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Removing microplastics from water

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Microplastics come from the breakdown of larger plastics in the environment as well as from direct use in various products such as certain cosmetics.  They are found everywhere, from oceans and mountain peaks to the air and water, and alarmingly, in our bodies.  They are ingested by all sorts of organisms, from tiny plankton to fish and marine mammals.  Microplastics just don’t go away.  They don’t biodegrade so they simply accumulate in the environment.

Researchers at North Carolina State University have recently demonstrated proof of concept for a system that actively removes microplastics from water.  Such a system has the potential for helping to cleanse oceans and other bodies of water from the tiny plastic particles.

The system makes use of soft dendritic colloids, which are tiny particles that have the ability to stick to just about any surface.  These sticky particles can attract microplastics and grab them, even in wet and salty conditions.  The colloids are made from chitosan, a harmless and biodegradable polymer made from processed shellfish waste.

The researchers produced small pellets of the colloids that also contain small amounts of magnesium, which makes them bubble up and rise to the surface of water.  The pellets are coated with a gelatin layer, which blocks the magnesium.  As the gelatin gradually dissolves away, the pellets collect microplastics.  Eventually, the result is a microplastic-laden scum that rises to the surface where it can be skimmed away.

The scum itself can be bioprocessed into more chitosan that can create more of these microcleaner pellets to then capture more microplastics.  The researchers are investigating how the process can be scaled up to become a valuable tool in dealing with the microplastics problem.

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New Water Microcleaners Self-Disperse, Capture Microplastics and Float Up for Removal

Photo, posted January 17, 2018, courtesy of Bo Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The importance of shallow water

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Vacationers love beaches with shallow water.  They are great for families with small kids and for less confident swimmers.  Such beaches often attract intense coastal development.  However, they are also fragile habitats that are disappearing around the world.

A new study led by the University of South Florida highlights the need to protect these marine ecosystems.  Shallow coastal waters are known as tidal flats, and they are critical to global seafood supplies, local economies, and overall marine health.  Shallow water ecosystems are interlinked with other marine habitats and are vital for the lifecycle of marine species far from shore.

Shallow water ecosystems are at risk not only from coastal development, but from harmful algal blooms triggered by human activity, from marine heatwaves, and from boats operating in sensitive habitats such as seagrass meadows. These habitats contribute millions of dollars to local economies such as those in Florida but there is not much direct habitat managements in place to protect these ecosystems.

The University of South Florida study, published in the journal Fisheries, enumerated ten core strategies that boaters, anglers, wildlife managers, and policymakers can adopt to prioritize and preserve shallow marine ecosystems from humans and from increasingly powerful weather events.  Foremost among these efforts are the protection of key fish species, such as tarpon, whose protection would benefit additional species that use the same habitats.

Habitat management and restoration should be essential concerns for coastal communities to provide long-term benefits for both themselves and for the marine life that depends on shallow-water habitats.

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Why shallow water at the beach is more important than you might realize

Photo, posted February 14, 2018, courtesy of Marcelo Campi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tearing down small dams to restore rivers

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There are more than 31,000 dams in the northeastern United States.  More than 4,000 of them are in the Hudson River watershed.  Most of these dams are quite small and were built in the 19th century to form ponds and to power grist, textile, paper, saw, and other kinds of mills as the region developed its industrial infrastructure.  The nonprofit organization American Rivers estimates that 85% of U.S. dams are unnecessary at best and pose risks to public safety at worst. 

Dam removals have been occurring for over 100 years, but the vast majority have taken place since the mid-2010s and have increased dramatically since the 2021 Bipartisan Infrastructure Law, which provided funding for such projects.

So far, 806 Northeastern dams have come down and hundreds more are in the pipeline.

Dam removals improve aquatic fish passage, water quality, watershed resilience, and habitat for all the organisms in river ecosystem food chains, ranging from insects to fish to otters to eagles.  Small dams have degraded habitat and altered downstream hydrology and sediment flows.  They have created warm, stagnant, low-oxygen pools that trigger algal blooms and favor invasive species.

But removing even small dams is not an easy matter.  Projects range in cost from $100,000 to $3 million and qualifying for funding – whether federal or state – requires projects to meet a variety of requirements including community support.  Not all dams can be removed, but many more should.

