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Hydrological Sciences

Imaggeo on Mondays: Salt shoreline of the Dead Sea

Imaggeo on Mondays: Salt shoreline of the Dead Sea

This beautiful aerial image (you’d be forgiven for thinking that it was a watercolour) of the Dead Sea was captured by a drone flying in 100m altitude over its eastern coastline.

Climate change is seeing temperatures rise in the Middle East, and the increased demand for water in the region (for irrigation) mean the areas on the banks of the lake are suffering a major water shortage. As a result, the lake is shrinking at an alarming rate. Currently, it is shrinking by over 1m/year. The image was captured as part of a survey in the wider project DESERVE (Kottmeier et al. 2016) addressing the environmental changes accompanying the lake level drop.

In this case, the special focus is to look for e.g. submarine springs or other geomorphological evidence in the shallow lake water that can later turn into hazardous sinkholes (cf. recent publication on that topic Al-Halbouni et. al. 2017). Learn more about the environmental challenges and geohazard risks the region faces in this December 2016 Imaggeo on Mondays post.

The round features see in this image, nevertheless have been identified as salt accumulations following basically the sinusoidal shoreline.

The different colours of the lake indicate water of varying densities, e.g. fresh water floating on top of saltier water and possible sediments inside.

The shoreline appears with different colours each year depending on the sediment mud & evaporite material. Each line represents the retreat of a given year!

[Editor’s note: this image was a finalsit in the 2017 Imaggeo Photo Contest]

By Laura Robert and Djamil Al-Halbouni of the German Research Center for Geosciences, Physics of the Earth, Potsdam, German

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

 

June GeoRoundUp: the best of the Earth sciences from around the web

June GeoRoundUp: the best of the Earth sciences from around the web

Drawing inspiration from popular stories on our social media channels, as well as unique and quirky research news, this monthly column aims to bring you the best of the Earth and planetary sciences from around the web.

Major Story

With June being the month when the world’s oceans are celebrated with World Ocean Day (8th June) and the month when the UN’s Ocean Conference took place, it seemed apt to dedicate our major story to this precious, diverse and remote landscape.

In fact, so remote and inaccessible are vast swathes of our oceans, that 95% of them are unseen (or unvisited) by human eyes. Despite their inaccessibility, humans are hugely reliant on the oceans.  According to The World Bank, the livelihoods of approximately 10 to 12% of the global population depends on healthy oceans and more than 90%of those employed by capture fisheries are working in small-scale operations in developing countries. Not only that, but the oceans trap vast amounts of heat from the atmosphere, limiting global temperature rise.

Yet we take this valuable and beautiful resource for granted.

As greenhouse gas emissions rise, the oceans must absorb more and more heat. The ocean is warmer today than it has been since recordkeeping began in 1880. Over the past two decades this has resulted in a significant change in the composition of the upper layer of water in our oceans. Research published this month confirms that ocean temperatures are rising at an alarming rate, with dire consequences.

Corals are highly sensitive to changes in ocean temperatures. The 2015 to 2016 El Niño was particularly powerful. As its effects faded, ocean temperatures in the Pacific, Atlantic and Indian oceans remained high, meaning 70 percent of corals were exposed to conditions that can cause bleaching. Almost all of the 29 coral reefs on the U.N. World Heritage list have now been damaged by bleaching.

This month, the National Oceanic and Atmospheric Administration (NOAA) declared that bleaching was subsiding for the first time in three years. Some of the affected corals are expected to take 10 to 15 years to recover, in stress-free conditions. But as global and ocean temperatures continue to rise, corals are being pushed closer to their limits.

Warmer ocean temperatures are also causing fish to travel to cooler waters, affecting the livelihoods of fishermen who depend on their daily catch to keep families afloat and changing marine ecosystems forever. And early this month, millions of sea-pickles – a mysterious warm water loving sea creature- washed up along the western coast of the U.S, from Oregon to Alaska. Though scientists aren’t quite sure what caused the bloom, speculation is focused on warming water temperatures.

It is not only warming waters which are threatening the world’s oceans. Our thirst for convenience means a million plastic bottles are bought around the world every minute. Campaigners believe that the environmental crisis brought about by the demand for disposable plastic products will soon rival climate change.

In 2015 researchers estimated that 5-13 million tonnes of plastics flow into the world’s oceans annually, much coming from developing Asian nations where waste management practices are poor and the culture for recycling is limited. To tackle the problem, China, Thailand, Indonesia and the Philippines vouched to try and keep more plastics out of ocean waters. And, with a plastic bottle taking up to 450 years to break down completely, what happens to it if you drop it in the ocean? Some of it, will likely find it’s way to the Arctic. Indeed, recent research suggests that there are roughly 300 billion pieces of floating plastic in the polar ocean alone.

