Tag: environment

Oceans could reach a dangerous tipping point by 2050

Source:University of California – Santa Barbara

Summary:UC Santa Barbara researchers project that human impacts on oceans will double by 2050, with warming seas and fisheries collapse leading the charge. The tropics and poles face the fastest changes, and coastal regions will be hardest hit, threatening food and livelihoods worldwide.Share:

    

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Oceans Near Breaking Point by 2050
By 2050, ocean impacts from climate change and overuse could double—unless urgent action is taken. Credit: Shutterstock

The seas have long sustained human life, but a new UC Santa Barbara study shows that rising climate and human pressures are pushing the oceans toward a dangerous threshold.

Vast and powerful, the oceans can seem limitless in their abundance and impervious to disturbances. For millennia, humans have supported their lives, livelihoods and lifestyles with the ocean, relying on its diverse ecosystems for food and material, but also for recreation, business, wellness and tourism.

Yet the future of our oceans is worrying, according to researchers at UCSB’s National Center for Ecological Analysis and Synthesis (NCEAS).

“Our cumulative impact on the oceans, which is already substantial, is going to double by 2050 — in just 25 years,” said marine ecologist and NCEAS director Ben Halpern, who led the effort to forecast the future state of marine environments as they bow under the combined pressures of human activities, which include ocean warming, fisheries biomass loss, sea level rise, acidification and nutrient pollution, among other impacts. “It’s sobering. And it’s unexpected, not because impacts will be increasing — that is not surprising — but because they will be increasing so much, so fast.”

The research team, which includes collaborators from Nelson Mandela University in South Africa, also finds that the tropics and the poles will experience the fastest changes in impacts, and that coastal areas will feel the brunt of the increased impacts.

Their research, supported in large part by the National Science Foundation, is published in the journal Science.

A comprehensive global model of human impacts

As human activity on the ocean and along the coast has intensified, so have impacts on the marine environment. Halpern and a group of scientists first tackled the challenge of understanding how these pieces fit together to affect the ocean nearly 20 years ago, laying the groundwork for the current study.

“People tracked one issue at a time, but not everything together,” Halpern said. “More importantly, there was a pervasive sense that the ocean is so huge the human impacts couldn’t possibly be that bad.”

Their quest to build a comprehensive model of human impacts on the ocean led to a 2008 paper in the journal Science, a landmark study that synthesized 17 global data sets to map the intensity and extent of human activity on the world’s oceans. That initial view revealed startling results: No place was untouched, and 41% of the world’s marine environments were heavily impacted.

“The previous paper tells us where we are; the current paper tells us where we are headed,” Halpern said.

Ocean warming and biomass loss due to fisheries are expected to be the largest overall contributors to future cumulative impacts. Meanwhile, the tropics face rapidly increasing rates of impact, while the poles, which already experience a high level of impact, are expected to experience even more. According to the paper, the high level of future impacts “may exceed the capacity of ecosystems to cope with environmental change,” in turn posing challenges for human societies and institutions in a variety of ways.”

The world’s coasts are expected to bear the brunt of these increasing cumulative impacts — an unsurprising reality, the researchers say, given most human uses of the ocean are near coasts. Yet it’s also a “worrisome result nonetheless,” according to the paper, because the coasts “are where people derive most value from the ocean.” Additionally, many countries are dependent on the ocean for food, livelihood and other benefits. “Many of these countries will face substantial increases,” Halpern said.

The authors contend that enacting policies to reduce climate change and to strengthen fisheries management could be effective ways to manage and reduce human impacts, given the outsize roles that ocean warming and biomass loss play in the estimate of future human impacts on the ocean. Likewise, prioritizing management of habitats that are expected to be heavily impacted — such as salt marshes and mangroves — could help reduce the pressures on them.

In presenting these forecasts and analyses, the researchers hope that effective action can be taken sooner rather than later to minimize or mitigate the effects of increased pressures from human activity.

“Being able to look into the future is a super powerful planning tool,” Halpern said. “We can still alter that future; this paper is a warning, not a prescription.”

Research in this paper was also conducted by Melanie Frazier and Casey C. O’Hara at UCSB, and Alejandra Vargas-Fonseca and Amanda T. Lombard at Nelson Mandela University in South Africa.

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https://www.sciencedaily.com/releases/2025/09/250905180728.htm

Even the toughest corals are shrinking in warming seas

Resilient coral growth predicted to decrease over next 3 decades, study finds.

Source:Ohio State University

Summary:Scientists found that Red Sea corals can endure warming seas but grow much smaller and weaken under long-term heat stress. Though recovery is possible in cooler months, rising global temperatures may outpace their resilience, endangering reefs and the people who depend on them.Share:

    

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Even the Toughest Corals Are Shrinking
Resilient Red Sea corals survive extreme heat but shrink and weaken, raising alarms about the future of marine life and reef-dependent communities. Credit: Shutterstock

As coral reefs decline at unprecedented rates, new research has revealed that some coral species may be more resilient to warming temperatures than others.

By studying how six months of elevated ocean temperatures would affect a species of coral from the northern Red Sea called Stylophora pistillata, scientists found that although these organisms can certainly survive in conditions that mimic future warming trends, they don’t thrive.

Stylophora pistillata tend to be tolerant of high ocean temperatures, but when continuously exposed to temperatures of 27.5 and 30 degrees Celsius (81.5 and 86 degrees Fahrenheit) — baseline warming expected in tropical oceans by 2050 and 2100 — scientists saw various changes in coral growth, metabolic rates, and even energy reserves. For instance, coral in 27.5 degrees Celsius waters survived, but were 30% smaller than their control group; those placed in 30 degrees Celsius waters wound up being 70% smaller.

