Human Activity Has Been Chemically Changing the Earth Since Well Before the Industrial Revolution - Canadanewsmedia
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Human Activity Has Been Chemically Changing the Earth Since Well Before the Industrial Revolution

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Photo: Tim Boyle / Staff (Getty)

It’s no secret that modern humans, with our fuel-burning cars, massive ranching and agriculture practices, and penchant for disposable goods, have had a huge impact on nearly every environment across the globe. But new research shows that even our ancestors in the Bronze Age changed the chemistry of the soils they farmed over 2,000 years ago. It’s some of the earliest evidence of humans having lasting a environmental impact on planet Earth.

“This is a new lens on one of the most profound shifts in human history: when humans go from being part of nature to being drivers of environmental processes,” said Eric Guiry, the lead author of the new study and a PhD candidate of anthrozoology at the University of British Columbia.

The finding has implications for how we establish the boundaries of the anthropocene, the current geologic age defined by human actions having a dominating influence on the planet’s climate and environment. Many link the start of the anthropocene with the Industrial Revolution, the burning of fossil fuels, or the testing of nuclear bombs. But it’s now evident that even ancient humans could alter the environment in lasting ways.

Specifically, these Bronze Age farmers changed the nitrogen makeup of their fields and the surrounding ecosystems. Plants need nitrogen to grow, but in many cases, those plants also deplete nitrogen from the soil. Though some bacteria and fungi in the ground can fix nitrogen from the air to make it usable for plants, farmers began fertilizing their fields with nitrogen-rich manure to ensure a bountiful harvest. Fertilizing is still done today, of course, whether it be on large farms with commercial fertilizers or just adding some Miracle-Gro to a houseplant.

“Nitrogen is part of every ecosystem, and it’s a building block of life,” Guiry told Gizmodo. “Being able to manage it is key for expanding society.” And though taking charge of the nitrogen cycle isn’t inherently a problem for the environment, excess nitrogen from fertilizers today can pollute waterways and contribute to greenhouse gases.

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Back in the Bronze Age, Irish farmers most likely started fertilizing and tilling their soil more often and on a larger scale as populations grew, Guiry said. More people ate more crops and owned more livestock—like cattle, pigs, goats, and sheep—which meant more poop from that livestock could be used to grow more crops.

That’s why the researchers saw an uptick in a certain nitrogen isotope associated with crop growing in animal bones from the middle and late Bronze Age, around 2,000 years ago. The farmers had disrupted the nitrogen cycle for the first time, changing the chemistry of their soils and the ecosystems that surrounded them—at least in Ireland.

“This is a tipping point for an entire ecological system,” said Sarah McClure, a zooarchaeologist at Penn State University who wasn’t involved in the study. “In the Bronze Age, you get these prolonged, deep shifts in the nitrogen composition of the soils due to human activity that never really go away.”

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The research team extracted this key isotope, nitrogen-15, from 712 animal bones that came from 90 different archaeological sites in Ireland and spanned the entire Holocene (the last 10,000 years). Nitrogen signatures in animal bones are a good indicator of what they ate in their last 10 or 15 years of life, so the researchers hoped to glean whether domesticated animals back then were eating fodder that had been grown in soils with altered chemistry.

“Those buried bones are providing a little time capsule back to when those animals were alive,” Fiona Beglane, a zooarchaeologist at the Institute of Technology, Sligo in Ireland and one of Guiry’s co-authors, told Gizmodo.

Nitrogen-15 signatures should have stayed steady, but in the mid- to late-Bronze Age they jumped to levels similar to what we see in the modern era, as described in the study published today in Science Advances. That was the tipping point where ancient humans in Ireland started altering Earth’s environment for their benefit instead of just living in it.

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“We didn’t realize to what extent they’d changed the nitrogen cycle essentially forever,” said McClure.

What’s more, nitrogen-15 also increased in bones from wild animals like red deer. The authors argue that this means farmers back then weren’t just impacting their own fields’ chemical makeup, but rather ecosystems across the entire island of Ireland.

And while this study was restricted to bones only from Ireland, McClure and Guiry said the method could easily be applied to other regions around the globe. Doing so could help pinpoint when major players of agropastoralism—the lifestyle of growing crops and raising livestock—started chemically changing Earth.

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“Until we understand the effects that people have on soil and the environment, it’s hard to look ahead and see the effects we continue to have now,” Beglane said. “People argue what we do today has no effect with seven billion of us. Now we’re showing people back in the Bronze Age made irreversible changes happen, and there were just a few million people then. If a small amount of people can have such a fundamental effect on the environment, it shows the numbers we’re working with today are bound to have an impact.”

[Science Advances]

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Thick Dust Clouds Spotted Near Martian Ice Cap

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ESA’s Mars Express took an incredible photo of dust clouds on Mars near the planet’s north polar ice cap in April 2018, shortly before a larger dust storm darkened the entire planet’s skies.

Credit: ESA/DLR/FU Berlin/CC BY-SA 3.0 IGO

A thick cloud of dust moves over the surface of Mars near the planet's north polar ice cap in a stunning photograph.

This June, a massive dust storm hit Mars, and before long, the storm had encapsulated the entire planet. But dust clouds are a common occurrence on Mars; before that storm, a smaller-scale tempest kicked up the impressive plumes in this new photo, taken in April by the European Space Agency's (ESA) Mars Express. The photoshows just how immense these clouds can get, with a thick dust cloud near the planet's north polar ice cap.

