When eight young northern elephant seals suddenly began showing up at a deep-sea observatory, researchers were taken by surprise. Their repeated visits to the research site, otherwise a speck in the vast, dark ocean, wasn’t a chance occurrence, a new study reveals. The mammals were likely drawn to the area by the observatory’s sonar pulses.

A team of scientists made the discovery while studying the effects of light and bait on fish behavior at a research site located 645 meters (2,116 feet) deep, at Barkley Canyon, off the west coast of Canada. The researchers used a high-definition camera, hydrophone and acoustic imaging sonar, a system that transmits sounds to map and image features and animals.

While reviewing the footage, the team unexpectedly came upon at least eight male elephant seals (Mirounga angustirostris), ages 4-7, who visited the observatory multiple times between June 2022 and May 2023.

“These repeat visits suggest that the seals may be using the general site as a focal foraging area,” study lead author Héloïse Frouin-Mouy, a marine biologist and bioacoustician at the University of Miami, U.S., told Mongabay in an email.

The footage gave the researchers some unique insights into elephant seal behavior in the deep sea. For instance, the videos showed that the young male elephant seals preferred to eat sablefish (Anoplopoma fimbria) over snailfish (Careproctus spp.).

“This was evident when an elephant seal we named Dennis mistakenly caught a snailfish while attempting to capture a sablefish, only to quickly release it,” Frouin-Mouy said. “This is important because the prey of males, in contrast with females, is not well known.”

Moreover, footage of only male seals at the research site, but no females, suggests that the two have different foraging habitats and behaviors. “We know from previously published tagging studies that female northern elephant seals forage in the open ocean on pelagic species, while male northern elephant seals forage on benthic species at the ocean floor along the continental shelf,” Frouin-Mouy said.

Most intriguing, she added, was the elephant seals’ ability to locate the small research site in the open ocean, in complete darkness, multiple times. The researchers suspect that the observatory’s sonar had a role to play.

The sonar pulse frequencies fall within the hearing range of northern elephant seals, Frouin-Mouy said, meaning the mammals can detect the sounds. Furthermore, the same individual seals visited the site repeatedly, mostly to eat fish available there, sometimes 10 or 30 days in a row, but only when the sonar was active. After the sonar failed, their visits declined drastically.

“Our findings suggest that the northern elephant seals learned to associate the sonar noise with food availability at the site — a phenomenon known as the ‘dinner bell’ effect — and used this acoustic cue to visit the site more frequently,” Frouin-Mouy said.

Banner image of northern elephant seal foraging for food. Image courtesy of Ocean Networks Canada.

Every year, massive herds of large mammals take on arduous long-distance migrations to find food, favorable weather and a suitable place to raise their young. An international team of scientists has now launched the first-ever online atlas showcasing the migration paths of several hooved mammals, also known as ungulates, from around the world.

The new Atlas of Ungulate Migration, developed by more than 80 scientists with the Global Initiative on Ungulate Migration (GIUM), provides up-to-date migratory paths of 20 global populations of mammals. Among these are well-known migrations, such as that of the wildebeest (Connochaetes taurinus), which migrates in herds of millions between Kenya and Tanzania, as well as the long trek of the African savanna elephant (Loxodonta africana) between Zimbabwe and Botswana (elephants aren’t true ungulates but are considered to be almost-ungulates with toes instead of hooves).

The atlas also maps lesser-known treks, such as those made by the saiga antelope (Saiga tatarica) in Kazakhstan, the Mongolian khulan or wild ass (Equus hemionus hemionus) in Mongolia, the takin (Budorcas taxicolor tibetana) in China, red deer (Cervus elaphus) in Europe, and mule deer (Odocoileus hemionus) in the western U.S.

This atlas, researchers say, can help governments, conservationists and wildlife managers better understand animal movement. It can also help them tackle various threats to migratory wildlife, including poaching, climate change and fragmentation of key habitats from infrastructure like roads, railways and fences.

“This atlas represents a major milestone for conservation worldwide, and we believe the migration maps will be a tangible and effective tool to help stem the loss of the world’s ungulate migrations,” Matthew Kauffman, a wildlife biologist with the U.S. Geological Survey (USGS) and member of the GIUM scientific advisory board, said in a statement.

Earlier this year, a report published by the Convention on the Conservation of Migratory Species of Wild Animals (CMS), a United Nations biodiversity treaty, found that nearly 44% of migratory species listed under the CMS are experiencing population declines. A key threat is the loss and fragmentation of their habitats due to human activities.

The interactive atlas maps some of these threats, such as a railway line that slices across the saiga antelope’s migratory path in Kazakhstan.

“Understanding how animals respond to the types of mitigation options available, in addition to where animals are being blocked by fencing or railways, is important for restoring migrations severed by development,” Nandintsetseg Dejid, a wildlife ecologist with the Senckenberg Biodiversity and Climate Research Center in Germany, said in the statement.