A bottle dropped in the water off the coast of China is likely be carried eastward by the north Pacific gyre and end up a few hundred miles off the coast of the US. Photograph: Graphic. Credit: If you drop plastic in the ocean, where does it end up? The Guardian. Original Source: Plastic Adrift by oceanographer Erik van Sebille. Click to run.

And it’s not only the ocean waters that are feeling the heat. As the demand for resources increases, the need to find them does too. The sea floor is a treasure trove of mineral and geological resources, but deep-sea mining is not without environmental concerns. Despite the ethical unease, nations are rushing to buy up swathes of the ocean floor to ensure their right to mine them in the future. But to realise these deep-water mining dreams, advanced technological solutions are needed, such as the remote-controlled robots Nautilus Minerals will use to exploit the Bismarck Sea, off the coast of Papua New Guinea.

What you might have missed

Lightning reportedly ignited a deadly wildfire in Portugal, seen here by ESA’s Proba-V satellite on 18 June.

“On June 17, 2017, lightning reportedly ignited a deadly wildfire that spread across the mountainous areas of Pedrógão Grande—a municipality in central Portugal located about 160 kilometers (100 miles) northeast of Lisbon”, reported NASA – National Aeronautics and Space Administration. The death toll stands at 62 people (as reported by BBC News). The fires were seen from space by satellites of both NASA and ESA – European Space Agency satellites.

Large wildfires are also becoming increasing common and severe in boreal forests around the world. Natural-color images captured by NASA satellites on June 23rd, shows wildfires raging near Lake Baikal and the Angara River in Siberia. At the same time, a new study has found a link between lightning storms and boreal wildfires, with lightning strikes thought to be behind massive fire years in Alaska and northern Canada. This infographic further explores the link between wildfires triggered both by lightning and human activities.

Meanwhile, in the world’s southernmost continent the crack on the Larsen C ice-shelf continues its inexorable journey across the ice. The rift is set to create on of the largest iceberg ever recorded. Now plunged in the darkness of the Antarctic winter, obtaining images of the crack’s progress is becoming a little tricker. NASA used the Thermal Infrared Sensor (TIRS) on Landsat 8 to capture a false-color image of the crack. The new data, which shows an acceleration of the speed at which the crack is advancing, has lead scientists to believe that calving of the iceberg to the Weddell Sea is imminent.

Links we liked

The EGU story

This month saw the launch of two new division blogs over on the EGU Blogs: The Solar-Terrestrial Sciences and the Geodynamics Division Blogs. The EGU scientific divisions blogs share division-specific news, events, and activities, as well as updates on the latest research in their field.

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

May GeoRoundUp: the best of the Earth sciences from around the web

May GeoRoundUp: the best of the Earth sciences from around the web

Drawing inspiration from popular stories on our social media channels, as well as  unique and quirky research news, this monthly column aims to bring you the best of the Earth and planetary sciences from around the web.

Major Story

In the last couple of weeks of May, the news world was abuzz with the possibility of Donald Trump withdrawing from the Paris Agreement. Though the announcement actually came on June 1st, we’ve chosen to feature it in this round-up as it’s so timely and has dominated headlines throughout May and June.

In withdrawing from the agreement, the United States becomes only one of three countries in rejecting the accord, as this map shows. The implications of the U.S joining Syria and Nicaragua (though, to be clear, their reasons for not signing are hugely different to those which have motivated the U.S withdrawal) in dismissing the landmark agreement have been widely covered in the media.

President Trump’s announcement has drawn widespread condemnation across the financial, political and environmental sectors. Elon Musk, Tesla and SpaceX CEO, was one of many in the business sector to express their criticism of the President’s decision. In response to the announcement, Musk tweeted he was standing down from his duties as adviser to a number of White House councils. While in early May, thirty business CEOs  wrote an open letter published in the Wall Street Journal to express their “strong support for the U.S. remaining in the Paris Climate Agreement.”

In a defiant move, U.S. States (including California, New York and Vermont), cities and business plan to come together to continue to work towards meeting the targets and plans set out by the Paris Agreement. The group, coordinated by former New York City mayor Mark Bloomberg, aims to negotiate with the United Nations to have its contributions accepted to the Agreement alongside those of signatory nations.

