An international team of paleontologists has spent more than 15 years excavating and studying fossils from Africa to expand our understanding of the Permian, a period of Earth’s history that began 299 million years ago and ended 252 million years ago with our planet’s largest and most devastating mass extinction. Led by researchers at the 91̽�� and the Field Museum of Natural History, the team is identifying the animals that thrived in southern — the planet’s single supercontinent at the time — just before the so-called “” wiped out about 70% of terrestrial species, and an even larger fraction of marine ones.��

“This mass extinction was nothing short of a cataclysm for life on Earth, and changed the course of evolution,” said , a 91̽��professor of biology and curator of vertebrate paleontology at the 91̽��. “But we lack a comprehensive view of which species survived, which didn’t, and why. The fossils we have collected in Tanzania and Zambia will give us a more global perspective on this unprecedented period in our planet’s natural history.”��

Sidor and , curator of paleomammalogy at the Field Museum, are co-editors of published Aug. 7 in the Journal of Vertebrate Paleontology featuring the team’s recent discoveries about the myriad of animals that made Permian Africa their home. These include saber-toothed predators, burrowing foragers and a large, salamander-like creature.����

All these finds were excavated in three basins across southern Africa: the Ruhuhu Basin in southern Tanzania, the Luangwa Basin in eastern Zambia and the Mid-Zambezi Basin in southern Zambia. Most were discovered by team members on multiple, month-long excavation trips to the region over the past 17 years. Others were analyses of specimens dug up decades prior that had been stored in museum collections.��

“These parts of Zambia and Tanzania contain absolutely beautiful fossils from the Permian,” said Sidor. “They are giving us an unprecedented view of life on land leading up to the mass extinction.”����

Starting in 2007, Sidor and his team, including 91̽��students and postdoctoral researchers, made five trips to the Ruhuhu Basin and four to the Mid-Zambezi and Luangwa basins, all in cooperation with the Tanzanian and Zambian governments. The researchers trekked between field sites miles apart to collect fossils. They stayed in villages or camped in the open — once waking during the night to the ground-quaking stomps of a nearby elephant herd. All fossils collected by the team will be returned to Tanzania and Zambia after researchers have completed their analyses.��

The Permian is the endpoint of what paleontologists call the Paleozoic Era. During this time, animal life — which evolved first in Earth’s oceans — began to colonize land and complex terrestrial ecosystems developed. By the Permian, a diverse array of amphibian and reptile-like creatures roamed environments ranging from early forests to arid valleys. The end-Permian mass extinction — whose precise cause scientists are still debating — obliterated many of these ecosystems and ushered in the Mesozoic Era, which saw the evolution of dinosaurs, as well as the first birds, flowering plants and mammals.��

For decades, scientists’ best understanding of the Permian, the Great Dying and the start of the Mesozoic came from the Karoo Basin in South Africa, which contains a near-complete fossil record of periods before and after the mass extinction. But beginning in the 1930s, paleontologists realized that basins in Tanzania and Zambia contain fossil records of this time range that are almost as pristine as the Karoo’s. The excavation trips by Sidor, Angielczyk and their colleagues represent the largest analysis to date of the region’s fossil record from before and after the Great Dying. In 2018, they published a comprehensive analysis of the post-Permian animals of the Ruhuhu and Luangwa basins. These new papers look further back into the Permian.��

“The number of specimens we’ve found in Zambia and Tanzania is so high and their condition is so exquisite that we can make species-level comparisons to what paleontologists have found in South Africa,” said Sidor. “I know of no better place on Earth for getting sufficient detail of this time period to make such detailed conclusions and comparisons.”��

The team’s papers describe a number of new species of dicynodonts. These small, burrowing, reptile-like herbivores first evolved in the mid-Permian. By the time of the mass extinction, dicynodonts — many of whom sported a beak-like snout with two small tusks that likely aided burrowing — were the dominant plant-eaters on land. The team’s findings also include several new species of large, saber-toothed predators called gorgonopsians, as well as a new species of temnospondyl, a large salamander-like amphibian.��

“We can now compare two different geographic regions of and see what was going on both before and after the end-Permian mass extinction,” said Sidor. “We can really start to ask questions about who survived and who didn’t.”����

