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Some Good News For The Great Barrier Reef | Earth Wise

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It seems like there has been nothing but dire news from Australia’s Great Barrier Reef.  Earlier this year, there was yet another mass bleaching event – the fourth in seven years and the first ever to strike during a cooler La Niña phase in the Pacific.  But this bleaching event was less severe than other recent ones, which makes it possible for parts of the reef to bounce back.

In particular, in the northern and central stretches of the reef, scientists have recorded the most extensive coral cover seen in 36 years of study.  In areas where coral cover has expanded, it is mostly fast-growing Acropora corals driving the growth.  That isn’t the best outcome, given that Acropora are particularly vulnerable to strong waves, highly susceptible to bleaching, and are the preferred target of crown-of-thorns starfish.

Those creatures are a major problem for the Great Barrier Reef.  In contrast to the upper stretches of the reef, the southern third actually saw coral cover drop from 38 to 34 percent over the course of the past year.  Scientists blame the decline on an outbreak of crown-of-thorns starfish, which prey on corals.  The starfish grow faster and eat more in warmer, more acidic waters.   Carbon emissions are both raising ocean temperatures and turning waters more acidic.

The large increases in hard coral cover in the reef are certainly good news, but it is important to understand that they can be quickly negated by disturbance on reefs where Acropora corals predominate.  Warming temperatures and mass bleaching events continue to pose a critical threat to all reefs, especially when there are crown-of-thorns starfish outbreaks and increasing frequency of tropical cyclones.

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Parts of Great Barrier Reef See Most Extensive Coral Cover In 36 Years

Photo, posted July 15, 2019, courtesy of Kenneth Lu via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Great Salt Lake Is Disappearing | Earth Wise

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Utah’s Great Salt Lake is the largest saltwater lake in the western hemisphere.  According to data from the US Geological Survey, the surface water elevation of the Great Salt Lake has fallen to the lowest level since records began in the mid-1800s.  The average elevation is now 4,190 feet above sea level.   With this drop in water level, the surface area of the lake is little more than half of its historical size.  The lower water level has exposed about 700 square miles of previously submerged lakebed.

The lake now contains about a quarter of the volume of water that it did at its high point in 1987.  The precipitous drop in water is a result of water usage from the lake coupled with climate change-fueled drought.   Increased water demand is due to the rapidly growing population of metropolitan Salt Lake City.  Utah’s population is projected to increase by almost 50% by 2060.

The Great Salt Lake goes though seasonal cycles of water loss and replenishment.  Rain and snow generally refill its level.  However, because of the ongoing megadrought in the West, water evaporation and depletion continue to exceed the amount of water entering the lake.  The water levels are expected to further decrease until fall or early winter, when incoming water is expected to equal or exceed evaporation.

The decline of the Great Salt Lake is a serious threat to the economy, ecology, and people of northern Utah.  The lake generates snowpack, is a refuge for hundreds of migratory birds and other wildlife and generates millions of dollars in the economy through mineral extraction and tourism.

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Utah’s Great Salt Lake is disappearing

Photo, posted October 6, 2020, courtesy of Julie Girard via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cleaning Up Forever Chemicals | Earth Wise

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PFAS, per- and polyfluoroalkyl substances, are chemical pollutants that threaten human health and ecosystem sustainability.  They are used in a wide range of applications including food wrappers and packaging, dental floss, firefighting foam, nonstick cookware, textiles, and electronics.  Over decades, these manufactured chemicals have leached into our soil, air, and water.  Chemical bonds in PFAS molecules are some of the strongest known, so the substances do not degrade easily in the environment.

Studies have shown that at certain levels, PFAS chemicals can be harmful to humans and wildlife and have been associated with a wide variety of health problems.

Currently, the primary way to dispose of PFAS chemicals is to burn them, which is an expensive multistep process.  Even trace levels are toxic, so when they occur in water in low amounts, they need to be concentrated in order to be destroyed.

Researchers at Texas A&M University have developed a novel bioremediation technology for cleaning up PFAS.  It uses a plant-derived material to absorb the PFAS which is then eliminated by microbial fungi that literally eat the forever chemicals.

