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Return of the frogs

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The mountain yellow-legged frog is a species that lives in the mountains of Southern California.  It is listed as an endangered species for protection by the federal government.   Surveys 20 years ago determined that the frog’s population was declining and on a trajectory toward extinction.  The frogs are severely impacted by water pollution and are vulnerable to the effects of wildfires, floods, disease, and drought.

A collaboration headed by the Scripps Institution of Oceanography at UC San Diego along with the San Diego Zoo Wildlife Alliance, UCLA, and the Big Bear Alpine Zoo has been raising mountain yellow-legged frogs in captivity as part of a long-running recovery program with partners at multiple federal and California state agencies.

In August, more than 350 of the frogs were reintroduced into the wild in Southern California’s San Bernardino Mountains, one of the largest releases of the captive-raised frogs to date.  This represented the first species reintroduction by the Scripps Institution and an important milestone in its growing conservation work.

The frogs were transported in coolers to the mountains where a team then hiked the frogs to three sites along a lake within a protected reserve.  The frogs were microchipped with passive transponder tags that will allow researchers to identify individuals during future surveys.  This will enhance long-term monitoring and inform ongoing conservation efforts.

The goal of these efforts is to help to delist or at least downlist the endangered status of the frogs by enhancing the genetic diversity of both captive and wild populations, optimizing reintroduction efforts, and increasing wild frog populations.

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Hundreds of Mountain Yellow-legged Frogs Leap Back Into the Wild

Photo, posted April 27, 2011, courtesy of Rick Kuyper / USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

What happened to the sea stars?

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Billions of sea stars off the Pacific coast of North America from Mexico to Alaska have died from a wasting disease since 2013.  This die-off is considered to be the largest ever marine epidemic.  Over 90% of the population of sunflower sea stars has succumbed to the disease.

The result has been an explosion in the population of the sea urchins that the sea stars feed on.  In turn, the sea urchins have devoured kelp forests that provide habitat for thousands of marine creatures.  These kelp forests support a multi-million-dollar economy through fisheries and tourism as well as sequestering carbon dioxide and protecting vulnerable coastlines. 

The disease begins with lesions and eventually kills sea stars by seemingly melting their tissues over a period of about two weeks.  Sea stars with the disease become contorted and lose their arms.

For years, the definitive cause of the wasting disease has been elusive.  But researchers from the University of British Columbia, the Hakai Institute, and the University of Washington have now identified a bacterium that is the disease-causing agent.

A strain of the Vibrio pectenicida bacteria – named FHCF-3 – is responsible.  The Vibrio genus of bacteria includes pathogens that infect corals, shellfish, and even humans.  Vibrio cholerae is the cause of cholera.

Research is now underway to understand the link between the disease and warming ocean temperatures due to climate change.  The hope is that the discovery of the cause of the wasting disease will help guide management and recovery efforts for sea stars and impacted ecosystems.

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‘Disease detectives’ discover cause of sea star wasting disease that wiped out billions of sea stars

Photo, posted April 16, 2011, courtesy of Brian Gratwicke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Air pollution and human health

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Climate change is making air quality worse in many parts of the world. Rising temperatures increase ground-level ozone, and more frequent wildfires release harmful smoke and particulates into the air. These changes, combined with ongoing pollution from sources like vehicle exhaust and industrial emissions, lead to longer and more intense episodes of unhealthy air.

A new study led by researchers from the University of Toronto in Canada examined more than 600 people and found that long-term exposure to air pollution is associated with early signs of heart damage.  The research, which was recently published in the journal Radiology, indicates that fine particulate matter in the air may contribute to diffuse myocardial fibrosis, a form of scarring in the heart muscle that can precede heart failure. 

Cardiovascular disease is the leading cause of death worldwide. 

Long-term exposure to common air pollutants is also linked to a significantly higher risk of dementia.  A separate study by researchers from the University of Cambridge in the UK analyzed data from nearly 30 million people and found that for every 10 micrograms of fine particulate matter per cubic meter of air, the risk of dementia increases by 17%.  The study, which was recently published in The Lancet Planetary Health, found that exposure to nitrogen dioxide and soot was also strongly associated with an increased risk of dementia.