In addition to the 91̽��and the Field Museum, the team includes scientists from the University of Chicago, Loyola University Chicago, Idaho State University, the National Museum of Natural History in Paris, Carleton University, the University of Southern California, the University of the Witwatersrand in South Africa, the Iziko South African Museum, Southern Methodist University, the North Carolina Museum of Natural Sciences, the Museum for Natural History in Berlin, the U.S. Geological Survey, the University of Oklahoma, the National Heritage Conservation Commission in Lusaka, Virginia Tech, and the Chipembele Wildlife Education Center in Mfume, Zambia. Seven of these scientists are former 91̽��postdoctoral researchers, doctoral students or undergraduate students. The research was funded by the U.S. National Science Foundation and the National Geographic Society.��

For more information, contact Sidor at casidor@uw.edu.����

A team of scientists based in the U.S. and Canada recently confirmed that carbon and other star-formed atoms don’t just drift idly through space until they are dragooned for new uses. For galaxies like ours, which are still actively forming new stars, these atoms take a circuitous journey. They circle their galaxy of origin on giant currents that extend into intergalactic space. These currents — known as the circumgalactic medium — resemble giant conveyor belts that push material out and draw it back into the galactic interior, where gravity and other forces can assemble these raw materials into planets, moons, asteroids, comets and even new stars.

“Think of the circumgalactic medium as a giant train station: It is constantly pushing material out and pulling it back in,” said team member , a 91̽�� doctoral candidate. “The heavy elements that stars make get pushed out of their host galaxy and into the circumgalactic medium through their explosive supernovae deaths, where they can eventually get pulled back in and continue the cycle of star and planet formation.”

Garza is lead author on a describing these findings that was published Dec. 27 in the Astrophysical Journal Letters.

“The implications for galaxy evolution, and for the nature of the reservoir of carbon available to galaxies for forming new stars, are exciting,” said co-author , 91̽��professor and chair of the Department of Astronomy. “The same carbon in our bodies most likely spent a significant amount of time outside of the galaxy!”

In 2011, a team of scientists for the first time confirmed the long-held theory that — and that this large, circulating cloud of material includes hot gases enriched in oxygen. Garza, Werk and their colleagues have discovered that the circumgalactic medium of star-forming galaxies also circulates lower-temperature material like carbon.

“We can now confirm that the circumgalactic medium acts like a giant reservoir for both carbon and oxygen,” said Garza. “And, at least in star-forming galaxies, we suggest that this material then falls back onto the galaxy to continue the recycling process.”

Studying the circumgalactic medium could help scientists understand how this recycling process subsides, which will happen eventually for all galaxies — even ours. One theory is that a slowing or breakdown of the circumgalactic medium’s contribution to�������� ��the recycling process may explain why a galaxy’s stellar populations decline over long periods of time.

“If you can keep the cycle going — pushing material out and pulling it back in — then theoretically you have enough fuel to keep star formation going,” said Garza.

For this study, the researchers used the Cosmic Origins Spectrograph on the Hubble Space Telescope. The spectrograph measured how light from nine distant quasars — ultra-bright sources of light in the cosmos — is affected by the circumgalactic medium of 11 star-forming galaxies. The Hubble readings indicated that some of the light from the quasars was being absorbed by a specific component in the circumgalactic medium: carbon, and lots of it. In some cases, they detected carbon extending out almost 400,000 light years — or four times the diameter of our own galaxy — into intergalactic space.

Future research is needed to quantify the full extent of the other elements that make up the circumgalactic medium and to further compare how their compositions differ between galaxies that are still making large amounts of stars and galaxies that have largely ceased star formation. Those answers could illuminate not just when galaxies like ours transition into stellar deserts, but why.

Co-authors on the paper are , research fellow at the Herzberg Astronomy and Astrophysics Research Centre in British Columbia; , a 91̽��postdoctoral researcher in astronomy; , a research fellow at the University of Colorado Boulder; , assistant professor of physics at North Carolina State University; and , professor of physics and astronomy at the University of Victoria. The research was funded by NASA and the National Science Foundation.

For more information, contact Garza at samgarza@uw.edu and Werk at jwerk@uw.edu.