The sustainable plant material serves as a framework to adsorb the PFAS.  That material containing the adsorbed PFAS serves as food for the fungus.  Once the fungus has eaten it, the PFAS is gone. 

The EPA has established a nationwide program to monitor the occurrence and levels of PFAS in public water systems and is considering adding PFAS threshold levels to drinking water standards.  If this happens, the technology developed at Texas A&M may become an essential part of municipal water systems.

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Texas A&M AgriLife develops new bioremediation material to clean up ‘forever chemicals’

Photo, posted August 10, 2013, courtesy of Mike Mozart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Lithium Mining And The Environment | Earth Wise

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The Salar de Atacama in Chile is a large, dry salt flat surrounded by mountain ranges and is one of the driest places on Earth. Parts of the Atacama Desert have gone without rain for as long as people have been keeping track. Water rich in dissolved salts lies beneath this flat surface and it is particularly rich in lithium salts.  Forty percent of the world’s known lithium deposits are the in the Salar.

Lithium is the key component of the batteries that power electric cars as well as cell phones and computers.  It is an essential part of the transition away from fossil fuels and towards green energy.  But it is important that this element is obtained responsibly with minimal damage to the environment.

Lithium, the lightest of the metals, tends to occur in layers of volcanic ash, but reacts quickly with water.  It leaches into groundwater and settles in flat basins where it remains in a briny solution.  This dense brine often ends up beneath pockets of fresh surface water, which are havens for fragile ecosystems.

A new study by the University of Massachusetts Amherst looked at the hydrological impact of lithium mining in the Salar.  The study found that the impact of lithium mining depends critically on how long surface water is in place.  Much of the fresh water there is at least 60 years old.  Both droughts and extreme rainfall can cause major changes to the surface water that ordinarily comes from mountain runoff.  Lithium mining itself only accounts for less than 10% of freshwater usage in the Salar. But the state of the surface water needs to be carefully monitored to protect the ecosystems as the climate continues to change.

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How environmentally responsible is lithium brine mining? It depends on how old the water is

Photo, posted February 21, 2016, courtesy of Jorge Pacheco via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Building Resilient Food Systems | Earth Wise

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According to the United Nations and The World Bank, global hunger levels in 2021 surpassed the previous record set in 2020.  The organizations also found that acute food insecurity – defined as when a person’s inability to consume adequate food puts their lives or livelihoods in immediate danger – could continue to worsen this year in many countries around the world. 

According to a new study led by researchers from the University of Colorado Boulder, increased demand for water will be the biggest threat to food security during the next 20 years, followed closely by heat waves, droughts, income inequality, and political instability.  

The report, which was recently published in the journal One Earth, calls for increased collaboration to build a more resilient global food supply.  The impacts of conflict and climate change are already measured and studied around the world.  While these pressing threats are not new, the researchers found that better collaboration between these areas of research could fortify and strengthen global food security. 

In 2019, before the COVID-19 pandemic, the researchers surveyed 69 experts in various fields related to food security.  They found that many effects of climate change – such as unpredictable weather changes – could have the greatest negative impacts on food security.  The researchers also found that threats to food security from income inequality, global price shocks, and political instability and migration are highly likely during the next two decades.  More than half of the world’s food insecure populations also live in conflict-prone regions.

According to the research team, food security has never been a problem of production.  It’s a problem of distribution, access, and poverty, and can be exacerbated by conflict.   

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Amid climate change and conflict, more resilient food systems a must, report shows

Photo, posted July 19, 2009, courtesy of Danumurthi Mahendra via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Progress On Artificial Photosynthesis | Earth Wise

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Photosynthesis is the process by which plants use the energy from sunlight to turn water and carbon dioxide into biomass and ultimately the foods we and other organisms eat.  Scientists at the University of California Riverside and the University of Delaware have found a way to create food from water and carbon dioxide without using biological photosynthesis and without needing sunlight.

The research, recently published in the journal Nature Food, uses a two-step electrocatalytic process to convert carbon dioxide, electricity, and water into acetate, which is the primary component of vinegar.   Food-producing microorganisms then consume the acetate in order to grow.   Solar panels are used to generate the electricity to power the electrocatalysis.  The result is a hybrid organic-inorganic system that is far more efficient in converting sunlight into food than biological photosynthesis.

