The eel trade is driven by high demand and a limited supply. This combination makes eel trading highly profitable, but also controversial due to concerns about sustainability, illegal trafficking, and the impact on endangered species.



Despite strict regulations on European eel exports, illegal trafficking persists. Juvenile eels are smuggled out of the EU to Asia, where they are farmed and sold as food.



Recent research has focused on the European eel (Anguilla anguilla), which is a critically endangered species. Although its trade outside of the EU is highly restricted, large numbers of juvenile eels continue to reach Asian markets.



However, new findings suggest a shift in the global eel trade, with another species increasingly appearing in the market.



<h2 class="wp-block-heading" id="h-targeting-the-american-eel">Targeting the American eel</h2>



Researchers at <a href="https://www.yale-nus.edu.sg/" target="_blank" rel="noreferrer noopener">Yale-NUS College</a> conducted a study to investigate the presence of endangered eel species in Singapore’s markets. The team purchased 327 eel products from 86 retailers, including supermarkets, restaurants, and wholesalers.



DNA barcoding revealed an unexpected result. While a few samples contained <a href="https://www.earth.com/news/marine-protected-areas-lack-critical-fish-habitats/" target="_blank" rel="noreferrer noopener">European eels</a>, 70% of the tested products were identified as Anguilla rostrata, commonly known as the American eel.



Unlike its European counterpart, the American eel is not critically endangered. However, it is still classified as an <a href="https://www.earth.com/news/what-is-the-future-of-the-endangered-species-act/" target="_blank" rel="noreferrer noopener">endangered species</a> and faces significant threats from overfishing and habitat loss. 



The study’s findings suggest that traders may be shifting focus from European eels to American eels due to increasing enforcement of EU export restrictions.



<h2 class="wp-block-heading" id="h-the-need-for-urgent-action">The need for urgent action</h2>



These findings raise concerns about the future of the American eel population. Without stronger regulations, it could face the same fate as the European eel. 



The research team has called for greater enforcement and monitoring of the American eel trade to prevent further population declines.



The study was conducted as part of Yale-NUS alumnus Joshua Choo’s Environmental Studies capstone project, under the supervision of Professor Benjamin Wainwright.



“It was sad to connect Singaporean unagi with the history of anguillid eel exploitation - where a crash in one anguillid’s stock repeatedly leads to another’s overexploitation and crash," said Choo.



"It was, however, heartening to see so many researchers and Indigenous groups invested in anguillid recovery in Liverpool - from Japan to Aotearoa to the EU and UK."



"There’s room for Southeast Asian perspectives in eel science - it’s important to protect tropical anguillids from the endangerment plaguing their temperate cousins, and to explore <a href="https://www.earth.com/news/effective-conservation-efforts-key-to-saving-biodiversity/" target="_blank" rel="noreferrer noopener">conservation</a> solutions for our food that can bypass profit-driven overexploitation."



<h2 class="wp-block-heading" id="h-mislabeling-and-wildlife-crime">Mislabeling and wildlife crime</h2>



The study highlights the widespread mislabeling of eel products, often sold as generic "eel" or "unagi," which obscures their true species identity. This deceptive practice not only threatens biodiversity but also poses potential risks to human health and fuels illegal <a href="https://www.earth.com/news/some-sunscreens-lose-effectiveness-and-become-harmful/" target="_blank" rel="noreferrer noopener">wildlife trade</a>.



“The trade in eels is described as the greatest wildlife crime on Earth; it supports vast criminal networks that illegally traffic many hundreds of millions of glass eels (juvenile eels) to Asia each year,” said Professor Wainwright.



“What we show with this work is a likely shift in trade; this shift could be the consequence of EU enforced rules and regulations making it harder to smuggle the European eel to Asia, consequently suppliers have now shifted their focus to the less regulated American eel." 



"If the American eel is to avoid a similar fate to that suffered by the European eels, it will be important to closely monitor the American eel trade and introduce rules and regulations designed to prevent overexploitation."



<h2 class="wp-block-heading" id="h-eel-trade-and-wildlife-conservation">Eel trade and wildlife conservation</h2>



The study’s findings highlight the need for proactive conservation measures. Stricter monitoring, better labelling practices, and increased awareness among consumers can help curb the illegal eel trade. 



Consumers, researchers, and policymakers will need to work together to ensure that the global eel trade does not continue at the expense of biodiversity.



If no action is taken, the American eel could become the next critically endangered species, and follow the same tragic path as the European eel.



Choo presented the research at the 2024 International Eel Science Symposium in Liverpool, UK.



The full study was published in the journal <a href="https://conbio.onlinelibrary.wiley.com/doi/10.1111/csp2.70013" target="_blank" rel="noreferrer noopener">Conservation Science and Practice</a>.



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Eel trade is pushing another species to the brink

The eel trade is driven by high demand and a limited supply. This combination makes eel trading highly profitable, but also controversial due to concerns about sustainability, illegal trafficking, and the impact on endangered species. Despite strict regulations on European eel exports, illegal trafficking persists. Juvenile eels are smuggled out of the EU to Asia, where they are farmed and sold as food. Recent research has focused on the European eel (Anguilla anguilla), which is a critically endangered species. Although its trade outside of the EU is...

New research has found that while many tropical forests may appear structurally undisturbed, hunting can exert significant pressure on wildlife and result in large population declines.

The review covered 176 studies, which spanned from South America to Asia and Africa, encompassing 97 bird and 254 <a href="https://www.earth.com/video/chewing-early-mammals-survive/">mammal</a> species. Hunted and unhunted sites were analyzed for mammal and bird abundance and the data was used to estimate the overall reduction in these populations.

They concluded that both bird and mammal populations were significantly reduced in hunted areas – 53% and 82% respectively. Furthermore, the study found a direct relationship between population reduction and distance from hunters’ access points, urban trading markets, and protected areas. So even though mammal populations were higher inside protected areas compared to non-protected areas, nearby hunting still had a negative impact on mammal abundance within the protected areas.

It was also found that smaller mammals were almost always more abundant in places with higher hunting pressure than larger species, which the researchers say is due to smaller species experiencing a decrease in predation pressure as a result of humans hunting the more desirable medium and large-sized animals. So it goes without saying that these smaller mammals are big fans of the current hunting practices.

The authors believe a possible solution to these problems would be to increase strategies that sustainably manage wildlife hunting in both protected and unprotected tropical regions, as current strategies aren’t doing the job.

While protecting certain regions of tropical forests may help sustain some of the wildlife in that specific area, it’s important to understand the impact of hunting practices in nearby forests. Since most non-human species have a tough time reading sign postings, they’re likely to unknowingly cross between protected and non-protected areas. Studies like this are important for giving us a reality check on whether or not our protection efforts are helping.

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By <a href="mailto:certz@earth.com">Connor Ertz</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Source: <a href="http://www.aaas.org/">American Association for the Advancement of Science</a>

Hunting significantly reduces bird and mammal populations

New research has found that while many tropical forests may...

Without any access to a GPS or Google Maps, its hard to imagine how certain migratory species are able to navigate over vast distances. While these abilities have been heavily studied in animals such as geese and salmon, new research reported in <a href="http://www.cell.com/current-biology/home">Current Biology</a> shows new insight into how young eels are able to make a similar journey.

