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University of Ottowa
University of Ottowa

Scientists Find Evidence of Earth’s Oldest Life

University of Ottowa
University of Ottowa

Researchers have discovered hints of life hundreds of millions of years earlier than previously known, according to a new study published in Nature. An international team of scientists led by University College London’s Matthew Dodd have found the oldest microfossils ever in what was once a hydrothermal vent system near Quebec, estimating they could be up to 4.3 billion years old.

Located on the eastern edge of Canada's Hudson Bay, the Nuvvuagittuq Greenstone Belt is left over from Earth’s earliest oceanic crust. There, within the quartz layers of banded iron formations, the researchers found remains of tubes and filaments (seen attached to a clump of iron in the image below) formed by bacteria on that early crust, which was part of an ancient deep-sea hydrothermal vent network.

M. Dodd

 
The bacterial remnants can be dated back at least 3.77 billion years, older than previously discovered evidence of the beginnings of life on Earth. The oldest confirmed evidence of bacterial life before this, discovered in western Australia, was dated at around 3.5 billion years ago.

Other research has pointed to life 3.7 billion years ago, but scientists were uncertain if the microfossils in question were really biological in origin or formed by some other process. In this study, researchers tested several ways the tubes and filaments discovered could have been created, like through temperature and pressure changes, but found that the most likely origin of the structures was biological. The tubes and filaments studied look much like those formed by bacteria in modern hydrothermal vents, according to the researchers.

M. Dodd

 
The newly discovered remains push the timeline of life on Earth back even further. They are probably from even earlier than 3.8 billion years ago and may date to 4.3 billion years ago, according to the study. The planet itself is thought to be around 4.5 billion years old, and multicelled organisms didn’t show up until 600 million years ago. “The findings support the theory that life emerged from hot, sea floor vents shortly after the formation of Earth,” co-author and University of Ottawa professor Jonathan O’Neil explains in a press statement.

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Human Activity Has Permanently Altered Earth, for Better or Worse (Mostly Worse)
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Modern humans have roamed Earth for just a few hundred thousand years. In the grand scheme of things, that's a very short period. But in that time, we’ve triggered mass extinctions of plants and animals, polluted the planet, and developed nuclear weapons—and our legacy will linger in both nature and the geologic record long after historical records have been lost, according to Ted-ED’s video below.

Modern humans have altered the Earth’s landscape and atmosphere so profoundly that some scientists say we’ve ushered in a new epoch called the Anthropocene, or "new age of humankind," from anthropo (human) and cene (new). Before this, we were living in the Holocene (meaning “entirely recent”), which began around 11,700 years ago and faded sometime around 1950.

The 1950s ushered in both the plastics revolution and the atomic age, both of which permanently introduced chemicals into Earth’s fossil record. Meanwhile, humans have also shaped long-term plant and animal evolution with agriculture, fishing, and hunting. In short, our actions have long-term consequences, even if the human species ends up being a blip on the geologic time scale. Remember that the next time you drink from a plastic bottle, or see a cloud of smoke billowing through the sky.

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Spelunkers Discover New Caverns in Montréal's Ancient Cave Network
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An ancient cave system beneath a Montréal park is much more vast than experts believed, the National Post reports.

In 1812, a farmer discovered a cave underneath his property in Montréal’s present-day Saint-Léonard borough. Once used to stockpile ammunition and conceal soldiers during the Rebellions of 1837, the Saint-Léonard cave system in Parc Pie XII is today a tourist attraction and historical landmark. But some speleologists (cave experts) suspected there was more to the natural wonder than met the eye.

Beginning in 2014, two amateur explorers named Daniel Caron and Luc Le Blanc began searching for undiscovered passages in the Saint-Léonard caverns, according to National Geographic. By 2015 they had some leads; in October 2017, they used drills and hammers to break down a cave’s wall to reveal a new cavern.

The stalactite-filled chamber has soaring 20-foot ceilings, and it's connected to a serpentine network of underground tunnels. These passages formed during the Ice Age around 15,000 years ago, when glacier pressure splintered underground rock.

So far, Caron and Le Blanc have explored between 820 to 1640 feet of virgin cave passage, and expect to find even more. They believe the vast network sits atop an aquifer, and ultimately leads to the Montréal water table.

Spelunking the Saint-Léonard cave system is challenging—some passages are filled with water or require special climbing or rock-breaking equipment. The explorers hope that the caves will be easier to investigate during the dry season, and that the receding waters will allow them to reach new depths below Montréal’s surface.

[h/t National Post]

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