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How Tearing Down Small Dams Is Helping Restore Northeast Rivers

Photo, posted September 20, 2010, courtesy of Doug Kerr via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sharks and rays in a warming world

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Sharks and rays belong to a group of cartilaginous fish called elasmobranchs, which have been swimming in the world’s oceans for 450 million years. The resilient species have survived five mass extinction events, and are older than dinosaurs, trees, and Mount Everest. 

But despite their resilience, many species of sharks and rays today are threatened by human activities, including overfishing, habitat loss, and climate change.  In fact, according to a new study led by researchers from the University of Vienna in Austria, more than one third of the shark and ray species known today are severely under threat. 

The study, which was recently published in the journal Biology, found that higher carbon dioxide levels were having a negative effect on sharks and rays, ranging from impacts on the animals’ senses to changes in the skeleton during embryonic development.  An examination of fossil records found that higher CO2 levels had contributed to the extinction of individual shark and ray species in the past. 

But the study also found that global warming could be creating opportunities for sharks and rays.  Rising sea levels and higher temperatures have historically expanded shallow coastal habitats and warm waters, supporting species biodiversity.

But according to the research team, the rapid environmental changes, combined with the impacts from human activities, outpace the ability of sharks and rays to adapt, making it unlikely that they will benefit from global warming.

Protecting sharks and rays is crucial not only for their survival but also for maintaining entire ocean ecosystems. Without top predators, these ecosystems could collapse, impacting both marine life and the people and industries that depend on it.

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Sharks and rays benefit from global warming – but not from CO2 in the Oceans

Myths About Sharks and Rays

Photo, posted November 27, 2007, courtesy of Laszlo Ilyes via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Microplastics in Antarctica

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Microplastics are small plastic pieces less than five millimeters long and typically far smaller than that.  They come from a variety of sources, often from larger plastic debris that degrades into smaller and smaller pieces.  There are also microbeads, which are tiny pieces of manufactured polyethylene plastic that are added to various health and beauty products.  Tiny bits of plastic easily pass through filtration systems and end up in the ocean and other bodies of water.

Microplastics are a pervasive problem for which nowhere on Earth is truly untouched.  Despite stringent regulations on materials entering Antarctica, scientists have discovered microplastics in the snow near some of the deep field camps there.

A study by the British Antarctic Survey made use of a new and advanced technique that can detect microplastics as small as 11 microns – about the size of a red blood cell.

The research team found microplastics at concentrations ranging from 73 to 3,099 particles per liter of snow. 

Snow samples from three different sites identified polyamide (used in textiles), polyethylene terephthalate (found in bottles and packaging), polyethylene, and synthetic rubber.  The results suggest that at least the polyamide, which accounted for half the microplastics found, came from local sources.

Additional research is needed to fully understand the sources of microplastic pollution in Antarctica and to understand the broader implications of microplastics in that frozen wilderness. Microplastics have already been detected in several penguin, seal, and fish species.

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Microplastics discovered in Antarctica

Photo, posted February 3, 2015, courtesy of Christian Stangl via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate change and fish migration

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The warming climate is changing the distribution of fish species.  Researchers at the University of Adelaide in Australia have observed that tropical fish species are moving into temperate Australian waters.

The Eastern Australian Current is strengthening as the climate warms and larvae of tropical fish are getting caught in the current and moving into more temperate regions.  These larvae would not normally survive in the cooler Australian ocean water, but the warming current keeps the baby fish warm and increases their chances for survival.  The fish migration observed in the study is an ongoing process that has strengthened in the last few decades due to ocean warming.

The novel populations of tropical fish in these temperate ecosystems are not having much impact at the present time, but they may do so in the future.  The water is still cooler than the fishes’ natural environment and therefore they do not grow to their maximum size.  As a result, they don’t represent stiff competition for the native species – at least not yet.

As the ocean temperatures continue to rise, these tropical species will eventually grow to their full size and their diets will overlap more and more with those of temperate fish species.  Tropical herbivores tend to overgraze temperate kelp while the impact of tropical fish that eat invertebrates is less well understood.  Tropical fish with varied diets are the most successful invaders.  The ultimate effects on temperate ecosystems remain to be seen but survival may become difficult for the native fish in rapidly warming temperate ocean environments.