Each year, these juvenile eels travel from breeding grounds in the Sargasso Sea to coastal and freshwater habitats from North Africa to Scandinavia, where they spend several years before returning to the Sargasso Sea to spawn and then die.

Scientists have discovered that their ability to navigate is based on detecting slight differences in the earth’s magnetic field, which guides them to swim in the direction of the Gulf Stream. The Gulf Stream then leads them home to Europe.

“We were not surprised to find that eels have a magnetic map, but we were surprised to discover how well they can detect subtle differences in magnetic fields,” says Lewis Naisbett-Jones at the <a href="http://www.unc.edu/">University of North Carolina, Chapel Hill</a>. What also surprised them was that their ocean simulation models had revealed that the young eels use their magnetic map to target the Gulf Stream, instead of targeting Europe.

The researchers used a “magnetic displacement” experiment to show how juvenile eels detect magnetic fields and modify their behavior based on what they find. This involved building an experimental apparatus that allowed them to create magnetic fields in two different locations along the eel’s migratory route. They then placed juvenile eels within the apparatus and recorded which direction they moved.

They found that eels exposed to magnetic fields that exist in two locations along the migratory pathway oriented in different directions. By using computer simulations that imitated ocean currents, they found that if young eels swim even weakly in the directions the researchers observed, many more of them would successfully enter the <a href="https://www.earth.com/news/slowing-gulf-stream-will-spare-europe-the-worst-of-climate-change/">Gulf Stream</a> and eventually reach Europe.

These findings place eels on the exclusive list of animals with the ability to navigate based on a magnetic “sixth sense”. The researchers believe their study can be used to better predict shifts in the eels’ migratory routes and assist with the recruitment and catch of European eels – one of Europe’s most important fisheries.

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By <a href="mailto:certz@earth.com">Connor Ertz</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Source: <a href="about:blank">Cell Press</a>

Young eels use magnetic “sixth sense” to find the Gulf Stream

Without any access to a GPS or Google Maps, its...

One of the most difficult aspects of studying <a href="https://www.earth.com/news/fish-converge-evolution/">fish</a> is actually needing to navigate bodies of water and search their depths for your species of interest – but scientists may have just found a solution. For the first time, scientists have recorded data for a fish migration simply by testing DNA samples in the water. 

“Environmental DNA” (eDNA) was found in one-liter samples taken weekly from New York’s East and Hudson Rivers over a six month period. The DNA found in these samples was able to reveal the presence or absence of several key fish species passing through the river on each test day.

Fish leave traces of their DNA in the water as they swim, either through excretions or as parts of their gelatinous outer coating slough off their bodies. Surprisingly, the DNA remains intact enough to appear in water samples. 

The study was led by Senior Research Associate Mark Stoeckle, who explains that the DNA “…persists despite currents and tides with a goldilocks quality just right for research. If the DNA disappeared too quickly, we couldn't obtain an informative sample; if it persisted for too long, there would be too much DNA in the water to yield useful, timely insights."

By taking weekly samples from these rivers, the researchers were able to create a distinct picture of the migration that correlated with previous migratory studies that had used fishnet trawls. This new study from <a href="http://www.rockefeller.edu/">The Rockefeller University</a> could establish a new way to monitor fish migrations without the effort, cost, and harm that come with previous methods such as trawling.

“We didn’t find anything shocking about the fish migration – the seasonal movements and the species we found are known already,” says Stoeckle. “That’s actually good news, adding to evidence that eDNA is a good proxy. It amazes me that we can get the same information from a small cup of water and a large net full of fish.”

However, the eDNA method has not be perfected just yet. There are some species scientists are unable to distinguish. For example, some members of the herring family have identical sequences in the region of DNA used for testing. Furthermore, the reference library for DNA sequences isn’t complete, meaning some of the DNA obtained could not be identified.

The next steps for this method also involve fine tuning its calibrations. This can be done by attaining more eDNA samples and comparing the results to traditional surveys so that population data can be better balanced. 

Despite some of its current shortcomings, this exciting new technique comes with a low cost and has wide applicability. Sampling bodies of water using eDNA allows scientists to get a read on fish stocks without disturbing the fish, while also preventing some of the damage done by fish trawling. It isn’t an exact science, but it seems to have a bright future.

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By <a href="mailto:certz@earth.com">Connor Ertz</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Source: <a href="http://www.rockefeller.edu/">The Rockefeller University</a>

DNA samples shed light on fish migration patterns

One of the most difficult aspects of studying fish is actually...

The earliest known dinosaur relative, just now discovered and revealed in a recent article published in <a href="http://www.nature.com/nature/index.html">Nature</a>, goes against most scientists’ pre-conceived notions of what an early dinosaur relative would look like. 

This six-foot-long carnivorous lizard-like species is much larger than what scientists had come to expect of dinosaur relatives from the distant past. In fact, the lizard (formally known as Teleocrater rhadinus) was first identified by a British paleontologist named Alan Charig back in the 1950s, using <a href="https://www.earth.com/news/ancient-reptile-skeleton/">fossils</a> that were collected in the 1930s. Unfortunately for Charig, he didn’t recognize the connection between this fossil and dinosaurs, so this missing link remained missing.

Charig can be forgiven for his error, as the understanding of dinosaur evolution back in the 1950s was limited and Teleocrater didn’t look much like a dinosaur. Based off fossil study, it is believed that Teleocrater would have likely resembled the monitor lizards that are around today.

As Ken Angielczyk, <a href="https://www.fieldmuseum.org/">The Field Museum’s</a> associate curator of fossil mammals and one of the paper’s authors explains, “Surprisingly, early dinosaur relatives were pretty profoundly not dinosaur-like.” Angielczyk and his colleagues think the species could have grown between six and ten feet long, which includes its long neck and tail. 

The researchers believe that Teleocrater is the earliest member of the bird-like side of the archosaurs – a group that contains dinosaurs, birds, pterosaurs, and crocodilians. This would make it not a direct ancestor of dinosaurs, but rather the oldest known dinosaur cousin. 

Although some of its features clearly place it on the bird-like archosaur side with dinosaurs, it also appears to have had a lot in common with its more distant crocodilian cousins. Based on its rotating ankle joints, the researchers think that it probably walked with a more splayed, crocodile-like gait.

These revelations give scientists new insight on how dinosaur-like features may have evolved. "We used to think that many of the distinctive features of bird-line archosaurs evolved very quickly after they diverged from the crocodile line because early bird-line archosaurs like Marasuchus, Dromoeron, and Lagerpetonwere small and very dinosaur-like,” says Angielczyk. But with this new information, it appears that bird-line archosaurs may have first inherited some of their crocodile-like features from the common ancestor of all archosaurs. They believe now that the “typical” bird-line features evolved more slowly in a step-wise fashion over time.

Angielczyk explains, “Scientists generally don’t love the term ‘missing link,’ but that’s kind of what Teleocrater is: a missing link between dinosaurs and the common ancestor they share with crocodiles.”

The paper’s lead author, Sterling Nesbitt of <a href="https://www.vt.edu/">Virginia Polytechnic Institute and State University</a>, is still reveling in these new findings: “The discovery of such an important new species is a once-in-a-lifetime discovery,” says Nesbitt. “Teleocrater fundamentally changes our ideas about the earliest history of dinosaur relatives.”

