Tag: climate-change

Local News

Northfield, Minnesota warns residents of unsafe drinking water for infants

By Jason Rantala

In 2019, city officials in Northfield, Minnesota said the town’s water supply tested for high levels of manganese.

In high doses, the metal can cause memory, attention and motor skills problems for adults, and particularly impacts infants, according to the Minnesota Department of Health.

Earlier this year, the city scrapped plans to build a new water treatment facility because costs became too high, rising from $60 million to $83 million.

“Certainly we’re all committed to safe and healthy drinking water here in Northfield,” said Ben Martig, Northfield’s city administrator.

City officials are now advising families with infants under 1 to have them drink bottled water or to treat the water themselves, like with a reverse osmosis system.

Officials said they have been warning residents about the water quality issues for years through multiple press releases.

“We’ve talked with local providers, letting them know to notify pregnant mothers and newborn families that they should be looking at different options for their water and making sure that it is further treated,” said Justin Wagner, the city’s utilities manager.

“It’s unsafe for children under 1 and people who are pregnant, and those are important and valuable people to our community, too,” said Ward 1 City Council Member Kathleen Holmes.

She said water treatment is a city need, and costs for the project will only increase as time passes.

“This is a situation for renters who can’t put in reverse osmosis or can’t afford it,” said Holmes.

Northfield resident Levi Prinzing is the parent of an infant, but said at this point he’s more worried about the financial impacts of a new treatment facility. Prinzing also filters his water.

“I don’t think we need a new treatment plant,” said Prinzing. “The treatment plant is a lot of money and we just raised our taxes a lot.”

“We have to find a way to work together as a council and find a solution that can help bridge that gap, that we can provide safe drinking water for all residents, and hopefully reduce the financial impact or financial burden that it is on residents,” said Holmes.

The City Council may reconsider the water treatment facility in June.

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https://www.cbsnews.com/minnesota/news/northfield-minnesotas-warns-residents-of-unsafe-drinking-water-for-infants/?intcid=CNM-00-10abd1h

Local News

Florida’s springs face pollution, climate threats as iconic waters risk losing natural beauty

Seen from the air, a Florida freshwater spring is a bit of liquid heaven, luring humans and wildlife to enjoy its aquamarine cool. With at least 1,000 of them — more than any other state — the springs serve as beaches for large swaths of central and northwestern Florida far from the ocean, with teenagers backflipping from docks and snorkelers peering into the crystalline depths.

But these treasures are under threat from agricultural pollution, rapid development and climate change.

Florida’s fragile freshwater springs under growing strain

Some places, such as fast-growing Zephyrhills in west-central Florida, have paused some construction as it struggles to stay within limits on the drinking water it can withdraw from a vast underground aquifer. Zephyrhills is home to Crystal Springs, source of the bottled water named after the town and several other brands.

“We really had to do something,” said Steven Spina, a member of the town council. “A lot of residents thought it was a good thing. People were happy to see us take a breath.”

The Floridan Aquifer: lifeline for 90% of the state’s drinking water

Covering an estimated 100,000 square miles (250,000 square kilometers), the underground Floridan Aquifer is the source of 90% of Florida’s drinking water. Because of the porous nature of the state’s bedrock, millions of gallons of water find their way to the surface in the form of clear, clean springs that, in turn, feed into rivers.

The highest concentration of springs are in central and northern Florida, including most of the 30 “first magnitude” springs — those that discharge at least 65 million gallons of water every day. All but four of them are considered polluted.

“We just have too much pollution going into the ground and too much water coming out of the ground,” said Ryan Smart, executive director of the nonprofit Florida Springs Council. “And when you get that combination, you end up with springs that are no longer blue and vibrant and full of life.”

Runoff, farming and algae blooms choke spring ecosystems

In rural Florida, runoff from fertilizers and pesticides used in farm fields is a major part of the problem. Fertilizers containing phosphates and nitrogen promote algae blooms that can suffocate a spring. Livestock waste contributes, too.

“When that algae covers everything, then you lose all of the seagrasses. The seagrasses are the forests of the water,” Smart said. “Then you begin to lose the biodiversity. And it even puts our drinking water at risk.”

Development and tourism add pressure to Florida’s springs

Elsewhere in Florida, rampant development is the threat. With over 1,000 people moving to Florida every day, more housing subdivisions are sprouting, along with the roads, strip malls, restaurants, golf courses and everything else that comes with them.

That means more paved surfaces that keep rainwater from percolating down into the aquifer and more pollutant-laden runoff from lawn fertilizers, parking lots, ever-widening roads and sometimes septic tanks. It also means more and more people, many of whom enjoy tubing, paddleboarding, kayaking and swimming in the springs.

It gets so busy in summer at some springs located in state and local parks that entry is halted by late morning. At Ichetucknee Springs State Park north of Gainesville, the daily limit of 750 tubers on the upper river is often reached within an hour after the park opens.