Hummingbird bills — their long, thin beaks — look a little like drinking straws. The frenetic speed at which they get nectar out of flowers and backyard feeders may give the impression that the bills act as straws, too. But new research shows just how little water, or nectar, that comparison holds.

In a published online Nov. 27 by the Proceedings of the Royal Society Interface, an international team led by , an assistant professor of biology at the 91̽��, reveals the surprising flexibility of the hummingbird bill. The team discovered that a drinking hummingbird rapidly opens and shuts different parts of its bill simultaneously, engaging in an intricate and highly coordinated dance with its tongue to draw up nectar at lightning speeds.

To human eyes, these movements are barely perceptible. But for hummingbirds, they’re a lifeline.

“Most hummingbirds drink while they’re hovering mid-flight,” said Rico-Guevara, who is also curator of ornithology at the UW’s . “Energetically, that is very expensive. Flying straight at commuting speeds uses up less energy than hovering to drink. So, hummingbirds are trying to minimize energy and drink as fast as they can — all from these hard-to-reach spaces — which requires special adaptations for speed and efficiency.”

Previous research showed that hummingbirds extend their tongues in rapid-fire movements when drinking nectar. But scientists did not know what role the bill itself played in feeding. The team collected high-speed video footage of individual hummingbirds from six different species drinking at transparent feeders at field sites in Colombia, Ecuador and the U.S. By analyzing the footage and combining it with data from micro-CT scans of hummingbird specimens at the Yale Peabody Museum, researchers discovered the intricate bill movements that underlie drinking:

• To extend its tongue, the hummingbird opens just the tip of its bill
• After the tongue brings in nectar, the bill tip closes
• To draw nectar up the bill, the hummingbird keeps the bill’s midsection shut tightly, while opening the base slightly
• Then, it opens its tip again to extend the tongue for a new cycle, a process many hummingbird species can do 10-15 times a second

Hummingbirds have intricately shaped tongues, some resembling origami-like patterns for unfolding and collecting nectar. This new research shows just how important the bill is for drinking and that, despite its rigid outward appearance, it is remarkably flexible.

“We already knew that hummingbird bills have some flexibility, for example bending their lower bill while catching insects,” said Rico-Guevara. “But now we know that the bill plays this very active and essential role in drawing up nectar that the tongue collects.”

The bill’s role also makes hummingbirds unique among animals by relying on two types of fluid collection and transport methods: the lapping mechanism — formally known as Couette flow — which animals like dogs and cats use to drink, and Poiseuille flow, a suction-driven mechanism used, for example, by mosquitoes drinking blood or by humans drinking through a straw. Often, animals employ one approach or the other. Hummingbirds are a rare example of using both.

“It makes sense that they would have to use both, given the pressure to reach the nectar deep within the flower and to feed quickly and efficiently,” said Rico-Guevara.

Future research could try to find the muscles that control these movements, and investigate how other uses for the bill — such as catching insects — impact its flexibility.

“As plants evolved flowers of different lengths and shapes, hummingbird bills have evolved accordingly,” said Rico-Guevara. “Every time we answer one set of questions about hummingbird adaptation, new ones arise. There’s so much more to learn.”

Co-authors on the study are , an associate professor at California State University, San Marcos; , a 91̽��assistant teaching professor of biology; independent researcher Jenny Hanna; , associate professor at Cornell University; and , a professor at the University of Cambridge. The research was funded by the Walt Halperin Endowed Professorship in the 91̽��Department of Biology, the Washington Research Foundation and U.K. Research and Innovation.

For more information, contact Rico-Guevara at colibri@uw.edu.

According to the fossil record, cetaceans — whales, dolphins and their relatives — evolved from four-legged land mammals that returned to the oceans beginning some 50 million years ago. Today, their descendants are threatened by a different land-based mammal that has also returned to the sea: humans.

Thousands of whales are injured or killed each year after being struck by ships, particularly the large container vessels that ferry 80% of the world’s traded goods across the oceans. Collisions are the leading cause of death worldwide for large whale species. Yet global data on ship strikes of whales are hard to come by — impeding efforts to protect vulnerable whale species. A new study led by the 91̽�� has for the first time quantified the risk for whale-ship collisions worldwide for four geographically widespread ocean giants that are threatened by shipping: blue, fin, humpback and sperm whales.