Anthony Sinclair, a wildlife ecologist at the University of British Columbia in Canada, told Science that the current atlas has information gaps in places like South America. However, the GIUM researchers noted in the statement that they’ll be adding migratory maps for many more ungulate populations in the future.

Banner image of saiga antelope by Yakov Fedorov via Wikimedia Commons (CC BY-SA 4.0).

Torrential rains and strong winds from Typhoon Yagi devastated northern Vietnam on Sept. 9, leaving a reported 58 people dead and 732 injured. Dozens more are missing.

In the week of Sept. 3, Yagi killed at least 20 people in the Philippines and four more in southern China. The total estimated death toll as of Sept. 10 morning has reached at least 82. Among the victims were an infant and a 1-year old, Vietnamese media reported.

The storm is the region’s strongest in a decade, with wind speeds exceeding 230 kilometers per hour (143 miles per hour). It has destroyed bridges, factories and farms, caused power outages, and forced hundreds of thousands of people forced to flee their homes.

The typhoon has now weakened to a tropical depression, but authorities warn of more potential flooding and landslides in the days ahead. Thirteen regions in Vietnam are under high risk for flash floods following the storm.

More than 3,500 households in Yen Bai in northeast Vietnam are being evacuated following rising water levels in the Red River. A bridge there collapsed on the morning of Sept, 9 while vehicles were crossing.

A 2018 report by the U.N.’s Intergovernmental Panel on Climate Change listed Vietnam as one of the most vulnerable nations to climate change impacts, citing rising sea levels and more powerful storms.

“There will continue to be extreme weather events as present, but coming faster than anticipated, more intense, more frequent and more difficult to predict,” Dao Xuan Lai, head of the climate change and environment unit at the United Nations Development Programme’s Vietnam office, told Mongabay.

Banner image: Satellite imagery of Typhoon Yagi in the South China Sea on Sept. 4. Image by NOAA (Public domain).

Update: The story was updated to reflect confirmed death toll as of Sept. 10, 2024.

Noncertified logging concessions in Gabon have much quieter soundscapes, a proxy for vocalizing wildlife, than either national parks or sustainably logged concessions, according to a recent study. However, forests that have never been logged are home to the highest diversity of vocalizing wildlife, researchers found.

“Therefore, conserving these increasingly rare never logged forests, in combination with forest certification, is vital to effectively protect wildlife in the Congo Basin,” study lead author Natalie Yoh, a postdoctoral researcher at the University of Kent, U.K., told Mongabay in an email.

Roughly 90% of Gabon is covered in forest, making it one of the most forested countries in the world. It has a network of protected areas and logging concessions, some of which are certified by schemes like the Forest Stewardship Council (FSC), which aim to encourage logging practices that reduce harms to biodiversity compared to noncertified concessions.

To find out how wildlife respond to logging, the researchers decided to listen to animals in different forest types. They deployed acoustic recorders at 110 sites across three national parks and six selective logging concessions (three FSC-certified and three noncertified). Additionally, they placed recorders in a proposed community reserve located in an unlogged part of a noncertified concession. The community area is managed by the Kota community of Massaha.

At each site, the scientists measured the soundscape saturation, with 100% indicating the site is full of sounds and has a high diversity of vocalizing animals, and 0% meaning the forest is silent, Yoh said.

The study found that noncertified concessions had the lowest soundscape saturation among all the forest types.

“This is certainly an interesting, if not surprising, finding, which can help promote the wider use of certified logging concessions in Central Africa,” Christos Astaras, a wildlife researcher at the Forest Research Institute in Greece, who wasn’t involved in the study, told Mongabay.

However, Astaras cautioned that the study had deployed recorders in a relatively small number of certified and noncertified logging concessions, three each. Every logging concession follows certification regulations to a different extent, so “it would be great if the study is expanded to a larger subset of logging concessions,” he said.

Gabon’s national parks have some logging history too. Most were established in retired concessions last logged 20 to 40 years ago, the authors write. The study found that these parks had greater soundscape saturation compared to recently logged concessions, suggesting that animal communities can recover once logging stops. But the parks were still quieter than the few never-logged, old-growth sites within the proposed community reserve. In effect, forests that have been “resting” for decades still do not sound quite the same as forests that have never been industrially logged, Yoh said.

This suggests that logging activity has a “lasting legacy” on the soundscape, the researchers write.

Banner image of western lowland gorilla by Rhett A. Butler/Mongabay.

Severe drought and soaring temperatures are causing lakes and rivers in the Amazon to reach dangerously high temperatures, threatening species like the Amazon river dolphin, according to a recent study’s preprint.

