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Bioacoustics

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Researchers are increasingly placing microphones in forests and other ecosystems to monitor birds, insects, frogs, and other animals.  Advances in technology are enabling the wide-spread use of bioacoustics as an important research tool.

Studying animals in their natural habitat Is often a difficult task.  For one thing, many animals are difficult to find, and the presence of humans disrupts their behavior or even drives them off.  Remote cameras are useful, but cameras can only see what is in front of them and aren’t much use for detecting small animals, hidden animals, or ones high up in trees.

Biologists have long recognized the value of recording sound to identify animals and learn about their havior.  Animal sounds can be as definitive a means of identification as visual images and microphones can pick up the sounds from animals located anywhere within their detection range.

The two advances in technology that are turning bioacoustics into a widely used tool are a steep drop in the price of recording equipment and the rapidly expanding capabilities of user-friendly artificial intelligence algorithms.

Autonomous environmental audio recorders tended to cost between $500 and $1000 until quite recently.  Now, such equipment can be had for as little as $70.

The other big challenge is analyzing audio data.  Finding specific animal sounds among hundreds of hours of recordings is an untenably tedious task.  Identifying the characteristic sounds of specific species in crowded environments is a tricky business.  But neural network-based artificial intelligence technology is making such big data analysis quite practical and, remarkably, it is becoming quite user-friendly.

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Listening to Nature: The Emerging Field of Bioacoustics

Photo, posted January 28, 2013, courtesy of Felix Uribe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Geoengineering And Volcanoes

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Solar geoengineering is a theoretical strategy for curbing the effects of climate change by introducing aerosol particles in the upper atmosphere to reflect some of the Sun’s radiation back into space and thereby cool the planet.  It would basically be intentionally tinkering with the climate system on a global scale.

The concept is fraught with the danger of unintended consequences and most experts consider the idea almost unthinkable.  But there are those who see it as a last resort if all our other efforts to mitigate the effects of climate change are unsuccessful.

Proponents of the idea like to describe the technique as being like a human-made volcano.  Major volcanic eruptions spew ash particles into the atmosphere which can linger for as long as a few years.  The result is cooler temperatures, sometimes across much of the globe.  The Krakatoa eruption of 1883 lowered average Northern Hemisphere temperatures by more than 2 degrees and created chaotic weather patterns until about 1888.

Researchers at the Carnegie Institution and two Chinese research institutions used sophisticated modeling techniques to compare the effects on the climate of a volcanic eruption with long-term geoengineering deployment.

They found that the volcanic eruption created a greater temperature difference between the land and sea than the geoengineering and resulted in very different precipitation scenarios.  In both cases, there would be less available water for people on land.

Overall, the study demonstrated that volcanic eruptions are imperfect analogs for geoengineering and that scientists should be very cautious about extrapolating too much from them.  It is important to evaluate geoengineering from an informed position, but the truth is that it represents a great and perilous unknown.

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Geoengineering Versus A Volcano

Photo, posted November 1, 2002, courtesy of the NASA Goddard Space Flight Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Eco-Friendly Agriculture

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Modern agriculture has steadily destroyed native grasslands, among other ecosystems.  In fact, farming is one of the most ecologically destructive things that humans do.  But we do have to eat.  In response, there is a growing movement for agrarian reform, from grain farming on the prairie, to agroforestry, to raising livestock more sustainably.  Efforts are accelerating to develop a kinder, gentler agriculture adapted to a changing world.

One such effort has come from the Land Institute, an organization in Kansas that works on natural systems agriculture, which seeks to retain the ecological stability of the prairie with its perennial seed plants along with a grain and seed yield comparable to that from annual crops.

After four decades of effort, the institute has introduced its first commercial grain, a trademarked variety called Kernza.  Kernza is a domesticated perennial wild grass – a so-called intermediate wheatgrass – that has a long, slender head that resembles wheat seeds.  People describe its taste as sweet and nutty.   Kernza is already being made into a cereal called Honey Toasted Kernza by Cascadian Farms.  Patagonia Provisions – a spin-off from the clothing company – is making beer from the new grain.

