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Mangrove Trees And Climate Change | Earth Wise

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Mangrove trees are small trees that grow in coastal saline or brackish water at tropical and subtropical latitudes.  Many mangrove trees can be identified by their dense tangle of prop roots.  These roots make the trees appear as if they are standing on stilts above the water.  The tangle of roots allows mangrove trees to handle the daily rise and fall of tides and to slow the movement of tidal waters.  

Mangrove forests provide many ecosystem services, including stabilizing the coastline by reducing erosion from storm surges, waves, and tides.  The intricate root system of mangrove trees are attractive to fish and other species seeking food and shelter from predators.  Mangrove forests also store large amounts of carbon.     

But according to a new study recently published in the journal Science, mangrove trees won’t survive sea level rise by 2050 if greenhouse gas emissions aren’t reduced.  

Using sediment data from 78 locations over the last 10,000 years, an international team of scientists led by Macquarie University in Australia estimated the chances of mangrove trees survival based on the projected rates of future sea-level rise.

When sea level rise rates exceeded 6 millimeters per year, which is similar to estimates under high-emissions scenarios for 2050, researchers found that mangrove trees were unlikely to keep pace with the rising water levels.  But when the annual increase was 5 millimeters or less – which is the projected low-emissions scenario this century – mangrove trees are much more likely to survive. 

These findings underscore the importance of reducing greenhouse gas emissions to mitigate rapid sea level rise.  The future of mangrove trees may depend on it.  

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Mangrove trees won’t survive sea-level rise by 2050 if emissions aren’t cut

Photo, posted December 17, 2012, courtesy of Edward Stojakovic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Making Use Of Invasive Seaweed | Earth Wise

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In recent years, millions of tons of brown Sargassum seaweed have formed gigantic blooms stretching all the way across the Atlantic Ocean from West Africa to the Gulf of Mexico.  The seaweed has become a problem for shorelines in the Caribbean, the Gulf of Mexico, and the east coast of Florida.  The massive increase in seaweed populations is related to changes in ocean chemistry resulting from nutrients from fertilizer use entering the water as well as from changes to the climate affecting ocean currents and temperatures.  The seaweed is harming the tourism industry as well as fisheries and ocean ecosystems.

Cleaning up the seaweed that washes ashore is labor-intensive and therefore expensive.  A research team led by two British universities has developed a cheap and simple way to pre-process seaweed to facilitate making it into bulk chemicals and biofuels.  With the new process, cleaning up the seaweed can be both economically and environmentally viable.

Previous techniques for processing seaweed generally required removing it from the saltwater, washing it in fresh water, and drying it – all of which add significant costs.  The new technique makes use of catalysts to release sugars from untreated seaweed that feed a yeast to produce a palm oil substitute.  At the same time, the process creates heat and pressure, turning the residual materials into a bio-oil that can be processed further into fuels, and a high-quality, low-cost fertilizer.

Apart from getting economic value out of the seaweed that is collected, any plastic collected alongside the seaweed can be converted to useful materials as well. 

It appears that the seaweed scourge is here to stay, so finding an economically viable way to deal with it is a welcome development.

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Solve invasive seaweed problem by turning it into biofuels and fertilisers

Photo, posted August 10, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Heat-Resistant Coral | Earth Wise

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Coral reefs are in decline all over the world.  Corals are under increasing pressure as water temperatures rise and the frequency and severity of coral bleaching events increase.  Nowhere is this more evident than in Australia’s Great Barrier Reef system, where severe bleaching events have happened in three of the past five years. Long-term prospects for the survival of the world’s largest reef system are now considered to be poor.

A team of scientists at Australia’s national science agency – the Commonwealth Scientific and Industrial Research Organization – along with the Australian Institute of Marine Science and the University of Melbourne have successfully produced in a laboratory setting a coral that is more resistant to increased seawater temperatures.

The team made the coral more tolerant to temperature-induced bleaching by bolstering the heat tolerance of the microalgae symbionts that live inside the coral tissue.  They isolated the microalgae from coral and cultured it in the laboratory using a technique called “directed evolution”.  Over the course of four years, they exposed the microalgae to increasingly warmer temperatures.  When the heat-adapted strain of algae was reintroduced into coral larvae, the newly established coral-algal symbiosis was more heat tolerant than the original one.  The heat-tolerant microalgae are better at photosynthesis and improve the heat response of the coral animal.