“In theory, if corals in the wild at these temperatures are smaller, reefs might not be as diverse and may not be able to support as much marine life,” said Ann Marie Hulver, lead author of the study and a former graduate student and postdoctoral scholar in earth sciences at The Ohio State University. “This could have adverse effects on people that depend on the reef for tourism, fishing or food.”

Overall, the team’s results suggest that even the most thermally tolerant coral species may suffer in their inability to overcome the consequences of warming seas.

The study was published on September 3 in the journal Science of the Total Environment.

While current predictions for coral reefs are dire, there is some good news. During the first 11 weeks of the experiment, researchers saw that corals were only minimally affected by elevated baseline temperatures. Instead, it was the cumulative impact of chronic high temperatures that compromised coral growth and caused them to experience a higher metabolic demand.

The coral later recovered after being exposed for a month to 25 degree Celsius waters, but had a dark pigmentation compared to corals that were never heated. This discovery implies that despite facing ever longer periods of threat from high ocean temperatures in the summer months, resilient coral like S. pistillata can bounce back when waters cool in the winter, researchers say.

Still, as ocean temperatures are expected to increase by 3 degrees Celsius by 2100, expecting coral reefs to predictably bend to projected climate models can be difficult, according to the researchers.

This team’s research does paint a more detailed picture of how coral reefs may look and function in the next 50 years, said Andrea Grottoli, co-author of the study and a professor in earth sciences at Ohio State.

“Survival is certainly the No. 1 important thing for coral, but when they’re physiologically compromised, they can’t do that forever,” said Grottoli. “So there’s a limit to how long these resilient corals can cope with an ever increasing warming ocean.”

Gaining a more complex understanding of how warming waters can alter coral growth and feeding patterns may also better inform long-term conservation efforts, said Grottoli.

“Conservation efforts could focus on areas where resilient coral are present and create protected sanctuaries so that there are some ecosystems that grow as high-probability-success reefs for the future,” she said.

For now, all coral reefs are still in desperate need of protection, researchers note. To that end, Hulver imagines future work could be aimed at investigating the resilience of similar species of coral, including replicating this experiment to determine if sustained warming might cause trade-offs in other biological processes, such as reproduction.

“For coral, six months is still a very small snapshot of their lives,” said Hulver. “We’ll have to keep on studying them.”

Other Ohio state co-authors include Shannon Dixon and Agustí Muñoz-Garcia as well as Éric Béraud and Christine Ferrier-Pagès from the Centre Scientifique de Monaco, and Aurélie Moya, Rachel Alderdice and Christian R Voolstra from the University of Konstanz. The study was supported by the National Science Foundation and the German Research Foundation.

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https://www.sciencedaily.com/releases/2025/09/250905112308.htm

Scientists fear the Atlantic’s great ocean conveyor could shut down

Source:Potsdam Institute for Climate Impact Research (PIK)

Summary:A new study projects that the Atlantic Meridional Overturning Circulation (AMOC)—the system of currents that includes the Gulf Stream—could shut down after 2100 under high-emission scenarios. This shutdown would drastically reduce heat transport northward, leaving Europe vulnerable to extreme winters, summers of drying, and shifts in tropical rainfall. Climate models show the tipping point is linked to collapsing winter convection in the North Atlantic, which weakens vertical mixing and creates a feedback loop that accelerates decline.Share:

    

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Atlantic’s Great Ocean Conveyor Could Shut Down
Scientists warn the AMOC could collapse after 2100, unleashing extreme winters, shifting rainfall, and climate upheaval. Early signals show the system weakening, making emission cuts vital to slow the risk. Credit: Shutterstock

Under high-emission scenarios, the Atlantic Meridional Overturning Circulation (AMOC), a key system of ocean currents that also includes the Gulf Stream, could shut down after the year 2100. This is the conclusion of a new study, with contributions by the Potsdam Institute for Climate Impact Research (PIK). The shutdown would cut the ocean’s northward heat supply, causing summer drying and severe winter extremes in northwestern Europe and shifts in tropical rainfall belts.

“Most climate projections stop at 2100. But some of the standard models of the IPCC – the Intergovernmental Panel on Climate Change – have now run centuries into the future and show very worrying results,” says Sybren Drijfhout from the Royal Netherlands Meteorological Institute, the lead author of the study published in Environmental Research Letters. “The deep overturning in the northern Atlantic slows drastically by 2100 and completely shuts off thereafter in all high-emission scenarios, and even in some intermediate and low-emission scenarios. That shows the shutdown risk is more serious than many people realize.”

Collapse of deep convection in winter as the tipping point 

The AMOC carries sun-warmed tropical water northward near the surface and sends colder, denser water back south at depth. This ocean “conveyor belt” helps keep Europe relatively mild and influences weather patterns worldwide. In the simulations, the tipping point that triggers the AMOC shutdown is a collapse of deep convection in winter in the Labrador, Irminger and Nordic Seas. Global heating reduces winter heat loss from the ocean, because the atmosphere is not cool enough. This starts to weaken the vertical mixing of ocean waters: The sea surface stays warmer and lighter, making it less prone to sinking and mixing with deeper waters. This weakens the AMOC, resulting in less warm, salty water flowing northward.

In northern regions, then, surface waters become cooler and less saline, and this reduced salinity makes the surface water even lighter and less likely to sink. This creates a self-reinforcing feedback loop, triggered by atmospheric warming but perpetuated by weakened currents and water desalination.

“In the simulations, the tipping point in key North Atlantic seas typically occurs in the next few decades, which is very concerning,” says Stefan Rahmstorf, Head of PIK’s Earth System Analysis research department and co-author of the study. After the tipping point the shutdown of the AMOC becomes inevitable due to a self-amplifying feedback. The heat released by the far North Atlantic then drops to less than 20 percent of the present amount, in some models almost to zero, according to the study.