Dementia is estimated to affect more than 57 million people worldwide, a number that is expected to swell to 152 million by 2050.

Strengthening efforts to reduce air pollution could make a real difference for the environment and human health.

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Even low levels of air pollution may quietly scar your heart, MRI study finds

Is the air you breathe silently fueling dementia? A 29-million-person study says yes

Photo, posted February 25, 2017, courtesy of CCO Bay via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A hidden cost of climate change

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Climate change is dramatically impacting food production by altering rainfall patterns, increasing temperatures, and triggering more frequent extreme weather events.  These changes make crops more vulnerable to droughts, floods, heatwaves, pests, and diseases, leading to lower yields and greater uncertainty for farmers worldwide.

But climate change isn’t just reshaping our planet.  It’s also changing what’s on our plates.  According to a new study by researchers from Liverpool John Moores University in the UK, rising carbon dioxide levels and warmer temperatures may be making food less nutritious.

The research team focused on popular leafy vegetables, including kale, rocket, and spinach.  The researchers simulated future UK climate conditions in growth chambers to study how the crops responded to hotter, CO2-rich environments.

The research team found that elevated CO2 levels help crops grow faster and bigger, but not healthier.  Over time, the crops showed a reduction in key minerals like calcium and certain antioxidant compounds.  These changes were exacerbated by increases in temperature.  In fact, the combination had complex effects.  The crops did not grow as big or fast, and the decline in nutritional quality intensified.

This nutritional imbalance poses serious human health implications.  Rising CO2 levels can increase sugar in crops while reducing essential nutrients, leading to calorie-rich but nutrient-poor diets. This shift may raise the risk of obesity, diabetes, and nutrient deficiencies, especially in vulnerable populations.

The challenge ahead isn’t just to grow enough food to feed a growing population, but to preserve the quality of that food in a changing climate.

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Bigger crops, fewer nutrients: The hidden cost of climate change

Photo, posted May 25, 2010, courtesy of Jason Bachman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

More trouble for bees

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Honeybees are a critical resource for American agriculture.  The western honeybee, Apis mellifera, pollinates more than 130 types of nuts, fruits, and vegetables, adding up to $15 billion worth of crops every year.  Honeybee health has been harmed by a combination of factors:  weather extremes, habitat loss, pesticides, and disease.  One of the biggest problems has been a parasite called varroa destructor, which is a Southeast Asian mite that first entered the United States in the 1980s.  The mites spread viruses to the bees.

The past year has been a particularly bad one for the bees.  Nearly 56% of managed honeybee colonies died off in the past year, the worst rate since annual reporting began in 2011. 

Even while American beekeepers seek solutions to the varroa problem, a potentially worse threat is on the horizon.  Another Southeast Asian mite, tropilaelaps, has been making its way across Asia and into Europe. If these mites arrive in North America, the results would be disastrous, wreaking havoc on honeybees and ravaging the nation’s food supply.

Western honeybees are the only honeybee species that is not native to Southeast Asia.  As the cradle of development of the bees, Southeast Asia has given rise to a bounty of parasites and viruses that are dependent upon them.  In turn, bees native to that region have had time to evolve defenses against these pathogens.  Western honeybees have not.

Beekeepers and authorities are taking measures to delay or prevent the arrival of tropilaelaps mites.  The stakes are very high.

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After Devastating Winter Losses, Another Threat Looms for U.S. Beekeepers

Photo, posted April 14, 2013, courtesy of Paul Rollings via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Indoor air and outdoor pollution

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The majority of us spend about 80% of our time indoors.   The quality of the air that we breathe depends on the age and type of building we occupy along with any sources of indoor pollution that may exist and, ultimately, the quality of the air outdoors.  The HVAC used to heat, ventilate, and cool the building plays an important role.

The College of Engineering at the University of Utah used its Salt Lake City campus as a living laboratory to explore how outdoor air pollution affects indoor air quality.  Specifically, the nature of outdoor pollution sources strongly affected how effectively HVAC systems prevented external sources from getting into buildings.

Of particular concern is fine particulate matter with a diameter of less than 2.5 microns.  These PM 2.5 particles can penetrate deeply into lungs, potentially causing health problems like respiratory irritation and heart disease.