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Tropical fish are invading Australian ocean water

Photo, posted March 28, 2017, courtesy of Ryan McMinds via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Artificial reefs

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The coral reefs that surround tropical islands are a refuge for a wide variety of marine life and also form a natural buffer against stormy seas.  The changing climate is bleaching coral reefs and breaking them down.  Extreme weather events are becoming more common and are threatening coastal communities with flooding and erosion.

Researchers at MIT are designing architected reefs – sustainable offshore structures that mimic the wave-buffering effects of natural reefs and can also provide habitats for fish and other marine life.

There are already artificial reefs in a number of places used to protect coastlines.  These are typically made from sunken ships, retired oil and gas platforms, and even assemblies of concrete, metal, car tires, and stones.  Generally, it takes quite a lot of material to form an effective barrier to waves.

The MIT group has developed a cylindrical structure surrounded by four rudder-like slats.  Their experiments have shown that when this structure stands in the way of a wave, it efficiently breaks the wave and creates turbulent jets that dissipate the energy in the wave.  The engineers calculated that the new design could reduce as much wave energy as existing artificial reefs but use 10 times less material.

Based on the initial experiments with lab-scale prototypes, these artificial reefs would reduce the energy of incoming waves by more than 95%.

Coral reefs are only found in tropical waters, whereas these artificial reefs don’t depend on temperature and could be placed along any coastline for protection.  In a time of rising seas and increasingly frequent storms, these artificial reefs may be just what coastlines need.

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Artificial reef designed by MIT engineers could protect marine life, reduce storm damage

Photo, posted December 9, 2010, courtesy of Phoenix Wolf-Ray via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An ice-free Arctic

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According to a new study by Colorado University, Boulder, the Arctic could see summer days with practically no sea ice as soon as sometime in the next few years.  Earlier predictions for when the first ice-free day in the Arctic could occur were sometime well into the 2030s.

By mid-century, the Arctic is likely to see an entire month without floating sea ice.  This would likely be in September, when ice coverage is at its minimum.  By the end of the century, the ice-free season could last for many months during the year.

Technically, an ice-free Arctic does not mean zero ice in the water.  The working definition is less than 386,000 square miles of ice, which represents less than 20% of what the minimum ice coverage was in the 1980s. In recent years, the coverage has been about 1.25 million square miles.

Sea ice coverage is a big deal because many Arctic animals rely on sea ice for survival, including seals and polar bears.  With warmer ocean water, invasive fish species could move into the Arctic Ocean, upsetting local ecosystems.  Sea ice loss also is a risk for coastal communities because the ice buffers the impact of ocean waves on the coastal land.  As the ice retreats, ocean waves would get bigger, eroding the coasts.

At this point, an ice-free Arctic is basically inevitable, but its annual duration will depend on society’s efforts to reduce carbon emissions.  Lengthy periods of minimal sea ice would transform the Arctic into a completely different environment with global effects that are mostly highly undesirable.  However, Arctic sea ice is resilient and could return fairly quickly if the atmosphere cools down.

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The Arctic could become ‘ice-free’ within a decade

Photo, posted July 9, 2022, courtesy of Reiner Ehlers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mercury in tuna

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Mercury is found throughout the ocean, and there is at least some of it in any fish one might eat. It is an element found naturally in the environment, but it is also a byproduct of manmade pollution. Generally speaking, bigger fish tend to have higher mercury levels than smaller ones, because they are higher up in the food chain. The more small fish those big fish eat, the more mercury builds up in their bodies.  Tuna aren’t the biggest fish in the ocean, but they are very common in many people’s diets.

Increased mercury levels are a result of human activities like burning coal and mining which release methylmercury into the air.  It then finds its way into the oceans in rainwater.  Methylmercury is a particularly toxic chemical that affects the nervous system.  Environmental protection policies in recent decades have helped to reduce mercury pollution.

However, a recent study by French researchers looked at the mercury levels in tuna over the past 50 years.  They found that the levels have basically not changed since 1971.  As a result, they are calling for more restrictive environmental policies to further lower mercury pollution levels.

The researchers explained that the lowering of mercury airborne levels to date has not necessarily been ineffective.  They theorized that the static levels in tuna may be caused by the upward mixing of “legacy” mercury from deeper ocean water into the shallower depths where tropical tuna swim and feed.  It could very well take decades to dramatically reduce ocean mercury levels. 

