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Forests And Water | Earth Wise

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We hear a great deal about the environmental services provided by forests.  Deforestation is one of the major factors contributing to increasing levels of carbon dioxide in the atmosphere.  And, of course, forests – most notably rainforests – are major contributors to biodiversity.  A new study by the U.S. Forest Service looked at the role forests play in providing water for Americans.

According to the study, published in the journal Water Resources Research, forested lands across the U.S. provide 83 million Americans with at least half of their water.  125 million people – well over a third of the country – receive at least 10% of their water from forests.  Notably, in the drought-stricken western U.S., nearly 40 million people get more than half of their drinking water from forests that are increasingly threatened by wildfires.

The study looked at surface water sources for more than 5,000 public water systems.  It provides a critical update to the map of where our water comes from.  The study focused on surface waters such as lakes, rivers, and streams because it is too difficult to trace sources of groundwater on a national scale.  Included is a new database of inter-basin water transfers, which are how surface water moves from places where it is plentiful to where it is not.  Examples are the California Aqueduct and the Central Arizona Project which respectively supply Los Angeles and Phoenix with drinking water.  

In Los Angeles, 69% of the water coming in through inter-basin transfers originated in forested lands.  In Phoenix, the figure is 82%.  There are many urban communities that obtain more than half of their drinking water from inter-basin transfers.  Even far from forests, water from forests is essential for millions of Americans.

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U.S. Forests Provide 83 Million People with Half Their Water

Photo, posted September 26, 2016, courtesy of Don Graham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Electricity From Bacteria | Earth Wise

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Microbiologists at Radboud University in the Netherlands have demonstrated in the laboratory that methane-consuming bacteria can generate electrical power.  Their study was recently published in the journal Frontiers in Microbiology.

The bacteria studied is called Candidatus Methanoperedens and in the natural environment it consumes methane in water sources that are contaminated with nitrogen including places like water-filled ditches and some lakes. The bacteria in the study make use of the nitrates in the water to break down and digest the methane. Methanogens, which are bacteria that reduce carbon dioxide to form methane, are the source of the methane in these places. 

The researchers exploited these complex interactions of bacteria to create a source of electrical power that is essentially a kind of battery with two terminals.  One of the terminals is a chemical terminal and one is a biological terminal.  They grew the bacteria on one of the electrodes where the bacteria donate electrons that result from its conversion of methane.  (Other microbiologists at the same institution had previously demonstrated electrical generation from a similar battery containing anammox bacteria that use ammonium rather than methane in their metabolic processing).

In the study, the Radboud scientists managed to convert 31% of the methane in the water into electricity but they are aiming at higher efficiencies. 

This approach represents a potential alternative to conventional biogas electricity generation.  In those installations, methane is produced by microorganisms digesting plant materials and the methane is subsequently burned to drive a turbine to generate power.  Those systems in fact have an efficiency of less than 50%.  The researchers want to determine whether microorganisms can do a better job of generating electricity from biological sources than combustion and turbines can do.

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Bacteria generate electricity from methane

Photo, posted December 3, 2008, courtesy of Martin Sutherland via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wastewater As A Freshwater Source | Earth Wise

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Water covers three-quarters of our planet, but freshwater – the water we drink, bathe in, and irrigate crops with – comprises only 3% of the world’s water and much of that is frozen in glaciers or otherwise unavailable.  Nearly 3 billion people suffer from water scarcity for at least some of the year.

Natural freshwater sources – lakes, rivers, and groundwater – are under stress from the effects of climate change and from the increasing demands of city populations.  The wastewater treatment plants in large cities represent a significant potential water source provided that sustainable and economical technologies to produce it can be developed.

Researchers at Lehigh University in Pennsylvania have patented an innovative ion exchange desalination process that is a legitimate candidate to transform wastewater into usable water.

Existing large-scale desalination systems make use of semipermeable reverse osmosis membranes that require an energy source to run the system.  The Lehigh process, which they call HIX-Desal, harnesses the unique chemistry of carbon dioxide to take the place of the energy used in reverse osmosis systems. 

Tests of the new system show that the salinity of treated wastewater can be reduced by more than 60% by the HIX-Desal process without requiring any reverse osmosis.  At an Allentown, Pennsylvania water treatment plant where the system was tested, the researchers estimated that using the system could save about a million kWh per day in electricity usage, enough energy to power 94 homes for a year.

With this system, waste carbon dioxide from landfills or turbine exhaust can be used to desalinate municipal wastewater.  It could be the basis of a circular economy.