Kaelin Gibbs, on vacation in June with his family from Georgia, was swimming in the Blue Hole Spring along the Ichetucknee River.

“This is simply incredible; the water is cool and clear,” said Gibbs. “We’ve been to Florida’s beaches and to Orlando. There is no comparison to how beautiful this spring is.”

But that’s in peril, said Dennis Jones, a Republican former legislator deeply involved in springs issues. He said the volume of permits being issued for water use isn’t sustainable.

“You cannot keep taking water out of the aquifer because it’s not an endless supply,” Jones said.

Mining, climate change and saltwater intrusion worsen threats

Phosphate mining has also taken a toll on springs. Their operations require a great deal of water, which reduces water pressure available for springs. Some have died almost completely from mining and other factors, including White Sulphur Springs in north Florida, which was a sacred place for Native Americans and later a tourist resort that attracted famous visitors such as Henry Ford and Theodore Roosevelt.

A more subtle threat to the health of springs involves Earth’s changing climate. It is altering rainfall patterns around the globe, threatening the balance that feeds Florida’s springs.

In addition, some springs along the coasts are facing an intrusion of salt water, according to the Southwest Florida Water Management District. Four major springs are becoming increasingly brackish because of sea level rise and declining rainfall.

“As a result, freshwater vegetation has a hard time surviving in this saltier environment and unwanted vegetation moves in,” the district said in a website post.

State funding, lawsuits and grassroots activism aim to save springs

Florida spends billions every year on water quality projects, including about $800 million this year for Everglades restoration work. State funding for springs runs about $50 million a year, according to state documents.

Two state efforts at improving springs’ quality, both around a decade old, remain bottled up in court and administrative challenges. One would strengthen rules for permits to draw water from the major springs. The other would enhance rules to reduce the amount of nutrients such as nitrogen and phosphates that goes into springs that are considered impaired.

Jones, the former legislator, said lobbying by powerful agricultural interests and related political pressures have blocked progress on the nitrogen reduction plan that was expected to take about 20 years.

“We’ve burned up almost 10 years and they haven’t got on stage one. We got more nitrates now than when we started,” Jones said.

In Congress, U.S. Rep. Randy Fine recently filed a bill that would create a Florida Springs National Park across several counties, centered around the Ocala National Forest. Fine said in a statement the designation would protect the springs and increase funding. “Our Florida springs are something unique, not just to Florida but to the country,” Fine said.

It costs bottling companies just $115 for a permit allowing them to withdraw millions of gallons of water in perpetuity. But they do pay local taxes.

Blue Triton, the company that bottles Zephyrhills water, pays about $600,000 a year in taxes for things like schools, public safety and so forth, said Spina of the city council.

“They are one of our largest taxpayers,” he said.

Though they have challenges, Florida’s freshwater springs have energetic friends, too.

Michelle Jamesson loves the springs; she grew up swimming in one and is determined to help protect them for future generations. She volunteers for SpringsWatch Citizen Science Program, coordinating and working with other volunteers for monthly tests on the Wekiva River, north of Orlando.

They test water quality, take photos of underwater vegetation, count birds and more, seeking to spot any big changes that may require action. The Wekiva is fairly stable, she said, though it carries a lot of excess nutrients.

“The wildlife and the ecology, and all of it — it’s so full of life,” Jamesson said.

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The Associated Press receives support from the Walton Family Foundation for coverage of water and environmental policy. The AP is solely responsible for all content. For all of AP’s environmental coverage, visit https://apnews.com/hub/climate-and-environment.

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https://www.cbsnews.com/miami/news/florida-springs-water-pollution-climate-change-report/?intcid=CNM-00-10abd1h

Chesapeake Bay pollution down, but water quality still short of goals, CBF says

By Christian Olaniran

Chesapeake Bay pollution down, but water quality still short of goals, CBF says

Pollution entering the Chesapeake Bay has dropped, but water quality remains below restoration targets, according to the Chesapeake Bay Foundation.

In 2023 nitrogen, phosphorus and sediment levels were significantly lower than the previous year, according to the CBF. Nitrogen fell 21.7%, phosphorus 26% and sediment 15.5%. These three pollutants are the leading contributors to the bay’s poor health.

The largest reductions came from the Pamunkey, Patuxent, Potomac and Susquehanna rivers. By contrast, nitrogen rose in the Appomattox, Mattaponi and Rappahannock rivers, where excess levels can trigger algae blooms that sap oxygen and threaten fish and crabs.

How pollution progress is measured

Researchers measure progress through the Bay TMDL Indicator, which uses modeled data to track how far pollution reductions move the bay toward a healthier ecosystem. To meet water quality goals, nitrogen must be cut by about 145 million pounds per year and phosphorus by about 9 million pounds.

Since 2009, projects such as tree planting, wastewater treatment upgrades and improved farming practices have reduced roughly 82 million pounds of nitrogen and 1.6 million pounds of phosphorus. 

Those efforts are expected to cut an additional 27 million pounds of nitrogen and 4 million pounds of phosphorus annually in the years ahead, according to the CBF. 

