and dynamics of ocean crust, which covers 70 percent of the planet’s surface. Now, Senior Research Scientist Beth Orcutt is co-leading a month-long journey to collect microbial samples from these portals into the Earth – and potentially reveal new information about the limits at which life can survive.

“Some microbes deep below the seafloor can live at high temperatures on incredibly small amounts of energy,” Orcutt said. “It has been nearly impossible to study these microbes before, but we now have sophisticated new tools that can help us learn about these communities.”

Earth’s largest aquifer sits beneath the seafloor, where water flows through the rocky upper layer of ocean crust. Together with the sediment that rains down from the ocean above, this vast system is called the marine deep biosphere. Orcutt has studied the microbes that thrive in this remote, extreme environment by capitalizing on holes drilled in the ocean crust – and she recently received international recognition for her work.

On August 22, the American Geophysical Union announced that Orcutt will be awarded the prestigious Asahiko Taira International Scientific Ocean Drilling Prize in December. This prize is granted annually to one scientist for excellence in research related to scientific ocean drilling. Orcutt’s many contributions to the field include novel research and discoveries, her advocacy for the International Ocean Drilling Program, and even co-leading the first drilling cruise whose science team was over fifty percent female.

Orcutt has participated in several research cruises through the International Ocean Discovery Program, a collaboration between 23 countries that conducts expeditions throughout the global ocean. Her work using installations in the ocean crust to study life in the deep biosphere has established Orcutt as a pioneer in ocean drilling research. She is continuing to push the field forward on her current fieldwork mission, which is her second as co-chief.

“Getting this award has been a great motivator for me to think about what the future of deep biosphere research looks like,” Orcutt said. “This is a pivotal time in the field of ocean drilling, and it is inspiring for me to think about the new questions we will explore.”

Orcutt is currently at sea on the JOIDES Resolution, a research vessel that drills into the ocean floor to collect and study samples of Earth’s core. She is leading the scientists aboard in an unusual mission – rather than drilling into the crust to collect new material, they are using new technologies to investigate two existing holes. The team aims to learn about the tectonic and geological history of the holes and about the marine microbes that live in the water flowing through them.

Both sites offer important opportunities for new insights into this extreme environment. At one site, the team will collect water and microbial samples from what scientists believe is the thermal boundary for life. Studying the chemistry of the water and the microbes that live at this boundary could reveal what life looks like at its furthest limits. At the other hole, Orcutt will investigate how conditions and the microbial communities compare to one of her main research sites, located off the coast of Washington. She suspects that the two areas are very similar, and that comparing the two sites could inform essential questions about how microbes interact with their environment in the deep biosphere.

“There are fundamental questions about life in the ocean crust that we have never been able to address because we have never been able to access two study sites that are so similar,” Orcutt said. “This research could allow us to answer interesting hypotheses about the boundaries of life and how microbes thrive in unbelievable places.”

The upper images is courtesy of the International Ocean Discovery Program. The lower image is courtesy of Bill Crawford, IODP, TAMU.