Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA Earth Observatory</a> features the Malaspina Glacier in southeastern Alaska. With a size of approximately 1,680 square miles, Malaspina is the world’s largest piedmont glacier. It covers an area larger than the state of Rhode Island.&nbsp;



"To human eyes, glacial ice typically looks white tinged with blue. But in this false-color satellite image, the rippled ice of Alaska’s Malaspina Glacier appears more fiery than frosty," said NASA.



"In this configuration, watery features are displayed in reds, oranges, and yellows; vegetation appears green; and rock is shown in shades of blue."



A piedmont glacier forms when steep valley glaciers spill into flat plains, where they spread out into bulbous, lobate shapes. Malaspina is fed by the Seward Ice Field and other smaller glaciers.&nbsp;



Despite its size, it's relatively thin for a glacier of its magnitude, averaging only about 600 meters (2,000 feet) in thickness.



The Malaspina Glacier is a classic example of a glacier experiencing significant retreat and thinning due to climate change. This has raised concerns about its long-term stability and the broader implications for sea-level rise.&nbsp;



The glacier's meltwater contributes to the Gulf of Alaska, and its changes are closely monitored by scientists.



Most of the Malaspina Glacier is located within Wrangell-St. Elias National Park. Its visually striking nature, including crevasses and moraines, makes it a subject of interest not only for scientists but also for photographers and nature enthusiasts.&nbsp;



The image was captured on October 27, 2023 by the OLI-2 (Operational Land Imager-2) on Landsat 9.&nbsp;



Image Credit: NASA Earth Observatory&nbsp;



Like what you read? <a href="https://www.earth.com/subscribe/">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



—--



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

Malaspina Glacier in southeastern Alaska 

Today's Image of the Day from NASA Earth Observatory features...

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/images/151929/indonesian-fires-return-in-2023" target="_blank" rel="noreferrer noopener">NASA Earth Observatory</a> features an astronaut photograph of the Moon peeking over Earth's horizon. The image was captured as the International Space Station was orbiting over Iraq. 



"Taken at an oblique angle from an altitude of 406 kilometers (252 miles), the photo has a perspective that highlights Earth’s atmospheric limb, or the edge of the atmosphere," says NASA.



"The blue-toned haze that fades into the darkness of space is the mesosphere, which reaches an altitude of about 80 kilometers (50 miles). Above the mesosphere is the thermosphere. Although this layer is part of Earth’s atmosphere, it is commonly considered part of outer space."



According to NASA, the Moon is about 405,500 kilometers (251,000 miles) away from Earth at its furthest point, or apogee.



"Below the wispy clouds in the middle of the view is Lake Assad, a Euphrates River reservoir in northern Syria," notes NASA.



"Lake Assad is Syria’s largest lake and a primary source of the region’s drinking and irrigation water. The Tabqa Dam, which created the lake, is the largest hydroelectric dam in the country."



Image Credit: NASA Earth Observatory&nbsp;



Like what you read? <a href="https://www.earth.com/subscribe/">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



—--



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

The Moon peeks over Earth's horizon

Today's Image of the Day from the <a href="https://www.esa.int/" target="_blank" rel="noreferrer noopener">European Space Agency</a> features a rare view of Elephant Island off the coast of Antarctica. The photo was captured by the Copernicus Sentinel-2 mission in February 2023.



Elephant Island is an ice-covered, mountainous island in the Southern Ocean. It is located in the outer reaches of the South Shetland Islands.



"The highest peaks are Mount Pendragon, which reaches around 970 meters, visible on the southern end, and, moving northeast, Mount Elder, which reaches around 945 meters," said ESA.



"North of Mount Elder, the wide Endurance Glacier can be seen in the centre of the image. It is the main discharge glacier on the island and drains to the south and into the Weddel Sea. Thin sea ice, visible in light blue in front of the calving front, separates the glacier terminus from the open ocean waters."



Elephant Island holds a special place in polar exploration history because of its role in the Ernest Shackleton's Imperial Trans-Antarctic Expedition (1914-1917). After their ship, the Endurance, was trapped and then crushed by ice in the Weddell Sea, Shackleton and his crew sailed lifeboats over treacherous seas to reach Elephant Island. It was an inhospitable place with no sources of food or shelter, but it was land.