Despite these reductions, the University of Maryland Center for Environmental Science gave the bay a “C” in its 2024 annual report, down from a C+ the previous year. 

The Maryland Department of Natural Resources also reported last month that underwater grasses in the state’s portion of the bay declined slightly in 2024. Both measures are considered key indicators of water quality.

Restoration efforts underway

Maryland continues to invest in bay improvements. In December, nearly $400,000 in federal grants went to five Maryland-based projects focused on environmental, cultural and historical conservation in the watershed.

Oyster restoration is also progressing. Oysters filter up to 50 gallons of water per day and provide habitat for small fish, worms and other prey species.

The Chesapeake Bay Program said in July it is on track to meet its 2025 goal of restoring oyster reefs in 10 tributaries, as set by the 2014 Chesapeake Bay Watershed Agreement.

Maryland’s restoration work includes Harris Creek, the Little Choptank, Tred Avon, Upper St. Mary’s and Manokin rivers. Virginia has completed restorations in its five tributaries and an additional site, while Maryland is finishing work in the Manokin.

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https://www.cbsnews.com/baltimore/news/chesapeake-bay-pollution-water-quality-cbf-goals/?intcid=CNM-00-10abd1h

The shocking reason Arctic rivers are turning rusty orange

Ice doesn’t just freeze, it fuels hidden chemistry that could turn rivers rusty as the planet warms.

Source:Umea University

Summary:Researchers found that ice can trigger stronger chemical reactions than liquid water, dissolving iron minerals in extreme cold. Freeze-thaw cycles amplify the effect, releasing iron into rivers and soils. With climate change accelerating these cycles, Arctic waterways may face major transformations.

    

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Why Arctic Rivers Are Turning Rusty Orange
An aerial view of the rust-colored Kutuk River in Gates of the Arctic National Park in Alaska. Thawing permafrost is exposing minerals to weathering, increasing the acidity of the water, which releases metals like iron, zinc, and copper. Credit: Ken Hill / National Park Service

Ice can dissolve iron minerals more effectively than liquid water, according to a new study from Umeå University. The discovery could help explain why many Arctic rivers are now turning rusty orange as permafrost thaws in a warming climate.

The study, recently published in the scientific journal PNAS, shows that ice at minus ten degrees Celsius releases more iron from common minerals than liquid water at four degrees Celsius. This challenges the long-held belief that frozen environments slow down chemical reactions.

“It may sound counterintuitive, but ice is not a passive frozen block,” says Jean-François Boily, Professor at Umeå University and co-author of the study. “Freezing creates microscopic pockets of liquid water between ice crystals. These act like chemical reactors, where compounds become concentrated and extremely acidic. This means they can react with iron minerals even at temperatures as low as minus 30 degrees Celsius.”

To understand the process, the researchers studied goethite – a widespread iron oxide mineral – together with a naturally occurring organic acid, using advanced microscopy and experiments.

They discovered that repeated freeze-thaw cycles make iron dissolve more efficiently. As the ice freezes and thaws, organic compounds that were previously trapped in the ice are released, fuelling further chemical reactions. Salinity also plays a crucial role: fresh and brackish water increase dissolution, while seawater can suppress it.

The findings apply mainly to acidic environments, such as mine drainage sites, frozen dust in the atmosphere, acid sulfate soils along the Baltic Sea coast, or in any acidic frozen environment where iron minerals interact with organics. The next step is to find out if the same is true for all iron-bearing ice. This is what ongoing research in the Boily laboratory will soon reveal.

“As the climate warms, freeze-thaw cycles become more frequent,” says Angelo Pio Sebaaly, doctoral student and first author of the study. “Each cycle releases iron from soils and permafrost into the water. This can affect water quality and aquatic ecosystems across vast areas.”

The findings show that ice is not a passive storage medium, but an active player. As freezing and thawing increase in polar and mountain regions, for the impact on ecosystems. and the natural cycling of elements could be significant.

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https://www.sciencedaily.com/releases/2025/09/250922074938.htm

Number of people suffering extreme droughts will double

Source:Michigan State University

Summary:A global research effort offers the first worldwide view of how climate change could affect water availability and drought severity in the decades to come. By the late 21st century, global land area and population facing extreme droughts could more than double — increasing from 3% during 1976-2005 to 7%-8%, according to a professor of civil and environmental engineering.Share:

    

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Michigan State University is leading a global research effort to offer the first worldwide view of how climate change could affect water availability and drought severity in the decades to come.

By the late 21st century, global land area and population facing extreme droughts could more than double — increasing from 3% during 1976-2005 to 7%-8%, according to Yadu Pokhrel, associate professor of civil and environmental engineering in MSU’s College of Engineering, and lead author of the research published in Nature Climate Change.

“More and more people will suffer from extreme droughts if a medium-to-high level of global warming continues and water management is maintained at its present state,” Pokhrel said. “Areas of the Southern Hemisphere, where water scarcity is already a problem, will be disproportionately affected. We predict this increase in water scarcity will affect food security and escalate human migration and conflict.”