Meanwhile, mercury content in tuna varies considerably by tuna type and source and there are both better and worse choices out there.  Consumers should learn the facts.

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Mercury levels in tuna remain nearly unchanged since 1971, study says

Photo, posted November 7, 2015, courtesy of Mussi Katz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Adirondack lakes becoming inhospitable for trout

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A combination of the warming climate and the phenomenon of lake browning are making the bottom of most lakes in New York’s Adirondack Mountains unlivable for cold water fish – such as trout, salmon, and whitefish – in the summer.

Lake browning occurs when dissolved organic matter from forests turns the water tea-brown.  Browning is the legacy of a century of acid rain and subsequently the fact that forest soils have suffered reduced capacity to absorb weak organic acids, leading to more dissolved plant matter flowing into lakes.  Climate change has increased the frequency of extreme precipitation events and the length of growing seasons, leading to more runoff of organic matter.

Browner water traps more of the sun’s heat at the top of the lake and blocks the sun’s rays from reaching deeper.  The result of the browning is lakes that are either too warm or too deoxygenated to support trout populations.

A study of 1,467 Adirondack lakes by Cornell University researchers found that only about 5% of them may continue to maintain water that is cold and oxygenated enough to support cold-water fish.

Deeper lakes fare much better because they have so much water that their oxygen is hard to deplete, but only 1% of all Adirondack lakes are deeper than 30 meters.  Another 4% are very clear because the influx of cold water outpaces the expansion of low-oxygen zones and limits the effects of browning.

The study urges the protection of as many lakes as possible from species invasions, nutrient and salt pollution, and other forms of environmental degradation. 

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Most Adirondack lakes will likely become unsuitable for trout

Photo, posted July 17, 2011, courtesy of Lida via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Thousands of species threatened

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The International Union for the Conservation of Nature is an organization working in the field of nature conservation and sustainable use of natural resources.  The IUCN has been around for nearly 75 years and is the global authority on the status of the natural world and the measures needed to safeguard it.

In its latest accounting, the IUCN has determined that more than 44,000 species worldwide are threatened with extinction.  Among them, nearly 7,000 face an immediate threat from climate change.

The organization tracks 157,000 species to compile its Red List and found that climate change poses a growing threat to many kinds of wildlife. At particular risk are freshwater fish including Atlantic salmon, which are now classified as “Near Threatened.” 

In all, about 25% of freshwater fish are threatened with extinction.  This is in part driven by rising sea levels which causes saltwater to be driven up into rivers.  Some 41% of amphibians are threatened with extinction, in part due to more intense heat and drought.  Many populations of green turtles are at risk of extinction because of rising temperatures lowering hatch rates and rising sea levels flooding nests.

It isn’t just animals at risk.  For example, big leaf mahogany, one of the world’s most commercially sought-after timber trees, has moved from Vulnerable to Endangered on IUCN’s Red List.  Thousands of trees have been added to the Red List, many of which are timber species, and some are keystone species in forests.

Endangered and threatened species are often irreplaceable parts of ecosystems which provide humans with many services that only the natural world can.

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More Than 44,000 Species Now Threatened With Extinction

Photo, posted November 22, 2010, courtesy of E. Peter Steenstra/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Seabirds rescuing coral reefs

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A new study by researchers at Lancaster University in the UK has found that the presence of seabirds on islands adjacent to tropical coral reefs can more than double the coral growth rates on those reefs.

The study found that when coral reefs grow faster, they can bounce back more quickly from bleaching events that occur when the seas become too warm.  The focus of the study was a type of coral called Acropora, which provides complex structures supporting fish populations and reef growth. 

The researchers found that Acropora around islands populated by seabirds recovered from bleaching events about 10 months faster than reefs located away from seabird colonies.  Speeding up coral recovery times could prove the difference between continuing to bounce back from bleaching events and dying off.

The seabirds are helping the coral reefs with their droppings.  The birds feed on fish in the open ocean far from islands and then return to the islands to roost.  They deposit nitrogen- and phosphorus-rich nutrients in the form of guano, some of which is washed off of the islands by rain and into the surrounding seas.  The nutrients fertilize corals and other marine species.