The next step is to further test the algal strains in adult colonies across a range of coral species.  This groundbreaking research provides a promising and novel tool to increase the heat tolerance of corals and might potentially lead to a way to save the Great Barrier Reef as the world continues to warm.

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Scientists successfully develop heat resistant coral to fight bleaching

Photo, posted September 22, 2010, courtesy of NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Floating Turbines For Offshore Wind | Earth Wise

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Offshore wind is big in Europe.  There are more than 5,000 offshore wind turbines across 12 European countries with a total capacity of more than 22 gigawatts.  Almost every one of those turbines sits on a long tower sunk into the seabed and bolted into place in places where the water is 60 to 160 feet deep.

But off the coast of northern Scotland, there is the Hywind Wind Park which has five 574-foot-tall turbines located 15 miles offshore where the water is 300 feet deep.  The giant masts and turbines sit on buoyant concrete-and-steel keels that allow them to stand upright and float on the water like a giant buoy.  The giant cylindrical bases are held in place with mooring cables attached to anchors that sit on the seafloor.

A key advantage of floating turbines is that they can access outlying ocean waters up to half a mile deep, which is where the world’s strongest and most consistent winds blow.  Another advantage is that such turbines can be installed over the horizon, out of sight of coastal residents who might not like to have wind turbines visible in their scenic ocean views.

Floating wind power has enormous potential for contributing to the expansion of renewable energy.  Offshore wind is still quite a bit more expensive than land-based turbines, and the cost of electricity from distant floating turbines is more than that from near-shore wind turbines.   But all of these costs are likely to come down with improving technology and increased production volume.

There are real challenges to the expanded used of floating wind farms, but the promise of harnessing so much of the open seas for electricity generation is an attractive proposition.

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Will Floating Turbines Usher in a New Wave of Offshore Wind?

Photo, posted July 17, 2017, courtesy of Crown Estate Scotland via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Keeping Charleston Dry | Earth Wise

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Charleston, South Carolina is visited by millions of tourists each year.  The town is a glimpse into the past, showcasing antebellum mansions, row houses, historic African American churches and scenic harbor views from a Civil War-era promenade.

Charleston is also visited more and more by water from rising seas and increasingly powerful storms.  The city is essentially drowning in slow motion and may soon face an existential threat to its survival.

Charleston has a harbor and three rivers and water from all these sources leaks in at every bend and curve, fills streets, disrupts businesses, and rushes into homes during storms.  Million-dollar antebellum mansions, built on spongy marsh and old tidal creeks, flood repeatedly.

City officials have endorsed a plan by the U.S. Army Corps of Engineers to wall off the historic downtown with an 8-mile-long seawall that would cost nearly $2 billion.  The proposed barricade is just one of many proposed projects to build seawalls, surge gates, levees, and other barriers to defend U.S. coastal cities in an era of rising seas and climate-fueled floods and storms.  A proposed flood wall in Miami would cost federal taxpayers $8 billion.

Researchers generally agree that sea levels are likely to rise by at least 3 feet by the end of the century.  Some experts believe the rise will be much greater.  So, a key question is whether these barriers will actually keep out the water.  Critics of many of the proposed solutions contend that they are doomed to fail.

Flooding has caused nearly $1 trillion worth of damage along the East and Gulf coasts over the past 40 years.  And things are almost certain to get worse in Charleston and other coastal cities.

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Fortress Charleston: Will Walling Off the City Hold Back the Waters?

Photo, posted October 7, 2015, courtesy of Jeff Turner via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Planting Trees and Climate Change | Earth Wise

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Forests are among the most important natural carbon sinks.  Trees remove carbon from the air and store it in their trunks, branches, and leaves, and transfer part of it into the soil.  But in some regions, these natural carbon sinks are starting to weaken due to deforestation, forest degradation, and the impacts of climate change.  This problem has led some climate mitigation projects to focus on increasing the overall number of trees on the planet. 