The research team, including MSU postdoctoral researcher Farshid Felfelani, and more than 20 contributing authors from Europe, China and Japan are projecting a large reduction in natural land water storage in two-thirds of the world, also caused by climate change.

Land water storage, technically known as terrestrial water storage, or TWS, is the accumulation of water in snow and ice, rivers, lakes and reservoirs, wetlands, soil and groundwater — all critical components of the world’s water and energy supply. TWS modulates the flow of water within the hydrological cycle and determines water availability as well as drought.

“Our findings are a concern,” Pokhrel said. “To date, no study has examined how climate change would impact land water storage globally. Our study presents the first, comprehensive picture of how global warming and socioeconomic changes will affect land water storage and what that will mean for droughts until the end of the century.”

Felfelani said the study has given the international team an important prediction opportunity.

“Recent advances in process-based hydrological modeling, combined with future projections from global climate models under wide-ranging scenarios of socioeconomic change, provided a unique foundation for comprehensive analysis of future water availability and droughts,” Felfelani said. “We have high confidence in our results because we use dozens of models and they agree on the projected changes.”

The research is based on a set of 27 global climate-hydrological model simulations spanning 125 years and was conducted under a global modeling project called the Inter-Sectoral Impact Model Intercomparison Project. Pokhrel is a working member of the project.

“Our findings highlight why we need climate change mitigation to avoid the adverse impacts on global water supplies and increased droughts we know about now,” Pokhrel said. “We need to commit to improved water resource management and adaptation to avoid potentially catastrophic socio-economic consequences of water shortages around the world.”

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https://www.sciencedaily.com/releases/2021/01/210111125605.htm

Climate changes lead to water imbalance, conflict in Tibetan Plateau

Melting glaciers are putting a hold on countries’ development

Source:Ohio State University

Summary:Climate change is putting an enormous strain on global water resources, and according to researchers, the Tibetan Plateau is suffering from a water imbalance so extreme that it could lead to an increase in international conflicts.Share:

    

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Climate change is putting an enormous strain on global water resources, and according to researchers, the Tibetan Plateau is suffering from a water imbalance so extreme that it could lead to an increase in international conflicts.

Nicknamed “The Third Pole,” the Tibetan Plateau and neighboring Himalayas is home to the largest global store of frozen water outside of the North and South Polar Regions. This region, also known as the Asian water tower (AWT), functions as a complex water distribution system which delivers life-giving liquid to multiple countries, including parts of China, India, Nepal, Pakistan, Afghanistan, Tajikistan and Kyrgyzstan.

Yet due to the rapid melting of snow and upstream glaciers, the area can’t sustainably support the continued growth of the developing nations that rely on it.

“Populations are growing so rapidly, and so is the water demand,” said Lonnie Thompson, distinguished university professor of earth sciences at The Ohio State University and senior research scientist at the Byrd Polar Research Center. “These problems can lead to increased risks of international and even intranational disputes, and in the past, they have.”

Thompson, who has studied climate change for nearly five decades, is intimately familiar with the precarious nature of the region’s hydrological situation. In 1984, Thompson became a member of the first Western team sent to investigate the glaciers in China and Tibet. Since then, he and a team of international colleagues have spent years investigating ice core-derived climate records and the area’s rapidly receding ice along with the impact it’s had on the local settlements that depend on the AWT for their freshwater needs.

The team’s latest paper, of which Thompson is a co-author, was published in the journal Nature Reviews Earth and Environment. Using temperature change data from 1980 to 2018 to track regional warming, their findings revealed that the AWT’s overall temperature has increased at about 0.42 degrees Celsius per decade, about twice the global average rate.

“This has huge implications for the glaciers, particularly those in the Himalayas,” Thompson said. “Overall, we’re losing water off the plateau, about 50% more water than we’re gaining.” This scarcity is causing an alarming water imbalance: Northern parts of Tibet often experience an overabundance of water resources as more precipitation occurs due to the strengthening westerlies, while southern river basins and water supplies shrink as drought and rising temperatures contribute to water loss downstream.

According to the study, because many vulnerable societies border these downstream basins, this worsening disparity could heighten conflicts or exacerbate already tense situations between countries that share these river basins, like the long-term irrigation and water struggles between India and Pakistan.

“The way that regional climate varies, there are winners and losers,” Thompson said. “But we have to learn to work together in order to ensure adequate and equitable water supplies throughout this region.” As local temperatures continue to rise and water resources become depleted, more people will end up facing ever diminishing water supplies, he said.

Still, overall increases in precipitation alone won’t meet the increased water demands of downstream regions and countries.

To combat this, the study recommends using more comprehensive water monitoring systems in data-scarce areas, noting that better atmospheric and hydrologic models are needed to help predict what’s happening to the region’s water supply. Lawmakers should then use those observations to help develop actionable policies for sustainable water management, Thompson said. If policymakers do decide to listen to the scientists’ counsel, these new policies could be used to develop adaptation measures for the AWT through collaboration between upstream and downstream countries.