Although Kernza is already being grown and sold commercially, it is not yet ready for prime time.  Last year, there were only about 1,000 acres in cultivation and the yield is only a third to a tenth of the yield of wheat. 

Developing a sustainable perennial polyculture of edible plants would have major benefits such as not having to plow every year, plants developing large root systems that can reach water far beneath the surface and, without annual plowing, having soil carbon remain in the ground.

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With New Perennial Grain, a Step Forward for Eco-Friendly Agriculture

Photo courtesy of Cascadian Farms/General Mills.

Earth Wise is a production of WAMC Northeast Public Radio.

Controlling Malaria Without Chemicals

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Nearly half of the world’s population lives in areas vulnerable to malaria.  The disease kills roughly 450,000 people each year, most of them children and pregnant women.  Malaria is spread by Anopheles mosquitoes and, over time, the mosquitoes have been developing resistance to the chemical insecticides that are used to control them.  In addition, there is great concern about the toxic side effects of the chemicals used on the mosquitoes.

About 30 years ago, scientists identified a type of bacteria that kills Anopheles, but the mechanism was not understood.  As a result, the bacteria could not be replicated or used as an alternative to chemical insecticides.

But now, an international research team, headed by researchers at UC Riverside, has identified the neurotoxin produced by the bacteria and has determined how it kills Anopheles.  The work is described in a paper published in Nature Communications.

It took the team 10 years to achieve a breakthrough in understanding the bacteria.  Modern gene sequencing techniques were the key.

While many neurotoxins target vertebrates and are highly toxic to humans, the neurotoxin that kills Anopheles mosquitoes does not affect humans, vertebrates, fish, or even other insects.  Known as PMP1, the substance is not even toxic to mice when given by direct injection.

The team has applied for a patent on this discovery and hopes to find partners to help them develop the bacteria-based insecticide.

There is a high likelihood that PMP1 actually evolved to kill the Anopheles mosquito.  This finding opens the door to new avenues of research into other environmentally friendly insecticides that would be targeted at other disease-spreading pests.

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Controlling deadly malaria without chemicals

Photo, posted June 9, 2018, courtesy of Mario Yardanov via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Keeping Lights On For Turtles

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Gillnets are one of the most common types of fishing gear and are used extensively in most places where people fish for food.  They operate by suspending a wall of netting in the water column.

Unfortunately, they are not selective in the species they catch.  Sea turtles are one of the most common bycatch species that become entangled in these nets.  When turtles are caught in gillnets, they can drown and die.  Marine mammals, seabirds, and sharks are also frequently caught in gillnets.

Recently, researchers have been experimenting with illuminating the nets with LED lights to see if increasing net visibility reduces sea turtle bycatch.

Studies in Mexico show green sea turtle bycatch is reduced between 40-60% with no changes in target catch.  Studies in Peru show green sea turtle bycatch is reduced between 65-80% with no changes in target catch.  Studies in Indonesia show green olive ridley, and hawksbill sea turtle bycatch is reduced by 60% with increases in target catch and catch value.

Recent research shows that net illumination also reduces bycatch of other protected species such as seabirds, sharks and rays, as well as dolphins and porpoises.

The use of illuminated gillnets could prove beneficial to both sea turtles and fisherman by reducing the bycatch that can damage fishing gear. 

Studies are now underway off the coast of North Carolina, where state gillnet fisheries are carefully managed to reduce turtle bycatch.  Initial studies show that net illumination does not change target catch rates and may even decrease the bycatch of unwanted fish species.  When it comes to protecting sea turtles, it looks like a good idea to keep the lights on.