But, according to a paper recently published in the journal Science, “we can’t plant our way out of climate change.”  That’s the simple message from Restoration Ecologist Karen Holl and University of São Paulo Professor Pedro Brancalion to anyone who thinks planting one trillion trees will reverse the effects of climate change.  They say planting more trees is only one piece of the puzzle.  Any initiatives like 1t.org or the Trillion Tree Campaign must be done carefully and be accompanied by commitments to long-term management.

Tree plantings can provide many environmental benefits, including improving water quality, biodiversity, and increasing shade.  But trees can sometimes have undesirable impacts, such as harming native species and ecosystems or reducing water availability, depending on where and how the trees are planted.

The authors suggest four principles that should guide forest enhancement initiatives: reduce forest clearing and degradation, balance ecological and social goals, view tree plantings as one part of a multifaceted solution, and plan, coordinate and monitor the work. 

While tree plantings can clearly be part of the solution, slowing the pace of climate change requires a comprehensive approach that must start with burning less fossil fuels.

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Challenges in tree-planting programs

Planting trees is no panacea for climate change

Photo, posted December 1, 2019, courtesy of Akuppa John Wigham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Recovering Marine Life By 2050 | Earth Wise

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Marine life has faced challenges for a long time.   There have been centuries of overfishing in many places and pollution of various types has been especially harmful in recent decades.   But despite all of this, a new scientific review published in the journal Nature contends that marine life in the world’s oceans could be fully restored in as little as 30 years provided that aggressive conservation policies are adopted.

The research spotlights the strong resiliency of ocean animals and cites the successful recovery of a number of marine species, including humpback whales.

The study indicates that nations around the world must agree to designate 20 to 30 percent of the oceans as marine protected areas, institute sustainable fishing guidelines, and regulate pollution.  These measures would not come cheaply.  The estimated cost would be around $20 billion a year. 

However, the report also estimates that the economic return on this investment would be tenfold and would create millions of new jobs.  Rebuilding fish stocks and maintaining sustainable fishing policies could increase global profits of the seafood industry by over $50 billion a year.  Conserving coastal wetlands could save the insurance industry more than $50 billion a year as well by reducing storm damage.

A major sticking point, however, is climate change.  Climate change is increasing ocean temperatures and driving acidification.  Unless these changes are brought under control, the restoration of marine life is not going to be successful.  We have reached the point where it is within our power to choose between a future with a resilient and vibrant ocean or an irreversibly disrupted ocean.  Whether we embrace that challenge remains to be seen.

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Marine Life Could Recover By 2050 With the Right Policies, Study Finds

Photo, posted April 20, 2012, courtesy of Matthias Hiltner via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protecting Fresh Produce | Earth Wise

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Fresh fruits and vegetables can sometimes become contaminated by microorganisms during their long journey from fields to restaurants and grocery stores.  Contaminated produce can spoil other produce, which increases the number of fruits and vegetables in the supply chain that can cause illnesses. 

In order to prevent this cross-contamination between produce, researchers from Texas A&M University have designed a coating that can be applied to food-contact surfaces, like buckets, rollers, and conveyor belts.  The newly-created dual-function coating is both water-repellent and germicidal.  In other words, it can both repel and kill.  Without water, the researchers say bacteria can’t stick or multiply on surfaces, drastically reducing contamination.

To make this dual-function coating, the researchers chemically-attached a thin layer of silica to an aluminum sheet.  They then added a mixture of silica and lysozyme, a naturally-occurring germicidal protein found in egg whites and tears.  Together, the silica-aluminum and the silica-lysozyme formed microscopic bumps and crevices.  According to the research team, this rough texture, albeit microscopic, is the key to the coating’s superhydrophobic properties.  

The researchers tested the coating’s effectiveness at curbing the growth of two strains of disease-causing bacteria:  Salmonella and Listeria.  Upon review, the number of bacteria found on the dual-coating surfaces was 99.99% less than what was found on the uncoated surfaces. 

Despite the success in preventing bacterial spread, the research team said more research needs to be done to see how well the coating works for mitigating viral cross-contamination.  Since the coating would need to be reapplied after a certain amount of use, the researchers also plan to develop more permanent, dual-function coatings. 