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By <a href="mailto:certz@earth.com">Connor Ertz</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Source: <a href="https://www.fieldmuseum.org/">Field Museum</a>

Image Credit: Museo Argentino de Ciencias Naturales

Discovery of new “missing link” in dinosaur ancestry

The earliest known dinosaur relative, just now discovered and revealed...

Way back in 1952, famed mathematician Alan Turing hypothesized mathematical equations that detailed how skin color patterns in certain animals arise from microscopic interactions between colored cells. 
In 1948, another mathematician named John von Neumann invented a specialized computation system describing cellular automata – cellular in this case referring to individual elements, and not actual cells. This system was originally meant to be an insight into the logical requirements for machine self-replication – in other words, an autonomous machine building another version of itself. 
Why are these two mathematical discoveries important for science? Well, researchers at the <a href="http://www.unige.ch/international/en/">University of Geneva (UNIGE)</a> and <a href="http://www.sib.swiss/">Swiss Institute of Bioinformatics</a> just published a study that combines both Turing and von Neumann’s mathematical theories in an unlikely place – the colored scales of a southwestern European lizard.
The study finds that the ocellated <a href="https://www.earth.com/news/frightful-lizard-bed/">lizard</a> changes its skin color through interactions among pigment cells described by the Turing equations, but it is done in a pattern similar to von Neumann’s computation system. 
A multidisciplinary team of biologists, physicists, and computer scientists led by Michel Milinkovitch, a professor at the Department of Genetics and Evolution at the <a href="http://www.unige.ch/international/en/">UNIGE</a>, found that the brown juveline ocellated lizard changes its skin color as it ages, eventually reaching an intricate adult labyrinthine pattern where each scale is either green or black.
This observation went against prior understanding of Turing’s mechanism involving colored cells, as the pattern was forming at the level of the scales rather than at the level of biological cells. 
In order to figure out why this was occurring, the researchers followed individual lizards during four years of their development from hatchlings to fully mature adults. They reconstructed the geometry and color of the network of scales along multiple times points, finding that the lizards’ scales changed back and forth from green to black during its lifetime.
These observations caused Milinkovitch to hypothesize that the skin scale network forms a “cellular automaton,” a direct relation to von Neumann’s theory. As a further explanation of this complicated theory – cellular automata are networks of elements in which each element changes its state (in this case it’s skin cells changing color) depending on the states of neighboring elements.
It’s somewhat confusing, but that’s because it’s two mathematical theories combined with lizard anatomy and physiology, so it might as well be performing brain surgery on a rocket ship of your own design.
But it’s also exciting. Because the research team may have discovered what appears to be the first case of a genuine 2D automaton appearing in a living organism. Through analysis of the four years of lizard observation, the researchers were able to confirm Milinkovitch’s hypothesis: the scales were changing color depending on the colors of their neighbor’s scales.
The researchers were left wondering how the interactions among pigment cells described in Turing’s equations could end up generating a von Neumann automaton perfectly superposed to skin scales. The answer was that the scales of the lizard were not flat, but rather much thicker towards the center. Given that Turing’s mechanism involves the movement of cells, or the diffusion of signals produced by cells, Milinkovitch realized that the variation of skin thickness could have an impact on Turing’s mechanism.
To test Milinkovitch’s theory, the researchers ran computer simulations that included skin thickness and saw a cellular automation behavior emerge. This showed that a cellular automation as a computational system is not just an abstract concept, but also corresponds to a natural biological process.
After years of long, complicated research, this multidisciplinary team of researchers had made a remarkable discovery. This study is a prime example of what can happen when scientists of different disciplines collaborate in an effort to discover more about the world around us.


[caption id="attachment_259440" align="aligncenter" width="720"]<a href="https://www.earth.com/wp-content/uploads/2017/04/137670_web.jpg"><img class="size-full wp-image-259440" src="https://www.earth.com/wp-content/uploads/2017/04/137670_web.jpg" alt="" width="720" height="480" /></a> Credit: ©UNIGE[/caption]
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By <a href="mailto:certz@earth.com">Connor Ertz</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer
Source: <a href="http://www.unige.ch/">Université de Genéve</a>
Image: UNIGE

The real reasons behind the changing skin patterns of lizards

Way back in 1952, famed mathematician Alan Turing hypothesized mathematical...

It has been well-known for years that elephants are one of the most intelligent species of animal sharing this planet with us today – and scientists may have discovered new evidence showing just how smart they really are.

Researchers from the <a href="https://www.cam.ac.uk/">University of Cambridge</a> found that Asian elephants are able to recognize their bodies as obstacles impeding their success in problem-solving tasks. They postulate that their findings are new evidence supporting elephants’ heightened intelligence and self-awareness.

We know of very few species that have been found to be capable of self-recognition – including great apes, dolphins, magpies, and elephants. This is an uncommon trait, which scientists believe can be linked to more complex forms of perspective taking and empathy.

Dr. Josh Plotnik, a visiting researcher at the <a href="https://www.cam.ac.uk/">University of Cambridge</a> and founder of <a href="http://thinkelephants.org/">Think Elephants International</a>, along with his colleague Rachel Dale came up with a new test for body and self-awareness. “Elephants are well regarded as one of the most intelligent animals on the planet, but we still need more empirical, scientific evidence to support this belief,” says Dale.

The test was adapted from an established study where human <a href="https://www.earth.com/news/children-notice-adults-dont/">children</a> were asked to push a shopping cart, but the cart was attached to a mat on which they were standing.

In devising this test for elephants, the researchers attached a stick to a rubber mat using a rope. Individual elephants were then asked to walk onto the mat, pick up the stick, and pass it to a human standing in front of them. This task was designed to demonstrate the elephant’s understanding of its body in relation to its physical environment.

If the elephant recognized the mat as an obstacle to success in the task, they would step off the mat in order to pass along the stick. Intriguingly, Plotnik and Dale observed elephants doing just that more than 87% of the time.

“This is a deceptively simple test, but its implications are quite profound,” explains Plotnik. “The elephants understood that their bodies were getting in the way, so they stepped aside to enable themselves to complete the task. In a similar test, this is something that young children are unable to understand until they are about two years old.”

The researchers believe the results show that elephants are able to recognize themselves as separate from objects and their environment – a rare ability in the animal kingdom. This may further imply that they have the capacity for self-understanding.

In the past, species that have demonstrated a capacity for self-recognition all show varying levels of cooperative problem-solving as well. They also tend to exhibit perspective taking and empathy, which leads scientists to believe that self-awareness may be related to effective cooperative living in socially intelligent animals. Furthermore, the identification of self-awareness and body awareness can help scientists better understand how an animal’s understanding of self and of its place in the environment may impact their social decision-making in the wild. 

Plotnik believes that by furthering our understanding of elephant behavior, we can have more success in areas where human-elephant conflicts are commonplace. Humans and elephants are competing for land in places like Thailand and India, requiring long-term solutions that studies such as this may lead to.

“The more we can understand about elephants’ behavior, the more we can understand what their needs are, how they think, and the strains they face in their social relationships,” says Plotnik. “This will help us if we are going to try to come up with viable long term solutions to the problems that these animals face in the wild, especially those that bring them into regular conflict with humans.”