In a published online Nov. 21 in Science, researchers report that global shipping traffic overlaps with about 92% of these whale species’ ranges.

“This translates to ships traveling thousands of times the distance to the moon and back within these species’ ranges each and every year, and this problem is only projected to increase as global trade grows in the coming decades,” said senior author , a 91̽��assistant professor of biology and researcher with the .

“Whale-ship collisions have typically only been studied at a local or regional level — like off the east and west coasts of the continental U.S., and patterns of risk remain unknown for large areas,” said lead author Anna Nisi, a 91̽��postdoctoral researcher in the Center for Ecosystem Sentinels. “Our study is an attempt to fill those knowledge gaps and understand the risk of ship strikes on a global level. It’s important to understand where these collisions are likely to occur because there are some really simple interventions that can substantially reduce collision risk.”

The team found that only about 7% of areas at highest risk for whale-ship collisions have any measures in place to protect whales from this threat. These measures include speed reductions, both mandatory and voluntary, for ships crossing waters that overlap with whale migration or feeding areas.

“As much as we found cause for concern, we also found some big silver linings,” said Abrahms. “For example, implementing management measures across only an additional 2.6% of the ocean’s surface would protect all of the highest-risk collision hotspots we identified.”

“Trade-offs between industrial and conservation outcomes are not usually this optimal,” said co-author , a research scientist with the National Oceanic and Atmospheric Administration and the University of California, Santa Cruz. “Oftentimes industrial activities must be greatly limited to achieve conservation goals, or vice versa. In this case, there is a potentially large conservation benefit to whales for not much cost to the shipping industry.”

Those highest-risk areas for the four whale species included in the study lie largely along coastal areas in the Mediterranean, portions of the Americas, southern Africa and parts of Asia.

The international team behind the study, which includes researchers across five continents, looked at the waters where these four whale species live, feed and migrate by pooling data from disparate sources — including government surveys, sightings by members of the public, tagging studies and even whaling records. The team collected some 435,000 unique whale sightings. They then combined this novel database with information on the courses of 176,000 cargo vessels from 2017 to 2022 — tracked by each ship’s automatic identification system and processed using an algorithm from Global Fishing Watch — to identify where whales and ships are most likely to meet.

The study uncovered regions already known to be high-risk areas for ship strikes: North America’s Pacific coast, Panama, the Arabian Sea, Sri Lanka, the Canary Islands and the Mediterranean Sea. But it also identified understudied regions at high risk for whale-ship collisions, including southern Africa; South America along the coasts of Brazil, Chile, Peru and Ecuador; the Azores; and East Asia off the coasts of China, Japan and South Korea.

The team found that mandatory measures to reduce whale-ship collisions were very rare, overlapping just 0.54% of blue whale hotspots and 0.27% of humpback hotspots, and not overlapping any fin or sperm whale hotspots. Though many collision hotspots fell within marine protected areas, these preserves often lack speed limits for vessels, as they were largely established to curb fishing and industrial pollution.

For all four species the vast majority of hotspots for whale-ship strikes — more than 95% — hugged coastlines, falling within a nation’s exclusive economic zone. That means that each country could implement its own protection measures in coordination with the U.N.’s International Maritime Organization.

“From the standpoint of conservation, the fact that most high-risk areas lie within exclusive economic zones is actually encouraging,” said Nisi. “It means individual countries have the ability to protect the riskiest areas.”

Of the limited measures now in place, most are along the Pacific coast of North America and in the Mediterranean Sea. In addition to speed reduction, other options to reduce whale-ship strikes include changing vessel routings away from where whales are located, or creating alert systems to notify authorities and mariners when whales are nearby.

“Lowering vessel speed in hotspots also carries additional benefits, such as reducing underwater noise pollution, reducing greenhouse gas emissions, and cutting air pollution, which helps people living in coastal areas,” said Nisi.

The authors hope their global study could spur local or regional research to map out the hotspot zones in finer detail, inform advocacy efforts and consider the impact of climate change, which will change both whale and ship distributions as sea ice melts and ecosystems shift.