Realizing that there was no chance of rescue from Elephant Island, Shackleton and a few crew members set out in a small lifeboat, the James Caird, to sail 800 miles to South Georgia Island where they hoped to find help. This journey is considered one of the greatest boat journeys ever accomplished. They did eventually reach South Georgia, and Shackleton was able to return to Elephant Island and rescue the remaining crew members.



Though it's largely ice-covered, Elephant Island is home to various wildlife, particularly seals, penguins, and seabirds. The island is uninhabited by humans, but it is a popular destination for expedition cruises and is often visited by those interested in polar exploration history.



Image Credit: ESA&nbsp;



Like what you read? <a href="https://www.earth.com/subscribe/">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



—--



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

Elephant Island off the coast of Antarctica

Today's Image of the Day from the European Space Agency...

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features Tunulliarfik Fjord, which is located along the southern perimeter of Greenland.



"On March 13, 2023, the Operational Land Imager-2 (OLI-2) on Landsat 9 acquired these natural-color images of Tunulliarfik Fjord. The images have been pan-sharpened to bring out more detail," says NASA.



"At the time, the fjord’s waters were capped with a layer of sea ice. Atop the ice there are several long, straight lines connecting the towns of Narsarsuaq and Qassiarsuk, and running the length of the fjord. Though cracks and ridges can form naturally in the ice, there are indications that people were likely involved with producing some of the tracks pictured here."



The images were reviewed by Nathan Kurtz and several other scientists in the Cryospheric Sciences Laboratory at NASA’s Goddard Space Flight Center. The experts determined that many of the tracks were produced by vehicles like snowmobiles. 



“It seems likely that residents from the town or nearby were out on the ice, possibly hunting or traveling,“ said Kurtz.



Tunulliarfik Fjord, also known as Erik's Fjord, is historically significant because it's close to the site where Erik the Red, the Norse explorer, established the first Norse settlements in Greenland around the year 985 AD. These Norse settlements, particularly Brattahlíð, were key starting points for the Norse exploration of the region and are the reason Greenland has its name.



The fjord offers picturesque landscapes typical of Greenland, with steep cliffs, icebergs, and vast open waters. The region is rich in history, and there have been numerous archaeological digs uncovering remnants of the old Norse settlements.



Today, the nearby town of Qaqortoq is one of the primary settlements in the area, providing modern amenities while retaining a deep connection to the region's historical and cultural significance.



Image Credit: NASA Earth Observatory&nbsp;



---



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.

Tunulliarfik Fjord in southern Greenland 

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA Earth Observatory</a> features the west coast of South America. The photo was captured by an astronaut aboard the International Space Station while orbiting over the Atacama Desert and Central Andes Mountains near the border of Bolivia, Peru, and Chile.



"Over the Pacific Ocean, marine stratocumulus clouds develop over cold water that rises from the ocean depths as the Peru current (Humboldt current) flows north along the west coast of South America," says NASA. "The coastline is marked by low mountains that are dissected by canyons carved by rivers that flow down the western side of the Andes."



The Atacama Desert receives less than 0.2 inches of rain per year on average. According to NASA, this dry environment provides an ideal setting to conduct Mars analog studies.



"Active and inactive volcanoes comprise the Central Andean Volcanic Arc within the Atacama Desert and Andes Mountains. One of the inactive volcanoes visible in this photo is Bolivia’s Nevado Sajama, which has a maximum elevation of 6,542 meters (21,463 feet). Nevado Sajama and other volcanoes in the region often have <a href="http://glaciers">glaciers</a> and snow cover due to their high elevation."



Image Credit: NASA Earth Observatory&nbsp;



---



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 Atacama Desert on the west coast of South America

Glacial ice, typically perceived as white with blue tinges to the human eye, takes on a dramatically different appearance in a recent false-color satellite image. Alaska's Malaspina Glacier, in this unique portrayal, appears more akin to a fiery landscape than a frosty one. This intriguing view was captured by the <a href="https://storymaps.arcgis.com/stories/beb06da1b28849e3b55f5a93c2b1e1eb" target="_blank" rel="noreferrer noopener">Operational Land Imager-2</a> (OLI-2) on the <a href="https://www.usgs.gov/landsat-missions/landsat-9" target="_blank" rel="noreferrer noopener">Landsat 9 satellite</a> on October 27, 2023.