More information on this study can be found in the journal <a href="https://www.nature.com/srep/">Scientific Reports</a>.

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By <a href="mailto:certz@earth.com">Connor Ertz</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Source: <a href="https://www.cam.ac.uk/">University of Cambridge</a>

Despite their large size, elephants are very body conscious

It has been well-known for years that elephants are one...

Scientists have found that many social insects tend to have an “every insect for themselves” understanding, where if you get left behind or injured, it’s unlikely you’ll receive any help or sympathy. This attitude makes sense, as there are generally so many individuals that it would simply be a waste of resources to provide excess care to just one. However, a German research team from the <a href="http://www.biozentrum.uni-wuerzburg.de/en/start/">University of Würzburg’s Biocenter</a> has recently discovered a clear rescue behavior in African Matabele ants (Megaponera analis). This ant species strictly preys on termites and is widespread south of the Saharan Desert.

These ants go out and hunt termites about two to four times per day. Marching in long, organized columns, M. analis raid termites at their foraging sites, killing as many workers as they can before hauling the <a href="https://www.earth.com/news/sharks-hear-preys-heartbeat-important/">prey</a> back to their nest. 

During these attacks, the soldier termites will often fight back – clamping onto the ants with their sharp, powerful jaws. Not surprisingly, some ants can get injured or killed in these battles. 

Researchers observed that when an ant is injured in a fight, it may excrete chemical substances that serve as a “call” for help to its ant brethren. Other ants then come to its rescue, carrying it back to the nest so it can recover and receive treatment. Since no ant operating rooms or therapy centers were observed, it appears that “treatment” involves other ants simply removing the termites still clinging to the wounded party.

Although it may not seem like much, this discovery is novel in the insect world. Erik Frank, a Ph.D. student at the <a href="https://www.uni-wuerzburg.de/en/ueber/university/">University of Würzburg</a>, explains, “We have observed helping behavior vis-à-vis injured animals for the first time in invertebrates.”

Although it is rare to see this helping behavior in the insect world, it’s likely that there are other species out there – perhaps undiscovered – that exhibit similar behaviors to the African Matabele ant. 

More information on this study can be found in the journal Science Advances.

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By <a href="mailto:certz@earth.com">Connor Ertz</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Source: <a href="https://www.uni-wuerzburg.de/en/ueber/university/">University of Würzburg</a>

Image Credit: Erik Frank

Ants have each other’s backs and rescue their injured

Scientists have found that many social insects tend to have...

A study published in the open access journal <a href="http://journals.plos.org/plosbiology/">PLOS Biology</a> has combined genetic analysis with an ambitious 19-year-long selection experiment in order to follow the evolution of a single color-vision gene in fish. The findings show that the mechanisms of adaptive evolution may actually be more predictable than previously thought.

For over 12,000 years, species of three-spined stickleback fish have flourished in the hundreds of freshwater lakes off the coast of British Columbia. Interestingly, these fish have branched out and formed independently evolving populations within their <a href="https://www.earth.com/news/road-salt-runoff-killing-twin-city-lakes/">lakes</a>.

All of these lakes can be broadly classified as either “clearwater” or “blackwater.” In clearwater lakes, full spectrum light is able to pass through the water relatively unimpeded, making visibility much easier for eyes such as our own. In blackwater lakes, most of the visible light is absorbed, creating an almost nocturnal environment where only dim, red-shifted light is able to get through.

The opsin protein SWS2 is sensitive to blue light, and can be found in the cone cells responsible for color vision in stickleback retina. Previous studies have show that amino acids changes in this protein allow it to be “tuned” to make it more sensitive to either the blue or red end of the light spectrum.

In this study, researchers compared the genetic sequences of SWS2 from marine, clearwater, and blackwater sticklebacks. Included in this group was a population of blackwater fish that the scientists had transplanted into an empty clearwater lake 19 years before, leaving them there to evolve.

Through genetic analysis, they found that the pattern of genetic changes in SWS2 in blackwater sticklebacks showed there had been a very strong selection for red-shift tuning. This means blackwater sticklebacks quickly evolved to see better in dark water. Not surprisingly, this adaption was not seen in clearwater sticklebacks.

The research team also found that the blackwater fish they had transplanted to a clearwater lake 19 years prior actually expressed a similar natural selection – except this time with the SWS2 becoming more sensitive to the abundant blue light in the clearwater lake. After only 13 generations, a significant portion of the population contained alternative versions of the gene that shifted to blue light sensitivity. These results show how remarkably fast this selective pressure can work.

Finally, the researchers also compared their stickleback results to other studies on the opsin genes of two related species of fish. The Bluefin killifish and black bream are distantly related to sticklebacks – separating on the evolutionary tree millions of years ago. These fish had also adapted to both blackwater and clearwater habitats.

Despite their distant relation, the researchers found two of the same genetic changes seen in stickleback SWS2 also show up in the SWS2 genes of these fish species. Because these same genetic changes occurred separately in their ancestor and in the sticklebacks, this is a perfect example of convergent evolution occurring over vastly different time scales (19 years versus millions of years).

David Marques of the <a href="http://www.uvic.ca/">University of Victoria</a> believes that the data “show that evolutionary ‘tinkering’ with a limited set of tools can lead to convergent ‘solutions’ to common problems both within species and between widely separated groups.” In other words, evolution may occur more predictably than we ever imagined.

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By <a href="mailto:certz@earth.com">Connor Ertz</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Source: <a href="https://www.plos.org/">PLOS</a>

Image Credit: Thomas E. Reimchen

Fish converge in evolution to assimilate to dark water

A study published in the open access journal PLOS Biology...

Polar bears are solitary and often elusive hunters. Their white-on-white camouflage into the snowy background of the <a href="https://www.earth.com/news/idea-tackle-arctic-ice-melt/">Arctic</a> can make it hard for prey to spot them, as well as for scientists to research them.

Despite these difficulties, researchers at the <a href="https://www.ualberta.ca/">University of Alberta</a> have recently discovered the tactics behind how polar bears hunt for ringed seals – one of their favorite prey species. Hold onto your hat because this answer may shock you: they use their sense of smell.

Although that “discovery” may seem rather obvious, it goes a little deeper than that. The researchers attained satellite telemetry data collected from more than 120 adult polar bears in Canada’s Hudson Bay over an 11-year period. They then combined the movements of these polar bears with wind patterns in order to see how the two matched up.

“Predators search for prey using odors in the air, and their success depends on how they move relative to the wind,” says Ron Togunov, <a href="https://www.ualberta.ca/">University of Alberta</a> alumnus and lead author on the study. Before beginning the study, the researchers had hypothesized that when a bear smells prey, it moves up-wind to find it. But they were left wondering what a polar bear might do before it even catches on to a smell.

As Togunov explains, “Travelling crosswind gives the bears a steady supply of new air streams and maximizes the area they can sense through smell.” This behavior was suspected in many animals, but this is the first time scientists have been able to quantify it in mammals.

The researchers found that the best conditions for this type of hunting usually occur at night in the Arctic winter. "Crosswind search was most frequent when winds were slow, when it is easier to localize the source of a certain smell, and at night when bears are relatively active and when vision is less effective, so bears rely more heavily on their sense of smell,” explains <a href="https://www.ualberta.ca/">University of Alberta</a> professor Andrew Derocher.

