Life on Earth was kick-started by a gas deadly to humans: study

By Mark Waghorn via SWNS

Life on Earth was kick-started by a gas that is deadly to humans, according to new research.

Carbon monoxide kills tens of thousands of people globally - every year.

But it created the first organisms - explaining how microbes in the deep ocean survive without sunlight.

The discovery has implications for alien hunters. Mysterious worlds rich in the chemical could host an array of weird creatures.

It reverses the idea marine ecosystems rely on the sun.

Many get their energy from carbon monoxide and hydrogen - an alternative to photosynthesis dubbed "chemosynthesis."

The five-year study found the gases fuel trillions of microbes in the sea - ranging from the tropics to the poles.

They are dominant in areas so dark and nutrient-poor that even starlight cannot penetrate.

Lead author Professor Chris Greening, of Monash University in Melbourne, said: "We showed chemosynthesis is dominant instead.

"Hydrogen and carbon monoxide, in fact, '"fed" microbes in all regions we've looked at - from urban bays to around tropical islands to hundreds of meters below the surface.

"Some can even be found beneath Antarctica's ice shelves."

The Australian team combined molecular measurements during voyages with experiments on organisms grown in the lab.

They also used a technique called metagenomic sequencing - to identify the genetic blueprints of the tiny bugs.

Co-lead author Dr. Rachael Lappan said: "We found the genes that enable hydrogen consumption across eight distantly related types of microbes - known as phyla.

"This survival strategy becomes more common the deeper they live."

The researchers were inspired by bacteria found in soil. They have previously shown most exist by consuming hydrogen and carbon monoxide from the atmosphere.

Dr. Lappan said: "The surface layers of the world's oceans generally contain high levels of dissolved hydrogen and carbon monoxide gases due to various geological and biological processes.

"So it made sense oceanic bacteria used the same gases as their terrestrial cousins."

The findings in the journal Nature Microbiology improve understanding of how life evolved.

Prof Greening said: "The first life probably emerged in deep-sea vents using hydrogen - not sunlight - as the energy source.

"It's incredible 3.7 billion years later so many microbes in the oceans are still using this high-energy gas. We've completely overlooked this until now."

It's been claimed some "exoplanets" outside the solar system could be even more habitable than Earth.

Billions of years ago, the early universe contained only hydrogen and helium.

The gases could extend the period of life to evolve. They were readily available in the planet-forming materials around young stars - such as our sun.

All planets built up atmospheres that were dominated by them. Earth eventually favored heavier elements.

Carbon monoxide is toxic to people. It claims more than 40,000 lives annually.