Dust storms happen on Mars most often during the southern summer season. At this time, the planet is closer to the sun along the elliptical Martian orbit, and the brightness increases the differences in temperature on Mars, which affect air movement on the planet. These temperature differences allow the Martian air to more easily lift dust particles on the surface, according to a statement from ESA.

However, while a planet-covering dust storm sounds terrifying, things aren't that chaotic on the surface. This is because storm wind speeds on Mars are usually less than half as fast as hurricane wind speeds on Earth. Additionally, because atmospheric pressure is so low on the Red Planet, even high-speed winds wouldn't do much damage to anyone on the planet. "You would probably feel a breeze, but it wouldn't be knocking you over," Michael Smith, who works at the NASA Goddard Space Flight Center, previously said to Space.com.

Mars Express captured this cloud using a high-resolution stereo camera on board. The dust storm that continues to rage on Mars is being imaged and monitored by five ESA and NASA orbiters, while NASA's Curiosity rover continues to collect data on the red, dusty surface.

Email Chelsea Gohd at cgohd@space.com or follow her @chelsea_gohd. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

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Unique Armored Dinosaur Discovered In Utah

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The fossil reveals new details about the diversity and evolution of ankylosaurid dinosaurs

In 2008, researchers found the fossil of a remarkable armored dinosaur in southern Utah. The North American Late Cretaceous ankylosaurid dinosaur was covered in a smooth bony armor but it seems to be more closely related to ankylosaurids found in Asia than to ones that lived in northern America.

The new species of ankylosaurid dinosaur lived 76 million years ago during the Late Cretaceous Period and roamed the lost continent of Laramidia. Although many ankylosaurids dinosaur fossils have been found over the years in the southwestern US, the recent fossil offers the most complete skeleton of an ankylosaurid in the region. The fossil includes a complete skull, vertebrae and limb bones, as well as a perfectly preserved bony body armor.

The most interesting thing about this dinosaur is its spiky bony armor covering the skull and snout. These defining features make it look surprisingly similar to Asian ankylosaurids that originated in Asia between 125 to 100 million years ago.

“A reasonable hypothesis would be that ankylosaurids from Utah are related to those found elsewhere in western North America, so we were really surprised to discover that Akainacephalus was so closely related to species from Asia.” Co-author of the study Randall Irmis said in a statement.

A new analysis indicates that the diversity and evolution of armored dinosaurs in the region was the result of brief intervals of lowered sea level that allowed Asian ankylosaurid dinosaurs to immigrate to North America several times during the Late Cretaceous. Lower sea levels exposed the Beringian land bridge and allowed dinosaurs and other animals to move between Asia and North America, which led to the presence of two separate groups of ankylosaurid dinosaurs.

“It is extremely fascinating and important for the science of paleontology that we can read so much information from the fossil record, allowing us to better understand extinct organisms and the ecosystems they were a part of,” said lead author Jelle Wiersma.

“…Akainacephalus johnsoni; not only is this the first described and named Late Cretaceous ankylosaurid dinosaur from Utah, but this unique animal also strengthens the idea the evidence that distinct northern and southern provincialism existed during the late Campanian stage in Laramidia, because to date, we don’t see this type of ankylosaurid dinosaurs in the fossil record of northern Laramidia.”

Akainacephalus johnsoni has been assigned to a new genus. The genus name comes from the Greek words akaina, which means ‘thorn’ or ‘spike’, and cephalus, meaning ‘head.’ The other part of the name honors Randy Johnson, a dedicated museum volunteer who skillfully reconstructed its skull.

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This Massive Dust Storm Could Engulf Mars for Months

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Every six to eight years, massive dust storms can envelop Mars’s whole surface. NASA’s Martian probes are currently watching one unfold over the Red Planet. Scientists saw a small-scale dust storm begin on May 30th, and by June 20th, it’d gone “global,” engulfing the whole planet. For the NASA Opportunity rover, visibility dropped from that of a sunny day to an overcast one. Because the rover runs on solar energy, researchers suspended it to preserve its batteries. According to NASA, it could take as long as September before the dust starts to settle, and the Opportunity starts reporting back.

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Meanwhile, numerous other Mars orbiters are helping scientists understand the dust storm. “This is one of the largest weather events that we’ve seen on Mars,” since spacecraft observations began in the 1960s, said Michael Smith, a scientist at NASA’s Goddard Spaceflight Center. Smith and other scientists are trying to understand how small, regional storms swarm to become such a large one. They’re also recording how the dust storm changes the planet’s atmospheric temperatures, which can change winds, which in turn can amplify the storm by stirring up more dust from the planet’s surface. “The very fact that you can start with something that’s a local storm, no bigger than a small [US] state, and then trigger something that raises more dust and produces a haze that covers almost the entire planet is remarkable,” said Rich Zurek, the project scientist for MRO, which maps the evolution of the storm daily in color images and atmospheric temperature.

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Meanwhile, the Mars Curiosity is on a mission to acquire rock samples and study the storm from the surface of Mars itself, and another orbiter is studying Mars’ high atmosphere, 100 kilometers above the surface, where the dust doesn’t reach. Every time you see Mars in the sky in the weeks ahead, NASA advises, “remember how much data scientists are gathering to better understand the mysterious weather of the Red Planet.”

(via NASA)

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