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Illuminated Nets Could Provide A Brighter Future For Sea Turtles

Photo, posted June 2, 2016, courtesy of NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Energy Demand

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Human beings are utterly dependent upon energy both for our well-being and for societal development.  Our energy use is highly dependent upon climate since so much energy is expended either keeping us warm in winter or cool in summer.  As the climate changes, it is important to understand how energy demand is likely to be affected.

A new study published in Nature Communications by researchers in Austria, Italy and the United States explored this topic.  The study is a global analysis using temperature projections from 21 climate models, and population and economy projections for five socioeconomic scenarios.  The purpose was to determine how energy demand would shift relative to today’s climate under modest and high-warming scenarios by the year 2050.

The findings indicate that, compared to scenarios in which energy demand is driven only by population and income growth, climate change will increase the global demand for energy by 11-27% by the year 2050 under a modest warming scenario.  With vigorous climate warming, energy demand would increase by 25-58%.  (Large areas of the tropics, as well as southern Europe, China, and the US are likely to experience the highest increases).

These findings are important because if energy use rises and leads to additional emissions of heat-trapping greenhouse gases, it will be increasingly difficult to mitigate future climate warming.  Quantifying this risk provides even more incentive for reducing greenhouse gas emissions before these effects upon demand are realized and it becomes even more difficult to prevent further impacts.

Policymakers need to be aware that even moderate levels of climate change will lead to increases in energy demand that will make it increasingly difficult to minimize the harmful effects on their societies.

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More energy needed to cope with climate change

Photo, posted December 15, 2008, courtesy of Matt Hintsa via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Microplastic Diet

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According to a new study published in the journal Environmental Science & Technology, Americans consume more than 70,000 microplastic particles every year from the food they eat, the water they drink, and the air they breathe.

While the health impacts of ingesting these tiny particles are largely unknown, there is the potential for the plastic to enter human tissues and cause an immune response or perhaps release toxic chemicals into the body.

The analysis by biologists at the University of Victoria in Canada examined data from 26 previous studies on microplastic contamination.  It found that Americans eat and drink an estimated 39,000 to 52,000 microplastic particles each year, depending on their age and sex.  The numbers jump to 74,000 to 121,000 when inhalation of microplastics is included.

Americans who drink water solely from plastic bottles consume an additional 90,000 particles annually, compared to only 4,000 particles for people who only drink tap water.

The researchers warn that their findings are likely to be drastic underestimates of the problem.  Several major U.S. food groups – including poultry, beef, dairy, grains, and vegetables – have not been studied for their microplastic contamination.  Thus, the estimate of microparticle ingestion is associated with only 15% of an average person’s caloric intake.  Furthermore, there is no assessment currently available for how much plastic might be entering our bodies from food packaging.

The report’s findings suggest that microplastics will continue to be found in the majority if not all items intended for human consumption.  Realistically, the only way to reduce the human consumption of microplastics will be to reduce the production and use of plastics.

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Americans Consume Tens of Thousands of Microplastic Particles Every Year

Photo, posted June 18, 2016, courtesy of Sirirat Kornsongkaew via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change Is Not Natural

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It has been the overwhelming consensus of the scientific community for a long time that human activity and other external factors are responsible for the continuing rise in global temperature.  Despite this widespread agreement, there have been those who argue that natural ocean cycles might be influencing global warming over the course of multiple decades.

A new study, published in the Journal of Climate, provides an answer to the question of how much influence natural cycles might have, and that answer is very little to none.

The study looked at observed ocean and land temperature data since 1850 and, apart from human-induced factors such as greenhouse gas concentrations, took into account other occurrences such as volcanic eruptions, solar activity, and air pollution peaks.  The findings demonstrated that slow-acting ocean cycles do not explain the long-term changes in global temperatures.

Based on the study, the researchers can state with confidence that human factors like greenhouse gas emissions and particulate pollution, along with year-to-year changes caused by natural phenomena like volcanic eruptions or El Niño, are sufficient to explain virtually all the long-term changes in temperature.  The idea that the oceans could have been driving the climate either in a colder or warmer direction for multiple decades in the past and therefore will do so in the future is unlikely to be correct.