The research showed that a wide range of food-producing organisms can be grown in the dark directly on the acetate output of the electrolyzer.  These include green algae, yeast, and the fungal mycelium that produce mushrooms.   Producing algae with this technology is about 4 times more energy efficient than growing it with photosynthesis.  Yeast production is about 18 times more energy efficient than the typical method of cultivating it using sugar extracted from corn.

Artificial photosynthesis has the potential to liberate agriculture from its complete dependence on the sun, opening the door to a wide range of possibilities for growing food under the increasingly difficult conditions imposed by the changing climate.

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Artificial photosynthesis can produce food without sunshine

Photo, posted September 7, 2016, courtesy of Kevin Doncaster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Environmental DNA | Earth Wise

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Marine protected areas are sections of the ocean where governments place limits on human activity.  They are intended to provide long-term protection to important marine and coastal ecosystems.  MPAs are important because they can protect depleted, threatened, rare, and endangered species and populations.

In January 2020, the Republic of Palau in the western Pacific Ocean created one of the world’s largest marine protected areas.  The Palau National Marine Sanctuary covers 80% of the country’s economic zone and prohibits all extractive activity like fishing and mining over a 183,000 square mile area in order for the island nation to ensure its food security and grow its economy in the face of climate change.

The Marine Sanctuary is an ambitious enterprise.  The question is how Palau can evaluate whether and how well it is working?

A team of scientists from Stanford University and Palau-based colleagues are making use of Environmental DNA – or eDNA – technology to monitor the large-scale marine protected area.  eDNA is the cells, waste, viruses, and microorganisms that plants and animals leave behind.  Samples of marine eDNA effectively provide a fingerprint of the organisms that have recently passed through the water in a given area.  This gives scientists a way to assess an ecosystem’s biodiversity and keep track of the types of species inhabiting a specific area.  Using eDNA, it is possible to keep track of all the  organisms that live below the surface and learn about things we can’t even see.

The team has embarked on a program of periodic sampling of the waters off Palau and hope to be able to monitor the results of establishing the Marine Sanctuary.

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eDNA: Bringing biodiversity to the surface

Photo, posted June 12, 2013, courtesy of Gregory Smith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mangrove Forests And Climate Change | Earth Wise

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Mangrove forests play a vital role in the health of our planet.  These coastal forests are the second most carbon rich ecosystems in the world.  A patch of mangrove forest the size of a soccer field can store more than 1,000 tons of carbon. It does this by capturing carbon from the air and storing it in leaves, branches, trunks, and roots.

Mangrove forests only grow at tropical and subtropical latitudes near the equator because they cannot withstand freezing temperatures.  These forests can be recognized by their dense tangle of prop roots that make the trees look like they are standing on stilts above the water.  These roots allow the trees to handle the daily rise and fall of tides.  Most mangroves get flooded at least twice a day.  The roots also slow the movement of tidal waters, which allows sediments to settle out of the water and build up on the muddy bottom.  Mangrove forests stabilize coastlines, reducing erosion from storms, currents, waves, and tides.

A new study by the University of Portsmouth in the UK looked at the effects of climate change on how carbon is stored in mangrove forests.  In mangrove ecosystems, a variety of organisms break down fallen wood.  These include fungi, beetle larvae, and termites.  Closer to the ocean, clams known as shipworms degrade organic material.

Climate change is disrupting these processes in at least two ways.  Rising sea levels are changing the way sediments build up and increased ocean acidity is dissolving the shells of marine organisms like shipworms.

Mangrove forests are crucial to mitigating climate change, and changes to the functioning of the carbon cycle of those ecosystems are a threat to their ability to perform that function.

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Study Reveals How Climate Change Can Significantly Impact Carbon-Rich Ecosystem

Photo, posted March 24, 2014, courtesy of Daniel Hartwig via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bidding ‘Adieu’ To Single-Use Plastics | Earth Wise

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Since the 1950s, more than nine billion tons of plastic have been produced, and 50% of that has been during the past 15 years.  While there are some use cases for plastic that are important, it generally serves as the poster child of our throwaway culture.

