University researcher contributes to study into the limits of life on Earth

A University of Plymouth researcher is part of an international team that has provided new in­sights into the tem­per­at­ure lim­its of life be­neath the ocean floor.

Dr Hayley Manners, Lecturer in Organic Chemistry, and colleagues from 29 different institutes found single-celled microorganisms living in sediments more than a kilometre into the ocean floor – and at a temperature of 120°C.

The study, published in Science, was carried out during a two-month research expedition in 2016 – in which Dr Manners participated – and forms a part of the work of Expedition 370 of the International Ocean Discovery Program (IODP).

It focused on the Nankai Trough off the coast of Japan, where the deep-sea scientific vessel Chikyu drilled a hole 1,180 meters deep to reach sediment at 120°C.

In detailed analyses of the samples, scientists found the con­cen­tra­tion of ve­get­at­ive cells de­creased sharply to a level of less than 100 cells per cu­bic centimetre of sed­i­ment at over 50°C.

However, the con­cen­tra­tion of en­dospores – dormant cells of cer­tain types of bac­teria that can re­act­iv­ate and switch to a live state whenever con­di­tions are favourable again – in­creases rap­idly and reaches a peak at 85°C.

The research was led by scientists at MARUM, the Centre for Marine and Environmental Sciences at the University of Bremen in Germany.