<h2 class="wp-block-heading" id="h-science-behind-the-colors">Science behind the colors</h2>



The image utilizes a specific band combination (1-5-7) from the satellite's capabilities, encompassing coastal/aerosol, near-infrared, and shortwave infrared bands. This configuration presents watery features in vivid reds, oranges, and yellows, while vegetation is shown in green, and rock formations are depicted in various shades of blue.



<h2 class="wp-block-heading" id="h-malaspina-glacier-a-natural-wonder">Malaspina Glacier: A natural wonder</h2>



Malaspina Glacier, or Sít’ Tlein as known in Tlingit, meaning “big glacier”, is a significant natural wonder located predominantly within Wrangell-St. Elias National Park. This glacier is the largest piedmont glacier globally, sprawling over approximately 1,680 square miles (4,350 square kilometers), an area exceeding that of Rhode Island. 



Primarily fed by the <a href="https://www.earth.com/news/decades-of-change-how-climate-is-affecting-glaciers/" target="_blank" rel="noreferrer noopener">Seward Glacier</a> from the St. Elias Mountains, it is further bolstered by other glaciers like the Agassiz, spreading across a coastal plain and merging to form the colossal Malaspina.



<h2 class="wp-block-heading" id="h-unique-features-and-movement">Unique features and movement</h2>



The glacier's distinct appearance is highlighted by dark blueish-purple lines, representing moraines. These are areas where the glacier has accumulated soil, rock, and other debris along its edges. 



The intriguing zigzag patterns of these debris are a result of variations in the ice's velocity, highlighting the dynamic nature of the glacier's movement.



Periodic surges, a phenomenon where <a href="https://www.earth.com/image/mendenhall-glacier-in-southeast-alaska/" target="_blank" rel="noreferrer noopener">glaciers</a> in this region of Alaska suddenly move forward for a duration ranging from one to several years, contribute to the unique textural characteristics seen on Malaspina. These irregular flows lead to the folding, compression, and shearing of the moraines.



<h2 class="wp-block-heading" id="h-climate-change-and-the-malaspina-glacier">Climate change and the Malaspina Glacier</h2>



At the glacier's terminus, a slender land strip forms a barrier between the ice and the <a href="https://www.earth.com/news/dust-storms-in-the-gulf-of-alaska-help-shape-the-global-climate/" target="_blank" rel="noreferrer noopener">Gulf of Alaska</a>. Satellite imagery over time has unveiled the gradual formation of a lagoon system along this barrier in recent decades. 



The small patches of open water visible in the image, depicted in a rusty red color, indicate that some of this water is almost as saline as the ocean. Recent research suggests that this could be due to the contact between relatively warm ocean water and the ice. Such interactions might accelerate large-scale calving, potentially hastening the retreat of the glacier.



In summary, the false-color satellite image of Malaspina Glacier offers more than just a visual spectacle. It provides crucial insights into the glacier's structure, movements, and the potential environmental impacts of its interaction with surrounding waters. As technology continues to evolve, such images become invaluable tools for understanding and monitoring the <a href="https://www.earth.com/news/melting-glaciers-are-fueling-earthquakes-in-alaska/" target="_blank" rel="noreferrer noopener">delicate balance</a> of our planet's natural wonders.



<h2 class="wp-block-heading" id="h-malaspina-glacier-in-depth">Malaspina Glacier in depth</h2>



Nestled in the southeastern region of Alaska, the Malaspina Glacier stands as a testament to the grandeur and dynamic nature of <a href="https://www.earth.com/news/alarming-study-previously-stable-glaciers-are-now-rapidly-disappearing/" target="_blank" rel="noreferrer noopener">Earth's glacial systems</a>. 



As touched upon previously in this article, Malaspina is the world's largest piedmont glacier. It captivates with its immense size and serves as a critical subject for scientific study and environmental monitoring.



<h3 class="wp-block-heading" id="h-formation-and-structure-of-malaspina-glacier">Formation and structure of Malaspina Glacier</h3>



Named after the Italian explorer Alessandro Malaspina, the Malaspina Glacier originates primarily from the ice flows of the Seward Glacier, as mentioned previously. These flows, descending from the rugged terrain of the St. Elias Mountains, converge with other glaciers like the Agassiz and Hayden to form Malaspina's vast expanse. 



