Life in the deep, dark biosphere

Image credit: Masanori Kaneko

Diverse and mostly uncharacterised microorganisms live in the deep biosphere, potentially playing a role in mediating global biogeochemical processes. 

The research conducted by Hayley Manners and colleagues at Plymouth University and the University of Southampton is investigating whether evidence of microorganisms colonising volcanic deposits in the deep biosphere can be detected using their organic remains. As part of this work Hayley participated in an International Ocean Discovery Programme (IODP) Expedition (Exp370 – T-Limit of the Deep Biosphere) last September, which aimed to investigate the temperature limit to life in the deep biosphere off Cape Muroto, Japan.

Understanding the origin, evolution and significance of this realm is important if we want to determine the role of the deep biosphere in the Earth system and how microorganisms thrive in such extreme environments, which in turn may provide insight into life elsewhere in the solar system.

The most poorly understood ecosystem

The deep biosphere describes any habitat located below the surface of the continents and the bottom of the ocean, and comprises much of the Earth’s total living biomass.

“Due to the importance the deep biosphere may play on Earth and also in the search for extra-terrestrial life, this realm has received considerable attention in research endeavours over the past three decades. Despite this, it is the most poorly understood ecosystem on Earth.”

Dr Hayley Manners

Image credit: Dr Hayley Manners