Like most studies done in the Arctic these days, the findings also gave scientists pause about the implications of climate change on these polar bears. “Wind speeds in the Arctic are projected to increase, potentially making olfaction more difficult,” explained Togunov. “It is important to understand how polar bear hunting success will be affected by these changing conditions.”

--

By <a href="mailto:certz@earth.com">Connor Ertz</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Source: <a href="https://www.ualberta.ca/">University of Alberta</a>

The secret weapon behind the hunting tactics of polar bears

Polar bears are solitary and often elusive hunters. Their white-on-white...

Imagine an earthquake this powerful: “The ground would be moving up and down and sideways like a ship in a strong storm.” You’d certainly get tossed around, but there’d be no building damage whatsoever. That’s because there would have been no buildings. In describing this particular quake, Norm Sleep, a professor of geophysics at <a href="https://www.stanford.edu/">Stanford University</a>, is setting the scene 65 million years ago. The place is present-day Trinidad Lakes State Park in Colorado and he’s describing a visible fault line that his team feels was created by the impact of a horribly lethal asteroid in present-day Yucatan Peninsula, Mexico.

In the theory laid out by Sleep and his colleagues, the impact was powerful enough to generated massive seismic waves that triggered a Magnitude 6 earthquake as far away as Colorado, in the center of a tectonic plate where no previous fault had existed. That quake, in turn, contributed to the end of the <a href="https://www.earth.com/news/dinosaur-species-similarities-humans/">dinosaur</a> reign on Earth.

Sleep and his colleagues found evidence for the fault in two areas in Colorado's Trinidad Lakes State Park, where a layer of iridium generated by the asteroid impact clearly marks the boundary between Cretaceous and Tertiary-age rocks, at the time of the dinosaurs' extinction about 65 million years ago.

At the two roadcuts, said Sleep, “there is a fault that slipped about a meter at the time of the impact. It offset the material below the impact layer but not above, but it's not something that would be obvious to the casual observer.”

The team feels that it would have taken such a massive jolt as the asteroid strike to trigger an earthquake in the middle of a tectonic plate with no previous faults.

<a href="http://news.nationalgeographic.com/2016/06/what-happened-day-dinosaurs-died-chicxulub-drilling-asteroid-science/">National Geographic paints an apocalyptic picture</a> of the event itself. The magazine says that the killer asteroid might have been the size of a mountain and slammed home with the force of 100 million tons of TNT. Depending on distance from impact, death would have come by vaporization, thermal radiation, tsunami winds, floods, earthquakes or starvation through years of lost sunlight from grit and soil thrown into the atmosphere.

-- 

By <a href="mailto:dsearls@earth.com">David Searls</a>,<a href="https://www.earth.com/staff/"> Earth.com</a> Staff Writer

Source:<a href="https://eurekalert.org/pub_releases/2017-04/ssoa-cac041117.php"> Seismological Society of America</a>,<a href="http://news.nationalgeographic.com/2016/06/what-happened-day-dinosaurs-died-chicxulub-drilling-asteroid-science/"> National Geographic</a>

Is Colorado fault line evidence of dino extinction asteroid hit?

Imagine an earthquake this powerful: “The ground would be moving...

It has been a long time since most humans have had to think about hunting animals for food – at least out of necessity, and given that you’re reading this on the internet that probably applies to you. Because of this, it’s easy to forget the dangers of hunting certain types of game. It’s also likely you’ve never been faced with a decision of which game to hunt for, unless you count standing amongst all the packaged meats at your local grocery store. So the phenomenon known as “prey switching” has likely never been a factor in many of our lives.

Prey switching has been observed amongst predacious species for a long time. It’s the tactic of changing the pursuit of one prey species for another, and can occur for a variety of reasons. One of those reasons is that a prey species may become less plentiful, so the predator switches to another, more abundant prey. For this reason alone, prey switching is ecologically important, as it helps stabilize wildlife populations.

But there are certain circumstances where a predator would rather hunt a scarce species than go after one that is abundant. 

<a href="https://www.usu.edu/">Utah State University</a> researchers Aimee Tallian and Dan MacNulty observed this exact circumstance play out amongst the wolves in <a href="https://www.earth.com/news/yellowstone-wild-bison-slaughter/">Yellowstone National Park</a>. The researchers found that Yellowstone wolves seldom hunt bison and instead pursue elk, even though the later is much more scarce.

“Prey switching has been observed in natural systems, where prey are small and generally helpless when attacked by a predator,” says Tallian. This, however, is not the case in Yellowstone. 

The researchers discovered the “data [revealed] wolves maintained a strong preference against bison, even when bison were twice as abundant as elk.” The reason for this: bison are incredibly dangerous game. An adult bull bison can weigh almost a ton.

“Hunting is hazardous business for wolves,” explains MacNulty. The researchers have observed wolves being kicked, gored, and stomped to death in the pursuit of large bison and other prey. “Wolves minimize the risk of injury by focusing on more vulnerable prey, which are generally rare.”

The study also revealed that wolves became increasingly resistant to hunting bison as the bison population increased. This is likely due to the fact that hunting bison becomes easier when the herd is smaller and wolves are able to target the more vulnerable and less dangerous calves.

Rather than hunting live bison, most wolves stuck to scavenging on bison carrion, which became more frequent as bison populations increased. Tallian believes an increase in bison carrion consumption also helps stabilize elk population dynamics, saying, “The ability of wolves and other predators to shift between hunting and scavenging is an under-appreciated behavior that may play an important role in the dynamics of ecological communities with dangerous prey.” 

Observations like the ones made in this study help us better understand the hunting behaviors and strategies of these predators, as well as how they impact the ecosystem as a whole.

--

By <a href="mailto:certz@earth.com">Connor Ertz</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Source: <a href="https://www.usu.edu/">Utah State University</a>

Image: Daniel Stahler, NPS

Yellowstone wolves avoid hunting bison as a means of self-preservation

It has been a long time since most humans have...

Try not to worry about this too much as you check into a hotel or motel, but <a href="https://www.earth.com/news/ancient-remains-bed-bug/">bed bugs</a> are becoming ever-more resistant to insecticides – and the main cause is world travel. That’s according to a study conducted at <a href="http://www.purdue.edu/">Purdue University</a> and published this month in the Journal of Economic Entomology.

The researchers used bed bugs contributed from the field and found significantly reduced susceptibility to the treatment chemical chlorfenapyr among three of the ten bed bug populations, and to bifenthrin among half of the populations. Reduced susceptibility was defined as when more than 25 percent of the bugs had survived after seven days’ exposure to the insecticide.

This is in addition to the already noted significant resistance shown by the common bed bug to the chemical deltamethrin and some other pyrethroid-based insecticides.

Organisms can develop resistance to chemical treatments after generations of exposure, so it takes continuous development of new chemicals to control a pest population. One factor to the bed bugs’ advantage is that their eggs aren’t vulnerable to the insecticides, according to the <a href="https://www.epa.gov/">Environmental Protection Agency</a>.

Travelers can pick up bed bugs in hotels and inadvertently take them home in shoes, clothing or luggage.