“We’re going to do everything America would have done if it had stayed committed,” Bloomberg, said in an interview.

Scientist and learned societies have also been vocal in expressing their criticism of the White House decision. Both Nature and Science collected reactions from researchers around the globe. The EGU, as well as the American Geophysical Union, and many in the broader research community oppose the U.S. President’s decision.

“The EGU is committed to supporting the integrity of its scientific community and the science that it undertakes,” said the EGU’s President, Jonathan Bamber.

For an in-depth round-up of the global reaction take a look at this resource.

What you might have missed

This month’s links you might have missed take us on a journey through the Earth. Let’s start deep in the planet’s interior.

The core generates the Earth’s magnetic field. Periodically, the magnetic field reverses, but what caused it to do so? Well, there are several, competing, ideas which might explain why. Recently, one of them gained a bit more traction. By studying the seismic signals from powerful earthquakes, researchers at the University of Oxford found that regions on top of the Earth’s core sometimes behave like a giant lava lamp. It turns out that blobs of rock periodically rise and fall deep inside our planet. This could affect the magnetic field and cause it to flip.

Meanwhile, at the planet’s surface, the Earth’s outer solid layer (the crust) and upper layer of the molten mantle,  are broken up into a jigsaw of moving plates which pull apart and collide, generating earthquakes, driving volcanic eruptions and raising mountains. But the jury is still out as to when and how plate tectonics started. The Earth is so efficient at recycling and generating new crustal material, through plate tectonics, that only a limited record of very old rocks remains making it very hard to decipher the mystery. A recently published article explores what we know and what yet remains to be discovered when it comes to plate tectonics.

Tectonic plate boundaries. By Jose F. Vigil. USGS [Public domain], distributed by Wikimedia Commons.

Oil, gas, water, metal ores: these are the resources that spring to mind when thinking of commodities which fuel our daily lives. However, there are many others we use regularly, far more often than we realise or care to admit, but which we take for granted. Sand is one of them. In the industrial world it is know as ‘aggregate’ and it is the second most exploited natural resource after water. It is running out. A 2014 United Nations Environment Programme report highlighted that the “mining of sand and gravel greatly exceeds natural renewal rates”.

Links we liked

  • Earth Art takes a whole new meaning when viewed from space. This collection of photographs of natural parks as seen from above is pretty special.
  • This round-up is usually reserved for non-EGU related news stories, but given these interviews with female geoscientists featured in our second most popular tweet of the month, it is definitely worth a share: Conversations on being a women in geoscience – perspectives on what being a female in the Earth sciences.
  • We’ve shared these previously, but they are so great, we thought we’d highlight them again! Jill Pelto, a scientist studying the Antarctic Ice Sheet and an artist, uses data in her watercolous to communicate information about extreme environmental issues to a broad audience.

The EGU story

Temperatures in the Arctic are increasing twice as fast as in the rest of the globe, while the Antarctic is warming at a much slower rate. A new study published in Earth System Dynamics, an EGU open access journal, shows that land height could be a “game changer” when it comes to explaining why temperatures are rising at such different rates in the two regions. Read the full press release for all the details, or check out the brief explainer video, which you can also watch on our YouTube channel.

 

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

Artificial floods: Restoring the ecological integrity of rivers

Artificial floods: Restoring the ecological integrity of rivers

“You can never step into the same river,
for new waters are always flowing on to you.”
—Heraclitus of Ephesus

Rushing rivers, with their unremitting twists and turns and continuous renewal, are often used as a metaphor for life, but the analogy is just as appropriate for scientific research, I reflected as I walked along the banks of a sparkling, turquoise-blue river in the heart of the Swiss National Park. The never-ending cycle of formulating, testing, and modifying evidence-based hypotheses is a hallmark of how humanity acquires new knowledge.

Conducting experiments with rivers is especially challenging because they can never be isolated from their social and ecological contexts. Worldwide, people have appropriated more than half the globe’s accessible surface water by erecting hundreds of thousands of dams. Although these dams provide many societal advantages, including hydropower, water storage, and flood control, they also severely disrupt the ecosystems within which they’re placed. Recently, however, there has been a growing focus on using intentional water releases from the very dams that disturb rivers as ecological restoration tools.

The Spöl River flows through the heart of the beautiful Swiss National Park. (Credit: Terri Cook)

Thanks to the support of an EGU Science Journalism Fellowship, I was hiking next to the Spöl River, a beautiful ribbon of crystal-clear water winding through a deep gorge carved into a soaring limestone upland in the Rhaetian Alps, which are tucked into the country’s southeastern corner. The craggy peaks and towering spruce, pine, and golden larch trees provided a startling contrast to the arid, high-desert scenery along the Colorado River in the Grand Canyon where, several years earlier, I had witnessed the Colorado River’s rapid rise following a so-called “artificial flood” unleashed from Glen Canyon Dam.

