Bay Paul Center


One of the largely unexplored habitats on Earth lies under the ocean: the sediments, rocks, and fluids layered under the pressure of a gigantic basin of water. What lives down there, and how deep does life go? What strategies do microbes have for surviving in this environment? MBL Associate Scientist Julie Huber is among the people asking these questions, and this week she contributes a commentary in the journal Science on a team’s discovery of the deepest subseafloor life yet.

Julie Huber. Credit: Diana Kenney

Julie Huber. Credit: Diana Kenney

Using a drilling system aboard a research vessel off the Shimokita Peninsula of Japan, the international team “drilled the deepest scientific borehole to date to examine the abundance, taxonomic composition, and biosignatures of subseafloor microbial communities in sediments from 400 to almost 2,500 meters (about 1.5 miles) beneath the seafloor,” Huber writes. They detected microbial life at all depths, including methane-producing archaea in deeply buried coal-bed deposits.

As expected from prior studies, the concentration of microbes decreased steadily with depth in the shallow subseafloor layers. However, microbes were scarce–barely detectable—below about 1,500 meters. This was surprising, given that temperatures in the deep samples didn’t exceed ~60 degrees C, “well within the growth range of most microbes,” and “both carbon and hydrogen are plentiful energy sources, particularly in the coal bed layers,” Huber writes.

“Why so little life, then?” Huber writes. “It is difficulties with biomolecule repair, as the authors suggest, or something else like porosity or pressure? Uncovering what limits the biomass in this unusual environment will certainly be a focus of future studies.”

Huber is associate director of the MBL’s Josephine Bay Paul Center, as well as associate director of the NSF Science and Technology Center for Dark Energy Biosphere Investigations (C-DEBI).

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Huber JA (2015) Making methane down deep. Science 349: 376-377.

Inagaki F et al (2015) Exploring deep microbial life in coal-bearing sediment down to ~2.5 km below the ocean floor. Science 349: 420-424.

Article in The Washington Post quoting Huber on Inagaki et al.

Kristin Gribble, assistant research scientist in the MBL’s Bay Paul Center, was awarded the “Runner-Up Best Paper Prize 2014” by the journal Aging Cell and the Council of the Anatomical Society. The award recognizes her paper, “Maternal caloric restriction partially rescues the deleterious effects of advanced maternal age on offspring” (Gribble K.E., G. Jarvis, M. Bock and D.B. Mark Welch Aging Cell 13: 623-630, 2014).

Gribble and colleagues discovered that advanced maternal age reduces the lifespan, fecundity, and size of offspring in the rotifer (B. manjavacas), a tiny aquatic animal that is becoming established as a model organism for aging research. However, the researchers were able to reduce the severity of some of these effects by putting the mothers on a calorie-restricted diet. More information is here.

female-Brachionus-manjavacas--rotifer-with-egg-by-Kristin-Gribble

Collaborative marine science took a leap of global proportions on June 21, 2014. At carefully orchestrated times on that day, hundreds of scientists around the world collected ocean samples, using standardized protocols, as part of the first international Ocean Sampling Day (OSD). They were united by the goal of identifying the microbial communities in all the samples–no small task given that one drop of seawater contains about 20 million microbes.

This movie features MBL Associate Scientist Linda Amaral-Zettler, who took a lead role in OSD as a scientific adviser to the project’s European sponsor, MicroB3, and who actively sampled and helped coordinate sampling in the Azorean Islands. Building a knowledge base of marine microbes is critical for understanding the impact of global challenges to ocean health, such as a warming climate.

“Sampling is expensive,” Amaral-Zettler says. “The more we can leverage individual regional efforts and resources, the better we will be in protecting the ocean.”

As soon as they were collected, the samples were frozen and shipped to Max Planck Institute for Marine Microbiology in Bremen, Germany. The next step is to identify “who” are in the samples through DNA extraction and analysis.

OSD will take place again in 2015 and hopefully into the future, Amaral Zettler says, which would provide a long-term perspective on how marine microbial diversity changes over time. “We need to understand how things are changing in order to protect them.”

Take a look at the eye-popping, deep-sea exploration footage in this video about the Center for Dark Energy Biosphere Investigations (C-DEBI). Julie Huber, associate director of the MBL’s Bay Paul Center, is also associate director of C-DEBI, a National Science Foundation Science and Technology Center at the University of Southern California.

The researchers involved with this collaborative national center, Huber says, are asking the “big questions” about life in the deep ocean and below the seafloor. “We are at the exponential exploratory phase,” says Huber, who is on the pioneering edge of discovering subterranean microbial life.

This video was produced by Mira Zimet at USC Dornsife College of Letters, Arts and Sciences.

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Contact:
Cheryl Dybas, NSF, (703) 292-7734, cdybas@nsf.gov

WOODS HOLE, Mass.–For decades, doctors have developed methods to diagnose how different types of cells and systems in the body are functioning. Now a team of scientists has adapted an emerging biomedical technique to study the vast body of the ocean.

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