Media Releases

Ancient, hydrogen-rich waters discovered deep underground at locations around the world

December 19, 2014

A quantum change in our understanding of how much of Earth’s crust may be habitable

TORONTO, ON — A team of sci­en­tists, led by the Uni­ver­si­ty of Toronto’s Bar­bara Sher­wood Lol­lar, has mapped the loca­tion of hydro­gen-rich waters found trapped kilo­me­tres beneath Earth’s sur­face in rock frac­tures in Cana­da, South Africa and Scan­di­navia.

Com­mon in Pre­cam­bri­an Shield rocks – the old­est rocks on Earth – the ancient waters have a chem­istry sim­i­lar to that found near deep sea vents, sug­gest­ing these waters can sup­port microbes liv­ing in iso­la­tion from the sur­face.

The study, to be pub­lished in Nature on Decem­ber 18, includes data from 19 dif­fer­ent mine sites that were explored by Sher­wood Lol­lar, a geo­sci­en­tist at U of T’s Depart­ment of Earth Sci­ences, U of T senior research asso­ciate Georges Lacrampe-Couloume, and col­leagues at Oxford and Prince­ton uni­ver­si­ties.

The sci­en­tists also explain how two chem­i­cal reac­tions com­bine to pro­duce sub­stan­tial quan­ti­ties of hydro­gen, dou­bling esti­mates of glob­al pro­duc­tion from these process­es which had pre­vi­ous­ly been based only on hydro­gen com­ing out of the ocean floor.

“This rep­re­sents a quan­tum change in our under­stand­ing of the total vol­ume of Earth’s crust that may be hab­it­able,” said Sher­wood Lol­lar.

Until now, none of the esti­mates of glob­al hydro­gen pro­duc­tion sus­tain­ing deep micro­bial pop­u­la­tions had includ­ed a con­tri­bu­tion from the ancient con­ti­nents. Since Pre­cam­bri­an rocks make up more than 70 per cent of the sur­face of Earth’s crust, Sher­wood Lol­lar likens these ter­rains to “a sleep­ing giant, a huge area that has now been dis­cov­ered to be a source of pos­si­ble ener­gy for life.”

One process, known as radi­olyt­ic decom­po­si­tion of water, involves water under­go­ing a break­down into hydro­gen when exposed to radi­a­tion. The oth­er is a chem­i­cal reac­tion called ser­pen­ti­za­tion, a min­er­al alter­ation reac­tion that is com­mon in such ancient rocks.

This study has impor­tant impli­ca­tions for the search for deep micro­bial life. Quan­ti­fy­ing the glob­al hydro­gen bud­get is key to under­stand­ing the amount of the Earth’s bio­mass that is in the sub­sur­face, as many deep ecosys­tems con­tain chemolithotroph­ic – so-called “rock-eat­ing” – organ­isms that con­sume hydro­gen. In the deep gold mines of South Africa, and under the sea, at hydrother­mal vents where breaks in the fis­sure of Earth’s sur­face that release geot­her­mal­ly heat­ed waters – hydro­gen-rich flu­ids host com­plex micro­bial com­mu­ni­ties that are nur­tured by the chem­i­cals dis­solved in the flu­ids. This study iden­ti­fies a glob­al net­work of sites with hydro­gen-rich waters that will be tar­get­ed for explo­ration for deep life over the com­ing years.

Fur­ther, because Mars – like the Pre­cam­bri­an crust – con­sists of bil­lions-of-year-old rocks with hydro­gen-pro­duc­ing poten­tial, this find­ing has ram­i­fi­ca­tions for astro­bi­ol­o­gy. “If the ancient rocks of Earth are pro­duc­ing this much hydro­gen, it may be that sim­i­lar process­es are tak­ing place on Mars,” said Sher­wood Lol­lar.

Oth­er key mem­bers of the research team are Chris Bal­len­tine of Oxford Uni­ver­si­ty, Tulis Onstott at Prince­ton Uni­ver­si­ty and Georges Lacrampe-Couloume of the Uni­ver­si­ty of Toron­to. The research was fund­ed by the Cana­da Research Chairs pro­gram, the Nat­ur­al Sci­ences & Engi­neer­ing Research Coun­cil, the Sloan Foun­da­tion Deep Car­bon Obser­va­to­ry, the Cana­di­an Space Agency and the Nation­al Sci­ence Foun­da­tion.

IMAGES and Nature paper:


For more infor­ma­tion, please con­tact:

Bar­bara Sher­wood Lol­lar
Depart­ment of Earth Sci­ences
Uni­ver­si­ty of Toron­to
Tel: 416–978-0770

Kim Luke
Com­mu­ni­ca­tions, Fac­ul­ty of Arts & Sci­ence
Uni­ver­si­ty of Toron­to
Tel: 416–978-4352