After all, when things go awry in one area of the world, like the butterfly effect, they tend to have long-lasting effects on the rest of Earth’s population. “Climate change is a global process,” Thompson said. “It doesn’t matter what country or what part of the world you come from. Sooner or later, you’ll have a similar problem.”

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https://www.sciencedaily.com/releases/2022/06/220623140114.htm

Gulf corals still suffering more than a decade after Deepwater Horizon oil spill, scientists report

Exposure to oil — and possibly the chemicals used to clean up oil spills — has made corals prone to breaking and showing signs of high stress, even today

Source:American Geophysical Union

Summary:Deep-water corals in the Gulf of Mexico are still struggling to recover from the devastating Deepwater Horizon oil spill in 2010, scientists report at the Ocean Science Meeting in New Orleans. Comparing images of more than 300 corals over 13 years — the longest time series of deep-sea corals to date — reveals that in some areas, coral health continues to decline to this day.Share:

    

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Deep-water corals in the Gulf of Mexico are still struggling to recover from the devastating Deepwater Horizon oil spill in 2010, scientists report at the Ocean Sciences Meeting in New Orleans. Comparing images of more than 300 corals over 13 years — the longest time series of deep-sea corals to date — reveals that in some areas, coral health continues to decline to this day.

The spill slathered hundreds of miles of shoreline in oil, and a slick the size of Virginia coated the ocean surface. Over 87 days, 134 million gallons of oil spilled directly from the wellhead at a depth of 1520 meters (nearly 5000 feet) into the Gulf. While the spill was most visible at the surface, negative ecological impacts extended hundreds of meters into the ocean.

In a presentation on Tuesday, 20 February, scientists will show that deep-water corals remain damaged long after the spill. Over 13 years, these coral communities have had limited recovery — some even continuing to decline.

“We always knew that deep-sea organisms take a long time to recover, but this study really shows it,” said Fanny Girard, a marine biologist and conservationist at the University of Hawai’i at Mānoa who led the work. “Although in some cases coral health appeared to have improved, it was shocking to see that the most heavily impacted individuals are still struggling, and even deteriorating, a decade later.”

The findings can help guide deep-water restoration efforts following oil spills.

Delicate and damaged 

A few months after the Deepwater Horizon well was capped, an interdisciplinary team of researchers surveyed the ocean floor 6 to 22 kilometers (3.7 to 13.7 miles) from the wellhead to record the damage. About 7 miles away and at 1,370 meters (4,495 feet) depth, they found a dense forest of tree-like Paramuricea corals that looked sickly.

“These corals were covered in a brown material,” Girard said. Testing showed the sludge contained traces of a combination of oil and chemical dispersants. A few months later, the researchers found two additional coral sites at 1,580 meters and 1,875 meters (4921 and 6233 feet, respectively) deep that were similarly damaged.

Deep-sea corals are suspension feeders and may have ingested contaminated particles, leading to the observed health impacts, the researchers said. Direct exposure to toxic chemicals contained in the mixture of oil and chemicals may have also damaged coral tissue. However, to date, scientists still do not exactly know how the oil and dispersant affected these vulnerable organisms.

Every year from 2010 to 2017, scientists visited those three sites to monitor damages, measure growth rates and note any recovery of the corals, as part of a large initiative aiming to better understand ecosystem impacts and improve our ability to respond to future oil spills. They used a remotely operated vehicle to take high-resolution photographs of corals at all three impacted sites and two far-removed reference sites, tracking more than 300 corals overall.

The researchers visited these sites again in 2022 and 2023 as part of the Habitat Assessment and Evaluation project, one of the projects funded through the Natural Resource Damage Assessment settlement. The images allowed the team to measure changes to coral health over time, including noting any breaks along the delicate branches of the coral caused by exposure to oil pollution.

Still suffering after all these years

The scientists found that even by 2022, the affected corals continued to show signs of stress and damage from the oil spill. The brown coating they had first observed was long gone, but upon closer inspection, the corals were weak and prone to breaking. The scarred spots where branches fell off were leaking mucus, and some corals whose skeletons were exposed had been colonized by other, parasitic coral species.

“Not only were some of these corals not recovering, but some of them seemed to be getting worse,” Girard said. She added that if the impacts are too heavy, ecosystems can struggle to recover at all, especially given the onslaught of climate change-related stressors like ocean acidification. “It’s really important to prevent damage in the first place, and the way to do that is through protection measures.”

Girard notes that their work is being used to inform restoration strategies, including trying to grow deep-sea corals for coral propagation from transplants, deploying artificial anchoring sites for recolonization or protecting the deepwater communities and letting nature heal itself. In the coming years, the team will continue to monitor to corals, looking for signs that they’re getting better — or worse.