This convergence occurs on a coastal plain, where the glacier spreads out like a fan, covering an area of approximately 1,680 square miles (4,350 square kilometers) - larger than the state of Rhode Island.



What sets Malaspina apart is its classification as a piedmont glacier. This type of glacier occurs when steep valley glaciers spill into relatively flat plains, where they spread out extensively. As a result, Malaspina presents a remarkable juxtaposition of rugged mountain ice flows and a sprawling ice plateau.



<h3 class="wp-block-heading" id="h-role-of-moraines-in-shaping-malaspina">Role of moraines in shaping Malaspina</h3>



As Malaspina Glacier advances, it carries with it an assortment of rocks, soil, and other debris. These materials accumulate along the glacier's edges and internal flow lines, forming prominent features known as moraines. The moraines of Malaspina are particularly noticeable, marked by dark, zigzag patterns that are visible from aerial and satellite imagery.



These <a href="https://www.earth.com/news/simulation-reveals-the-evolution-of-alpine-ice-over-120000-years/" target="_blank" rel="noreferrer noopener">moraines</a> play a significant role in the glacier's dynamics. They indicate areas of different ice velocities and provide clues about the glacier's past movements and surge events. These surge events, characterized by rapid forward movements of the glacier, dramatically reshape the moraines, adding to the glacier's complex texture.



<h3 class="wp-block-heading" id="h-environmental-significance">Environmental significance</h3>



Malaspina Glacier is a focal point for glaciologists and climate scientists. Due to its size and sensitivity to climate variations, the glacier acts as an indicator of environmental changes. Scientists study Malaspina to understand glacial dynamics, ice-ocean interactions, and the broader implications of climate change on glacial systems.



Recent observations have shown signs of thinning and retreating in parts of Malaspina Glacier. This retreat is particularly concerning as it contributes to sea-level rise and affects the regional ecosystem. The glacier's interaction with the <a href="https://www.earth.com/image/dust-streams-over-the-gulf-of-alaska/" target="_blank" rel="noreferrer noopener">Gulf of Alaska</a> is also of interest, as warming ocean temperatures could accelerate its melting.



In summary, the Malaspina Glacier, with its vast size and dynamic nature, is a crucial component of Earth's cryosphere, acting as both a subject for scientific inquiry and a barometer for environmental changes. As we continue to witness the impacts of climate change, understanding and monitoring glaciers like Malaspina becomes increasingly important in our global effort to comprehend and mitigate these changes.



---



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



---



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

Breathtaking NASA photo of the Malaspina Glacier resembles an abstract painting

Glacial ice, typically perceived as white with blue tinges to...

In a recent development hailed as a conservation success, bluefin tuna have made a remarkable return to Northern European waters. This resurgence, however, is shadowed by concerns over rising sea temperatures in their Mediterranean nursery grounds. 



New research led by the <a href="https://www.southampton.ac.uk/" target="_blank" rel="noreferrer noopener">University of Southampton</a> suggests that this recovery may be fleeting due to the impending climate change.



<h2 class="wp-block-heading" id="h-impact-of-rising-temperatures">Impact of rising temperatures</h2>



According to the research, the Mediterranean Sea is expected to reach temperatures that could drive juvenile bluefin <a href="https://www.earth.com/news/tunas-billfishes-and-sharks-are-sentinels-of-global-ocean-health/" target="_blank" rel="noreferrer noopener">tuna</a> out within the next 50 years. 



Professor Clive Trueman is the lead author and a Geochemical Ecology expert at the University of Southampton. He emphasized the critical temperature threshold, saying, “We have found that anything over 28 degrees Celsius will adversely impact bluefins’ growth.”



The study predicts a potential shift in the tuna's nursery areas to cooler regions like the <a href="https://www.earth.com/image/desert-dust-over-the-bay-of-biscay/" target="_blank" rel="noreferrer noopener">Bay of Biscay</a>. This migration poses a new challenge as juvenile tuna might end up in existing <a href="https://www.earth.com/news/global-fisheries-threatened-by-climate-change/" target="_blank" rel="noreferrer noopener">fisheries</a> for sardines and anchovies. This confluence of events would necessitate a change in fishery management practices.