There are multiple sources of PM 2.5.  The Utah study found that wildfire smoke had four to five times more PM 2.5 infiltration into buildings than pollution from inversions and wind-driven dust events.

An additional finding was that commercial HVAC systems that use air-side economizers are much less effective at keeping out particulate matter.  These systems use special duct and damper systems that reduce energy use by drawing air from outdoors when temperature and humidity levels are optimum.

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Does outdoor air pollution affect indoor air quality?

Photo, posted June 15, 2024, courtesy of Peter Burka via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Coexisting birds and solar energy

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Floating photovoltaic systems – known as floatovoltaics – are becoming increasingly popular.  These are arrays of solar panels installed over artificial water bodies such as irrigation ponds, wastewater treatment plants, and reservoirs.  These projects maximize the space for producing clean energy while not taking up natural lands.

Wherever there are bodies of water, there are waterbirds.  A recent study by researchers at the University of California, Davis looked at the potential impact of floating solar projects on birds and other wildlife. 

Birds face many threats from habitat loss, climate change, pollution, and disease.  Many bird populations are in decline.  So, it is important to consider the effects of floating solar projects on birds. 

The researchers have observed birds resting on floating solar structures before dawn, birds jockeying for favorable sites on the structures, and some nesting under the panels.  These are positive interactions.  On the other hand, it is possible that pollutants could be released or leached from floating solar infrastructure.  Such risks must be mitigated.

Floating solar on irrigation ponds and reservoirs can reduce evaporation and reduce algae growth, which benefits both humans and wildlife.

The researchers will continue to monitor bird behavior at floating solar installations using expertise in ecology and energy system science to identify risks and solution pathways so that negative impacts are avoided, and potential ecological benefits are realized.  It is important that as floating solar continues to become more popular, it and waterbirds can coexist.

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Helping Birds and Floating Solar Energy Coexist

Photo, posted February 28, 2019, courtesy of Renee Grayson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A starfish to the rescue

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Beginning in 2013, a mysterious disease associated with a marine heatwave decimated the population of sunflower sea stars.  Those huge, colorful 24-armed starfish thrived along the Pacific Coast between Alaska and Baja California.  But in fairly short order, nearly six billion of the creatures perished, amounting to 94% of the global population.  California lost 99% of its sea stars to the wasting disease.

The result was an ecological disaster.  Sunflower sea stars are carnivorous and purple urchins are the mainstay of their diet.  Without sea stars to balance the food web, the urchin population exploded.  Urchins devour kelp and over the past decade, 96% of the region’s kelp forests vanished.  Kelp forests serve as shelter and food for a vast array of marine life and kelp sequesters carbon as much as 20 times more than terrestrial forests.

Researchers in California and Alaska are breeding sunflower sea stars in captivity to try to produce enough of the creatures to support reintroduction.  The first successful spawning of sea stars took place last year at the Birch Aquarium at San Diego’s Scripps Institution of Oceanography.  But all of these are siblings, which is not a desirable breeding stock for a new population.  So, they are now working with the Alaska SeaLife Center, which has the largest collection of the animals in the world.  The center will provide animals to introduce genetic diversity to the growing population in captivity.

The hope is to be able to reintroduce sea stars to the Pacific region within three to five years.

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A rare, giant starfish could hold the key to restoring kelp forests on the California coast

Photo, posted November 11, 2007, courtesy of Patrick Briggs via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Bananas and climate change

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Bananas are one of the most widely produced fruits globally, with more than 100 million tons grown every year.  They are a key export crop worth approximately $11 billion annually. Bananas are also a staple food in many tropical countries, playing a vital role in both the economies of these nations and in global food security.

The Cavendish variety of banana dominates commercial exports, accounting for nearly 47% of global production. However, the Cavendish banana is highly susceptible to diseases like Panama disease, prompting ongoing efforts to develop disease-resistant alternatives. The spread of these diseases is exacerbated by climate change, which alters growing conditions and weakens banana plants. Additionally, climate change poses further threats to the banana industry by impacting crop yields and distribution patterns.