A number of previous studies have compared flawed observations with flawed modeling results to claim that naturally-occurring ocean cycles have played a large role in global temperatures.  The new study shows that such cycles have little influence on the climate.  Reducing greenhouse gas emissions is really what we need to do.

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Global temperature change attributable to external factors, confirms new study

Photo, posted November 13, 2007, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Forecasting A Massive Dead Zone

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The Gulf of Mexico dead zone occurs every summer, and is considered one of the largest dead zones in the world.  This cyclical event occurs where the Mississippi River empties into the Gulf of Mexico, just off the coast of Louisiana and Texas. 

This annual dead zone is primarily caused by excess nutrient pollution from human activities, such as urbanization and agriculture, occurring throughout the Mississippi River watershed.  Washed off the land by spring rains, these excess nutrients stimulate an overgrowth of algae once they reach the Gulf of Mexico.  The algae in the Gulf eventually die, and then sink and decompose in the water. The resulting area of the ocean ends up with a condition known as hypoxia, which is an insufficient amount of oxygen to support most marine life.  In hypoxic or dead zones, animals that can’t swim away will often suffocate and die. 

Scientists from the National Oceanic and Atmospheric Administration estimate that this year the dead zone in the Gulf of Mexico will be approximately 8,000 square miles, which is roughly the size of Massachusetts.  The research team uses U.S. Geological Survey river flow and nutrient data to make its forecast. 

According to NOAA, the abnormally high amount of spring rainfall is a major factor contributing to this year’s dead zone.  Last month, nitrate loads entering the Mississippi River watershed were 18% above the long-term average, and phosphorus loads were about 49% above the long-term average. 

While the 2019 forecast is slightly less than the record size of more than 8,700 square miles set in 2017, it’s still much larger than the five year average size of 5,700. 

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Very large dead zone forecast for the Gulf of Mexico

Massive 8,000-mile ‘dead zone’ could be one of the gulf’s largest

Photo, posted May 22, 2009, courtesy of Michael McCarthy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

How Much CO2 Can The Oceans Hold?

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The carbon dioxide that enters the atmosphere doesn’t necessarily stay there.  As part of the natural carbon cycle, much of it goes into plants, soil and, very significantly, the ocean.  In fact, the world’s oceans are a sink for human-generated carbon dioxide without which the extent of global climate change would be far worse.

Oceans takes up CO2 in two steps: first the CO2 dissolves in the surface water.  Then, the ocean’s overturning circulation distributes it.  Currents and mixing processes transport the dissolved CO2 from the surface deep into the ocean’s interior, where it accumulates over time.

A long-standing priority for climate researchers is to determine how much of the CO2 we produce is being absorbed by the oceans and, ultimately, how much can they hold?

An international team of scientists has recently provided some answers.  As reported in Science, the researchers have determined that the oceans have taken up from the atmosphere as much as 37 billion tons of human-made carbon between 1994 and 2007.  This figure corresponds to nearly a third of all the anthropogenic CO2 emitted during that time.

Furthermore, they found that the percentage of CO2 taken up by the oceans has remained relatively stable compared to the preceding 200 years even as the absolute quantity has increased.  So, evidently, the oceans’ capacity for carbon dioxide has not yet been saturated.

That’s the good news.  The bad news is that putting all that CO2 into the oceans has a steep price:  the dissolved CO2 acidifies the water.  The consequences for a wide range of marine life including coral reefs are serious and getting worse.  We need to drastically reduce carbon emissions.

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Ocean sink for human-made carbon dioxide measured

Photo, posted November 5, 2018, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Earth Day

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Today is Earth Day.  On April 22, 1970, millions of Americas took to the streets in peaceful demonstrations in favor of environmental reform.  Since that first time, Earth Day has now become a global event each year.  Estimates are that as many as a billion people in 192 countries take part in Earth Day events.