Multiple manmade floods have been conducted in the Grand Canyon to benefit the corridor’s physical, cultural, and biological resources, most notably endangered native fish and the disappearing sandbars upon which many organisms, as well as the multimillion-dollar rafting industry, depend. Following years of intensive scientific study and negotiations between the numerous stakeholders, the U.S. government recently implemented a long-term strategy for releasing manmade floods following large sand inputs from tributaries that join the main stem below Glen Canyon Dam. The reason for this timing is to move the recently introduced sand up onto the banks to replenish the shrinking sandbars.

Although these events have been widely reported in the press, few people realize that one of the most important models for designing the Grand Canyon experiments was the Spöl River. I had thus traveled to Switzerland to report on the globe’s best example of how, using carefully designed and monitored floods, scientists and managers have collaborated for a decade and a half to restore—and sustain—this river’s ecological integrity.

Of Fish and Floods

From the Livigno Reservoir on the Italian-Swiss border, the Spöl flows through Switzerland’s only national park before joining the Inn River, a tributary of the Danube, 28 kilometers downstream. Inside the park, the Spöl is sandwiched between two dams, the 130-meter-high Punt dal Gall on the Italian border and the 73-meter-high Ova Spin downstream. Built in the 1960s following a contentious vote, the dams are towering concrete barriers that seemed to me to be out of proportion to the river’s modest size.

Punt dal Gall Dam: The 130-meter-high Punt dal Gall Dam was built in the 1960s on the Swiss-Italian border. (Credit: Terri Cook)

Studies in the national park in the late 1980s confirmed that two decades of reduced flows had severely altered the stream, Ruedi Haller, the park’s Research and Geoinformation Manager, told me as we hiked. The riverbed had become choked with fine-grained sediments, reducing brown trout spawning grounds and changing its assemblage of fauna.

In 1990, a mandated flushing of the safety release gates at the base of the upper Punt dal Gall Dam noticeably improved the ecological conditions downstream, flushing out many of the fine-grained sediments and decreasing the accumulations of mosses, algae, and bottom-dwelling fauna that had taken advantage of the low and steady dam-controlled flows. Within months, however, the Spöl returned to its prior condition. As Chris Robinson of the Swiss Federal Institute of Aquatic Science and Technology explained to me, this first experiment indicated that a single artificial flood could not sustain the river’s ecological integrity over the long term.

Following this initial success, park authorities, researchers, and representatives of the Engadin Hydropower Company, which operates the dams, gradually overcame their former distrust and began to work together to design and implement a flood release program to improve the river’s long-term health. Since then, operators have unleashed more than 25 experimental floods that, by mimicking the seasonally variable conditions to which native fauna and flora have adapted, have recreated an ecosystem much more typical of an Alpine stream. The current flood release program incorporates two artificial floods per year, with the magnitudes determined by annual monitoring.

The Sarine

I also visited a second managed river, the Sarine, near Bern, to watch scientists assess the results of an artificial flood that had just been completed. Among the team working at the site was Michael Doering of the Zurich University of Applied Sciences. He was using a drone to snap post-flood photographs to compare with images taken just before the event to provide a bird’s-eye view of the changes the water had wrought.

Michael Doering uses images taken by a drone to determine the amount of sediment relocated during an artificial flood. (Credit: Terri Cook)

Once analyzed, these and other data will show whether the Sarine flood was large enough to achieve the goals of moving sediment from the banks into the stream and raising the water level high enough to benefit the aquatic and terrestrial ecosystems straddling its banks. Both are necessary, explained Doering, to support a healthy amount of biodiversity, which dammed rivers typically lack.

Through a revision to its Water Protection Act, Switzerland has committed to eliminating the negative impacts of hydropower plants on all of the country’s rivers. Of the more than 700 facilities that need to be mitigated by 2030, it is envisaged that up to about 40 will use artificial floods, according to Martin Pfaundler of the Swiss Federal Office for the Environment. To accomplish this, scientists and water managers will rely on the experience obtained not only from Swiss rivers, but also—as part of the ever-flowing research cycle—from the new knowledge gained from the Colorado.

By Terri Cook, a science and travel writer and winner of the EGU’s 2016 Science Journalism Fellowship.

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