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https://www.sciencedaily.com/releases/2024/02/240220144632.htm

Scientists stunned by salt giants forming beneath the Dead Sea

Source:University of California – Santa Barbara

Summary:The Dead Sea isn’t just the saltiest body of water on Earth—it’s a living laboratory for the formation of giant underground salt deposits. Researchers are unraveling how evaporation, temperature shifts, and unusual mixing patterns lead to phenomena like “salt snow,” which falls in summer as well as winter. These processes mirror what happened millions of years ago in the Mediterranean, leaving behind thick salt layers still buried today.Share:

    

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Salt Giants Rising Beneath the Dead Sea
The Dead Sea’s extreme salinity and shifting water layers produce salt giants and even summer “salt snow.” Studying these rare processes provides clues to ancient oceans and modern coastal stability. Credit: Shutterstock

The Dead Sea is a confluence of extraordinary conditions: the lowest point on the Earth’s surface, with one of the world’s highest salinities. The high concentration of salt gives it a correspondingly high density, and the water body’s status as the deepest hypersaline lake gives rise to interesting and often temperature-related phenomena below the water’s surface that researchers are still uncovering.

One of the most intriguing features of the Dead Sea continues to be revealed: salt giants, large-scale salt deposits.

“These large deposits in the Earth’s crust can be many, many kilometers horizontally, and they can be more than a kilometer thick in the vertical direction,” said UC Santa Barbara mechanical engineering professor Eckart Meiburg, lead author of a paper published in the Annual Review of Fluid Mechanics. “How were they generated? The Dead Sea is really the only place in the world where we can study the mechanism of these things today.”

Indeed, while there are other bodies of water in the world with massive salt formations, such as the Mediterranean and Red seas, only in the Dead Sea can one find them in the making, which allows researchers to tackle the physical processes behind their evolution, and in particular, the spatial and temporal variations in their thickness.

Evaporation, precipitation, saturation

In their paper, Meiburg and fellow author Nadav Lensky of the Geological Survey of Israel cover the fluid dynamical and associated sediment transport processes currently governing the Dead Sea. These processes are influenced by several factors, including the Dead Sea’s status as a saltwater terminal lake — a lake with no outflow — leaving evaporation as the primary way water leaves the lake, which has been shrinking for millennia and leaving salt deposits as it does so. More recently, damming of the Jordan River, which feeds into the lake, has accelerated lake level decline, estimated at roughly 1 meter (3 feet) per year.

Temperatures along the water column also play a role in the dynamics behind salt giants and other formations such as salt domes and chimneys. A once “meromictic” (stably stratified) lake — the Dead Sea was layered such that less dense warmer water at the surface overlaid a more saline, cooler layer at depth throughout the entire year.

“It used to be such that even in the winter when things cooled off, the top layer was still less dense than the bottom layer,” Meiburg explained. “And so as a result, there was a stratification in the salt.”

That changed in the early 1980s thanks to the partial diversion of the Jordan River, which resulted in evaporation outpacing the rate of freshwater inflow. At that time, the surface salinity reached the levels found at depth, enabling mixing between the two layers and transitioning the lake from meromictic to holomictic (a lake that experiences annual overturns in the water column). The Dead Sea continues to stratify, but only for eight of the warmer months of the year.

In 2019, Meiburg et al identified a rather unique process occurring in the lake during the summer: halite crystal precipitation or “snow” that was more typical in the cooler season. Halite (“rock salt”) precipitates when the concentration of salt exceeds the amount that the water can dissolve, hence the deeper, colder, denser conditions of the bottom layer are where it is most likely to happen, and in the cooler months. However, they observed that during the summer, while evaporation was increasing the salinity of the upper layer, salts were nonetheless continuing to dissolve in that layer due to its warmer temperature. This leads to a condition called “double diffusion” at the interface between the two layers, in which sections of the saltier warmer water of the top layer cool down and sink, while portions of the lower, cooler, relatively less dense water warm up and rise. As the upper, denser layer cools down, salts precipitate out, creating the “salt snow” effect.

The combination of evaporation, temperature fluctuations and density changes throughout the water column, in addition to other factors including internal currents and surface waves, conspire to create salt deposits of various shapes and sizes, assert the authors. In contrast to shallower hypersaline bodies in which precipitation and deposition occur during the dry season, in the Dead Sea, these processes were found to be most intense during the winter months. This year-round “snow” season at depth explains the emergence of the salt giants, found in other saline bodies such as the Mediterranean Sea, which once dried up during the Messinian Salinity Crisis, about 5.96 to 5.33 million years ago.

“There was always some inflow from the North Atlantic into the Mediterranean through the Strait of Gibraltar,” Meiburg said. “But when tectonic motion closed off the Strait of Gibraltar, there couldn’t be any water inflow from the North Atlantic.” The sea level dropped 3-5 km (2-3 miles) due to evaporation, creating the same conditions currently found in the Dead Sea and leaving behind the thickest of this salt crust that can still be found buried below the deep sections of the Mediterranean, he explained. “But then a few million years later the Strait of Gibraltar opened up again, and so you had inflow coming in from the North Atlantic and the Mediterranean filled up again.”