To determine whether the faster growth rates were really due to the bird-supplied nutrients, the researchers studied rat-infested islands that had no bird populations.  The study confirmed that it was the presence of seabirds that provided enhanced nutrients for the coral reefs.  In fact, a primary outcome of the study was to add further weight to the growing body of evidence of the ecological damage across ecosystems on land and sea from invasive rats on tropical islands.

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Feathered friends can become unlikely helpers for tropical coral reefs facing climate change threat

Photo, posted September 15, 2019, courtesy of Rickard Zerpe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Action on the toxic chemical from tires

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Since the 1990s, populations of coho salmon in streams and urban creeks up and down the West Coast have been dying in large numbers.  Scientists at the University of Washington began studying the mysterious deaths and it took years to figure out what was going on.  They analyzed water samples from urban creeks and found that chemicals from vehicle tires were present.  By soaking tires in water, they found that more than 2,000 chemicals were present.  It took three years to narrow down the suspect list to one chemical:  a toxin called 6PPD-quinone, which is produced when the common tire preservative 6PPD mixes with oxygen.  It is that chemical that was responsible for the salmon die-off.

6PPD-quinone is toxic enough to quickly kill some fish.  Studies showed that concentrations of the chemical in stormwater were found to be lethal for coho salmon following exposures lasting only a few hours.

Despite the discovery, the tire industry has continued to use the chemical in its products.  The industry says 6PPD is an antioxidant and antiozonant that helps prevent degradation and cracking of tires in the environment and is essential for the performance and safety of vehicles.

Last year, California regulators directed the tire industry to seek out substitutes for 6PPD.  The U.S. Tire Manufacturers Association pledged to investigate possible safer alternatives to the chemical.

In November, spurred by a petition by West Coast tribes whose lifeways depend on coho salmon, the EPA said it will study the impact of 6PPD with an eye to potentially banning its use. 

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After Salmon Deaths, EPA Takes Aim at Toxic Chemical Issuing from Car Tires

Photo, posted May 31, 2021, courtesy of Chris Yarzab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Pollution From Tires | Earth Wise

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A few years ago, researchers investigating massive deaths of coho salmon in West Coast streams discovered that the water contained particles from vehicle tires.  The cause of the fish mortality turned out to be a chemical called 6PPD that is added to tires to prevent cracking and degradation.  The mystery was solved, but so far, the chemical continues to be used by all major tire manufacturers and is found on roads and in waterways around the world.

Worse still, the acute toxicity of 6PPD and the chemicals that it transforms into when exposed to ground-level ozone is only the tip of the tire pollution iceberg.  Tire rubber contains more than 400 chemicals and compounds, many of which are carcinogenic. 

About 2 billion tires are sold across the globe each year and that number is expected to reach 3.4 billion by 2030.  Tires are made from about 20% natural rubber and 24% synthetic rubber, which requires about 4 gallons of petroleum per tire.  Hundreds of other ingredients – including steel, fillers, heavy metals like copper, cadmium, lead, and zinc – make up the rest.

Tire wear particles are emitted continually as vehicles travel.  They range in size from visible pieces of rubber or plastic to microparticles.  Research has shown that a car’s four tires collectively emit half a trillion ultrafine particles per mile driven.  These particles are small enough to be breathed into the lungs and can travel throughout the body and even cross the blood-brain barrier.  Particle pollution from tires exceeds that from tailpipes.

Tire pollution is a huge problem that is just starting to receive the attention it deserves.

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Road Hazard: Evidence Mounts on Toxic Pollution from Tires

Photo, posted June 22, 2018, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rivers And Climate Change | Earth Wise

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Our planet is heating up.  Scientists have concluded that the changing climate is primarily the result of increased greenhouse gas emissions from human activities.  Some of the effects of global climate change include thawing permafrost, rising seas, intensifying storms and wildfires, and warming oceans.   

According to a new study led by researchers from Penn State University, rivers are warming and losing oxygen even faster than oceans.  The study, which was recently published in the journal Nature Climate Change, found that warming occurred in 87% and oxygen loss occurred in 70% of the nearly 800 rivers studied.

The research team projects that within the next 70 years some river systems, especially those in the American South, will experience such low oxygen levels that the rivers could “induce acute death” for some fish species and threaten the aquatic diversity of river ecosystems. 