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Desalination tech uses CO2 to tap into municipal wastewater as alternative freshwater source

Photo, posted November 28, 2020, courtesy of Richard Ricciardi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving Water At Power Plants | Earth Wise

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Nearly 40% of all the water taken from lakes, rivers, and wells in the U.S. isn’t used for agriculture, drinking, or sanitation.  It is used to cool power plants that produce electricity by burning fossil fuels or with nuclear reactors.   Two-thirds of these power plants use evaporative cooling, which produces huge white plumes billowing from cooling towers.

A new company using technology developed at MIT has the goal of reducing the water needs of power plants and helping to alleviate water shortages in areas where power plants strain the capacity of local water systems.

The technology is relatively simple in principle but developing it to the point where it can be applied at full scale at industrial power plants was a greater challenge. 

The basic idea is to capture water droplets from both natural fog and from the plumes from power plant cooling towers.  The MIT researchers had to improve the efficiency of fog-harvesting systems, which previously captured only 1-3% of the water droplets that pass through them.  They found that water vapor collection could be made much more efficient by zapping the tiny droplets of water with an ion beam, giving them a slight electric charge, thereby making it easy to capture them with the metal mesh of the harvesting system.

The system can essentially eliminate cooling tower plumes and produce large quantities of high-purity water in the process, which has uses at many power plants.  The new company, called Infinite Cooling, has arranged to install their equipment on two operating commercial power plants later this year.  They expect the system to reduce the overall need for water by 20%.

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Vapor-collection technology saves water while clearing the air

Photo, posted March 5, 2019, courtesy of Sam LaRussa via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Beavers And The Warming Arctic | Earth Wise

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Beavers have a remarkable ability to transform landscapes.  Using their sharp teeth, they fell trees and shrubs and build dams, which cause small valleys to fill with water and form new lakes.  Some of these lakes measure five or ten acres in size, or even more.  And beavers are very efficient builders; they often build their dams at precisely those points where can they have the greatest effect with the least effort.

Scientists studying beaver activity in the Arctic regions of Alaska have found that the changing climate is leading to a substantial increase in beaver populations and their effect on the landscape.

In 2018, researchers found that the beavers living in a 7,000 square-mile area in northwest Alaska had created 56 new lakes in just five years.  Thanks to rising temperatures, more and more habitats offer the shrubs that beavers need for food and building material.  In addition, the lakes, which used to freeze solid, now offer beaver-friendlier conditions.  Also, beavers are not hunted as intensively as in the past.

The scientists were surprised that beavers have seized the opportunity so intensively.  There is basically an exponential growth in beaver dams.  This is actually a worrisome situation.  Forming all these new lakes degrades ice-rich permafrost in the area.  In the Kotzebue region of Alaska, the overall water area has increased by more than 8% over the past 17 years, and roughly two-thirds of that is due to beavers.

The degradation of the Arctic’s permafrost is a dangerous situation and it appears that anyone who wants to predict its future has to keep the activity of beavers in mind.

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Beavers gnawing away at the permafrost

Photo, posted June 23, 2018, courtesy of Becky Matsubara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Carbon Dioxide From Thawing Permafrost | Earth Wise

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The Arctic is warming much faster than the rest of the planet.  Stories about the loss of polar ice and hundred-degree temperatures in Siberia have become commonplace.  One of the most troubling aspects of the warming Arctic is the thawing of permafrost.  Permafrost is ground that remains frozen for at least two years; some of it has been frozen for tens or hundreds or even thousands of years.  Found under a layer of soil, permafrost is composed of rock, soil, sediments, and varying amounts of ice.  It stores the carbon-based remains of plants and animals that froze before they could decompose.  Permafrost covers almost a quarter of North America, but it is starting to thaw.

Scientists estimate that there are more than 16,000 billion tons of carbon locked away in Arctic permafrost, which is almost double the amount of carbon that is currently in the atmosphere.  Climate models predict that the warming of the Arctic could lead to 5 to 15% of that carbon to be emitted as carbon dioxide by the year 2,100, which would be enough to raise global temperatures by 0.3 to 0.4 degrees Celsius.

New research has increased this estimate because it includes a key pathway for CO2 to enter the atmosphere that earlier models ignored.   When carbon from thawing permafrost escapes into Arctic lakes and rivers, it is oxidized by ultraviolet and visible light and it then escapes into the atmosphere as CO2.  This process is known as photomineralization and is estimated to raise permafrost-related CO2 emissions by 14%.

Recent studies project that with every 1-degree Celsius increase in temperature, 1.5 million square miles of permafrost could be lost through thawing.