<a href="https://www.epa.gov/bedbugs/do-it-yourself-bed-bug-control">The EPA offers this advice</a> on how to attempt to control the pests with and without insecticides, but be warned in advance – it ain’t fast or easy.

“There is a plethora of research that has shown that if insecticides are integrated with additional control measures such as vacuuming, steam or heat, mattress encasements, traps, and desiccant dusts, effective bed bug control can be accomplished and theoretically this should reduce the risk of resistance build-up in populations,” said Ameya D. Gondhalekar, Ph.D., research assistant professor at <a href="https://extension.entm.purdue.edu/urban/">Purdue's Center for Urban and Industrial Pest Management</a> and a member of the research team.

-- 

By <a href="mailto:dsearls@earth.com">David Searls</a>,<a href="https://www.earth.com/staff/"> Earth.com</a> Staff Writer

Source:<a href="https://academic.oup.com/jee/article-abstract/110/2/i5/3574029/Journal-of-Economic-Entomology-April-2017-Volume?redirectedFrom=fulltext"> Journal of Economic Entomology</a>

Bed bugs becoming increasingly resistant to insecticides

Try not to worry about this too much as you...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Nushagak Bay, a large estuary in southwest Alaska. Nushagak runs mainly north to south and exits in Bristol Bay, a large body of water in the Bering Sea.



"The bay is primarily fed by the Nushagak River, which begins in the Alaska Range and flows southwest approximately 450 km. The bay is also fed by several additional rivers including the Wood, Igushik, Snake and Weary rivers," says ESA.



"The dark colors of the Nushagak River are most likely due to tannins or lignins (chemical substances found in plants). Tannins and lignins from roots, leaves, seeds, bark and soil can leach into the water and give it a brown or even black colour. The sediments then flow southwards where it is mixed with the bluer waters of the bay."



Video/ Image Credit: ESA



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Nushagak Bay in southwest Alaska

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Today's Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> (ACS) reveals that proteins on flu viruses are actually flexible, tilting and waving in a “breath-like” motion. According to the experts, these proteins could be used to better defend against the flu.



"The main antigenic targets of influenza virus are two surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). Whereas the structural and dynamical properties of both glycoproteins have been studied previously, the understanding of their plasticity in the whole-virion context is fragmented," wrote the researchers.



To investigate, the team conducted detailed simulations of the influenza A H1N1 virion, or the swine flu. The experts concluded that the visualizations show many new vulnerable states of flu viruses, which could improve future vaccines and antiviral drugs.



Video/ Image Credit: American Chemical Society&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Flu viruses are more flexible than expected

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Lake Trasimeno, which is located west of Perugia in central Italy. It is the fourth largest lake in the country. While Trasimeno’s water level varies, it has a maximum depth of approximately six meters.&nbsp;



"In this Copernicus Sentinel-2 image, captured on 6 August 2022, the lake’s emerald green colour is likely due to the presence of phytoplankton. Streaks in the water, particularly visible in the west, indicate the presence of soil and sediments which have been stirred up by winds. Dark colored waters in the southern part of the lake indicate a presence of submerged and floating macrophytes (aquatic plants) as well as algae," says ESA.



"Surrounded by hills on three sides, Trasimeno is subject to heavy storms created by winds, especially from the north and west. There are three islets in the lake: Maggiore, Minore and Polvese (the largest). The lake’s shores are sparsely inhabited with only two popular villages: Castiglione del Lago and Passignano sul Trasimeno."



"Italy is experiencing its worst drought in 70 years which has affected drinking water supplies, hydroelectric power and agricultural production. High temperatures, hot winds and lack of rainfall are the main causes of drought in the Umbrian region which saw Lake Trasimeno’s drop 1.3 m, reaching the limit of the hydrometric zero in July 2022."



Video/Image Credit: ESA&nbsp;



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Lake Trasimeno in Central Italy

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Today's Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> describes a new self-powered nanosensor that can instantly detect mercury contamination with the tap of a finger.&nbsp;



The oxidized form of mercury can be harmful when it is ingested through contaminated water or food. This makes it necessary for experts to develop sensors that can quickly and accurately detect the presence of mercury.&nbsp;



Zong-Hong Lin and colleagues have now created a triboelectric nanosensor (TENS) that can detect mercury by simply by touching a sample. According to the researchers, their TENS could serve as the basis for similar devices to safely and remotely monitor other pollutants.



Video Credit: American Chemical Society&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Detecting mercury contamination with the tap of a finger

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Today’s Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> explores the ability of salt to transform the way that foods and beverages taste. Salt is known to cover up undesirable flavors, such as bitterness in coffee or beer, but how exactly does sodium chloride change the taste of other compounds?



One previous study showed that, not only does salt suppress bitterness, but also enhances sweetness and sourness. Another study revealed that bitterness reduction by salt seems to be happening at the tongue receptor level as well as in the brain.&nbsp;



While it is known that salt taste is mediated by the presence of sodium channels in the form of taste buds, experts believe that there is also an unknown receptor responsible for how we taste salt that has not yet been identified.&nbsp;



Video Credit: ACS Reactions



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

How does salt makes things taste better?

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Santiago, the capital city of Chile. The city is located in the center of the Santiago Metropolitan Region, which has a population of about eight million people.&nbsp;



'The weather of Santiago resembles the Mediterranean climate with dry and warm summers with temperatures reaching up to 35°C (from October to March) and cool and humid winters that can drop to 0°C (from April to September)."



"The city lies in the centre of the country’s central valley around 80 km from the Pacific Ocean to the west and borders Argentina to the east. A tiny part of Argentina is visible in the top-right corner of the image where the mountain crest of the Andes Mountains acts as a divider between the two countries," says ESA.



Video/ Image Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Santiago, Chile in South America

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Spiral,Galaxy,,Illustration,Of,Milky,Way

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Astronomers at <a href="https://www.jhu.edu/">Johns Hopkins University</a> have created an interactive map of the universe, including the actual position and real colors of 200,000 galaxies. The map allows the public to access data that was previously only available to scientists.



The map was developed using data collected by the Sloan Digital Sky Survey. For over two decades, a telescope in New Mexico was aimed at slightly different locations to capture the night sky.&nbsp;



"Growing up I was very inspired by astronomy pictures, stars, nebulae and galaxies, and now it's our time to create a new type of picture to inspire people," said map creator Brice Ménard, a professor at Johns Hopkins. "Astrophysicists around the world have been analyzing this data for years, leading to thousands of scientific papers and discoveries. But nobody took the time to create a map that is beautiful, scientifically accurate, and accessible to people who are not scientists. Our goal here is to show everybody what the universe really looks like."



"In this map, we are just a speck at the very bottom, just one pixel. And when I say we, I mean our galaxy, the Milky Way which has billions of stars and planets. We are used to seeing astronomical pictures showing one galaxy here, one galaxy there or perhaps a group of galaxies. But what this map shows is a very, very different scale."



"From this speck at the bottom, we are able to map out galaxies across the entire universe, and that says something about the power of science."



The <a href="https://mapoftheuniverse.net/">interactive map</a> is available online, where it can be downloaded for free.



Video Credit: Johns Hopkins&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Interactive map of the universe includes 200,000 galaxies

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Lesotho: Africa's "Kingdom in the Sky" Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features northwest Lesotho in South Africa.