Meanwhile, salinity fluxes and the presence of springs on the sea floor contribute to the formation of other interesting salt structures, such as salt domes and salt chimneys, according to the researchers.

In addition to gaining a fundamental understanding of some of the idiosyncratic processes that can occur in evaporating, hypersaline lakes, research into the associated sediment transport processes occurring on the emerging beaches may also yield insight on the stability and erosion of arid coastlines under sea level change, as well as the potential for resource extraction, the authors state.

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https://www.sciencedaily.com/releases/2025/09/250916221828.htm

Antarctica’s frozen heart is warming fast, and models missed it

First long-term study on the East Antarctic interior ice sheet region reveals the Indian Ocean mechanism driving this change

Source: Nagoya University

Summary: New research has revealed that East Antarctica’s vast and icy interior is heating up faster than its coasts, fueled by warm air carried from the Southern Indian Ocean. Using 30 years of weather station data, scientists uncovered a hidden climate driver that current models fail to capture, suggesting the world’s largest ice reservoir may be more vulnerable than previously thought. Share:

    

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Antarctica’s Frozen Heart Is Warming Fast
Scientists discovered that East Antarctica’s interior is warming faster than its coasts due to warm air flows from the Southern Indian Ocean. Current climate models don’t capture this effect, suggesting ice loss could be underestimated. Credit: Shutterstock

Scientists have confirmed that East Antarctica’s interior is warming faster than its coastal areas and identified the cause. A 30-year study, published in Nature Communications and led by Nagoya University’s Naoyuki Kurita, has traced this warming to increased warm air flow triggered by temperature changes in the Southern Indian Ocean. Previously considered an observation “blind spot,” East Antarctica contains most of the world’s glacial ice. This newly identified warming mechanism indicates that current predictions may underestimate the rate of future Antarctic ice loss.

Collecting data in Earth’s most extreme environment

Antarctica, the world’s coldest, driest, and windiest continent, contains about 70% of Earth’s freshwater frozen in its massive ice sheets. Climate change in the region has been studied using data from manned stations located mostly in coastal areas. However, the Antarctic interior has only four manned stations, with long-term climate data available for just two: Amundsen-Scott Station (South Pole) and Vostok Station (East Antarctic Interior). Therefore, the actual state of climate change in the vast interior remained largely undocumented.

The research group collected observation data from three unmanned weather stations in East Antarctica where observations have continued since the 1990s: Dome Fuji Station, Relay Station, and Mizuho Station. They created a monthly average temperature dataset spanning 30 years, from 1993 to 2022.

Annual average temperature changes showed that all three locations experienced temperature increases at a rate of 0.45-0.72°C per decade, faster than the global average. The researchers analyzed meteorological and oceanic data and traced this temperature rise to changes in the Southern Indian Ocean that alter atmospheric circulation patterns and transport warm air toward Antarctica’s interior.

Current climate models do not capture this warming process, so future projections of temperature for Antarctica may be underestimated. “While interior regions show rapid warming, coastal stations have not yet experienced statistically significant warming trends,” Professor Naoyuki Kurita from the Institute for Space-Earth Environmental Research at Nagoya University said. “However, the intensified warm air flow over 30 years suggests that detectable warming and surface melting could reach coastal areas like Syowa Station soon.”

The Southern Indian Ocean-East Antarctica climate connection

Ocean fronts — areas where warm and cold ocean waters meet — create sharp temperature boundaries in the Southern Indian Ocean. Because global warming heats ocean waters unevenly, it intensifies these temperature differences: stronger oceanic fronts lead to more storm activity and atmospheric changes that create a “dipole” pattern, with low pressure systems in mid-latitudes and high pressure over Antarctica. The high-pressure system over Antarctica pulls warm air southward and carries it deep into the continent.

Now, for the first time, scientists have comprehensive weather station data demonstrating that East Antarctica’s interior is warming faster than its coasts and have identified the major cause of this change. The study provides important insights into how quickly the world’s largest ice reservoir will respond to continued global warming.

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https://www.sciencedaily.com/releases/2025/09/250909031503.htm

Hungry flathead catfish are changing everything in the Susquehanna

New study suggests that smallmouth bass and channel catfish are changing what they eat to avoid having to compete with or being eaten by the invader.