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Climate Models Underestimate CO2 Emissions from Permafrost by 14 Percent, Study Finds

Photo, posted July 7, 2014, courtesy of NPS Climate Change via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wildlife Reclaims Yosemite National Park | Earth Wise

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Our stories often discuss how human activities change the natural environment.  With most of us confined to our homes, the lack of human activities is having profound effects on the environment.  We are talking about some of these this week.

Yosemite National park is normally awash in humanity – there were over 300,000 visitors in April of 2019 and typically 4 million people visit each year.  But as of March 20, the park was closed to tourists to prevent the spread of the coronavirus.  Only a skeleton crew of employees remains in the park.

Without all the people, wildlife is coming out of hiding.  It did so in previous park closures during government shutdowns, but those closures were pretty short.  This one is expected to be the longest on record.

The bear population within the park has quadrupled and many larger animals – such as bobcats and coyotes – are congregating outside of cabins and other buildings and prowling empty roads and walkways instead of hanging back at the edges of human settlements. 

In addition, the air at Yosemite is cleaner due to the lack of exhaust and diesel, and Yosemite Valley is nearly silent, apart from natural sounds from the river and the wind.  According to some observers, the park’s current condition is probably similar to what visitors in the 19th century witnessed. 

The few park employees sheltering in place are taking advantage of the virtually unimpeded natural amenities of the park.  Many are hiking to its lakes and waterfalls, enjoying trails that are empty apart from animals.  As some of the people staying in the park have noted, one could not ask for a better place to be isolated.

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Coyotes, bobcats and bears: Wildlife is reclaiming Yosemite National Park

Photo, posted October 30, 2019, courtesy of Ania Mendrek via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Melting Permafrost | Earth Wise

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The Arctic is warming faster than any region on Earth and mostly we’ve been hearing about the rapid disappearance of Arctic sea ice.  But the land in the Arctic is also undergoing major changes, especially to the permafrost that has been there for millennia.

Permafrost occurs in areas where the temperature of the ground remains below freezing for two years or more.  About a quarter of the Northern Hemisphere’s landscape meets this criterion.  Most of the world’s permafrost is found in northern Russia, Canada, Alaska, Iceland, and Scandinavia.

Permafrost regions previously carpeted in cranberries, blueberries, shrubs, sedges, and lichen are now being transformed into nothing but mud, silt, and peat.  So-called regressive thaw slumps – essentially landslides – are creating large craters in the landscape.  (The Batagaika Crater in the Yana River Basin of Siberia is a kilometer long and 100 meters deep).

Apart from the violence being done to the Arctic landscape, the greatest concern is that the permafrost has locked in huge stores of greenhouse gases, including methane, carbon dioxide, and nitrous oxide.  It is estimated that the permafrost contains twice as much carbon as is currently contained in the atmosphere.  As the permafrost thaws, these gases will be released.  With them will be pathogens from bygone millennia whose impact cannot be predicted.  Climatologists estimate that 40% of the permafrost could be gone by the end of the century.

As the permafrost thaws, the region’s ecosystems are changing, making it increasingly difficult for subsistence indigenous people and Arctic animals to find food.  Landslides are causing stream flows to change, lakes to suddenly drain, seashores to collapse, and water chemistry to be altered.

The warming Arctic is about much more than disappearing sea ice.

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How Thawing Permafrost Is Beginning to Transform the Arctic

Photo, posted February 9, 2017, courtesy of the U.S. Geological Survey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Decline Of Earth’s Largest Freshwater Creatures

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While nearly 70% of the globe is covered by water, only 2.5% of it is freshwater.  The rest is saline and ocean-based.  And only 1% of our freshwater is easily accessible, with much of it locked away in snowfields and glaciers.  

Despite freshwater only making up a small fraction of all water on the planet, it’s home to one third of all vertebrate species.  Some have survived hundreds of millions of years, but many of the world’s largest freshwater creatures – including fish, reptiles, amphibians, and mammals – may soon find themselves on the brink of extinction.

According to a study recently published in the journal Global Change Biology, scientists from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries and international colleagues have quantified the global decline of freshwater megafauna for the first time.  In four decades since 1970, the global populations of these freshwater giants have declined 88% – twice as much as the loss of vertebrate populations on land or in the oceans. 

Freshwater megafauna include all freshwater animals that weigh 30 kilograms (about 66 pounds) or more, such as certain dolphins, beavers, crocodiles, turtles and sturgeons.