Plastic pollution can be found everywhere on earth, from the top of the tallest mountains to the bottom of the deepest oceans.  It’s in our food, water, and air. 

By 2040, researchers predict that there will be nearly 90 million tons of plastic pollution entering the environment each year.  By some estimates, single-use plastics account for half of all our plastic waste.    

Many cities, states, and even countries are limiting or even banning single-use plastics.  Canada recently announced a ban on single-use plastics.  The ban includes things like plastic shopping bags, cups, cutlery, straws, stirrers, and take-out food containers.

The ban will phase in over the next several years, beginning with a ban on the manufacture and import of single-use plastics by the end of this year.  Sales of these items will be prohibited in 2023, and the export of plastics will cease by the end of 2025.  

Canada’s southern neighbor, the United States, leads the world in plastic waste generation.  While some states have approved single-use plastic reforms, most of the effort at the federal level has focused on improving recycling rates.  However, a recent report from several environmental organizations found that plastic recycling rates in the U.S. have actually declined in the last several years, from an already-dismal 8.7% to less than 6%.    

Suggesting the plastic waste problem can be solved with improved recycling rates is greenwashing the issue. 

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Canada is banning single-use plastics, including grocery bags and straws

Photo, posted October 31, 2011, courtesy of Mara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Resilient Microalgae | Earth Wise

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The plight of the world’s coral reefs has been a growing environmental crisis for many years.  Coral reefs provide sustenance and income to half a billion people, are major tourist attractions, protect coastlines, and are important centers of biodiversity.   And because of the warming climate as well as other effects of human activity, more than half of the world’s coral reefs are under stress.

The primary threat is coral bleaching, which is the disruption of the symbiotic relationship between coral polyps (which are tiny animals) and the heavily pigmented microalgae that live within the coral structures and provide most of the energy for the polyps. When corals are stressed, often because water temperatures are too high, they expel the microalgae within them.  The structures then become transparent, leaving only the white skeletal corals.  Bleached corals aren’t dead, but they are at great risk of starvation and disease until and unless new symbiont algae are acquired.

A new study by scientists at Uppsala University in Sweden investigated how different species of coral symbiont algae react to temperature stress.  They discovered differences among symbiont cells that enable the prediction of how temperature stress tolerant the cells are.  Such predictive ability could provide the means to identify and select more temperature-tolerant coral symbionts that could conceivably be introduced into coral host larvae in order to make corals more robust against climate change.

The research has a ways to go, but the new tools may help coral reef monitoring and increase the speed at which reef restoring efforts can create stocks of climate-resistant symbionts.

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Climate resilient microalgae could help restore coral reefs

Photo, posted September 28, 2009, courtesy of Matt Kieffer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Less Phytoplankton In The Gulf Of Maine | Earth Wise

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Phytoplankton, also known as microalgae, are the base of the marine food web and also play a key role in removing carbon dioxide from the air.  They are eaten by primary consumers like zooplankton, small fish, and crustaceans. 

Phytoplankton, like land plants, absorb carbon dioxide from the atmosphere and use photosynthesis to grow.  Then they become a food source for other organisms and ultimately for people who depend upon marine ecosystems.   If phytoplankton productivity is disrupted, there can be adverse effects on regional fisheries and the communities that depend on them.

The Gulf of Maine is becoming warmer and saltier, because of ocean currents pushing warm water into the gulf from the Northwest Atlantic.  These temperature and salinity changes have led to a significant decrease in the productivity of phytoplankton.   According to a new paper from scientists at Bigelow Laboratory of Ocean Sciences in Maine, phytoplankton are about 65% less productive in the gulf than they were 20 years ago.

The study’s results come from the analysis of the Gulf of Maine North Atlantic Time Series, a 23-year sampling program of the temperature, salinity, chemical, biological, and optical measurements of the gulf.  The scientists refer to what they describe as a giant windmill effect happening in the North Atlantic, which is changing the circulation of water coming into the Gulf of Maine.  In the past, inflows from the North Atlantic brought water from the Labrador Current, which made the gulf cooler and fresher.  The new circulation is making the water warmer and saltier.

These changes have significant implications for higher marine species, fisheries, the lobster industry, and other activities in the states that border the Gulf of Maine.