Lead author Drijfhout adds that “recent observations in these deep convection regions already show a downward trend over the past five to ten years. It could be variability, but it is consistent with the models’ projections.”

It is crucial to cut emissions fast

To arrive at these results, the research team analyzed CMIP6 (Coupled Model Intercomparison Project) simulations, which were used in the latest IPCC Assessment Report, with extended time horizons to years from 2300 to 2500. In all nine high-emission simulations, the models evolve into a weak, shallow circulation state with the deep overturning shutting down; this result is produced in some intermediate and low-emission simulations as well. In every case, this change follows a mid-century collapse of the deep convection in North Atlantic seas.

“A drastic weakening and shutdown of this ocean current system would have severe consequences worldwide,” PIK researcher Rahmstorf points out. “In the models, the currents fully wind down 50 to 100 years after the tipping point is breached. But this may well underestimate the risk: these standard models do not include the extra fresh water from ice loss in Greenland, which would likely push the system even further. This is why it is crucial to cut emissions fast. It would greatly reduce the risk of an AMOC shutdown, even though it is too late to eliminate it completely.”

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https://www.sciencedaily.com/releases/2025/08/250830001201.htm

A monster seaweed bloom is taking over the Atlantic

Source:Florida Atlantic University

Summary:Sargassum has escaped the Sargasso Sea and exploded across the Atlantic, forming the massive Great Atlantic Sargassum Belt. Fueled by nutrient runoff, Amazon outflows, and climate events, these blooms now reshape ecosystems, economies, and coastlines on a staggering scale.Share:

    

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Monster Seaweed Bloom Taking Over the Atlantic
Sargassum on a beach in Palm Beach County in 2021. Credit: Brian Lapointe, FAU Harbor Branch

Researchers at Florida Atlantic University’s Harbor Branch Oceanographic Institute have released a landmark review tracing four decades of changes in pelagic sargassum – free-floating brown seaweed that plays a vital role in the Atlantic Ocean ecosystem.

Once thought to be primarily confined to the nutrient-poor waters of the Sargasso Sea, sargassum is now recognized as a rapidly growing and widely distributed marine organism, whose expansion across the Atlantic is closely linked to both natural processes and human-induced nutrient enrichment.

The review, published in the journal Harmful Algae, sheds new light on the origins and development of the Great Atlantic Sargassum Belt, a massive recurring bloom of sargassum that stretches across the Atlantic Ocean from the coast of West Africa to the Gulf of America.

Since its first appearance in 2011, this belt has formed nearly every year – except in 2013 – and in May, reached a new record biomass of 37.5 million tons. This does not include the baseline biomass of 7.3 million tons historically estimated in the Sargasso Sea.

By combining historical oceanographic observations, modern satellite imagery, and advanced biogeochemical analyses, this review provides a comprehensive framework for understanding the dramatic changes in sargassum distribution, productivity and nutrient dynamics. It also highlights the broader implications of anthropogenic nutrient enrichment on ocean ecology and the need for coordinated international efforts to monitor and manage the impacts of these massive seaweed blooms.

“Our review takes a deep dive into the changing story of sargassum – how it’s growing, what’s fueling that growth, and why we’re seeing such a dramatic increase in biomass across the North Atlantic,” said Brian Lapointe, Ph.D., lead author and a research professor at FAU Harbor Branch. “By examining shifts in its nutrient composition – particularly nitrogen, phosphorus and carbon – and how those elements vary over time and space, we’re beginning to understand the larger environmental forces at play.”

Early in the review, Lapointe and co-authors Deanna F. Webber, research coordinator; and Rachel Brewton, Ph.D., an assistant research professor, both with FAU Harbor Branch, explain that early oceanographers charted the Sargasso Sea based on surface sightings of sargassum, believing the seaweed thrived in its warm, clear, but nutrient-poor waters. However, this notion created a paradox when mid-20th-century oceanographers described the region as a “biological desert.”

However, recent satellite observations, ocean circulation models, and field studies have resolved this paradox by tracing the seasonal transport of sargassum from nutrient-rich coastal areas, particularly the western Gulf of America, to the open ocean via the Loop Current and Gulf Stream. These findings support early theories by explorers who proposed that Gulf-originating sargassum could feed populations in the Sargasso Sea.

Remote sensing technology played a pivotal role in these discoveries. In 2004 and 2005, satellites captured extensive sargassum windrows – long, narrow lines or bands of floating sargassum – in the western Gulf of America, a region experiencing increased nutrient loads from river systems such as the Mississippi and Atchafalaya.

“These nutrient-rich waters fueled high biomass events along the Gulf Coast, resulting in mass strandings, costly beach cleanups and even the emergency shutdown of a Florida nuclear power plant in 1991,” Lapointe said. “A major focus of our review is the elemental composition of sargassum tissue and how it has changed over time.”

Laboratory experiments and field research dating back to the 1980s confirmed that sargassum grows more quickly and is more productive in nutrient-enriched neritic waters than in the oligotrophic waters of the open ocean. Controlled studies revealed that the two primary species, sargassum natans and sargassum fluitans, can double their biomass in just 11 days under optimal conditions. These studies also established that phosphorus is often the primary limiting nutrient for growth, although nitrogen also plays a critical role.

From the 1980s to the 2020s, the nitrogen content of sargassum increased by more than 50%, while phosphorus content decreased slightly, leading to a sharp rise in the nitrogen-to-phosphorus (N:P) ratio.

“These changes reflect a shift away from natural oceanic nutrient sources like upwelling and vertical mixing, and toward land-based inputs such as agricultural runoff, wastewater discharge and atmospheric deposition,” said Lapointe. “Carbon levels in sargassum also rose, contributing to changes in overall stoichiometry and further highlighting the impact of external nutrient loading on marine primary producers.”