<h2 class="wp-block-heading" id="h-innovative-use-of-otolith">Innovative use of otolith</h2>



An international team, including the <a href="https://www.bas.ac.uk/" target="_blank" rel="noreferrer noopener">British Antarctic Survey</a> and Spain's <a href="https://www.azti.es/en/" target="_blank" rel="noreferrer noopener">AZTI</a> science and technology centre, used a novel method involving the <a href="https://www.earth.com/wp-content/uploads/2023/11/bluefin-tuna-otolith_credit-Clive-Trueman_1medium.jpg" target="_blank" rel="noreferrer noopener">otolith</a> -- a tissue found behind the brains of bony fish. 



This method was pioneered by Professor Trueman. It analyzes the otolith's chemistry to measure the tuna’s metabolic rate, offering insights into the ideal living conditions for these fish.



The otolith, or 'ear stone', is crucial for a fish’s ability to hear and balance. Professor Trueman explained its significance, saying, “Our new work uses variations in the levels of natural stable isotopes of carbon and oxygen in the otolith to reveal each tuna’s individual metabolic rate. This can tell us when waters are getting too hot for the fish to handle - it’s like a natural fitness tracker.”



<h2 class="wp-block-heading" id="h-bluefin-tuna-value">Bluefin tuna value</h2>



Bluefin <a href="https://www.earth.com/news/record-payment-tuna-ocean-fish/" target="_blank" rel="noreferrer noopener">tuna</a> are among the largest and most powerful fish in the sea. They are capable of impressive speeds, leaping out of the water at 43 miles per hour. These fish are not just ecologically significant but also economically valuable, with their meat being a prized component in sushi and sashimi.



The <a href="https://www.earth.com/news/experts-pinpoint-blue-corridors-for-large-migratory-fish/" target="_blank" rel="noreferrer noopener">fish</a> spawns on both sides of the Atlantic Ocean, with Eastern Atlantic bluefin spending their first year in the Mediterranean. Upon reaching maturity, they venture into the Atlantic. Bluefin will often cross the ocean in search of prey like sardines and herring, before returning to the Mediterranean to spawn.



In summary, the return of bluefin <a href="https://www.earth.com/news/mercury-levels-in-bluefin-tuna-reveal-patterns-of-ocean-pollution/" target="_blank" rel="noreferrer noopener">tuna</a> to Northern European waters is a testament to successful conservation efforts. However, the looming threat of climate change, specifically the rising temperatures in their Mediterranean nursery grounds, presents new challenges. 



This research highlights, most importantly, the resilience of bluefin tuna. However, it also underscores the need for adaptive management in fisheries and a deeper understanding of the impact of climate change on <a href="https://www.earth.com/news/marine-protected-areas-improve-well-being-in-coastal-communities/" target="_blank" rel="noreferrer noopener">marine life</a>.



<h2 class="wp-block-heading" id="h-more-about-bluefin-tuna">More about bluefin tuna</h2>



As discussed previously, bluefin tuna are one of the ocean's most magnificent creatures. They command the attention of environmentalists, fishermen, and seafood connoisseurs alike. Let's now delve into their biology, behavior, and the challenges they face in today's oceans.



<h3 class="wp-block-heading" id="h-biology-and-characteristics">Biology and characteristics</h3>



Impressive Size and Speed -- Bluefin <a href="https://www.earth.com/news/tuna-contain-toxic-mercury-levels/" target="_blank" rel="noreferrer noopener">tuna</a> stand out for their size and speed. They can grow up to three meters in length and weigh over 680 kilograms (1,500 pounds). Known for their incredible speed, they swim at bursts of up to 70 kilometers per hour (43 miles per hour), as mentioned above.



Unique Physiological Traits -- These fish possess several unique physiological adaptations. Unlike most fish, bluefins can regulate their body temperature, allowing them to thrive in diverse water temperatures. Their streamlined bodies and powerful tails make them highly efficient swimmers.



<h3 class="wp-block-heading" id="h-habitat-and-migration-patterns">Habitat and migration patterns</h3>



Diverse Habitats -- Bluefin tuna inhabit various oceanic environments. They primarily roam the Atlantic Ocean and the Mediterranean Sea, with distinct populations in the Eastern and Western Atlantic.



Long-Distance Migrations -- These fish are renowned for their long-distance migrations, crossing oceans for feeding and spawning. Western Atlantic bluefins migrate between North American waters and the Gulf of Mexico, while Eastern Atlantic populations travel between European waters and their spawning grounds in the Mediterranean.