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New dual-action coating keeps bacteria from cross-contaminating fresh produce

Photo, posted April 14, 2012, courtesy of U.S. Department of Agriculture via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Conservation In Vermont | Earth Wise

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In recent times, Vermont and neighboring states have been losing forest land to development at a rate of almost 1,500 acres per year.  With forest fragmentation gaining ground across New England, conserving land for future generations of people, wildlife, and plants has become both increasingly important and increasingly difficult.

According to a new study published by researchers at the University of Vermont, the state has already protected a third of the highest priority targeted lands needed to protect and connect valuable wildlife habitats and corridors.  The protected lands amount to 1.3 million acres.

Most of the currently conserved lands are forested.  However, there are high-priority targeted surface water and riparian areas – ponds, rivers, shorelines, and wetlands – and not nearly enough of these have been protected.  (Many animals require zones along waterways in which to travel between the habitats they need to survive).

The state of Vermont and a number of partners have laid out a comprehensive and thoughtful vision that would ensure that Vermont remains a good place for all forms of life in the future.  The new study provides a crucial benchmark of current levels of forest protection to help prioritize future conservation actions. 

Three groups dominate in responsibility for the state’s protected lands:  the federal government, the state government, and private non-profit organizations.  (Each of these account for roughly a third of existing protected lands).

Going forward, Vermont’s nonprofits will play an increasingly important role in land conservation, especially in continuing to protect those areas that are rich with species diversity.  Nonprofits are engaging more and more deeply in restoring wetlands that were previously degraded, planting new forests along river shores, and protecting unique natural communities while also protecting working forests and farmland.

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Vermont Has Conserved One Third of the Land Needed for an Ecologically Functional Future

Photo, posted June 15, 2014, courtesy of Wesley Carr via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Coronavirus And European Energy | Earth Wise

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As people all over the world shelter in place and much ordinary commerce and other activities have ground to a halt, there have been big changes in energy usage.   With production halted, offices shut down, schools closed, and public transport operated on reduced timetables, the demand for energy has decreased dramatically.

In Europe, as a result of all this, during the first quarter of this year, renewables’ share of total energy production was greater than 60%.  Wind farms provided more than 40% of the renewables’ share of total electricity generation.   During February, Denmark, Germany and Ireland saw nearly 50% of their electricity demand met with wind power.  Hydroelectric power was the second largest source of renewable energy during the first quarter, with Norway providing the largest share of this.  In contrast, generation from nuclear plants was at its lowest first quarter figure for the past five years.

The large shift to renewable generation was in great part due to the overall reduction in demand.  This impacts nuclear and fossil-fuel generation much more than renewables because those plants can be throttled back or shut down entirely so as not to needlessly consume costly fuels.   Generation that runs on sunlight, wind, or flowing water does not require fuel expenses, so it makes sense to prefer them when demand is reduced.

The reduction in demand has in turn had a major effect on fuel costs as oil reached low prices that haven’t been seen in years.

The decline in demand and fuel prices and the enhanced role of renewables are expected to continue in the current quarter as the timetable for renewed economic activity remains unknown.

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Renewables achieve clean energy record as COVID-19 hits demand

Photo, posted June 25, 2010, courtesy of Martin Abegglen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Why The Arctic Is Warming So Fast | Earth Wise

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The Arctic has been warming at the fastest rate of any place on Earth.  There have long been observations of amplification of Arctic warming, meaning that its temperature increases have been well above what would be expected from the global temperature rise.

Many climate models have attributed this warming to the melting of sea ice.  As the bright white ice disappears for longer periods of the year, the dark surface waters that are exposed absorb sunlight rather than reflecting it back into space the way the ice does.  This is known as the ice-albedo feedback.  But it does not entirely explain the amount of warming in the Arctic.

Researchers at the Scripps Institution of Oceanography have developed a new theory that helps to explain what is going on.

In the areas of the Arctic Ocean where there is sea ice, the water is actually warmer at depth and colder near the surface.  The deeper waters are fed by the relatively warm Pacific and Atlantic Oceans while the surface water is cooled by the ice.  The increasing temperature difference between surface and deeper water causes a greater upward flow of heat.  This was first observed in research cruises that revealed evidence that the Arctic Ocean water was becoming more turbulent over time.

According to computer modeling, this phenomenon is responsible for about 20% of the amplification of global warming that occurs in the Arctic.