Source:Penn State

Summary: Flathead catfish are rapidly reshaping the Susquehanna River’s ecosystem. Once introduced, these voracious predators climbed to the top of the food chain, forcing native fish like channel catfish and bass to shift diets and habitats. Using stable isotope analysis, researchers uncovered how the invaders disrupt food webs, broaden dietary overlaps, and destabilize energy flow across the river system. The findings show how a single invasive species can spark cascading ecological consequences. Share:

    

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Flathead Catfish Take Over the Susquehanna
Flatheads grow fast in this river system, attain large body sizes and can eat a variety of prey. Because adult flatheads have few natural predators, they can exert strong control over the ecosystem. Credit: Penn State

Flathead catfish, opportunistic predators native to the Mississippi River basin, have the potential to decimate native and recreational fisheries, disrupting ecosystems in rivers where they become established after their introduction or invasion from a nearby river drainage. That concern led a team of researchers from Penn State, the U.S. Geological Survey (USGS), and the Pennsylvania Fish and Boat Commission to assess how flatheads are affecting the food web and energy flow in the Susquehanna River in Pennsylvania, where they were first detected in 1991. Their population has grown rapidly in the decades since.

“Flatheads grow fast in this river system, attain large body sizes and can eat a variety of prey,” said study first author Olivia Hodgson, a master’s degree student in Penn State’s Intercollege Graduate Degree Program in Ecology. “Because adult flatheads have few natural predators, flathead catfish can exert strong control over the ecosystem.”

Hodgson is working with Tyler Wagner, a scientist with the USGS Pennsylvania Cooperative Fish and Wildlife Research Unit Program and a Penn State affiliate professor of fisheries ecology. He is senior author on the study. In findings published Sept. 4 in Ecology, the researchers reported that flathead catfish are apex predators.

Flatheads had the highest trophic position — the level an organism occupies in a food web, based on its feeding relationships — even higher than resident top predators such as smallmouth bass and channel catfish. Channel catfish had a lower trophic position in areas with flathead catfish. This means they now eat lower on the food chain, likely because they are being outcompeted by flatheads or avoiding them, the researchers explained. In areas with flathead catfish, they found, all species showed broader and overlapping diets.

“This suggests that resident species are changing what they eat to avoid competing with or being eaten by the invader,” Hodgson said. “These findings support the ‘trophic disruption hypothesis,’ that says when a new predator enters an ecosystem, it forces existing species to alter their behavior, diets and roles in the food web. This can destabilize ecosystems over time. Our study highlights how an invasive species can do more than just reduce native populations — it can reshape entire foodwebs and change how energy moves through ecosystems.”

Although the predatory effects of invasive catfishes on native fish communities have been documented — such as in a recent study on the Susquehanna River led by researchers at Penn State — the impacts of invasion on riverine food webs are poorly understood, Hodgson noted. This study quantified the effects of invasive flathead catfish on the food web in the Susquehanna by comparing uninvaded river sections to invaded sections, focusing on several key species: flathead catfish — invader, channel catfish and smallmouth bass — resident predators, and crayfish and minnows — prey.

In addition to evaluating trophic position, the researchers analyzed the isotopic niche occupied by the fish species — the range of carbon and nitrogen markers found within the tissues of an organism, reflecting its diet and habitat, providing insights into its ecological role.

To reach their conclusions, the researchers employed stable isotope analysis, a widely used tool that can explain patterns within a food web, highlighting links between trophic positions, as well as the breadth and overlap of trophic niches. Stable isotope analysis is especially useful for studying invasion ecology, such as investigating trophic reorganization and trophic overlap between introduced and resident species.

When fish eat, their bodies incorporate the isotopic signature of their food. By sampling their tissues, scientists can measure nitrogen isotopes and determine their diet, carbon isotopes to determine habitat use, and compare isotopic signatures across regions to deduce fish migration or habitat shifts. For this study, channel catfish, smallmouth bass, minnows and crayfish were selected as focal species because a previous diet analysis conducted in collaboration with Penn State, USGS, and Pennsylvania Fish and Boat Commission researchers within the Susquehanna River, showed that these species are important prey for flathead catfish.

The researchers collected a total of 279 fish and 64 crayfish for stable isotope analysis, including 79 flathead catfish, 45 smallmouth bass, 113 channel catfish and 42 minnows comprising nine species. All samples were oven dried and ground to a fine powder using a mortar and pestle. Stable isotope samples were sent to Penn State’s Core Facilities and the Michigan State University Stable Isotope Laboratories for isotope determination.

“Stable isotope analysis explained patterns within the Susquehanna food web in habitats invaded and not invaded by the flathead catfish, and it allowed us to understand links between different species in the river food web and how invasive species might lead to changes in how native species interact and compete, what they eat and how their diets overlap, and if they might be displaced from preferred habitats by the invader,” Hodgson said. “We were able to infer resource use, helping us to better understand potential competition for resources and how this changes when flathead catfish become established.”

Contributing to the research were: Sydney Stark, recent Penn State graduate with a master’s degree in wildlife and fisheries science; Megan Schall, associate professor of biology and science at Penn State Hazleton; Geoffrey Smith, Susquehanna River biologist for the Pennsylvania Fish and Boat Commission; and Kelly Smalling, research hydrologist withtheU.S. Geological Survey, New Jersey Water Science Center.

Funding for this research was provided by Pennsylvania Sea Grant and the U.S. Geological Survey.

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https://www.sciencedaily.com/releases/2025/09/250909031516.htm