The research team used artificial intelligence and deep learning to analyze water quality data from nearly 800 rivers across the U.S. and central Europe.  The researchers found that rivers are warming up and deoxygenating faster than oceans, which could have serious implications for both aquatic life and humans.

While climate change has led to warming and oxygen loss in oceans and lakes around the world, the researchers did not expect to find warming and deoxygenation in shallower, flowing rivers.  Since life in water depends on temperature and dissolved oxygen, the researchers hope this study serves as a wake up call.  Warming and deoxygenating rivers have significant implications for water quality and the health of aquatic ecosystems worldwide.

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Rivers are rapidly warming, losing oxygen; aquatic life at risk

Photo, posted June 2, 2017, courtesy of Francisco Anzola via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Top Fish Predators And Climate Change | Earth Wise

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Climate change is taking its toll on forests, farms, freshwater sources, and the economy, but ocean ecosystems remain the epicenter of global warming.  In fact, oceans have absorbed more than 90% of the excess heat from greenhouse gas emissions since the 1970s.

As a result, many marine fish species are responding to ocean warming by relocating towards the poles.  According to new research recently published in the journal Science Advances, climate change is causing widespread habitat loss for some of the ocean’s top fish predators, driving these species northward.

The research team studied 12 species of highly migratory fish predators, including sharks, tuna, and billfish, such as marlin and swordfish, inhabiting the Northwest Atlantic Ocean and the Gulf of Mexico.  These two regions are undergoing rapid changes in sea surface temperatures, and are among the fastest warming ocean regions on earth.

The research, which was led by researchers from Woods Hole Oceanographic Institution in Massachusetts, with collaboration from San Diego State University, NOAA, and several other U.S. institutions, found that most species will encounter widespread habitat losses by 2100.  Some species could lose upwards of 70% of suitable habitat by that year.  Areas offshore of the Southeast United States and Mid-Atlantic coasts were identified as likely hotspots of multi-species habitat loss. 

According to the researchers, strategies for managing fish have historically been static. But marine systems need to be treated as dynamic and changing.  This study helps provide the scientific data needed for marine conservation and fisheries management efforts.

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Top fish predators could suffer wide loss of suitable habitat by 2100 due to climate change

Photo, posted March 18, 2015, courtesy of Kenneth Hagemeyer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Beaver Believers | Earth Wise

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Beavers are ecosystem engineers based on their ability to construct dams and create ponds.  By doing so, they create wetland habitat for other species.  They create biodiversity by allowing plant species to emerge in new places as they clear out existing trees and other plants.  Beavers improve water quality and their dams store water during droughts.  Their handiwork minimizes flood risk and mitigates flooding impacts.

Before beavers were widely trapped, there were beaver dams just about everywhere in the American west.  Now beaver rewilding is trying to restore many western ecosystems. In places like Idaho, ranchers have gone from seeing beavers as a nuisance to actually recruiting them onto their land.  One cattle rancher began stream restoration on his land with beaver rewilding in 2014.  By 2022, he was a firm “beaver believer”.  There are now over 200 beaver dams along Birch Creek near Preston, Idaho, and the stream now flows 40 days longer into the year.

NASA has established a team to investigate the extent to which beavers can have an outsized and positive impact on local ecosystems.  The team is using NASA’s Earth Observation satellites to observe the effects beavers are having.  Satellites can collect data from large areas and can pass over the same areas regularly and across seasons.  The goal is to support people on the ground who are implementing beaver rewilding efforts to increase water availability and to increase habits for fish and other species.  NASA’s project will run through 2025 and it plans to expand it to other states with similar terrain and water management strategies.

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Researchers Become “Beaver Believers” After Measuring the Impacts of Rewilding

Photo, posted February 23, 2021, courtesy of Deborah Freeman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Global Aquaculture And Environmental Change | Earth Wise

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Blue foods are fish, invertebrates, algae, and aquatic plants that are captured or cultured in freshwater and marine ecosystems.  They include approximately 2,200 species of fish, shellfish, plants and algae as well as more than 500 species farmed in freshwater.  Blue foods play a central role in food and nutrition security for billions of people, and are a cornerstone of the livelihoods, economies, and cultures of many communities around the world.