In 2023, the Amazon experienced its worst drought in recorded history, coupled with the hottest dry season on record. The extreme climate caused the surface area of Brazil’s Tefé Lake to shrink by approximately 75%, with vast sections of the lake reduced to less than 1 meter (3.3 feet) in depth. As air temperatures peaked at 39.1° Celsius (102° Fahrenheit), the little water that remained in the lake quickly overheated. The average surface water temperature for tropical lakes is around 30°C (86°F), but in 2023, Tefé Lake reached 41°C (105°F).

Using advanced hydrodynamic modeling, the researchers found that the entire water column, up to 2 meters (6.6 feet) deep, reached 40°C (104°F), leaving no refuge for animals seeking cooler temperatures.

The study focused on Tefé Lake because of the mortality event observed the same year, 2023, when more than 200 endangered Amazon river dolphins (Inia geoffrensis) and tucuxi dolphins (Sotalia fluviatilis) perished. The researchers say the deaths were likely caused by the extreme water temperatures that year. The scientists caution that with ongoing climate change, temperatures that exceed heat tolerances for aquatic species will become more common.

Tefé Lake is not an anomaly. Five out of the 10 lakes examined in the study had exceptionally high daytime temperatures. The findings reflect a broader, long-term warming trend in Amazonian waters. Satellite data show that the region’s lakes have warmed by an average of 0.6°C (1.08°F) per decade over the past 30 years, the researchers found.

This decadal temperature rise “is a notable increase compared to global averages for lake warming,” Iestyn Woolway, an independent research fellow with Bangor University, U.K., told Mongabay in an email. “This data is critical as it provides a regional perspective that has often been overlooked in broader climate studies.” Woolway was not involved in the study.

Woolway added that the models used to simulate the conditions on Tefé Lake are robust, but on-site data collection would be more precise, a limitation the study’s authors also acknowledge in the paper.

“Overall this study focuses on a specific event in a particular region, and while the data is compelling, more research across different tropical freshwater systems is needed to understand their broader implications,” Woolway said.

The study has been submitted for peer review and preliminary data were presented at the annual meeting of the Brazilian Society for the Advancement of Science.

Banner image: A researcher examines a dolphin that likely died from extreme heat in Tefé Lake. Image courtesy of Miguel Monteiro/Mamirauá Institute.

See related coverage of heat and drought in the Amazon

Acre’s communities face drinking water shortage amid Amazon drought

Amazon drought cuts river traffic, leaves communities without water and supplies

Drought forces Amazon Indigenous communities to drink mercury-tainted water

A new study finds that the potential for carbon capture and storage is much more limited, by a factor of five or six, than the capacity projected by the United Nations to fight climate change.

The U.N.’s Intergovernmental Panel on Climate Change estimates a maximum of 30 gigatons of carbon dioxide can be trapped underground by 2050. But the study by researchers at Imperial College London finds a best-case scenario of just 5-6 gigatons. The study says the IPCC estimates are unfeasible and argues that projections, particularly regarding China’s future carbon capture, are greatly inflated.

“The existing models assess the use of CO2 storage based on very loosely constrained limitations,” lead author Yuting Zhang told Mongabay by phone, adding that some of these models simply evaluated how much CO2 the Earth’s subsurface was able to hold.

“[Our study] provides a clearer pathway for policymakers, as well as the business sector and modeling community, to start organizing and aligning their actions around this benchmark,” Zhang said.

To date, more than $83 billion has been invested into carbon capture and storage (CCS) globally. A total of 41 commercial projects are now running worldwide; almost all are operated by large fossil fuel companies.

An estimated 83% of the world’s current CCS capacity features compressed CO2 injected into the ground via pipelines to extract oil, a process called enhanced oil recovery. Roughly 40% of that carbon leaks back into the atmosphere in the process, Mark Jacobson, a civil and environmental engineering professor at Stanford University, who was not involved in the study, told Mongabay by phone.

Zhang’s study found that most future projects plan to keep carbon underground rather than using it to assist in oil production. But this approach would require heavy public funding as there’s currently little incentive to do so, especially for the fossil fuel companies that receive the bulk of the current and planned government subsidies for CCS.

So far, the projects overpromise and underperform, an energy economics report concluded. Operational projects have the capacity to capture up to 65 million tons of carbon globally. But a report found that a sample of facilities are only capturing between 33% and 90% of their maximum capacity.

According to Jacobson, the carbon emissions math also doesn’t add up when you look at the bigger picture: CCS facilities require huge amounts of energy and infrastructure to operate and are largely used to extract more oil, which will eventually lead to more emissions.

After factoring in all the associated emissions from a CCS facility, they may even end up emitting more than they capture, he added.

Banner image: Shell’s carbon capture infrastructure at the Scotford Complex in Alberta, Canada. Image by Alberta Newsroom via Flickr (CC BY-NC-ND 2.0).