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NASA-funded Study: Gulf of Maine’s Phytoplankton Productivity Down 65%

Photo, posted November 15, 2015, courtesy of Paul VanDerWerf via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Removing Lead From Water With Beer Yeast | Earth Wise

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Lead and other heavy metals in water are a serious global problem that is worsening because of electronic waste and discharges from mining operations.  In the U.S., over 12,000 miles of waterways are impacted by mine-drainage water that is rich in heavy metals.

Lead in particular is highly toxic, especially to children.  The European Union established a standard for allowable lead in drinking water of only 5 parts per billion.  In the US, the EPA has declared that no level of lead at all is safe.

Researchers at MIT have recently discovered that inactive yeast can be effective as an inexpensive, abundant, and simple material for removing lead contamination from drinking water supplies.  The MIT study shows that the method works even at parts-per-billion levels of contamination.

The method is called biosorption, in which inactive biological material is used to remove heavy metals from water.  Previously, it has been studied at parts-per-million contaminant levels, but the MIT study shows that it works at much lower levels as well.

The team studied a type of yeast widely used in brewing.   The yeast cells used are inactive and desiccated and require no special care.  Such yeast is abundantly available as a waste product from beer brewing and various other fermentation-based industrial processes. 

The researchers estimate that to clean a water supply for a city the size of Boston would require about 20 tons of yeast a day, or 7,000 tons a year.  That seems like a lot, but one single brewery, the Boston Beer Company, generates 20,000 tons a year of surplus yeast that is no longer useful for fermentation.

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Could used beer yeast be the solution to heavy metal contamination in water?

Photo, posted September 5, 2017, courtesy of Allagash Brewing via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reshaping Our Planet | Earth Wise

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Human activity – especially agriculture – has altered 70% of the land on our planet.  According to a new report from the United Nations, damage to the Earth’s lands has put the planet on “crisis footing”.

Our health, our economy, and our well-being depend on land.  The food we eat, the water we drink, and the air we breathe all rely on status of the land to at least some extent.

According to the report, up to 40% of the planet’s land is already degraded, affecting half of the people alive today.  At current rates, an additional area nearly the size of South America will be degraded by 2050.

Degradation of land occurs in various ways, including deforestation, desertification, and the loss of wetlands or grasslands.  All of these things are caused by human activities.  As forests, savannas, wetlands, and mangrove swamps are converted to agriculture or are lost to urban expansion, greenhouse gas emissions rapidly increase, adding to the effects of climate change.  The climate crisis, biodiversity loss, and land degradation are integrally linked.

Much of the blame for degraded landscapes is on humanity’s ever-expanding need for food and the modern farming systems that produce it.  The global food system is responsible for 80% of the world’s deforestation, 70% of freshwater use, and is the greatest driver of land-based biodiversity loss.  Modern agriculture has altered the face of the planet more than any other human activity.

The report urges efforts at restoration of land.  Restoration can take multiple forms, including planting forests and shrubs or grazing livestock and growing crops between trees instead of clearing existing forests.

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UN Report Says Humanity Has Altered 70 Percent of the Earth’s Land, Putting the Planet on a ‘Crisis Footing’

Photo, posted June 20, 2010, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Marine Predation And Climate Change | Earth Wise

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Climate change is taking a toll on forests, farms, freshwater resources, and economies all around the world.  But ocean ecosystems remain the center of global warming.

Despite their vast ability to absorb heat and carbon dioxide, oceans are warming.  In fact, according to scientists, the oceans have absorbed 90% of all the warming that has occurred during the past 50 years. 

The ocean’s surface layer, which is home to most marine life, takes most of this heat.  As a result, the top 2,300 feet of global ocean water has warmed approximately 1.5°F since 1901.

Well it turns out that a hotter ocean is also a hungrier ocean.  According to a new study recently published in the journal Science, researchers discovered that predator impacts in the Atlantic and Pacific oceans peak at higher temperatures.  The effects of more intense marine predation could disrupt ecosystem balances that have existed for millennia. 