There are multiple ongoing studies looking at the Arctic warming trend.  Other factors that have contributed over time are the presence of chlorfluorocarbons in the atmosphere.   That contribution is waning since the use of CFCs has been phasing out over time.

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Researchers Find New Reason Why Arctic is Warming So Fast

Photo, posted April 19, 2017, courtesy of Markus Trienke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A New Membrane For Converting Carbon Dioxide | Earth Wise

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Methanol is a valuable chemical used as fuel in the production of countless products. Carbon dioxide is a greenhouse gas that is produced by countless industrial processes.  Carbon dioxide can be converted into methanol, which is one way all that CO2 can be put to good use instead of causing harm. 

In research recently published in Science, chemical engineers from Rensselaer Polytechnic Institute have developed a process that converts CO2 to methanol in a more efficient way by using a highly effective separation membrane they produced.  

The chemical reaction responsible for the transformation of CO2 into methanol also produces water, which severely restricts the continued reaction. The Rensselaer team has found a way to filter out the water as the reaction is happening, without losing other essential gas molecules. 

They produced a membrane made up of sodium ions and zeolite crystals that was able to carefully and quickly permeate water through small pores — known as water-conduction nanochannels — without losing gas molecules. The sodium ions effectively only allow water to go through. When water was effectively removed from the process, the team found that the chemical reaction was able to happen very quickly. By removing the water, the equilibrium shifts, which means more CO2 will be converted and more methanol will be produced.  

The team is now working to develop a scalable process and a startup company that would allow this membrane to be used commercially to produce high purity methanol.  This membrane could also be used to improve a number of other reactions. 

In industry there are many reactions limited by water and this RPI membrane could be an important enhancement for many of them. 

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Water-Conducting Membrane Allows Carbon Dioxide To Transform into Fuel More Efficiently

Photo courtesy of RPI.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar-Powered Desalination | Earth Wise

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About 1% of the world’s population is dependent on desalinated water to meet daily needs, but water scarcity is a growing problem that experts believe will affect 14% of the world’s population within the next five years.

Desalination takes much more energy than, for example, transporting fresh water over large distances.  In general, desalination costs are much higher than those associated with fresh water, but beyond costs, freshwater is simply not always available.

Researchers at MIT and Shanghai Jiao Tong University in China have developed a completely passive solar-powered desalination system that could provide more than 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area.   Such a system could provide an efficient, low-cost water source for coastal areas that are off the grid.

The system uses multiple layers of flat solar evaporators and condensers topped with transparent aerogel insulation.  The key to its efficiency is the way it uses each of its multiple stages to desalinate water.  At each stage, heat released by the previous stage is harnessed instead of wasted.  The proof-of-concept device, which was tested on an MIT building rooftop, produced more than twice as much water as the record amount produced by any previous passive solar-powered desalination system.

The researchers plan further experiments aimed at optimizing the choice of materials and configurations and to test the system under realistic conditions.  The hope is to have a technology that can play a role in alleviating water scarcity in parts of the world where electricity is scarce, but seawater and sunlight are abundant.

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Simple, solar-powered water desalination

Photo courtesy of MIT/researchers.

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.

Storing CO2 Underground | Earth Wise

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Capturing the carbon dioxide emitted from power plants and factories and safely storing it so it can’t enter the atmosphere has long been an attractive and desirable goal.  Even though the use of renewable energy sources has been expanding rapidly, it will still be a long time before fossil fuel plants go away entirely.

The most widely considered method of carbon capture and storage is underground storage.  The idea is to send the carbon dioxide through a pipeline to a place where underground rock formations can store it safely and permanently.  Typically, it would be pumped deep underground – often more than half a mile down – and the site would be monitored to make sure the CO2 doesn’t leak back up to the atmosphere or into the water table.

A new study looked at how much carbon dioxide the suitable geological formations on Earth can store.  The conclusion of the study is that drilling about 12,000 carbon storage wells globally could provide enough capacity to store 6 to 7 billion tons of CO2 a year by 2050.  That is about 13% of global emissions.

Drilling 12,000 wells is equivalent to the amount of oil and gas drilling that has taken place just in the Gulf of Mexico over the last 70 years.  The study identified locations worldwide that could handle the pressures associated with storing injected carbon dioxide.