In fact, a new study led by researchers from the University of Exeter in the U.K. has found that by 2080, rising temperatures will make growing bananas for export economically unsustainable in many regions of Latin America and the Caribbean.  Colombia and Costa Rica will be among the countries most negatively impacted as they are expected to become too hot for optimal banana cultivation. 

The study, which was recently published in the journal Nature Food, found that 60% of the regions currently producing bananas around the world will struggle to grow the fruit unless there are urgent interventions to tackle climate change.  The researchers propose several adaptation strategies, including expanding irrigation systems, developing heat- and drought-resistant banana varieties, and helping banana producers manage climate-related risks.

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Climate change threatens future of banana export industry

Photo, posted June 26, 2024, courtesy of JJ Musgrove via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate change and the global food supply

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One of the most troubling aspects of global climate change is its potential to severely disrupt the production, distribution, and quality of food. While food security is already challenged by many factors, including population growth, poverty, and changing eating habits, climate change intensifies these issues by altering weather patterns, causing more frequent droughts, floods, and extreme temperatures that damage crops and reduce yields. 

These shifts not only threaten agricultural productivity and increase food prices, but they also impact water resources, pests, and disease dynamics, further destabilizing food systems and exacerbating vulnerabilities, particularly in regions already facing food insecurity.

According to a new paper, which was co-authored by 21 scientists from 9 different countries, climate change will cause widespread food shortages, leading to famine, mass migration, and global instability, unless swift action is taken to develop climate-resilient crops.

Adding to the urgency is the fact that agriculture itself also contributes approximately 30% of global greenhouse gas emissions, creating a vicious feedback loop that threatens to further accelerate global climate change.

The research, which was recently published in the journal Trends in Plant Science, outlines five key recommendations to address this crisis: Study plants in real-world conditions, strengthen partnerships with farmers, streamline regulations for faster innovation, build public trust in new technologies, and create global research initiatives that unite scientists from developed and developing nations to share resources and expertise.

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Climate Change Threatens Global Food Supply: Scientists Call for Urgent Action

Photo, posted September 21, 2014, courtesy of Peter via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Regrowing forests naturally

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Deforestation is one of the major causes of climate change and restoring and enhancing forests is a major activity around the world as a way to mitigate its effects.  There are high-profile initiatives to plant millions of trees, but these projects are often ill-conceived and poorly managed.

One of the most dramatic failures was the planting of over a million mangrove seedlings on the Filipino island of Luzon back in 2012.  A study 8 years later found that fewer than 2 percent of the trees had survived.  The rest died or were washed away.

The causes of failure in tree planting programs include planting of trees that become vulnerable to disease, competing demands for land, changing climate, planting in areas not previously forested, and a lack of aftercare including watering seedlings.

A multinational study recently published in Nature has found that forests could regrow naturally on more than 800,000 square miles of land around the tropics without the need for planting trees by hand.  This is an area larger than Mexico.

The researchers mapped areas where forests would be likely to regrow – areas where soils are healthy and where there is already forest nearby to supply seeds.  In some places, lands are so degraded that it is necessary to plant trees by hand, but this is costly and prone to failure.  Forests that regrow naturally tend to fare better and make better habitats for wildlife.

The effect of regrown forests on the climate would be very substantial.  If these forests were allowed to grow for three decades, they would absorb enough carbon to offset 50 years of emissions by Australia, the home of the lead researcher of the study. 

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Tropical Forests Could Regrow Naturally on Area the Size of Mexico

Photo, posted February 16, 2018, courtesy of Jason Houston / USAID via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

PFAS and groundwater

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Per- and polyfluoroalkyl chemicals, more commonly known as PFAS, are a family of human-made chemicals that have been manufactured and used in a variety of industries since the 1940s.  They provide water-resistance, oil-resistance, dirt-resistance, and corrosion-resistance to a wide range of products, including food wrappers and packaging, clothing, dental floss, nonstick cookware, textiles, and electronics.

Exposure to PFAS has been linked to birth defects, thyroid disease, liver disease, kidney disease, and cancer.  These chemicals do not break down in the environment and therefore, over time, become concentrated in plants, animals, and people. 