The review also explores how nutrient recycling within sargassum windrows, including excretion by associated marine organisms and microbial breakdown of organic matter, can sustain growth in nutrient-poor environments. This micro-scale recycling is critical in maintaining sargassum populations in parts of the ocean that would otherwise not support high levels of productivity.

Data from sargassum collected near the Amazon River mouth support the hypothesis that nutrient outflows from this major river contribute significantly to the development of the GASB. Variations in sargassum biomass have been linked to flood and drought cycles in the Amazon basin, further connecting land-based nutrient inputs to the open ocean.

The formation of the GASB appears to have been seeded by an extreme atmospheric event – the negative phase of the North Atlantic Oscillation in 2009 to 2010, which may have helped shift surface waters and sargassum from the Sargasso Sea southward into the tropical Atlantic.

However, the researchers caution that there is no direct evidence of this movement. Moreover, genetic and morphological data suggest that some sargassum populations, particularly the dominant S. natans var. wingei, were already present in the tropical Atlantic prior to 2011, indicating that this region may have had an overlooked role in the early development of the GASB.

“The expansion of sargassum isn’t just an ecological curiosity – it has real impacts on coastal communities. The massive blooms can clog beaches, affect fisheries and tourism, and pose health risks,” said Lapointe. “Understanding why sargassum is growing so much is crucial for managing these impacts. Our review helps to connect the dots between land-based nutrient pollution, ocean circulation, and the unprecedented expansion of sargassum across an entire ocean basin.”

This work was funded by the Florida Department of Emergency Management, United States Environmental Protection Agency, South Florida Program Project, and the NOAA Monitoring and Event Response for Harmful Algal Blooms program. Historical studies included within the review were funded by the NASA Ocean Biology and Biogeochemistry Program and Ecological Forecast Program, NOAA RESTORE Science Program, National Science Foundation, “Save Our Seas” Specialty License Plate and discretionary funds, granted through the Harbor Branch Oceanographic Institute Foundation, and a Red Wright Fellowship from the Bermuda Biological Station.

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https://www.sciencedaily.com/releases/2025/08/250830001159.htm

Harmful microplastics infiltrating drinking water

Wastewater treatment plants are still not effectively removing dangerous microplastics

Source:University of Texas at Arlington

Summary:Despite advances in wastewater treatment, tiny plastic particles called microplastics are still slipping through, posing potential health and environmental hazards, according to new research.Share:

    

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Despite advances in wastewater treatment, tiny plastic particles called microplastics are still slipping through, posing potential health and environmental hazards, according to new research from The University of Texas at Arlington.

Because plastic is inexpensive to produce yet lightweight and sturdy, manufacturers have found it ideal for use in nearly every consumer good, from food and beverage packaging to clothing and beauty products. The downside is that when a plastic item reaches the end of its useful life, it never truly disappears. Instead, it breaks down into smaller and smaller pieces called microplastics — particles five millimeters or less, about the width of a pencil eraser — that end up in our soil and water.

“What our systematic literature review found is that while most wastewater treatment facilities significantly reduce microplastics loads, complete removal remains unattainable with current technologies,” said Un-Jung Kim, assistant professor of earth and environmental sciences at UT Arlington and senior author of the study published in Science of the Total Environment.

“As a result, many microplastics are being reintroduced into the environment, likely transporting other residual harmful pollutants in wastewater, such the chemicals Bisphenols, PFAS and antibiotics,” Dr. Kim added. “These microplastics and organic pollutants would exist in trace level, but we can get exposure through simple actions like drinking water, doing laundry or watering plants, leading to potential long-term serious human health impacts such as cardiovascular disease and cancer.”

According to the study, one of the main challenges in detecting and mitigating microplastics is the lack of standardized testing methods. The researchers also call for a unified approach to define what size particle qualifies as a microplastic.

“We found that the effectiveness of treatments varies depending on the technology communities use and how microplastics are measured to calculate the removal rates,” said the study’s lead author, Jenny Kim Nguyen. “One way to better address the growing microplastics issue is to develop standardized testing methods that provide a clearer understanding of the issue.”

Nguyen began this research as an undergraduate student in Kim’s Environmental Chemistry Lab. She is now pursuing a master’s degree in earth and environmental sciences at UTA, where she is working to develop standardized experimental protocols for studying microplastics in air and water.

“This work helps us understand the current microplastics problem, so we can address its long-term health impacts and establish better mitigation efforts,” said Karthikraj Rajendiran, a co-author of the study and assistant professor of research from UTA’s Bone Muscle Research Center within the College of Nursing and Health Innovations.

The team also emphasizes the need for greater public awareness of microplastics to help consumers make more eco-friendly choices.

“While communities must take steps to improve microplastic detection and screening at the wastewater and water quality monitoring, consumers can already make a difference by choosing to buy clothing and textiles with less plastics whenever feasible, knowing that microfibers are the most common microplastic continually released through wastewater,” Kim added.

Funding for the project was provided by UTA’s Research Enhancement Program, which supports multidisciplinary researchers in launching new projects.

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https://www.sciencedaily.com/releases/2025/04/250421162936.htm

Wildfires threaten water quality for up to eight years after they burn

A study of 100,000 water samples from 500 river basins found elevated levels of contaminants persist for years after a fire.

Source:University of Colorado at Boulder

Summary:Wildfires don’t just leave behind scorched earth—they leave a toxic legacy in Western rivers that can linger for nearly a decade. A sweeping new study analyzed over 100,000 water samples from more than 500 U.S. watersheds and revealed that contaminants like nitrogen, phosphorus, organic carbon, and sediment remain elevated for up to eight years after a blaze.Share:

    

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Wildfires Leave Rivers Polluted for 8 Years
Wildfires leave a hidden trail: rivers tainted by long-lasting pollution. New research shows water contamination can linger up to eight years, with storms often triggering delayed surges of toxic runoff. Credit: Shutterstock

Years after wildfires burn forests and watersheds, the contaminants left behind continue to poison rivers and streams across the Western U.S. — much longer than scientists estimated.