<h3 class="wp-block-heading" id="h-bluefin-tuna-diet-and-feeding-habits">Bluefin tuna diet and feeding habits</h3>



Predatory Nature -- Bluefin tuna are apex predators, feeding on a diet rich in fish and cephalopods. Their preferred prey includes herring, mackerel, and squid. They hunt both individually and in schools, showcasing impressive coordination.



Foraging Strategies -- Bluefins employ various foraging strategies, from swift, powerful attacks to cooperative hunting in groups. Their keen eyesight and heightened sense of smell aid in locating prey.



<h3 class="wp-block-heading" id="h-reproduction-and-life-cycle">Reproduction and life cycle</h3>



Spawning Rituals -- Bluefin tuna spawn in warm waters, typically in the Mediterranean Sea for the Eastern Atlantic population. Spawning occurs annually, with females releasing millions of eggs, ensuring a higher chance of survival for the offspring.



Growth and Development -- Young bluefins grow rapidly, a necessity for survival in the competitive oceanic environment. They reach sexual maturity at around 3-5 years, embarking on their first spawning migrations.



<h3 class="wp-block-heading" id="h-conservation-status-and-threats">Conservation status and threats</h3>



Overfishing and Population Decline -- Bluefin tuna face significant threats from overfishing. Their high market value, particularly for sushi and sashimi, has led to intense fishing pressure, causing a stark decline in their populations.



Environmental Challenges -- As mentioned previously in this article, climate change and pollution also pose grave threats to bluefin tuna. Changes in ocean temperatures affect their spawning grounds and migration patterns, while pollution impacts their health and the ecosystems they inhabit.



In summary, bluefin tuna are not only a seafood delicacy, they are integral to the marine ecosystem. Understanding their biology, behavior, and the challenges they face is crucial for their conservation. 



Efforts to manage fisheries sustainably and address environmental issues are vital to ensure the survival of these magnificent creatures for future generations.



The full study was published in the journal <a href="https://www.nature.com/articles/s41467-023-41930-2" target="_blank" rel="noreferrer noopener">Nature Communications</a>.



---



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



---



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

Bluefin tuna, a sushi delicacy, will likely be extinct within 50 years

In a recent development hailed as a conservation success, bluefin...

Female,Pupils,And,Brain,Function,,Reveal,A,Hidden,Signal,About

In a recent study led by Dr. Shawn Olsen at the <a href="https://alleninstitute.org/" target="_blank" rel="noreferrer noopener">Allen Institute</a>, researchers have made significant strides in understanding how our brains perceive - or fail to perceive - visual stimuli. The research, focusing on a mind-blowing phenomenon known as visual masking, reveals intriguing insights into the mechanisms of conscious perception in the <a href="https://www.earth.com/news/secrets-of-learning-how-the-brain-stores-new-information/">brain</a>.



<h2 class="wp-block-heading" id="h-what-is-visual-masking">What is visual masking?</h2>



Visual masking occurs when an individual fails to consciously <a href="https://www.earth.com/news/our-sense-of-smell-can-change-the-colors-we-see/" target="_blank" rel="noreferrer noopener">perceive</a> an image due to the rapid succession of another image. 



For the effect to occur, the first image must appear and disappear swiftly, followed rapidly (within about 50 milliseconds) by the second image. The current study explores visual masking in mice for the first time.



Scientists discovered this puzzling phenomenon in the 19th century, but the underlying mechanisms remain a mystery.&nbsp;



From previous studies, the scientists knew that neurons in the retina and parts of the <a href="https://www.earth.com/news/secrets-of-learning-how-the-brain-stores-new-information/" target="_blank" rel="noreferrer noopener">brain</a> in that pathway are activated even when a person is not aware that they are seeing an image. This means that your brain can see things without your knowledge.



<h2 class="wp-block-heading" id="h-visual-masking-and-awareness">Visual masking and awareness</h2>



Dr. Olsen and his team, including Dr. Christof Koch and Dr. Sam Gale, trained mice to respond to visual stimuli. The mice were taught to turn a tiny LEGO wheel in the direction of a briefly flashed image to receive a treat.&nbsp;



When a masking image was introduced immediately after the target image, the mice failed to perform the task correctly, indicating a loss of <a href="https://www.earth.com/news/children-and-adults-perceive-time-differently/" target="_blank" rel="noreferrer noopener">conscious perception</a> of the original image.