According to a new first-of-its kind study by scientists at the U.S. Geological Survey, more than 20% of the U.S. population could be drinking groundwater contaminated with PFAS.  The study, which was recently published in the journal Science, found that those living in the Eastern U.S. are particularly likely to be exposed.

The study is the first to report national estimates of PFAS in untreated groundwater that supplies drinking water to private and public wells. The USGS research also provides the first estimate of the total number of Americans – anywhere from 71 to 95 million – who might be exposed to this contamination.

The researchers note that their estimates merely measure the existence of PFAS – before the water has undergone any treatment or filtering – meaning that, while they may be present, they may be at very low levels. 

To find a link to the detailed USGS map showing the probability of PFAS groundwater contamination in your region, visit our website: EarthWiseRadio.org.

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PFAS in US Groundwater Interactive Dashboard

Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States

Photo, posted January 12, 2008, courtesy of Andrew Kraker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Industrial agriculture and the risk of pandemics

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The domestication of pigs, cows, chickens, and other animals as livestock for their meat, milk, and eggs was historically revolutionary.  It boosted food security by giving people a readily-available means of feeding themselves as opposed to more traditional methods such as hunting and fishing.

But the industrialization of agriculture has led to horrendous conditions for animals.  Many are kept in huge quantities and packed together with little regard for their health and welfare.  This approach is designed to maximize production while minimizing costs.

With its chemical inputs and toxic outputs, intensive animal agriculture is also a major threat to the environment.  In fact, it’s a major driver of habitat degradation and biodiversity loss all around the globe.  

According to a new study led by researchers from the University of Exeter in the U.K., intensive livestock farming can also increase the risk of new pandemics.  These findings go against the widely held belief that industrialized farming reduces the risk of disease transmission between animals and humans. 

Zoonotic diseases are those that are spread from animals to humans.  According to the CDC, zoonotic infections account for three in every four new or emerging infectious diseases in humans.  The current bird flu outbreak in the U.S. is an example of this. 

In the paper, which was recently published in the journal Royal Society Open Science, the researchers conclude that the effects of intensifying animal agriculture “are at best uncertain and at worst may contribute to emerging infectious disease risk.”

Industrial animal agriculture is a threat to both human health and the health of our planet.

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Intensive farming could raise risk of new pandemics

Photo, posted January 29, 2016, courtesy of Farm Watch via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Beware of the blob

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For the past 10 years, there have been several occurrences of a vast expanse of ocean stretching from Alaska to California in which water temperatures are as much as 7 degrees Fahrenheit warmer than normal.  Known jocularly as “the Blob,” the phenomenon can last for several years and decimates fish stocks, starves seabirds, creates blooms of toxic algae, prevents salmon from returning to rivers, and displaces sea lions and whales.

Until recently, there was no accepted explanation for this abrupt ocean heating.  Climate change, even combined with natural cycles like El Niños, is not enough to account for it.

In depth analysis by an international team of researchers has found that the extraordinary heating is the result of a dramatic cleanup of Chinese air pollution.  The decline of smog particles, which to some extent shield the planet from the sun’s rays, has accelerated warming and set off a chain of atmospheric events across the Pacific, essentially cooking the ocean.

This is an example of what can be called the pollution paradox in which global warming is actually increased when air pollution is reduced.  Reduced air pollution on the US West Coast has even been identified as a factor contributing to increased wildfires.  However, air pollution causes more than 4 million premature deaths from cancers and respiratory and cardiovascular diseases each year. 

Nobody thinks that we should stop cleaning up the air to slow down global warming.  The only viable solution is to reduce greenhouse gas emissions as rapidly as possible.

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Pollution Paradox: How Cleaning Up Smog Drives Ocean Warming

Photo, posted December 18, 2017, courtesy of SGUP via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hope for amphibians

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There are more than 7,000 known species of amphibians, the group of animals that includes frogs, toads, and salamanders.  Over the past 25 years, more than 90 species are believed to have gone extinct and at least 500 more have declining populations.

There are many factors contributing to the decline of amphibian populations but the most alarming is a fungus called Batrachochytrium dendrobatidis – or Bd – that ravages the skin of frogs and toads and eventually causes heart failure.  The fungus has been devastating amphibians on nearly every continent.