A new study, published on June 23 in Nature Communications Earth & Environment, analyzed water quality in more than 500 watersheds across the Western U.S., and is the first large-scale assessment of post-wildfire quality.

The research was led by scientists from the Cooperative Institute for Research in Environmental Science (CIRES) at the University of Colorado Boulder.

“We were attempting to look at notable trends in post-wildfire water quality across the entire U.S. West, to help inform water management strategies in preparing for wildfire effects,” said Carli Brucker, lead author and former CU Boulder and Western Water Assessment PhD student.

The results showed contaminants like organic carbon, phosphorus, nitrogen, and sediment can degrade water quality for up to eight years after a fire. Water managers can use this data to help them plan for the future and respond appropriately when wildfires strike.

CIRES Fellow and Western Water Assessment Director Ben Livneh was the principal investigator and co-author of the study. Much of his research focuses on hydrology, or water supply, on a continental scale. When he realized he could use the same approach to understand large-scale trends in water quality, he was excited to test the method.

“There’s been a lot of work, for example, in the National Climate Assessment and the International Panel on Climate Change talking about changes in global water supply,” said Livneh, associate professor in the Department of Civil, Environmental and Architectural Engineering. “But those assessments point to this gap in water quality assessments in a continental scale context, whereas people like me in physical hydrology have been thinking about the continental scale challenges for a while.”

Researchers have long known that fire ash and soil destruction contribute to degraded water quality. Yet, past research has largely been limited to state and municipal studies — cities and towns test water quality in local streams and rivers following large fires.

For the new study, the team analyzed more than 100,000 water samples from 500 sites: half from burned river basins and half from unburned. They measured levels of organic carbon, nitrogen, phosphorus, and sediment as well as turbidity, or cloudiness, of each sample.

To understand wildfire-driven impacts, the team built data-driven models to measure how much contaminants changed in each basin before and after wildfires. In the final step, they compiled data to find the average across the burned basins for each pre- and post-wildfire year, and then compared those to the unburned basins.

The results showed watersheds take longer to recover after wildfires than previous studies found. Organic carbon, phosphorus, and turbidity are significantly elevated in the first one to five years post-fire. Nitrogen and sediment show significant increases up to eight years post-fire. Fire-driven impacts were worse in more forested areas.

“It can take two years, up to eight years, for the effect to be fully felt,” Livneh said. “Sometimes it can be a delayed effect, meaning, it’s not all happening right away, or sometimes you need a big enough storm that will mobilize enough of the leftover contaminants.”

Each watershed in the study felt the impacts differently. This is likely tied to where the fire struck — a fire closer to the river would be worse than an upstream fire. Different soils, vegetation, and weather also change the impact in each watershed, making it difficult to plan for the future.

“There’s a huge amount of variability in sedimentation rates,” said Brucker, who now works as a consultant. “Some streams are completely clear of sediment after wildfires, and some have 2000 times the amount of sediment.”

Despite variability across river basins, the study provides concrete numbers that give insight to water managers across the Western U.S. Researchers hope the results provide better direction on informing future planning efforts for increasing wildfire resilience.

“I’m hoping that providing concrete numbers is very impactful to water managers,” Brucker said. “You can’t fund resilience improvements on general concerns alone. Water managers need real numbers for planning, and that’s what we’re providing,” Brucker said.

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https://www.sciencedaily.com/releases/2025/06/250624044332.htm#google_vignette

Drought Depletes Turkey’s Tekirdag Reservoirs, Forcing Emergency Water Curbs

By Reuters

Reuters

Reuters

A drone view shows the receding waterline and exposed lakebed in the dried basin of Turkmenli Dam, as drought conditions continue to affect water levels, in Marmara Ereglisi, in the northwestern Tekirdag province, Turkey, August 11, 2025. REUTERS/Murad Sezer

By Ali Kucukgocmen

TEKIRDAG, Turkey (Reuters) -A drought in Turkey’s northwestern province of Tekirdag has left the area’s main dams without potable water, straining infrastructure and leaving some homes without water for weeks, due to a sharp drop in precipitation in the country this year.

Authorities say drought is a critical issue, with several provinces warning of limited fresh water supply this summer.

Various areas in Izmir, Turkey’s third-most populous province, have experienced frequent water cuts this month, while the municipality in the western province of Usak was told over the weekend it would have access to water just six hours a day, with the main water reservoir depleted.

Rainfall slumped 71% in July across the country from a year ago, according to Turkey’s Meteorological Service. In the Marmara region, which includes Tekirdag and Istanbul, it shrank 95% below the monthly norm in July.

In the ten months to August, precipitation sank 32% in Marmara compared to the norm, while it fell 26% across Turkey to the lowest in 52 years.

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The water level in Tekirdag’s Naip Dam, which has not seen any rainfall in June and July, fell to zero percent in August.

MORE: Places the U.S. Government Warns Not to Travel Right Now

That has forced authorities to find alternatives like delivering irrigation water for domestic use and building a pump system for delivery into urban areas.

The dam’s water level was 21% this time last year, according to the State Hydraulic Works.

Mehmet Ali Sismanlar, head of Tekirdag’s Water and Sewerage Administration (TESKI), said rainfall in Tekirdag has reduced dramatically over the past decade, and severe drought over the last two years has spurred frequent water cuts in some areas this summer.

“We are the area and the province that has been affected the most by the drought in Turkey,” he said, attributing it to climate change.

The water in Turkmenli dam, usually used for irrigation, was used to supply water to Tekirdag’s Marmaraereglisi district, where some neighbourhoods faced water cuts.