“Protecting whales from the impact of ship strikes is a huge global challenge. We’ve seen the benefits of slowing ships down at local scales through programs like ‘’ in California. Scaling up such programs will require a concerted effort by conservation organizations, governments and shipping companies,” said��co-author Jono Wilson, director of ocean science at the California Chapter of , which helped identify the need for this study and secured its funding. “Whales play a critical role in marine ecosystems. Through this study we have measurable insights into ship-collision hotspots and risk and where we need to focus to make the most impact.”

Co-authors on the study are , a research scientist with the Commonwealth Scientific and Industrial Research Organisation in Australia; research scientists Callie Leiphardt and Rachel Rhodes, and professor , all at the University of California, Santa Barbara; , research ecologist with NOAA’s Southwest Fisheries Science Center; , associate vice president, Anderson Cabot Center for Ocean Life, New England Aquarium; the UW’s , professor of aquatic and fishery sciences, and , a research scientist with the Center for Ecosystem Sentinels; , professor at the Universidade do��Vale do Itajaí��in Brazil; senior research biologist with the Cascadia Research Collective; data scientist , chief scientist and senior manager with Global Fishing Watch; research scientists Lauren Dares and Chloe Robinson with Ocean Wise; with Oceanswell in Sri Lanka and the University of Western Australia; with Carleton University; biologist with the British Antarctic Survey; , emeritus research scientist with the University of Rhode Island; Russell Leaper with the International Fund for Animal Welfare; Ekaterina Ovsyanikova at the University of Queensland; and Simone Panigada with the in Italy.

The research was funded by The Nature Conservancy, NOAA, the Benioff Ocean Science Laboratory, the National Marine Fisheries Service, Oceankind, Bloomberg Philanthropy, Heritage Expeditions, Ocean Park Hong Kong, National Geographic, NEID Global and the Schmidt Foundation.

For more information, contact Nisi at anisi@uw.edu and Abrahms at abrahms@uw.edu.

Researchers from the 91̽�� have discovered a new way to help liquid flow in only one direction — but without flaps. In a published Sept. 24 in the Proceedings of the National Academy of Sciences, they report that a flexible pipe — with an interior helical structure inspired by shark intestines — can keep fluid flowing in one direction without the flaps that engines and anatomy rely upon.

Human intestines are essentially a hollow tube. But for sharks and rays, their intestines feature a network of spirals surrounding an interior passageway. In a 2021 , a different team proposed that this unique structure promoted one-way flow of fluids — also known as flow asymmetry — through the digestive tracts of sharks and rays without flaps or other aids to prevent backup. That claim caught the attention of 91̽��postdoctoral researcher , lead author on the new paper.

“Flow asymmetry in a pipe with no moving flaps has tremendous technological potential, but the mechanism was puzzling,” says Levin. “It was not clear which parts of the shark’s intestinal structure contributed to the asymmetry and which served only to increase the surface area for nutrient uptake.”

To answer these questions, Levin led a team that included co-authors and , both 91̽��professors of chemistry, and Naroa Sadaba, a fellow 91̽��postdoctoral researcher. They 3D-printed a series of “biomimetic pipes,” all with interior helices inspired by the layout of shark intestines. They varied the geometrical parameters among these prototype pipes, such as the pitch angle of the helix or the number of turns. Their first pipes were printed from rigid materials, and they found that some showed a strong preference for unidirectional flow.

“The first measurement of flow asymmetry was a ‘Eureka’ moment,” said Levin. “Until that instant, we didn’t know if our idealized structures could reproduce the flow effects seen in sharks.”

By further tuning the geometrical parameters and printing new designs, the researchers increased the flow asymmetry until it rivaled and even exceeded designs of famed inventor Nikola Tesla, who more than a century ago the Tesla valve, a with no moving parts.

“You don’t get to beat Tesla every day!” said Levin.

But shark intestines — like human intestines — aren’t rigid. The team suspected that so-called “deformable structures,” which are made from more flexible materials, might perform even better as Tesla valves. They 3D-printed a second series of prototypes made from the softest polymer that is both printable and commercially available. These flexible pipe designs, which are better mimics for shark intestines through both their “deformability” and their interior helices, performed at least seven times better compared to all previously measured Tesla valves.