In a recent paper in the journal Current Biology, scientists at the University of California Riverside documented the discovery of a virus that infects Bd and could be engineered to control the fungal disease.

The researchers were studying the population genetics of the Bd fungus with DNA sequencing technology and uncovered the virus inside the fungal genome.  Some strains of the fungus are infected with the virus and others are not.  They are now looking for insights into the ways that the virus operates to see how it gets into the fungal cells.  The goal is to engineer the virus to infect more strains of the fungus and potentially end the global amphibian pandemic.

Frogs and toads control bad insects, crop pests, and mosquitos.  If their populations around the world collapse, it could be devastating.  They are already having difficulty coping with warmer temperatures, stronger UV light, and worsening water quality in many places. 

Some amphibian species are already acquiring resistance to Bd.  The UCR researchers are hoping to assist nature in taking its course.

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Discovery could end global amphibian pandemic

Photo, posted August 25, 2010, courtesy of Kev Chapman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Major species turnover forecasted for North American cities

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Climate change affects animal species in many ways.  It induces habitat loss, disrupts migration and breeding patterns, threatens marine life, and facilitates an increased spread of disease.  It may also affect where animals can be found in the future. 

According to a new study led by researchers from the University of Toronto Mississauga and Apex Resource Management Solutions in Canada, climate change may dramatically affect the animal species observed in North American cities by the end of the century.

The researchers used species distribution data combined with machine learning to study the impact of human-caused climate change on more than 2,000 animal species historically found in the 60 most populous North American cities. 

According to the research team, changes in biodiversity are brewing for almost every city it studied by the year 2100.  In fact, cities with a rich history of biodiversity are predicted to have the largest declines and fewest gains in species. Cooler and wetter cities like Quebec, Ottawa, Winnipeg, Kansas City, and Omaha are expected to welcome the most new species.  Warmer cities with higher precipitation – like cities in coastal California – are projected to lose the most species. 

More than 95% of bird and insect species are predicted to experience a change in the number of cities they call home.  Canines, most amphibians, and aquatic birds are expected to experience the greatest losses.  Toads, turtles, mice and pelicans are projected to become more common overall. 

The researchers hope their findings will encourage more efforts to protect biodiversity.

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North American cities may see a major species turnover by the end of the century

Photo, posted September 29, 2013, courtesy of Jonathan Kriz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Confusion about monarch butterflies

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For years, we have heard that the iconic monarch butterfly is in great peril.  Monarchs east of the Rocky Mountains undertake a 4-generation, 3,000-mile migration in late summer to their winter home in central Mexico.  Since the 1990s, the overwintering monarch colonies began a steep decline causing scientists to fear for the sustainability of the species.  Trying to help, ordinary citizens have been planting milkweed – the food for the caterpillars – and have been rearing eggs and caterpillars on their porches and releasing adult butterflies.

A number of recent studies have rocked the world of monarch science.  A growing group of scientists now believe that monarchs are not in fact imperiled and that the home rearing and commercial breeding of monarchs is actually a major threat to the butterfly.

According to a comprehensive 2022 study, there has been no sharp decline in Eastern monarch populations across their summer breeding range.  The long-term declines in winter colony sizes are real but do not appear to be affecting the collective breeding population of Eastern monarchs. 

An undisputed major threat to monarchs is a parasite known as OE, which weakens butterflies and also makes it unlikely for them to complete migrations.  It turns out that overcrowding of butterflies resulting from the efforts of backyard and commercial breeders is increasing the spread of the disease.  The butterflies are in need of social distancing.

Monarch scientists are split into two camps.  One group calls for the protection of the butterfly under the Endangered Species Act.  The other says that what monarchs most need is for us to leave them alone.  It is a confusing situation.

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Rethinking Monarchs: Does the Beloved Butterfly Need Our Help?

Photo, posted October 1, 2021, courtesy of Renee Grayson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

More mosquitoes in a warming climate

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Over millions of years, Earth’s climate has warmed up and cooled down many times. However, today the planet is warming much faster than it ever has over human history.  According to scientists, the warming is primarily the result of increased anthropogenic greenhouse gas emissions.  In fact, human activities are responsible for nearly all of the increase in atmospheric greenhouse gas emissions over the last 150 years. 