So far, less than two dozen projects exist that capture and store carbon dioxide from fossil fuel plants.  In total, these plants can capture about 36 million tons a year, which is far less than what is needed.  But the new study at least shows that finding places to put captured carbon is not a problem.

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Ample Geological Capacity Exists to Store Large Quantities of Captured CO2

Photo courtesy of Equinor.

Earth Wise is a production of WAMC Northeast Public Radio.

American Households and Food Waste | Earth Wise

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Food waste is a big problem.  According to the United Nations, approximately one-third of the food produced globally – more than 1.4 billion tons – goes to waste.  If food waste was a country adding carbon to the atmosphere, it would be the world’s third largest emitter of greenhouse gases – behind only the U.S. and China.  All of this food waste takes place in a world where 815 million people – more than 10% of the people on the planet – are chronically undernourished.

A new study recently published in the American Journal of Agricultural Economics has analyzed the level of food waste for individual American households. It found that American households waste, on average, nearly one-third of all the food they acquire.  This wasted food has an estimated aggregate value of $240 billion annually.  Divided by the number of U.S. households, this food waste could be costing the average household about $1,866 per year. 

According to researchers, the households with higher household incomes generate more food waste.  Those with healthier diets, which include more perishable fruits and vegetables, also waste more food.  

Meanwhile, households with greater food insecurity, especially those that participate in the federal SNAP food assistance program, as well as those households with a larger number of members, were associated with less food waste.  Households that use shopping lists and those that travel further to reach the grocery store were also associated with lower levels of food waste. 

When food is wasted, the resources used to produce food, including land, energy, water and labor, are wasted as well.  We have to do better. 

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SAVE FOOD: Global Initiative on Food Loss and Waste Reduction

US households waste nearly a third of the food they acquire

Photo, posted March 22, 2009, courtesy of Nick Saltmarsh via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Harvesting Blue Energy | Earth Wise

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There are various ways to generate renewable energy from the world’s oceans, most obviously from the power of tides and waves.  But there is also an oceanic energy source called osmotic or “blue” energy.  Osmotic energy uses the differences in pressure and salinity between freshwater and saltwater to generate electricity. 

When freshwater and saltwater are mixed together, large amounts of energy are released. If the freshwater and seawater are then separated via a semi-permeable membrane, the freshwater will pass through the membrane and dilute the saltwater due to the chemical potential difference. This process is called osmosis. If the salt ions are captured completely by the membrane, the passing of water through the membrane will create a pressure known as osmotic pressure. This pressure can be used to generate electricity by using it to drive a turbine.  This has been demonstrated to work as far back as the 1970s, but the materials we have to use are not adequate to withstand ocean conditions over the long term and tend to break down quickly in the water.

New research, published in the journal Joule, looked to living organisms for inspiration to develop an improved osmotic energy system.  Scientists from the U.S. and Australia combined multiple materials to mimic the kind of high-performance membranes that are found in living organisms.  They created a hybrid membrane made from aramid microfibers (like those used in Kevlar) and boron nitride.  The new material provides both the flexibility of cartilage and the strength and stability of bone.

The researchers believe that the low cost and high stability of the new hybrid membrane will allow it to succeed in volatile marine environments.  They also expect the technology will be both efficient and scalable. 

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Inspired by the Tissues of Living Organisms, Researchers Take One Step Closer to Harvesting “Blue Energy”

Photo, posted February 14, 2017, courtesy of Marian May via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Rising Threat Of Rising Seas | Earth Wise

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Global sea level rose by about 6 inches during the 20th century.  It is currently rising more than twice as fast and accelerating.  The rate of rise was 2.5 times faster from 2006 to 2016 than it was for nearly all of the 20th century.

Sea level rise occurs when glaciers and ice sheets lose mass.  Much of that meltwater comes from Greenland and Antarctica.  But levels also rise because, as water warms, it expands.  Added to that are the effects of human activities such as groundwater depletion and a geological phenomenon called isostatic adjustment that is going on in parts of the East Coast where the land is actually sinking.

In Atlantic Canada, sea level rise is outpacing the global average and has already led to boardwalks swamped by swelling tides, drowned forests, submerged wharfs, and threatened historic shoreline buildings.