“Chemists were already motivated to develop polymers that are simultaneously soft, strong and printable,” said Nelson, an expert in developing new types of polymers. “The potential use of these polymers to control flow in applications ranging from engineering to medicine strengthens that motivation.”

“Actual intestines are still about 100 times softer than our soft material, so there is plenty of room for improvement,” said Sadaba.

Keller credits the project’s success to the team’s interdisciplinary ideas from biology, chemistry and physics, and to the sharks themselves.

“Biomimicry is a powerful way of discovering new designs,” said Keller. “We never would have thought of the structures ourselves.”

The research was funded by the National Science Foundation, the Washington Research Foundation and the Fulbright Foundation.

For more information, contact Keller at slkeller@uw.edu, Nelson at alshakim@uw.edu and Levin at idolevin@uw.edu.

A team led by researchers at the 91̽�� and the National Oceanic and Atmospheric Administration has uncovered key information about what resident killer whale populations are eating. Researchers had long known that resident killer whales — also known as resident orcas — prefer to hunt fish, particularly salmon. But some populations thrive, while others have struggled. Scientists have long sought to understand the role that diet plays in these divergent fates.

“Killer whales are incredibly intelligent, and learn foraging strategies from their matriarchs, who know where to find the richest prey resources in their regions,” said , 91̽��assistant professor of aquatic and fishery sciences, who began this study as a postdoctoral researcher with NOAA’s . “So we wanted to know: Does all of that social learning affect diet preferences in different populations of resident killer whales, or in pods within populations?”

In a published Sept. 18 in the journal Royal Society Open Science, Van Cise and her colleagues report the cuisine preferences of two resident killer whale populations: the Alaska residents and the southern residents, which reside primarily in the Salish Sea and off the coast of Washington, British Columbia, Oregon and northern California. The two populations show broad preference for salmon, particularly Chinook, chum and coho. But they differ in when they switch to hunting and eating different salmon species, as well as the other fish species they pursue to supplement their diets.

Southern resident killer whales are critically endangered, while other populations are growing. This new study will inform conservation efforts for resident killer whales from northern California to the Gulf of Alaska.

“We know that lack of food is one of the main threats facing the endangered southern resident killer whales,” said Van Cise. “We figured that if we could compare their diet to the dietary habits of a healthy and growing population, it might help us better understand how we can steward and protect this vulnerable population.”

While the rivers of Alaska, British Columbia and the Pacific Northwest have historically provided resident killer whales with abundant levels of salmon, humans have recently disrupted this food supply — both directly by polluting waters and building dams that reduce salmon runs, and indirectly by generating noise pollution that interferes with hunting. In addition, in the latter half of the 20th century, resident killer whales — particularly southern residents — were captured and penned in amusement parks, which disrupted their social structure and further reduced their numbers.

This anthropogenic impact has left its mark. While Alaska resident killer whales number in the thousands and the northern resident killer whale population is growing steadily, southern resident killer whale numbers have plateaued at approximately 75 individuals. Recent research has implicated noise pollution from cargo vessels and higher rates of pregnancy failure as factors.

For this study, the team from 2011 to 2021 collected fecal samples from both southern resident and Alaska resident killer whales at various points during the year. The researchers analyzed DNA in the fecal samples to determine what the killer whales were eating. They discovered that the summer diet of Alaska residents included more chum and coho salmon, in contrast to the Chinook-heavy summer diet of a southern resident killer whale.

“Chinook are clearly an important resource for resident killer whales in any population. They’re large and energy-rich, which makes them a delicious and nutritious meal,” said Van Cise. “But what we’ve learned from the Alaska residents is that stable sources of other fishes — chum and coho salmon, even flatfishes like arrowtooth flounder — may be an important nutritional supplement helping this population thrive.”

In recent years the team has obtained more fecal samples outside of the summer months. Those samples revealed an unexpectedly diverse diet for resident killer whales. Sablefish, arrowtooth flounder, lingcod, Pacific halibut and big skate all feature in the diets of these whales, which were previously thought to eat salmon exclusively. The two populations differ in the non-salmon species they choose to supplement their diet, and when they switch among species. These dietary patterns reflect a delicate balance between regional abundance of different fish species, as well as a matriarch’s knowledge of reliable foraging locations.

