Diliff via Wikimedia Commons // CC BY-SA 3.0
Diliff via Wikimedia Commons // CC BY-SA 3.0

England’s White Cliffs Are Crumbling at an Accelerated Rate

Diliff via Wikimedia Commons // CC BY-SA 3.0
Diliff via Wikimedia Commons // CC BY-SA 3.0

Buddhist nun Pema Chödron may have said it best: “Everything—every tree, every blade of grass, all the animals, insects, human beings, buildings, the animate and the inanimate—is always changing, moment to moment.” Though they often operate on a timescale that can be beyond our human perception, geological features are not exempt from the flow of time. In some places, that change happens fast. Geologists say chalk cliffs on England’s southern shore are eroding 10 times faster than they once did. The researchers published their findings in the Proceedings of the National Academy of Sciences.

The picturesque chalk cliffs known as the Seven Sisters swoop gracefully along the British coast, attracting tourists and photographers. Yet for their serene appearance, the cliffs are not exactly safe.

Chalk is one of the softest minerals and easily broken—especially when it’s being constantly pounded by the sea. The site saw major landslides in 1999 and 2001, and a massive cliff-fall in May 2016 sent tons of rock into the water below. (“While we would encourage people to enjoy the beautiful coastline of East Sussex," reads the Seven Sisters Country Park website, “we would remind visitors that you do have a duty of care and responsibility for your own safety.”)

Understanding coastal erosion has become a big issue in a world facing rising sea levels. The tricky part is studying something that, by definition, is no longer there. Even tons of fallen rock will break down and be scattered by the sea.

But the ghosts of the old coastline still haunt the rock that remains. To find them, geologists used a technique called cosmogenic nuclide dating, which measures the extent of cosmic radiation in rock to determine its age and how long it’s been exposed. This, in turn, can paint a picture of how that rock has moved or been changed over time.

The white cliffs are studded with pieces of hard, chemically inert flint—a rock that makes a far more reliable historical witness than soft chalk. Working perpendicular to the cliffs themselves, the researchers pulled chunks of flint from exposed rock in a line beginning at the cliff and ending near the water’s edge.

They crushed the flint into microscopic pieces, then put them through a cosmogenic nuclide array to determine their age and history.

Next, the researchers fed that data into a mathematical model of the coastline, which allowed them to estimate the cliffs’ rate of erosion going back thousands of years.

They found that the coast is indeed crumbling fast—but they also learned that this pace is a relatively recent development. For most of the cliffs’ history, the authors write in their paper, the rate of erosion held steady at between 2 and 6 centimeters per year. But that rate has accelerated mightily in the last few centuries, now cruising along at 22 to 32 centimeters a year.

What changed (or changed more)? The authors can’t say for sure. Natural climate change is one possibility; wave action did become more violent during the so-called Little Ice Age, which took place from the 14th to 19th centuries. The cliffs have also become more vulnerable over the last few centuries, as ocean currents and human engineers picked away at the band of sediment protecting the coast from the ocean’s full force.

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An Eco-Friendly Startup Is Converting Banana Peels Into Fabric for Clothes
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A new startup has found a unique way to tackle pollution while simultaneously supporting sustainable fashion. Circular Systems, a “clean-tech new materials company,” is transforming banana byproducts, pineapple leaves, sugarcane bark, and flax and hemp stalk into natural fabrics, according to Fast Company.

These five crops alone meet more than twice the global demand for fibers, and the conversion process provides farmers with an additional revenue stream, according to the company’s website. Fashion brands like H&M and Levi’s are already in talks with Circular Systems to incorporate some of these sustainable fibers into their clothes.

Additionally, Circular Systems recycles used clothing to make new fibers, and another technology called Orbital spins those textile scraps and crop byproducts together to create a durable type of yarn.

People eat about 100 billion bananas per year globally, resulting in 270 million tons of discarded peels. (Americans alone consume 3.2 billion pounds of bananas annually.) Although peels are biodegradable, they emit methane—a greenhouse gas—during decomposition. Crop burning, on the other hand, is even worse because it causes significant air pollution.

As Fast Company points out, using leaves and bark to create clothing may seem pretty groundbreaking, but 97 percent of the fibers used in clothes in 1960 were natural. Today, that figure is only 35 percent.

However, Circular Systems has joined a growing number of fashion brands and textile companies that are seeking out sustainable alternatives. Gucci has started incorporating a biodegradable material into some of its sunglasses, Bolt Threads invented a material made from mushroom filaments, and pineapple “leather” has been around for a couple of years now.

[h/t Fast Company]

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Undersea Internet Cables Could Be Key to the Future of Earthquake Detection
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Considering that 70 percent of the planet is covered by oceans, we don't have all that many underwater earthquake sensors. Though there's plenty of seismic activity that happens out in the middle of the ocean, most detection equipment is located on land, with the exception of a few offshore sensor projects in Japan, the U.S., and Canada.

To get better earthquake data for tremors and quakes that happen far from existing sensors, a group of scientists in the UK, Italy, and Malta suggest turning to the internet. As Science News reports, the fiber-optic cables already laid down to carry communication between continents could be repurposed as seismic sensors with the help of lasers.

The new study, detailed in a recent issue of Science, proposes beaming a laser into one end of the optical fiber, then measuring how that light changes. When the cable is disturbed by seismic shaking, the light will change.

This method, which the researchers tested during earthquakes in Italy, New Zealand, Japan, and Mexico, would allow scientists to use data from multiple undersea cables to both detect and measure earthquake activity, including pinpointing the epicenter and estimating the magnitude. They were able to sense quakes in New Zealand and Japan from a land-based fiber-optic cable in England, and measure an earthquake in the Malta Sea from an undersea cable running between Malta and Sicily that was located more than 50 miles away from the epicenter.

A map of the world's undersea cable connections with a diagram of how lasers can measure their movement
Marra et al., Science (2018)

Seismic sensors installed on the sea floor are expensive, but they can save lives: During the deadly Japanese earthquake in 2011, the country's extensive early-warning system, including underwater sensors, was able to alert people in Tokyo of the quake 90 seconds before the shaking started.

Using existing cable links that run across the ocean floor would allow scientists to collect data on earthquakes that start in the middle of the ocean that are too weak to register on land-based seismic sensors. The fact that hundreds of thousands of miles of these cables already crisscross the globe makes this method far, far cheaper to implement than installing brand-new seismic sensors at the bottom of the ocean, giving scientists potential access to data on earthquake activity throughout the world, rather than only from the select places that already have offshore sensors installed.

The researchers haven't yet studied how the laser method works on the long fiber-optic cables that run between continents, so it's not ready for the big leagues yet. But eventually, it could help bolster tsunami detection, monitor earthquakes in remote areas like the Arctic, and more.

[h/t Science News]

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