But many of the world’s largest aquatic food producers are highly vulnerable to human-induced environmental change.  According to a new paper recently published in the journal Nature Sustainability, more than 90% of global blue food production is at risk from environmental changes, with top producers like the United States, Norway, and China facing the biggest threat.  Alarmingly, the research also found that some of the highest-risk countries in Asia, Latin America and Africa demonstrate the lowest capacity for adaptation. 

The paper is the first-ever global analysis of environmental stressors impacting the production quantity and safety of blue foods. A total of 17 anthropogenic stressors were surveyed, including rising seas and temperatures, ocean acidification, changes in rainfall, algal blooms, pollution, and pesticides. 

The research is one of seven scientific papers published by the Blue Food Assessment as part of a global effort to inform future aquatic food sustainability. 

The report calls for more transboundary collaboration and for a diversification of blue food production in high-risk countries to cope with the impact of environmental change. 

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Vulnerability of blue foods to human-induced environmental change

New research finds that more than 90% of global aquaculture faces substantial risk from environmental change

Photo, posted December 30, 2014, courtesy of NOAA’s National Ocean Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Value Of Seagrass | Earth Wise

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Seagrasses are found in shallow salty and brackish waters in many places around the world, from the tropics to the Arctic Circle.  They get their name from their long green, grass-like leaves.  They are not seaweeds at all but are more closely related to flowering plants on land. 

We hear a lot about threatened ocean ecosystems and most of the attention is on coral reefs and coastal mangrove forests.  Seagrass meadows get much less press, but they in fact provide wide-ranging services to society and store a great deal of carbon.

A new study by the University of Michigan demonstrates that seagrass ecosystems should be high up on the global conservation agenda.  The study puts a dollar value on the many services – which include storm protection, fish habitat, and carbon storage – provided by seagrasses in the Caribbean.  The numbers are enormous.

The researchers estimate that the Caribbean holds up to half of the world’s seagrass meadows by surface area, and it contains about a third of the global carbon storage by seagrasses.  They calculated that the Caribbean seagrasses provide about $255 billion in services to society each year, which includes $88 billion in carbon storage.

In the Bahamas alone, ecosystems services provided by seagrasses are valued at more than 15 times the country’s 2020 gross domestic product.

Blue carbon is the name used to describe carbon stored in coastal and open-ocean ecosystems.  The idea of selling blue carbon offset credits, which monetize the carbon stored in this way, is gaining traction.  For many Caribbean nations, this is likely to provide impetus for protecting seagrass ecosystems from human impacts, including nutrient pollution and overfishing.

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Caribbean seagrasses provide services worth $255B annually, including vast carbon storage, study shows

Photo, posted June 27, 2023, courtesy of Daniel Eidsmoe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Below-Average Dead Zone In The Gulf of Mexico | Earth Wise

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The Gulf of Mexico dead zone, or hypoxic area, is an area of low oxygen content that can kill fish and other marine life.  It occurs every summer and is mostly a result of excess nutrient pollution from human activities in cities and farms throughout the Mississippi River watershed.  The nutrients carried by the river into the gulf stimulate an overgrowth of algae, which eventually die and decompose, which depletes oxygen in the water as the algae sink to the bottom.

The resultant low oxygen levels near the bottom of the gulf cannot support most marine life.  Fish and shrimp often leave the area seeking better places to be.  Animals that can’t swim away – like mussels and crabs – can be stressed by the low oxygen level or even killed.

The National Oceanic and Atmospheric Administration produces a dead zone forecast each year based on a suite of models developed by NOAA and partners at multiple universities. 

The latest forecast, completed in May, found that the discharge of nutrients in the rivers was about one-third below the long-term average between 1980 and 2022.  Nitrate loads were down 42% and phosphorous levels down 5%.

Based on these measurements, the scientists forecast a summer dead zone that will cover an estimated 4,155 square miles, which is 22% lower than the 36-year average of 5,364 square miles.  Ongoing efforts by the Interagency Mississippi River and Gulf of Mexico Hypoxia Task Force to reduce nutrient levels seem to be paying off.

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NOAA forecasts below-average summer ‘dead zone’ in Gulf of Mexico

Photo, posted September 6, 2013, courtesy of NOAA Photo Library via Flickr.

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