According to a new study published in the journal Ecology, the warming climate may soon mean more mosquitoes.  A research team, led by scientists from Virginia Commonwealth University, found that rising temperatures, often linked to climate change, can make predators of mosquito larvae less effective at controlling mosquito populations.  According to researchers, these warmer temperatures accelerate the development time of larvae, which leads to a smaller window of time in which predators like dragonflies could eat them.  As a result, twice as many mosquito larvae could make it to adulthood in the study area. 

Predators help stabilize ecosystems and food webs.  The study looked at predator-prey interactions between dragonfly nymphs and mosquito larvae.  In the study of Belle Isle along the James River in Richmond, Virginia, the research team found that warmer pools had more aquatic rock pool mosquito larvae – even when their predators that naturally control the populations were present.

While this species of mosquito is not an important disease vector, the researchers emphasize that these findings likely apply to other mosquito species that do act as vectors for diseases, such as West Nile or Zika virus.

The changing climate is creating the perfect environment for mosquitoes to thrive. 

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Hotter weather caused by climate change could mean more mosquitos, according to VCU-led study

Photo, posted June 20, 2014, courtesy of John Tann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tracking down PFAS toxins

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PFAS – per- and polyfluoralkyl substances – are a group of organic compounds that have been extensively used to provide water-, oil-, and dirt-resistance to a wide range of products ranging from non-stick pans, clothing, and packaging to paint, car polish, and fire-suppressant foam.  Exposure to specific PFAS compounds is associated with multiple adverse health effects, including altered immune and thyroid function, liver disease, kidney disease, poor reproductive and developmental outcomes, and cancer.  PFAS compounds do not break down in the environment and therefore, over time, become concentrated in plants, animals, and people.

Government agencies such as the EPA in this country and the EU have set strict limits for allowable levels of PFAS in drinking water.  Testing water for the trace amounts of PFAS that constitute the limits is time-consuming and expensive and requires complex equipment and experienced personnel.

Researchers at MIT have now introduced a technique for making a portable, inexpensive test that can easily and selectively detect PFAS in water samples.  The test makes use of a special polymer containing fluorinated dye molecules that cause the polymer to fluoresce red.  If PFAS are present in the sample, they enter the polymer and displace the dye molecules and switches off the red fluorescence. 

The new technique is suitable for on-site detection in highly contaminated regions.  Detecting smaller concentrations can be achieved with sufficient precision after pre-concentrating the samples using the process of solid-phase extraction.

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Tracking down Environmental Toxins

Photo, posted October 16, 2021, courtesy of Nenad Stojkovic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Protecting berries with sunflower extract

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Many of us buy blueberries, raspberries, blackberries, and more in those little clear plastic clamshell boxes.  We try to check them out at the store to make sure they are ok and even if are, many soon end up coated with gray mold and other fungi.  It is a problem that is both disappointing and expensive.

Researchers from several Chinese Universities recently reported that compounds extracted from sunflower crop waste are quite effective at preventing rotting in blueberries.  They suggest that the food industry could use these natural compounds to protect berries from postharvest diseases.

Sunflowers are grown globally for their seeds and oil.  The flower stems themselves are generally considered to be a waste product.  Sunflowers are known to be particularly resistant to many plant diseases so the researchers decided to investigate whether there might be chemical constituents within the plants that are responsible for the protective property.

Their research led to the isolation of 17 different compounds known as diterpenoids, including four that have never been identified before.  They found that 4 of the compounds, including 2 of the newly discovered ones, were effective at preventing the growth of fungus on the blueberries. 

Berries were wetted with the compounds and then dried off and injected with mold spores.  Half of the treated berries were protected from the mold.

There is no reason that the method couldn’t be applied to a variety of crops.  There is great appeal in the concept of using a harmless extract from a plant to render a food crop safe from fungal infestation.  The technique holds great promise in preventing postharvest disease in fruit.

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Sunflower extract fights fungi to keep blueberries fresh

Photo, posted August 26, 2006, courtesy of Liz West 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...)