“The survival of her family depends on whether the foraging sites she knows are reliable from year to year,” said Van Cise.

In both the United States and Canada, resident killer whales have gained fame, particularly the very public plight of southern residents. The team believes that their findings and follow-up dietary studies are key to aiding their recovery.

“While protecting key populations of Chinook salmon will always be vital to supporting the recovery of the endangered southern resident killer whale population, this study has taught us that we might need to think more holistically about how we can conserve the whole ecosystem of fishes that together make up the annual diet of predator populations like this one,” said Van Cise.

Co-authors on the study are M. Bradley Hanson, Candice Emmons and Kim Parsons of NOAA’s Northwest Fishery Science Center; Dan Olsen and Craig Matkin of the Alaska-based North Gulf Oceanic Society; and Abigail Wells of Lynker Technologies. The research was funded by the North Gulf Oceanic Society, the National Fish and Wildlife Federation, Shell, SeaWorld, NOAA, the Exxon Valdez Trustee Council and the U.S. Marine Mammal Commission.

For more information, contact Van Cise at avancise@uw.edu.��

The Salish Sea — the inland coastal waters of Washington and British Columbia — is home to two unique populations of fish-eating orcas, the northern resident and the southern resident orcas. Human activity over much of the 20th century, including reducing salmon runs and capturing orcas for entertainment purposes, decimated their numbers. This century, the northern resident population has steadily grown to more than 300 individuals, but the southern resident population has plateaued at around 75. They remain critically endangered.

New research led by the 91̽�� and the National Oceanic and Atmospheric Administration has revealed how underwater noise produced by humans may help explain the southern residents’ plight. In a published Sept. 10 in Global Change Biology, the team reports that underwater noise pollution — from both large and small vessels — forces northern and southern resident orcas to expend more time and energy hunting for fish. The din also lowers the overall success of their hunting efforts. Noise from ships likely has an outsized impact on southern resident orca pods, which spend more time in parts of the Salish Sea with high ship traffic.

“Vessel noise negatively impacts every step in the hunting behavior of northern and southern resident orcas: from searching, to pursuing and finally capturing prey,” said lead author , a senior research scientist at the UW’s , who began this study as a postdoctoral researcher with NOAA’s . “It shines a light on why southern residents in particular have not recovered. One factor hindering their recovery is availability and accessibility of their preferred prey: salmon. When you introduce noise, it makes it even harder to find and catch prey that is already hard to find.”

Northern and southern resident orcas search for food via echolocation. Individuals transmit short clicks through the water column that bounce off other objects. Those signals return to orcas as echoes that encode information about the type of prey, its size and location. If the orcas detect salmon, they can initiate a complex pursuit and capture process, which includes intensified echolocation and deep dives to try to trap and capture fish.

The team — which also includes scientists at Fisheries and Oceans Canada, Wild Orca, the Cascadia Research Collective and the University of Cumbria in the U.K. — analyzed data from northern and southern resident orcas, whose movements were tracked using digital tags, or “Dtags.” The cellphone-sized Dtags, which attach noninvasively just below an orca’s dorsal fin via suction cups, collect data on three-dimensional body movements, position, depth and other environmental data including — critically — the sound levels at the whales’ locations.

“Dtags are a critical innovation for us to understand firsthand the environmental conditions that resident orcas experience,” said Tennessen. “They open a window into what orcas are hearing, their echolocation behavior and the very specific movements they initiate when they hunt for prey.”

The researchers analyzed data from 25 Dtags placed on northern and southern resident orcas for several hours on specific days from 2009 to 2014. The team’s deep dive into Dtag data showed that vessel noise, particularly from boat propellers, raised the level of ambient noise in the water. The increased noise interfered with the orcas’ ability to hear and interpret information about prey conveyed via echolocation. For every additional decibel increase in maximum noise levels around orcas, the researchers observed:

• An increased chance of male and female orcas searching for prey
• A lower chance of females pursuing prey
• A lower chance that both males and females would actually capture prey

Dtags also recorded “deep dive” hunting attempts by orcas. Out of 95 such attempts, most occurred in low or moderate noise. But six deep-hunting dives occurred in particularly loud settings, only one of which was successful.