Overexploitation is one of the main threats to freshwater megafauna.  (These animals are often targeted for their meat, eggs, and skin).  The other main threat is the loss of free-flowing rivers. Many of the world’s large rivers are already highly fragmented, which impacts access to spawning and feeding grounds.  The research team says another 3700 large dams are planned or under construction, including 800 in habitats rich with freshwater megafauna, including the Amazon, Congo, and Ganges river basins.

Current conservation measures are clearly failing our freshwater creatures. 

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88 percent decline of big freshwater animals

Earth’s largest freshwater creatures at risk of extinction

Photo, posted March 25, 2012, courtesy of the U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sand Mining And The Environment

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In discussions of the environment, we don’t hear much about sand mining.  But sand mining is the world’s largest mining endeavor, responsible for 85% of all mineral extraction.  Sand and gravel are mined on a huge scale around the world.  The UN estimates that the total exceeds 40 billion tons a year.  Most of this activity is unregulated and unmeasured, and much of it is corrupt and environmentally destructive.

Concrete is the predominant use for sand.  Every ton of cement requires six to seven tons of sand and gravel in order to make concrete.  But sand also makes up 90% of asphalt on roads and it is used for land reclamation in places like Singapore.  Sand is also widely used in industries such as glass manufacturing and fracking.

There are different sorts of sand.  Desert sand is mostly useless for making concrete because its grains are too rounded by erosion and don’t bind well in the concrete.   Marine sand is not great for concrete either because it has to be washed clean of corrosive salts.

As a result, salt miners mostly get sand from pits on land and dredged up from lakes and riverbeds.  Dredging massive quantities of sand from rivers and lakes drastically alters river flow, erodes riverbanks, dries up tributaries, lowers water tables, and trashes wetlands and fisheries.  In many countries, this even goes on in national parks where officials turn a blind eye to the activity.  India is the world’s second-largest sand mining country (after China) and widespread illegal extraction occurs throughout the country run by highly organized and even violent “sand mafias.”

Sand mining is a huge problem and, to date, is one that is pretty much off of most people’s radar.

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The Hidden Environmental Toll of Mining the World’s Sand

Photo, posted June 3, 2017, courtesy of Andrey Talalov via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Problem Of Microplastics

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In recent years, there have been multiple reports of microplastic contamination seemingly everywhere:  in the ocean, in lakes and rivers, in beverages and foods, and in the bodies of birds, fish, and even people.  As the world tries to come to grips with this growing problem, there are many things that we simply don’t know.

Microplastics are usually formed by the breakdown of larger pieces of plastic.  Shopping bags and cups degrade into microplastics.  Microfiber clothing generates microplastics in washing machines.  And some manufacturers still intentionally add microplastics to personal care products like toothpaste and facial scrubs.

Technically, a microplastic is any piece of plastic measuring five millimeters in size down to one micron – which is one thousandth of a millimeter.  But there can be even smaller plastic particles classified as sub-microplastics and even nanoplastics.

A real concern is that it is not actually clear how dangerous microplastics are for living organisms.  We know that aquatic and terrestrial species – including humans – can and do absorb microplastic particles, but whether there is actual toxicity and the nature of any detrimental effects is not yet well understood.

Another real problem is that it is actually not easy to distinguish microplastics from other particles in a given sample.   When you are looking at a particle that is smaller than a millimeter in size, it is not easy to tell whether it is a grain of sand, a bit of cellulose from a plant, or a microplastic.  There are reliable and definitive ways to analyze samples for microplastics, but they are not as simple and commonplace as just looking through a microscope.

Microplastics are a rapidly growing problem and we don’t even really know how big and how bad the problem is.

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How dangerous is microplastic?

Photo, posted January 10, 2015, courtesy of Daria Nepriakhina via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fish In Small Lakes

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There are millions of lakes on our planet.  Many are quite large such as the Great Lakes in our country and Lake Victoria in Africa, but one-third of the world’s standing water is contained in lakes and ponds of 25 acres or less.  Many of these lakes are found in remote, often mountainous areas with no inflow and outflow.   Nevertheless, in most of these lakes there are fish.

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Global Warming And The Nitrogen Problem

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Excess nitrogen in the environment is a big problem.  The most visible aspect of the problem is the spread of toxic algae blooms in oceans, lakes and other bodies of water.  But there are other effects as well such as unwanted alterations to ecosystems.

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Terrestrial Plants and Lake Ecosystems

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Most of the planet’s freshwater stores are found in the northern hemisphere, a region that is changing rapidly in response to human activity and shifting climate trends. A recent study analyzed 147 northern lakes and found that many rely on nutrients from tree leaves, pine needles, and other land-grown plants to feed aquatic life.

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