An international research team led by the Smithsonian Institution and Temple University analyzed predator and prey data collected from 36 sites, running along the Atlantic and Pacific coasts from Alaska in the north to Tierra de Fuego at the tip of South America.  The research team found that, in warmer waters, predators’ more voracious appetites left outsized marks on the prey community.  Total prey biomass plunged in warmer waters when prey were left unprotected.  However, in the coldest zones, leaving prey exposed or protected made nearly no difference at all.  

As the oceans continue to warm, more intense predation will create winners and losers and could jeopardize the overall health of marine ecosystems.  

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As the ocean heats up hungrier predators take control

Photo, posted July 14, 2017, courtesy of Jonathan Chen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Methane From Thawing Permafrost | Earth Wise

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The Arctic permafrost contains a massive amount of carbon in the form of frozen soil, which contains remnants of plants and animals that died millennia ago.  Estimates are that there is 2 ½ times as much carbon trapped in this Arctic soil than there is in total in the atmosphere today.

As the Arctic warms, the permafrost is starting to thaw.  Once that happens, microbes begin to consume the previously frozen organic matter trapped in the soil.  As part of this process, the microbes produce large amounts of methane, which is an extremely potent greenhouse gas.   Thus, there continues to be great concern that wide-scale thawing of the permafrost would result in massive amounts of methane being released into the atmosphere.

A recent study in northern Sweden revealed a glimmer of hope.  The study gauged methane emissions from a swath of permafrost that thawed in the 1980s and another that thawed 10 or 15 years later. 

In the first area, as ice melted underground, water on the surface sank down into the soil.  As the surface dried out, new plants emerged that helped to keep methane emissions buried underground.

Grasses found in wet areas have straw-like structures that convey oxygen to their roots.  The straws also allow methane in the soil to escape into the atmosphere.  As the areas dry out, other plants lacking the straws can sometimes replace the grasses.  When methane can’t escape, soil bacteria break it down into carbon dioxide.

The result is that the permafrost releases only a tenth of the methane as expected.  The hope is that changes in plant cover driven by climate change may limit methane emissions from thawing permafrost.

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Thawing Permafrost In Sweden Releases Less Methane Than Feared, Study Finds

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

Earth Wise is a production of WAMC Northeast Public Radio.

Air Pollution: The Greatest Danger | Earth Wise            

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The effort to reduce and ultimately eliminate the use of fossil fuels has largely been driven by the potentially catastrophic consequences of global climate change.  The need to stop dumping greenhouse gases into the atmosphere has become increasingly urgent.  But there is an equally compelling reason to stop burning fossil fuels.  According to a study published in the journal Lancet Planetary Health, outdoor air pollution is “the largest existential threat to human and planetary health.”

Pollution of various types was responsible for an estimated 9 million deaths around the world in 2019.  Half of those fatalities – 4.5 million deaths – were the result of outdoor air pollution coming from vehicles and industrial sources like power plants and factories.

The number of deaths attributed to air pollution has increased by 55% just since the year 2000.

The growth in air pollution deaths has offset a decline in deaths from other pollution sources that especially affect people living in extreme poverty, such as indoor air pollution and water pollution.  Overall, countries with lower collective incomes tend to bear a disproportionate share of pollution deaths.  Roughly 16% of deaths around the world are attributable to pollution, also resulting in more than $4 trillion in economic losses.

The peer-reviewed study was produced by the 2017 Lancet Commission on Pollution and Health.  The study notes that despite the enormous health, social, and economic impacts of pollution, preventing it is largely overlooked in the international development agenda.  The study calls upon governments, businesses, and other entities to abandon fossil fuels and adopt clean energy sources.

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Study Identifies Outdoor Air Pollution as the ‘Largest Existential Threat to Human and Planetary Health’

Photo, posted November 4, 2019, courtesy of Ninara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Sounds Of Coral Reefs | Earth Wise          

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Coral reefs around the world face multiple threats from climate change, pollution, and other impacts of human activity.  Reef conservation and restoration projects must be able to monitor the health of reefs and that is not such a simple matter.  Surveying reefs generally is labor-intensive and time consuming.  But in a new study, scientists at the University of Exeter in the UK have found a new way to do it.

The fish and other creatures living on coral reefs produce a vast range of sounds.  The meaning of these various sounds is for the most part unknown, but reefs nonetheless have distinctive sonic signatures.