This year, the theme for Earth Day is “Protect our Species.”  The focus is on the fact that the world is facing the greatest rate of extinction since the demise of the dinosaurs more than 60 million years ago.

But unlike the extinctions from that time that were linked to so-called acts of god like asteroid collisions, the rapid extinction of species in our world today is mostly the result of human activity.

The global destruction and rapid reduction of plant and wildlife populations are directly linked to climate change, deforestation, habitat loss, trafficking and poaching, unsustainable agriculture, pollution, and pesticides.

In order to stem the tide of destruction, the Earth Day Network is asking people to help raise awareness about the accelerating rate of extinction of millions of species and the causes and consequences of this phenomenon.  We need to push for the creation of policies that protect broad groups of species as well as individual species and their habitats.  There needs to be a global movement that embraces nature and its values. And we need to eat less meat and curtail the use of pesticides and herbicides.

We share the planet with many species, and we need them to be here in order to sustain our own species.  Something to remember on Earth Day 2019.

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Earth Day Network

Photo, posted January 24, 2012, courtesy of Jonas Bengtsson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Humans And Vertebrate Mortality

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According to a new study, more than one-quarter of the planet’s land vertebrates die because of humans.  This is a “disproportionately huge effect” on the other land vertebrates that share planet’s surface with us. 

Researchers from the SUNY College of Environmental Science and Forestry and the U.S. Department of Agriculture reviewed 1,114 published studies in which nearly 43,000 animals had perished.  Their study, which was recently published in the journal Global Ecology and Biogeography, found that 28% of the animals’ deaths were directly attributable to humans.  The other 72% died from natural sources.  

Mammals, birds, reptiles, and amphibians that died between 1970 and 2018 in the Americas, Asia, Africa, Europe, and Oceania were the foundation of the study.  All of these vertebrates had been either collared or tagged as part of other research projects. 

The researchers point out that humans are only one among more than 35,000 species of terrestrial vertebrates globally.  The fact that humans are responsible for more than one-quarter of their deaths illustrates the profound magnitude of the problem.  And that statistic is just the direct causes.  According to the researchers, when urban growth and other land use changes that erode habitat are considered, the human impact is likely even greater. 

The study found that the impact of humans across all the different species was not equal. In fact, larger animals were more likely to be killed by humans than smaller animals. Adult animals were more likely to be killed by humans than juveniles. 

The researchers conclude that humans are such a major contributor to terrestrial vertebrate mortality that they could potentially impact both evolutionary processes and ecosystem functioning. 

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On the land, one-quarter of vertebrates die because of humans

Photo, posted March 6, 2019, courtesy of USFWS Midwest Region via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing Polar Bear Attacks

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The increasing reduction of sea ice in the Arctic is changing the behavior of polar bears.  Because they are spending more time on land, they are interacting with people much more frequently, occasionally with deadly results.

A study, published in 2017, looked at 144 years’ worth of polar bear attacks on humans in the Arctic.  Between 1960 and 2009, there were a reported 47 attacks by polar bears on people – between 7 and 12 per decade.  Between 2010 and 2014, as sea ice reached record lows, there were 15 attacks, a record for a four-year period.  Since 2000, 88% of attacks have occurred between July and December, when sea ice is at its lowest level of the year.

Last July, a young male polar bear attacked and killed a man who was berry picking with his children.  A month later, a mother polar bear attacked and killed an Inuit hunter and injured two others.  This was the first known fatal attack by a mother polar bear.

As a result, Inuit communities in the Nunavut region are asking for higher legal polar bear harvest quotas, arguing that bear populations have increased to a dangerous level.

These recent human fatalities have also provided an impetus for developing new non-lethal conflict-resolution tools than can be used in northern communities before more people as well as bears are killed.

There are now polar bear patrol teams tasked with driving bears away from settlements.  There is a bear hotline and electric fencing around sled dog compounds.

The changing face of the Arctic is creating growing stress on the polar bear population and on the people who make their home in that region.