TESKI was working to open new wells to use ground water, not usually a preferred measure, Sismanlar said. He said ground water had sunk to twice its original depth over the years.

Mehmet, 70, a resident who lives in the Dereagzi neighbourhood with his family, said their home has had no water for two months, leaving them unable to shower or perform chores, and they were fetching water from nearby areas in large bottles.

“I have been living in filth for the past two months,” he said, standing among dirty piles of dishes in the kitchen, and adding that he last showered when he went to Istanbul, around 130 kilometres (81 miles) away.

His wife, Fatma, 65, said the family stayed up at night to fill up bottles in case water supply is resumed.

Remzi Karabas, 71, said he takes his laundry to Istanbul to be washed, but was done with living in Tekirdag. 

“We’ll leave some day soon. What can we do here? Water does not flow at all.”

(Editing by Tuvan Gumrukcu and Bernadette Baum)

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https://www.usnews.com/news/world/articles/2025-08-19/drought-depletes-turkeys-tekirdag-reservoirs-forcing-emergency-water-curbs

Protected seas help kelp forests bounce back from heatwaves

Date:August 20, 2025

Source:British Ecological Society

Summary:Kelp forests bounce back faster from marine heatwaves when shielded inside Marine Protected Areas. UCLA researchers found that fishing restrictions and predator protection strengthen ecosystem resilience, though results vary by location.Share:

    

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Protected Seas Help Kelp Forests Bounce Back
Marine Protected Areas give kelp forests a recovery edge after heatwaves, showing that local protections can buffer global climate pressures. Credit: Shutterstock

New research finds that Marine Protected Areas can boost the recovery of globally important kelp forests following marine heatwaves. The findings are published in the British Ecological Society’s Journal of Applied Ecology.

Using four decades of satellite images, University of California, Los Angeles (UCLA) researchers have looked at impacts Marine Protected Areas (MPAs) are having on kelp forests along the coast of California.

They found that although the overall effect of MPAs on kelp forest cover was modest, the benefits became clear in the aftermath of marine heatwaves in 2014-2016, when kelp forests within MPAs were able recover more quickly, particularly in southern California.

“We found that kelp forests inside MPAs showed better recovery after a major climate disturbance compared to similar unprotected areas.” Explained Emelly Ortiz-Villa, lead author of the study and a PhD researcher at UCLA Department of Geography.

“Places where fishing is restricted and important predators like lobsters and sheephead are protected saw stronger kelp regrowth. This suggests that MPAs can support ecosystem resilience to climate events like marine heatwaves.”

Professor Rick Stafford, Chair of the British Ecological Society Policy Committee, who was not involved in the study said: “It’s great to see these results and they clearly show that local action to protect biodiversity and ecosystem function can help prevent changes caused by global pressures such as climate change.

“However, it also demonstrates the need for effective MPAs. In this study, all the MPAs examined regulated fishing activity, and this is not the case for many sites which are designated as MPAs worldwide – including many in the UK.”

Kelp forests: a globally important and threatened ecosystem

Kelp forests our found around coastlines all over the world, particularly in cool, temperate waters such as the pacific coast of North America, The UK, South Africa, and Australia.

These complex ecosystems are havens for marine wildlife, including commercially important fish, and are one of the most productive habitats on Earth. They’re also efficient in capturing carbon and protect coastlines by buffering against wave energy.

However, kelp forests across the west coast of North America have declined in recent yeadue to pressures such as marine heatwaves, made more frequent and intense with climate change, and predation from increasing numbers of sea urchins, which have benefitted from population collapses of sea stars, which predate them.

Kyle Cavanaugh, a senior author of the study and professor in the UCLA Department of Geography and Institute of the Environment and Sustainability said: “Kelp forests are facing many threats, including ocean warming, overgrazing, and pollution. These forests can be remarkably resilient to individual stressors, but multi-stressor situations can overwhelm their capacity to recover. By mitigating certain stressors, MPAs can help enhance the resilience of kelp.”

Marine protected areas as a conservation tool

MPAs are designated areas of the ocean where human activity is limited to support ecosystems and the species living there. However, protections vary widely and while some areas are no-take zones, others have few restrictions or lack comprehensive management and enforcement. Many even allow destructive practices like bottom trawling.

Effective MPAs form a key part of the Kunming-Montreal Global Biodiversity Framework, agreed at COP15 in 2022, which commits nations to protecting at least 30% of oceans and land by 2030.

“Our findings can inform decisions about where to establish new MPAs or implement other spatial protection measures.” said Kyle Cavanaugh. “MPAs will be most effective when located in areas that are inherently more resilient to ocean warming, such as regions with localized upwelling or kelp populations with higher thermal tolerance.”

Emelly Villa added: “Our findings suggest that kelp forests could be a useful indicator for tracking the ecological health and climate resilience of protected areas and should be included in long-term monitoring strategies.”

Measuring the impact of marine protected areas

To understand the effects MPAs were having on kelp, the researchers used of satellite data from 1984-2022 to compare kelp forests inside and outside of 54 MPAs along the California coast.

By matching each MPA with a reference site with similar environmental conditions, they were able to test whether MPAs helped kelp forests resist loss or recover from extreme marine heatwaves which took place in the North pacific between 2014 and 2016.

The researchers warn that while their findings show that MPAs can help kelp recovery after marine heatwaves, the effect was highly variable depending on location.

“On average, kelp within MPAs showed greater recovery than in the reference sites. However, not all MPAs outperformed their corresponding reference sites, suggesting that additional factors are also play a role in determining resilience.” said Kyle Cavanaugh.

The researchers say that future work could look to identify these factors to better understand where and when MPAs are most effective at enhancing kelp resilience.