The Exeter researchers decided to make use of machine learning technology.  They trained a computer algorithm using multiple recordings of both healthy and degraded coral reefs.  This essentially taught the computer to learn the difference between them.  A computer can pick up patterns that are undetectable to the human year.  This application of artificial intelligence can tell us faster and more accurately how a reef is doing.

The computer was then used to analyze a set of new recordings, and successfully identified reef health 92% of the time.  The team then was able to use this technique to track the progress of reef restoration efforts.

It is generally much cheaper and easier to deploy an underwater hydrophone on a reef and leave it there instead of having expert divers make repeated visits to a reef to survey its status.  Sound recorders and artificial intelligence could be used around the world to monitor the health of coral reefs and determine whether efforts to protect and restore them are working.

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AI learns coral reef “song”

Photo, posted January 11, 2015, courtesy of Falco Ermert via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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.

Life In The Great Pacific Garbage Patch | Earth Wise

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The world’s oceans contain five gyres, which are large systems of circular currents created by global wind patterns and the Earth’s rotation.   Gyres act like gigantic whirlpools.  Anything that floats into one of them eventually ends up in the center.   Ever since floating plastic waste started entering the ocean, it has poured into these gyres and created so-called garbage patches.  The largest of these is the Great Pacific Garbage Patch, located halfway between Hawaii and California.  According to the Ocean Cleanup Foundation, the Great Pacific Patch contains at least 79,000 tons of plastic.

A recent study has shown that the garbage patch is not just a place where drifting plastics aggregate; it is also a place where drifting animals aggregate.

It turns out that the Great Pacific Garbage Patch is absolutely teeming with life, primarily small surface-dwelling animals that are collectively known as neuston.  A ship surveying the garbage patch found that in some places, there were nearly as many neuston as there are pieces of plastic.

Typical creatures in the patch are blue dragon nudibranchs, Portuguese man-o-wars, anemones, sea snails, blue buttons (which are related to jellyfish) and hydrozoans.  It appears that these creatures are reproducing within the garbage patch.  Little is actually known about the life history and ecology of these creatures, so that studying the garbage patch is offering valuable insights to scientists.

Two nonprofit organizations are working to remove floating plastic from the Great Pacific Garbage Patch.  Evidently, removing this existing pollution from the ocean is likely to have unexpected effects on the local ecosystem and is a source of at least some controversy.  One thing that isn’t controversial, however, is that we need to stop the flow of plastic into the ocean.

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The Ocean’s Biggest Garbage Pile Is Full of Floating Life

Photo, posted in April, 2012, courtesy of Steven Guerrisi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Scourge Of Salt | Earth Wise

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Rising seas are increasing saltwater intrusion on land and rising temperatures are causing greater evaporation.   The result is mounting levels of salt in waters and in soils.

Rising sea levels cause salty ocean water to push further into river deltas.  There is already a surge in saltiness across all inhabited continents.   Seawater works its way further upstream when dams hold back water.  Pumps that remove fresh water from underground sources for irrigation and drinking supplies add to the problem.  In dry regions, irrigation systems delivering water to crops increasingly bring salt onto fields.

People add to the problem by pouring saline drainage water from mines into rivers and by using salt to de-ice roads in the winter.

A modeling study pinpointed hotspots for climate change-induced salinization in numerous locations including the U.S. Southwest, wide areas of Australia, Mexico, South Africa, Brazil, central India, northern China, and more.

Some ecosystems are adapted to saline environments but major alterations in the balance between saline and fresh water is creating growing problems for ecosystems, lake fisheries, crop growing, and even human health.

The damage caused by salt is likely to be so severe that salinization will become a major cause of environmental refugees when the land they live on can no longer sustain them. 

Salt will be a growing threat to the world’s food supplies, especially where farmers depend on artificial irrigation.  About a third of the world’s food is grown in irrigated fields, and a fifth of those fields are deemed to already be salt-contaminated.  Ultimately, only a halt to climate change will be capable of combatting the scourge of salt.

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Web Links

Salt Scourge: The Dual Threat of Warming and Rising Salinity

Photo, posted June 3, 2017, courtesy of Jason Jacobs 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...)