“This is an interesting observation, where what is present in the world is not accurately reflected in your perception,” said Dr. Olsen. “Like other visual illusions, we think that it tells us something about the way the visual system works and ultimately about the neural circuits that underlie visual awareness.”



<h2 class="wp-block-heading" id="h-conscious-perception">Conscious perception </h2>



<a href="https://www.earth.com/news/where-in-the-brain-does-consciousness-reside-scientists-think-they-might-know/" target="_blank" rel="noreferrer noopener">Conscious perception</a> refers to the awareness that one has of their surroundings and internal states through sensory experiences. It involves the recognition and interpretation of sensory inputs, such as sights, sounds, and tactile sensations, as well as internal stimuli like thoughts and emotions.



The researchers pinpointed a specific brain region that is necessary for visual masking illusion to work. They propose that the visual cortex or higher areas of the cortex are responsible for <a href="https://www.earth.com/news/conscious-awareness-when-does-our-sense-of-purpose-emerge/" target="_blank" rel="noreferrer noopener">conscious perception</a>.



<h2 class="wp-block-heading" id="h-human-and-mouse-perception-nbsp">Human and mouse perception&nbsp;</h2>



The experts wanted to confirm that the optical illusion they showed the rodents is relevant to humans. They tested 16 people using a keystroke instead of the wheel. The results showed that human and mouse perception - or lack thereof - is very similar.&nbsp;



The fact that human and mouse perceptions of this visual masking illusion were similar reinforces the theory that conscious perception resides in the cortex of mammals. That fits with the general sentiment in the field that the cortex is the seat of conscious perception in mammals, including us, said Dr. Koch.



In summary, the Allen Institute's research offers profound insights into how our <a href="https://www.earth.com/news/most-advanced-brain-mapping-yet-reveals-how-we-think/" target="_blank" rel="noreferrer noopener">brains process</a> visual information and what factors contribute to our conscious perception of the world. It opens new avenues for understanding more about the <a href="https://www.earth.com/news/blinking-stability-vision/" target="_blank" rel="noreferrer noopener">visual system</a> and the neural circuits that govern visual awareness.



<h2 class="wp-block-heading" id="h-more-about-visual-masking">More about visual masking</h2>



As discussed above in the Allen Institute study analysis, visual masking is a fascinating phenomenon in the realm of perceptual psychology that offers key insights into how our visual system processes information. It occurs when the perception of one visual stimulus (the mask) impairs the visibility of another stimulus (the target) when they are presented in close temporal succession.



To reiterate and further clarify, the process of visual masking can be broken down into two primary types: backward masking and forward masking. In backward masking, the mask appears after the target, disrupting the processing of the initial stimulus. This type is particularly intriguing because it suggests that our perception is not instantaneous but rather involves a certain degree of processing time. 



Forward masking, on the other hand, involves the mask appearing before the target. It demonstrates the preparatory effect of the visual system in anticipating and processing incoming stimuli.



Visual masking has significant implications in understanding the temporal dynamics of visual processing. It reveals that our perception of the present is partially influenced by recent visual experiences. This aspect is crucial in fields like cognitive psychology, neurology, and even in practical applications like the design of user interfaces and visual displays.



In summary, visual masking is not just a curious trick of perception but a window into the complex and dynamic nature of how we interpret and understand visual information. Its study continues to uncover the intricate workings of the human visual system, enhancing our comprehension of the brain and perception.



The study is published in the journal <a href="http://dx.doi.org/10.1038/s41593-023-01488-0" target="_blank" rel="noreferrer noopener">Nature Neuroscience</a>.&nbsp;



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



—-



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

Visual masking: Your brain can see and process information without "your" knowledge

In a recent study led by Dr. Shawn Olsen at...

<div class="vdb_player vdb_591c9e3c9efa894c3c6e150b58d96b98cd4fed198a0d2a49">
<script src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" type="text/javascript"></script></div>
‘Mr Copernicus’ provides an introduction to Europe’s Copernicus environment monitoring program. Join him for a brief history of the initiative and an overview of the Sentinel satellites.
&#8212;
<a href="http://www.nasa.gov" target="_blank" rel="noopener">European Space Agency</a>

Europe’s Copernicus Environment Monitoring Program