According to ESA, Lesotho is the only nation in the world that lies completely above 1,000 m in elevation. The country is famous for its tall mountains and narrow valleys, and is known as Africa's "Kingdom in the Sky."



Out of a population of around two million people, about 80 percent live in rural areas. More than 75 percent of these people are engaged in <a href="https://www.earth.com/news/climate-change-will-have-a-global-impact-on-agriculture/">agriculture</a>, including rainfed cereal production and animal grazing.&nbsp;



ESA reports that the country’s agricultural system faces a growing number of issues, with climate-related vulnerabilities such as drought, floods and extreme temperatures occurring more frequently. 



Diamonds are amongst the minerals found in the mountains. Indeed, Lesotho can truly be called the Kingdom in the Sky. Beautiful, culturally rich, safe, affordable, and easily accessible from Durban and Johannesburg, mountainous Lesotho is a vastly underrated travel destination. the Kingdom of Lesotho (Sotho: 'Muso oa Lesotho) is an enclaved country in southern Africa. It is just over 30,000 km2 (11,583 sq mi) in size and has a population of around 2 million.



Video Credit: ESA&nbsp;&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer 



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Lesotho: Africa's "Kingdom in the Sky"

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Today's Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Dublin, the capital and largest city of Ireland. Beyond its pub culture, Dublin is known as a modern culinary destination and a UNESCO City of Literature.



"Dublin is located near the midpoint of Ireland’s east coast in the province of Leinster. The city, which covers an area of around 115 square kilometers, is bordered by the Dublin Mountains, a low mountain range to the south, and is surrounded by flat farmland to the north and west," says ESA.



"The city straddles the River Liffey, which rises in the Wicklow Mountains and flows around 80 kilometers eastwards through the city of Dublin, in which it is canalised and bordered with quays. It then empties into Dublin Bay, an arm of the Irish Sea."



Dublin has an abundance of green spaces, including one of the largest enclosed public parks in any European capital city. Phoenix Park, which was originally formed as a royal hunting park in the 1660s, includes 707 hectares of green space.



Video Credit: ESA&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

The city of Dublin on Ireland's east coast

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Today's Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features the province of Zaragoza in northeast Spain. The image was captured by the Copernicus Sentinel-2 mission.



"Together with the provinces of Huesca and Teruel, Zaragoza formed the old kingdom of Aragon. Its capital, also called Zaragoza (not visible in this image) is home to around half of Aragon’s population," says ESA.



"The Ebro River can be seen winding its way through the province from west to east in this image. Between its source in the Cantabrian Mountains in the northwest and its delta on the Mediterranean coast, the Ebro River is fed by more than 200 tributaries as it flows 910 km across much of northern Spain."



Since rainfall is very scarce in this region, irrigation in the Ebro basin is critically important. In the valleys surrounding the Ebro River, many fields are used for growing crops such as corn, wheat, and barley.



Video/ Image Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

The province of Zaragoza in northeast Spain

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Today’s Video of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> reveals the evolution of the Columbia Glacier in southeastern Alaska. Columbia is among the fastest shrinking glaciers in the world, and the video documents its rapid retreat over the years.&nbsp;



Columbia Glacier is a large, multi-branched calving glacier that flows out of the Chugach Mountains to the Prince William Sound.&nbsp;



According to USGS, Columbia had a long history of stability prior to 1980, with a length 41 miles, and small, short-lived advances or retreats.



In the years since 1980, however, satellite images have captured Columbia’s alarming retreat. By using false-color images, scientists can distinguish between snow and ice, open water, vegetation, and rocky debris on the glacier’s surface.



The series of false-color images featured in today's video were acquired over the span of 35 years. You can see that by 2021, the glacier’s main branch had retreated about 15 miles from its initial position.



The Columbia Glacier has also lost more than 50 percent of its volume, mostly due to calving. <a href="https://www.earth.com/video/nasa-reveals-3d-visual-of-an-atmospheric-river/">NASA</a> reports that while climate change likely started the retreat, mechanical processes kept the disintegration going.



The NASA images are provided by Jesse Allen, Robert Simmon, Joshua Stevens, and Lauren Dauphin using data from Landsat satellites, from the U.S. Geological Survey, and data from MODIS on NASA’s Terra satellite. The structure of Columbia’s moraine played a large role in the stability of the glacier before 1980. 



Like other tidewater glaciers, the Columbia built up a moraine over time, and the mixture of ice and rock functioned like a dam keeping out the sea. It was supported on one end by the shoreline and by the underwater terminal moraine at the other.



Video Credit: NASA Earth Observatory/&nbsp; NASA’s Scientific Visualization Studio



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

The rapid retreat of the Columbia Glacier

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features the Pyrenees Mountains, which form a natural boundary between France and Spain in southwest Europe.



The mountain range is 430 kilometers in length. It stretches from the Mediterranean Sea on the east to the Atlantic Ocean on the west.



At an elevation of 3404 meters, Pico de Aneto is the highest mountain peak in the Pyrenees, and the third-highest peak in Spain. Pico de Aneto is located in the Posets-Maladeta Natural Park, which spans more than 82,000 acres.&nbsp;



"Geological studies have revealed that the Pyrenees Mountains have been around for longer than the Alps, with their sediments first deposited in coastal basins during the Paleozoic and Mesozoic eras," reports ESA.



"The entire mountain range formed due to the upwelling of large sedimentary rocks by the collision of the Iberian and the Eurasian plate around 100 to 150 million years ago, followed by intense erosion from ice and water."



The western Pyrenees receive more precipitation due to moisture blowing in from the Atlantic Ocean. The mountain range contains many lakes, several small glaciers, and some of the highest waterfalls in Europe.



Video &amp; Image Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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The Pyrenees Mountains in southwest Europe

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Earth,Like,Exoplanet,3d,Render

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Today's Video of the Day from <a href="https://www.nasa.gov/goddard">NASA Goddard</a> describes two exoplanets that are orbiting a star 218 light-years away. A team of researchers led by the University of Montreal has found evidence that these planets are "water worlds."



The experts used data from NASA’s Hubble and Spitzer Space Telescopes. They discovered that exoplanets Kepler-138 c and Kepler-138 could be composed largely of water.



"We previously thought that planets that were a bit larger than Earth were big balls of metal and rock, like scaled-up versions of Earth, and that's why we called them super-Earths," explained study co-author Björn Benneke.&nbsp;



"However, we have now shown that these two planets, Kepler-138 c and d, are quite different in nature and that a big fraction of their entire volume is likely composed of water. It is the best evidence yet for water worlds, a type of planet that was theorized by astronomers to exist for a long time."



Video Credit: NASA Goddard



Image Credit: NASA, ESA, and Leah Hustak (STScI)



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Two distant planets may be "water worlds"

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Satellites reveal how Earth's systems are interconnected Today’s Video of the Day from <a href="https://www.nasa.gov/goddard">NASA Goddard</a> describes Earth’s interconnected systems, and how this network is affected by rising temperatures.&nbsp;



During 2020, average global temperatures matched the hottest year on record. The hurricane season was also record-breaking, with many of the storms intensifying at extraordinary speeds. Hot water in the ocean is fuel for hurricanes. The satellite data shows that it's all one interconnected system showing how Satellites reveal how Earth's systems are interconnected.