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https://www.sciencedaily.com/releases/2025/08/250820000805.htm#google_vignette

Unprecedented climate shocks are changing the Great Lakes forever

Heat waves and cold spells are now more common on the Great Lakes, according to U-M research, with implications for the region’s weather, economy and ecology.

Summary:Extreme heat waves and cold spells on the Great Lakes have more than doubled since the late 1990s, coinciding with a major El Niño event. Using advanced ocean-style modeling adapted for the lakes, researchers traced temperature trends back to 1940, revealing alarming potential impacts on billion-dollar fishing industries, fragile ecosystems, and drinking water quality.

Great Lakes temperature extremes have surged since the late ’90s, threatening ecosystems, fisheries, and water quality. Advanced modeling now offers a detailed history back to 1940 and could help forecast future risks. Credit: Shutterstock

Heat waves and cold spells are part of life on the Great Lakes. But new research from the University of Michigan shows that is true today in a fundamentally different way than it was even 30 years ago.

“The appearance of these extreme temperatures is increasing,” said Hazem Abdelhady, a postdoctoral research fellow in the U-M School for Environment and Sustainability, or SEAS. “For most lakes, the appearance is up more than 100% compared with before 1998.” That timing is significant because it coincides with the 1997-1998 El Niño, which is one of the strongest on record, he added.To reveal this trend, Abdelhady and his colleagues developed a state-of-the-art approach to modeling the surface temperature of the Great Lakes, which allowed them to study heat waves and cold spells dating back to 1940. The surface water temperature of the Great Lakes plays an important role in the weather, which is an obvious concern for residents, travelers and shipping companies in the region.But the uptick in extreme temperature events could also disrupt ecosystems and economies supported by the lakes in more subtle ways, Abdelhady said.

“These types of events can have huge impacts on the fishing industry, which is a billion-dollar industry, for example,” Abdelhady said. Tribal, recreational and commercial fishing in the Great Lakes account for a total value of more than $7 billion annually, according to the Great Lakes Fishery Commission.

While fish can swim to cooler or warmer waters to tolerate gradual temperature changes, the same isn’t always true for sudden jumps in either direction, Abdelhady said. Fish eggs are particularly susceptible to abnormal temperature spikes or drops.

Hot and cold streaks can also disrupt the natural mixing and stratifying cycles of the lakes, which affects the health and water quality of lakes that people rely on for recreation and drinking water.Now that the researchers have revealed these trends on each of the Great Lakes, they’re working to build on that to predict future extreme temperature events as the average temperature of the lakes — and planet — continue to warm. In studying those events and their connections with global climate phenomena, such as El Niños and La Niñas, we can better prepare to brace for their impact, Abdelhady said.

“If we can understand these events, we can start thinking about how to protect against them,” Abdelahdy said.

The study was conducted through the Cooperative Institute for Great Lakes Research, or CIGLR, and published in Communications Earth & Environment, part of the Nature journal family. The work was supported by the National Science Foundation, its Global Centers program and the National Oceanic and Atmospheric Administration, or NOAA.

Capturing the greatness of the lakes

One of the challenges of this work was the size of the problem itself. Although researchers have developed computer models that can simulate processes in most lakes around the world, the Great Lakes aren’t most lakes.

For starters, they’re an interconnected system of five lakes. They also contain more than a fifth of the world’s fresh surface water. And the length of their shoreline is comparable to that of the U.S.’s entire Atlantic coast — including the gulf states.In many regards, the Great Lakes have more in common with coastal oceans than with other lakes, said study coauthor Ayumi Fujisaki-Manome, who is an associate research scientist with SEAS and CIGLR.

“We can’t use the traditional, simpler models for the Great Lakes because they really don’t do well,” Fujisaki-Manome said.

So Abdelhady turned to modeling approaches used to study coastal oceans and tailored them for the Great Lakes. But there was also a data hurdle to overcome in addition to the modeling challenges.

Satellites have enabled routine direct observations of the Great Lakes starting about 45 years ago, Fujisaki-Manome said. But when talking about climate trends and epochs, researchers need to work with longer time periods.

“The great thing with this study is we were able to extend that historical period by almost double,” Fujisaki-Manome said.

By working with available observational data and trusted data from global climate simulations, Abdelhady could model Great Lakes temperature data and validate it with confidence back to 1940.”That’s why we use modeling a lot of the time. We want to know about the past or the future or a point in space we can’t necessarily get to,” said coauthor Drew Groneworld, an associate professor in SEAS and a leader of the Global Center for Climate Change and Transboundary Waters. “With the Great Lakes, we have all three of those.”

David Cannon, an assistant research scientist with CIGRL, and Jia Wang, a climatologist and oceanographer with NOAA’s Great Lakes Environmental Research Laboratory, also contributed to the study. The study is a perfect example of how collaborations between universities and government science agencies can create a flow of knowledge that benefits the public and the broader research community, Gronewold said.

The team’s model is now available for other research groups studying the Great Lakes to explore their questions. For the team at U-M, its next steps are using the model to explore spatial differences across smaller areas of the Great Lakes and using the model to look forward in time.

“I’m very curious if we can anticipate the next big shift or the next big tipping point,” Gronewold said. “We didn’t anticipate the last one. Nobody predicted that, in 1997, there was going to be a warm-winter El Niño that changed everything.”

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https://www.sciencedaily.com/releases/2025/08/250813083616.htm

332 colossal canyons just revealed beneath Antarctica’s ice

Summary:Deep beneath the Antarctic seas lies a hidden network of 332 colossal submarine canyons, some plunging over 4,000 meters, revealed in unprecedented detail by new high-resolution mapping. These underwater valleys, shaped by glacial forces and powerful sediment flows, play a vital role in transporting nutrients, driving ocean currents, and influencing global climate. Striking differences between East and West Antarctica’s canyon systems offer clues to the continent’s ancient ice history, while also exposing vulnerabilities as warm waters carve away at protective ice shelves.