Recent research suggests that globally, land now occupied by 300 million people could be affected by floods at least once a year by 2050 unless carbon emissions are significantly reduced, and coastal defenses strengthened.  (This new figure is more than three times higher than earlier estimates).

Researchers at Dalhousie University in Nova Scotia are studying nature-based strategies for mitigating the effects of the rising seas.  These include conserving or restoring coastal ecosystems like dunes, wetlands, and reefs which could provide protection at a lower cost than building seawalls and other man-made obstacles.  Wetlands, for example, can reduce the force of waves and act as obstacles to storm surges, while also trapping sediment and stemming erosion.  Wetlands also serve as important carbon stores, but it is estimated that roughly half of the world’s coastal wetlands have been lost over the past 100 years to human activity and extreme weather events.

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The Looming Threat of Rising Sea Levels – And What We Can Do About it

Photo, posted February 14, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Converting A Toxin Into An Industrial Chemical | Earth Wise

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Nitrogen dioxide is a prominent air pollutant produced by internal combustion engines burning fossil fuels as well as by a variety of industrial processes.  It is a toxic material associated with a number of respiratory illnesses. 

Researchers at the University of Manchester in the UK along with an international team of scientists have developed a new advanced material that can convert nitrogen dioxide from an exhaust gas stream into useful industrial chemical using only water and air.

The material is a metal-organic framework (or MOF) that provides a selective, fully reversible, and repeatable capability to capture nitrogen dioxide.  MOFs are tiny three-dimensional structures that are porous and can trap gases inside as though there were tiny cages.  MOFs have enormous amounts of surface area for their size.  One gram of material can have a surface area as large as a football field.

The material, named MOF-520, can capture nitrogen dioxide at ambient temperatures and pressures and even at low concentration and during flow in the presence of moisture, sulfur dioxide, and carbon dioxide.  Such conditions are typical of the exhaust of internal combustion engines. In fact, the process works best at the typical temperature of automobile exhausts.

Once the nitrogen oxide is absorbed, treating the material with water in air converts it into nitric acid and restores the MOF for additional use.  Nitric acid is the basis of a multi-billion dollar industry with uses including agricultural fertilizers, rocket propellant, and nylon.  Thus, there is great potential for recouping the costs of using the MOF technology and even profiting from it.

It would be great to convert a toxic pollutant into valuable industrial chemicals.

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Clean air research converts toxic air pollutant into industrial chemical

Photo courtesy of the University of Manchester.

Earth Wise is a production of WAMC Northeast Public Radio.

Road Salt Pollution

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Mirror Lake is a popular recreational lake located in the Village of Lake Placid.  It is the most developed lake within the Adirondack Park, which is a publicly protected area that is actually larger than Yellowstone, Yosemite, Glacier, and Grand Canyon National Parks combined.

New research has revealed that road salt runoff into Mirror Lake is preventing natural water turnover which poses a risk to the balance of its ecology.  The study, which was published in Lake and Reservoir Management, found that road salt runoff is preventing spring mixing of the water column.    This creates more anoxic water conditions, meaning there is less oxygen in the water, and limits the ability of the habitat to support the native lake trout. 

Mirror Lake is the first lake in the Adirondack Park to show an interruption in lake turnover due to road salt.  Many lakes in northern climes experience so-called “dimictic turnover”, which is a natural process where wind and less stratified water conditions of spring and fall allow mixing of the water column that redistribute oxygen and nutrients throughout the lake.  High levels of surface-water chloride introduced into the lake from road salt runoff inhibit the mixing of the water column.

The lack of mixing and oxygenation is bad news for fish species such as lake trout, which require cold, oxygenated water to survive.  It may also put the lake at a greater risk of algal blooms.

Mirror Lake is small, surrounded by concentrated development, and receives the direct discharge of stormwater.  So, it is particularly vulnerable to road salt contamination.  Other lakes elsewhere in New York may experience similar conditions.  The researchers are confident that natural turnover conditions could be restored to the lake if road salt application in the watershed is reduced.

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Road salt pollutes lake in one of the largest US protected areas, new study shows

Photo, posted January 5, 2018, courtesy of MTA of the State of NY via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)