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As Polar Bear Attacks Increase in Warming Arctic, a Search for Solutions

Photo, posted September 28, 2015, courtesy of Anita Ritenour via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Natural Climate Solutions Are Not Enough

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A new policy perspective published in Science by researchers at seven prestigious institutions looked at the role of natural science solutions in stabilizing the Earth’s climate for people and ecosystems.   While they asserted that it is imperative to ramp up natural climate solutions, they also concluded that natural solutions alone will not be sufficient.

Natural science solutions include such things as enhancing carbon sinks from forests, agriculture and other lands.  Doing these things are very beneficial in their own right as they lead to improved forests, croplands, grazing lands, and wetlands.

However, these things will not be enough to meet the goals of the Paris Climate Agreement and must be combined with rapid efforts to decrease emissions from the energy and industrial sectors.  Among their various findings, the researchers warn that a ten-year delay in emissions reductions from these sectors could completely negate any potential benefits of natural climate solutions.

As has become increasingly clear, there is not an either-or situation with regard to the actions that need to be taken with respect to climate change.

Maximizing natural climate solutions and reducing emissions from the energy and industrial sectors will provide broad benefits beyond climate change mitigation.  Doing these things will improve forests and habitats, reduce the risk of wildfires, and decrease air and water pollution thereby improving human health and well-being.

Of course, to reduce cumulative emissions and put a cap on the warming of the planet, there will need to be policy mechanisms and incentives in place that support both natural climate solutions and increasing mitigation efforts across the energy and industrial sectors.

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Natural Climate Solutions Are Not Enough

Photo, posted February 11, 2012, courtesy of Joao Andre O. Dias via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Breakthrough In Animal Identification

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Researchers from the University of Wyoming have developed a computer model that can identify wild animals in camera-trap photographs with remarkable accuracy and efficiency.

This breakthrough in artificial intelligence (AI), detailed in a paper recently published in the scientific journal Methods in Ecology and Evolution, represents a significant advancement in the study and conservation of wildlife. According to the paper’s authors, “the ability to rapidly identify millions of images from camera traps can fundamentally change the way ecologists design and implement wildlife studies.”

This study builds on previous research from the university in which a computer model analyzed 3.2 million images captured by camera traps in Africa.  The A-I technique called deep learning categorized animal images at a 96.6% accuracy rate.  This was the same accuracy rate as teams of human volunteers achieved, but the computer model worked at a much more rapid pace. 

In the latest study, UW researchers trained a deep neural network on a powerful computer cluster to classify wildlife species using 3.37 million camera-trap images of 27 different animal species.  The model was tested on nearly 375,000 images at a rate of about 2,000 images per minute. It achieved a 97.6% accuracy rate, which is likely the highest accuracy to date in using machine learning for wildlife image classification. 

Artificial intelligence has been used in environmental science in other ways as well. For example, AI has been used to increase agricultural yields in farm fields and to help predict extreme weather. 

Maybe artificial intelligence can prove to be a game changer for the environment.   


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Researchers Successfully Train Computers to Identify Animals in Photos

Photo, posted January 8, 2012, courtesy of the U.S. Fish and Wildlife Service via Flickr. 

Earth Wise is a production of WAMC Northeast Public Radio.

Microplastics And Humans

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Microplastics are everywhere.  The tiny plastic particles pose a massive environmental challenge.  Microplastics are polluting oceans at an alarming rate.  Much of the oceanic microplastics result from the breakdown of plastic litter.  Another source of microplastics pollution is microbeads.  Microbeads, which are commonly added to cleansing and exfoliating personal care products, pollute the environment when they get flushed down the drain.   

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Mammals Can’t Seem To Evolve Fast Enough

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Our planet has been through five upheavals over the past 450 million years.  During each one, the environment on earth changed so dramatically that most plant and animal species became extinct.  After each of these mass extinction events, evolution slowly filled the gaps in the environment with new species. 

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