A groundbreaking seafloor map reveals 332 Antarctic canyons—giant, glacially carved corridors shaping climate, ocean currents, and ice shelf survival. Credit: Shutterstock

Submarine canyons are among the most spectacular and fascinating geological formations to be found on our ocean floors, but at an international level scientists have yet to uncover many of their secrets, especially of those located in remote regions of the Earth like the North and South Poles. Now, an article published in the journal Marine Geologyhas brought together the most detailed catalogue to date of Antarctic submarine canyons, identifying a total of 332 canyon networks that in some cases reach depths of over 4,000 meters.

The catalogue, which identifies five times as many canyons as previous studies had, was produced by the researchers David Amblàs, of the Consolidated Research Group on Marine Geosciences at the Faculty of Earth Sciences of the University of Barcelona, and Riccardo Arosio, of the Marine Geosciences Research Group at University College Cork. Their article shows that Antarctic submarine canyons may have a more significant impact than previously thought on ocean circulation, ice-shelf thinning and global climate change, especially in vulnerable areas such as the Amundsen Sea and parts of East Antarctica.Submarine canyons: the differences between East and West Antarctica

The submarine canyons that form valleys carved into the seafloor play a decisive role in ocean dynamics: they transport sediments and nutrients from the coast to deeper areas, they connect shallow and deep waters and they create habitats rich in biodiversity. Scientists have identified some 10,000 submarine canyons worldwide, but because only 27% of the Earth’s seafloor has been mapped in high resolution the real total is likely to be higher. And despite their ecological, oceanographic, and geological value, submarine canyons remain underexplored, especially in polar regions.

“Like those in the Arctic, Antarctic submarine canyons resemble canyons in other parts of the world,” explains David Amblàs. “But they tend to be larger and deeper because of the prolonged action of polar ice and the immense volumes of sediment transported by glaciers to the continental shelf.” Moreover, the Antarctic canyons are mainly formed by turbidity currents, which carry suspended sediments downslope at high speed, eroding the valleys they flow through. In Antarctica, the steep slopes of the submarine terrain combined with the abundance of glacial sediments amplifies the effects of these currents and contributes to the formation of large canyons.The new study by Amblàs and Arosio is based on Version 2 of the International Bathymetric Chart of the Southern Ocean (IBCSO v2), the most complete and detailed map of the seafloor in this region. It uses new high-resolution bathymetric data and a semi-automated method for identifying and analysing canyons that was developed by the authors. In total, it describes 15 morphometric parameters that reveal striking differences between canyons in East and West Antarctica.

“Some of the submarine canyons we analyzed reach depths of over 4,000 meters,” explained David Amblàs. “The most spectacular of these are in East Antarctica, which is characterized by complex, branching canyon systems. The systems often begin with multiple canyon heads near the edge of the continental shelf and converge into a single main channel that descends into the deep ocean, crossing the sharp, steep gradients of the continental slope.”

Riccardo Arosio noted that “It was particularly interesting to see the differences between canyons in the two major Antarctic regions, as this hadn’t been described before. East Antarctic canyons are more complex and branched, often forming extensive canyon-channel systems with typical U-shaped cross sections. This suggests prolonged development under sustained glacial activity and a greater influence of both erosional and depositional sedimentary processes. In contrast, West Antarctic canyons are shorter and steeper, characterized by V-shaped cross sections.”According to David Amblàs, this morphological difference supports the idea that the East Antarctica Ice Sheet originated earlier and has experienced a more prolonged development. “This had been suggested by sedimentary record studies,” Amblàs said, “but it hadn’t yet been described in large-scale seafloor geomorphology.”

About the research, Riccardo Arosio also explained that “Thanks to the high resolution of the new bathymetric database — 500 meters per pixel compared to the 1-2 kilometres per pixel of previous maps — we could apply semi-automated techniques more reliably to identify, profile and analyse submarine canyons. The strength of the study lies in its combination of various techniques that were already used in previous work but that are now integrated into a robust and systematic protocol. We also developed a GIS software script that allows us to calculate a wide range of canyon-specific morphometric parameters in just a few clicks.”

Submarine canyons and climate change

As well as being spectacular geographic accidents, the Antarctic canyons also facilitate water exchange between the deep ocean and the continental shelf, allowing cold, dense water formed near ice shelves to flow into the deep ocean and form what is known as Antarctic Bottom Water, which plays a fundamental role in ocean circulation and global climate.

Additionally, these canyons channel warmer waters such as Circumpolar Deep Water from the open sea toward the coastline. This process is one of the main mechanisms that drives the basal melting and thinning of floating ice shelves, which are themselves critical for maintaining the stability of Antarctica’s interior glaciers. And as Amblàs and Arosio have explained, when the shelves weaken or collapse, continental ice flows more rapidly into the sea and directly contributes to the rise in global sea level.

Amblàs and Arosio’s study also highlights the fact that current ocean circulation models like those used by the Intergovernmental Panel on Climate Change do not accurately reproduce the physical processes that occur at local scales between water masses and complex topographies like canyons. These processes, which include current channeling, vertical mixing and deep-water ventilation, are essential for the formation and transformation of cold, dense water masses like Antarctic Bottom Water. Omitting these local mechanisms limits the ability that models have to predict changes in ocean and climate dynamics.As the two researchers conclude, “That’s why we must continue to gather high-resolution bathymetric data in unmapped areas that will surely reveal new canyons, collect observational data both in situ and via remote sensors and keep improving our climate models to better represent these processes and increase the reliability of projections on climate change impacts.”

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https://www.sciencedaily.com/releases/2025/08/250809100910.htm