Costa Rica Convergent Margin: Biology Meets Subduction

This project draws together biologists, geochemists, petrologists, and outreach professionals to take a regional view of the deep subsurface biosphere across a convergent margin. The Costa Rica convergent margin is caused by the oceanic Cocos plate being subducted under the Caribbean plate. As the plate is subducted, dewatering due to compression and serpentinization reactions between water and rock drive nutrient rich hot springs whose surface expression reflects the deep processes that feed it. We are taking a multi-disciplinary approach to connecting these surface expressions to the deep subsurface biosphere. We work with collaborators at OVISCORI and Volcanes Sin Fronteras

(Left) Logo from Biology Meets Subduction. (Right) Karen Lloyd and collaborator Donato Giovannelli (ELSI, Tokyo Tech) on the shores of the Poas volcano crater lake. Photo by Donato Giovannelli.

PhD student Kate Fullerton documenting samples on the flank of Irazu volcano, Costa Rica. Photo by Tom Owens.

We sampled Poas volcano crator lake in February 2017. Photo by Tom Owens. Check out the current eruption status of Poas here.

Deep oceanic subsurface

We are working on the IODP Leg 347: Baltic Sea Paleoenvironment and IODP Leg 366: Mariana Convergent Margin and South Chamorro Seamount. Here, we analyze deep subsurface microbial communities buried in up to 86 meters beneath the seafloor into either pelagic sediments (Leg 347) or serpentinizing mud volcanoes (Leg 366).

PhD student, Richard Kevorkian, processing a deep subsurface core aboard the Joides Resolution in IODP Leg 366: Mariana Convergent Margin and South Chamorro Seamount.

Greatship Manisha outfitted for the Leg 347 expedition to the Baltic Sea.

PhD student, Richard Kevorkian, working with deep subsurface samples back at the University of Tennessee.

Arctic fjords 

The effects of climate change are exacerbated in polar regions. We are examining feedbacks between the novel, uncultured microorganisms and marine sediments at the foot of the receding glaciers in marine fjords in Ny Alesund, Svalbard, 79°N. For this, we work with the AWIPEV Arctic Research Base.

PhD students Joy Buongiorno and Katie Sipes in Ny Alesund, Svalbard, 79°N.

PhD student Joy Buongiorno sampling sediments in Kongsfjorden, Svalbard.

Glacier in Kongsfjorden, Svalbard.

Siberian permafrost

Long-term frozen permafrosts present a unique situation to study microbes that have been preserved in time, or are growing very slowly in small saline pockets of liquid water. We are on a project headed by Tatiana Vishnivetskaya (Center for Environmental Biotechnology, University of Tennessee) to examine such permafrosts in Siberia. See videos from that project under the outreach tab.

Low Energy Methanogens

Methane-producing archaea (methanogens) are responsible for almost all of the methane on Earth. Although natural methanogens often operate under severely nutrient limited conditions, most of what is known about methanogen physiology comes being grown under high energy conditions. When grown at low substrate concentrations, methanogens are one of the lowest energy life forms on Earth. We are studying natural methanogens from the White Oak River estuary and Cape Lookout Bight, both in North Carolina, to determine the properties of low energy methanogens. These will provide key constraints in the search for extraterrestrial microbial life, which, if present, is likely to include methanogens.


Undergraduate students Taylor Pickett, Talor Noordhoek, and Jacob Rosalsky sampling estuarine mud to search for low energy methanogens in the White Oak River estuary, North Carolina

© Karen Lloyd 2018