According to NASA, dust swept up from Northern Africa plays a major role in the formation of hurricanes, and is also a key source of fertilization in the Amazon rainforest. As a result of<a href="https://www.earth.com/news/seagrass-wasting-disease-is-fueled-by-climate-change/"> climate</a> change, dust plumes are expected to decline, which will have an effect on vegetation far away.&nbsp;



Images from Earth-observing satellites show how the world’s plant life is affected by natural disasters, fires, and deforestation. Satellites also reveal how widespread changes in vegetation impact waterways,&nbsp; the climate, air quality. Satellites communicate by using radio waves to send signals to the antennas on the Earth. "Earth From Space" is a groundbreaking two-hour special that reveals a spectacular new space-based vision of our planet. 



Video Credit: NASA Goddard&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Satellites reveal how Earth's systems are interconnected

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Today’s Video of the Day from the <a href="https://welcome.miami.edu/">University of Miami</a> Rosenstiel School of Marine and Atmospheric Science explores how changes in water temperatures have affected tiger shark habitats and movements in the North Atlantic Ocean. The study reveals that rising temperatures have caused the sharks to shift toward the poles over the past 40 years.



“Tiger shark annual migrations have expanded poleward, paralleling rising water temperatures,” explained study lead author Neil Hammerschlag. “These results have consequences for tiger shark conservation, since shifts in their movements outside of marine protected areas may leave them more vulnerable to commercial fishing.”



The researchers analyzed nine years of tracking data from satellite-tagged tiger sharks, combined with four decades of conventional tag and recapture data provided by National Oceanic and Atmospheric Administration (NOAA) Cooperative Shark Tagging Program.



The experts found that during the last decade of record heat, for every one-degree Celsius increase in water temperatures, tiger sharks migrated further poleward by over 400 kilometers. They also migrated two weeks earlier than usual to waters off the northeastern coast of the United States.



“Given their role as apex predators, these changes to tiger shark movements may alter predator-prey interactions, leading to ecological imbalances, and more frequent encounters with humans,” concluded Professor Hammerschlag.



Video Credit: University of Miami Rosenstiel School of Marine and Atmospheric Science



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Tiger sharks are shifting poleward as temperatures rise

Today’s Video of the Day from the University of Miami...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> is focused on the melt ponds that emerge during the spring and summer on the Greenland Ice Sheet, which is the largest ice mass in the northern hemisphere.



"Melt ponds are vast pools of open water that form on both sea ice and ice sheets and are visible as turquoise-blue pools of water in this Copernicus Sentinel-2 image," says ESA.



"When snow and ice melts atop glaciers, water flows in channels and streams and collects in depressions on the surface. These melt ponds can speed up the melting of the surrounding ice since they greatly reduce the ice’s ability to reflect sunlight."



"This can create a positive feedback where an increasing number of melt ponds absorb more heat which causes ice cover to melt even faster."



According to ESA, Greenland has been hit with a late-season heatwave that began in early September. This caused the type of melt event that usually occurs in the middle of summer.



"In a recent paper published in Nature Climate Change, scientists found that major sea-level rise from the melting of the Greenland ice cap is now ‘inevitable’ even if the burning of fossil fuels were to halt overnight," says ESA. "Using satellite observations of Greenland ice loss and ice cap from 2000 to 2019, the team found the losses will lead to a minimum rise of 27 cm regardless of climate change."



Video Credit: ESA&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Melt ponds on the Greenland Ice Sheet

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> describes a new map of Mars that is providing insight into the planet’s watery past. The map also reveals where future missions could safely land on Mars.&nbsp;



The map has been created over the last decade using observations of water-rich rocks and mineral deposits. The images were captured by ESA’s Mars Express and NASA’s Mars Reconnaissance Orbiter.



"A big surprise is the prevalence of these minerals, with the map revealing hundreds of thousands of water-affected locations in the oldest parts of the planet," says ESA. "The new data will help answer exciting questions about Mars’ climate history, whether water was globally persistent or confined to short, intense episodes, and whether the conditions were ever suitable for life."



"Specifically, the map shows the locations and abundances of aqueous minerals. These are from rocks that have been chemically altered by the action of water in the past, and have typically been transformed into clays and salts."



According to John Carter of the Institut d’Astrophysique Spatiale (IAS), our collective understanding of Mars has been oversimplified. He explained that planetary scientists have tended to think that only a few types of clay minerals on Mars were created during its wet period, then as the water gradually dried up, salts were produced across the planet.



The new map shows that the composition of Mars is much more complicated than what we thought. For example, while many salts formed after Martian clays, there are some salts that are presumed to be older than some of the clays.&nbsp;



“The evolution from lots of water to no water is not as clear cut as we thought, the water didn’t just stop overnight. We see a huge diversity of geological contexts, so that no one process or simple timeline can explain the evolution of the mineralogy of Mars. That’s the first result of our study. The second is that if you exclude life processes on Earth, Mars exhibits a diversity of mineralogy in geological settings just as Earth does,” said Carter.



Video Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

The history of Mars is much more complex than we thought

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Today's Video of the Day from the <a href="https://www.stowers.org/">Stowers Institute for Medical Research</a> describes how cavefish adapted to a sedentary lifestyle over tens of thousands of years. 



The experts found that the muscle metabolism of cavefish has been genetically reprogrammed over time. As a result, the animals have experienced major changes in their morphology and behavior. Despite these changes, however, the cavefish remain healthy and fit.



The research may provide new clues about the evolutionary consequences of prolonged physical inactivity in humans.&nbsp;



“It’s no surprise that people are moving less and less as technology has advanced,” said Rohner. “With cavefish, we have a unique system where we can study what might happen if people remained couch potatoes over very, very long periods of time.”



Video Credit: Stowers Institute for Medical Research



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Cavefish are healthy despite their sedentary lifestyle

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Today’s Video of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> some of the most incredible waves in the world, as seen by Landsat satellites.



"With more than 370,000 miles of coastline on Earth, there are plenty of places where epic waves build up, curl over, and hurtle toward the shore.- much to the thrill of surfers," says NASA. "There are some places where these waves are so magnificent that they can be seen from space."



"With the broad perspective of satellites, we can see how these iconic waves develop into the world’s tallest, longest, fastest, and heaviest."



Video Credit: NASA Earth Observatory&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Satellites capture the world's biggest and fastest waves

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> describes why satellite images and measurements of our planet have become "essential to our survival, offering a new outlook of our world."&nbsp;



Rising sea levels pose one of the biggest societal threats associated with climate change. According to ESA, satellite altimeter missions such as Copernicus Sentinel-6 are essential in monitoring global and regional changes in sea level.



"Unbeknown to many, the island of Crete, Greece, plays an important role in the Copernicus satellite altimetry constellation and on an international stage," reports ESA.



"Satellite altimetry data have to be continuously monitored at the ESA’s Permanent Facility for Altimetry Calibration where different techniques have pioneered the use of transponders to provide the best measurements to validate satellite altimeters in space soon after launch."



Dr. Craig Donlon explains that, by understanding planet Earth through satellite measurements, we are able to find evidence of change.&nbsp;



Video Credit: European Space Agency&nbsp;



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Satellites have become essential to our survival

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