The team found that noise had a disproportionately negative impact on females, who were less likely to pursue prey that had been detected during noisy conditions. Dtag data did not indicate the reason, though potential explanations include a reluctance to leave vulnerable calves at the surface while engaging prey in long chases that may not be fruitful, and the pressure for lactating females to conserve energy. Though southern resident orcas often share captured prey with one another, the impact of noise may contribute to nutritional stress among females, which previous research has linked to high rates of pregnancy failure among southern residents.

Reducing vessel speeds leads to quieter waters for the orcas. Both sides of the U.S.-Canada border include voluntary speed-reduction programs for vessels: the , initiated in 2014 by the Vancouver Fraser Port Authority, and , launched in 2021 for Washington state waters. But reducing noise is only one factor in saving southern resident orcas and helping northern residents continue to recover.

“When you factor in the complicated legacy we’ve created for the resident orcas — habitat destruction for salmon, water pollution, the risk of vessel collisions — adding in noise pollution just compounds a situation that is already dire,” said Tennessen. “The situation could be turned around, but only with great effort and coordination on our part.”

Co-authors on the paper are Marla Holt, Brad Hanson and Candice Emmons with NOAA’s Northwest Fisheries Science Center; Brianna Wright and Sheila Thornton with Fisheries and Oceans Canada; Deborah Giles with Wild Orca and the UW’s Friday Harbor Laboratories; Jeffrey Hogan with the Cascadia Research Collective; and Volker Deecke with the University of Cumbria. The research was funded by NOAA, Fisheries and Oceans Canada, the University of Cumbria, the Marie Curie Intra-European Fellowship, the University of British Columbia and the Natural Sciences and Engineering Research Council of Canada.

For more information, contact Tennessen at jtenness@uw.edu.

An international team led by researchers at the 91̽�� has uncovered surprising details about mosquito mating, which could lead to improved malaria control techniques and even help develop precision drone flight. In a published Aug. 30 in the journal Current Biology, the team revealed that when a male Anopheles coluzzii mosquito hears the sound of female-specific wingbeats, his vision becomes active.

Many mosquito species have relatively poor vision, and Anopheles coluzzii — a major spreader of malaria in Africa — is no exception. But the team found that when a male hears the telltale buzz of female flight, his eyes “activate” and he visually scans the immediate vicinity for a potential mate. Even in a busy, crowded swarm of amorous mosquitoes, which is how Anopheles coluzzii mates, the researchers found that the male can visually lock on to his target. He then speeds up and zooms deftly through the swarm — and avoids colliding with others.

“We have discovered this incredibly strong association in male mosquitoes when they are seeking out a mate: They hear the sound of wingbeats at a specific frequency — the kind that females make — and that stimulus engages the visual system,” said lead author Saumya Gupta, a 91̽��postdoctoral researcher in biology. “It shows the complex interplay at work between different mosquito sensory systems.”

This strong link between males hearing the female-like buzz and moving toward an object in their field of vision may open up a new route for mosquito control: a new generation of traps specific to the Anopheles mosquitoes that spread malaria.

“This sound is so attractive to males that it causes them to steer toward what they think might be the source, be it an actual female or, perhaps, a mosquito trap,” said senior author , a 91̽��professor of biology.

Like most Anopheles species, Anopheles coluzzii mate in large swarms at sunset. The bulk of the bugs in these swarms are males, with only a few females. To human eyes, the swarms may appear chaotic. Mosquitoes of both sexes rapidly zip past each other. Males must use their senses to both avoid collision and find a rare female.

Gupta, Riffell and their colleagues — including scientists from Wageningen University in the Netherlands, the Health Sciences Research Institute in Burkina Faso, and the University of Montpelier in France — wanted to understand the interplay between mosquitoes’ senses and how they work together in these swarms. To test the flight behavior of individual male mosquitoes, they built a miniature arena that uses a curved, pixelated screen to mimic the visual chaos of a swarm. The arena is essentially a mosquito flight simulator. In it, the mosquito test subject, which is tethered and cannot freely move, can still see, smell and hear, and also beat its wings as if it is in flight.

In arena tests with dozens of male Anopheles coluzzii mosquitoes, the researchers discovered that males responded differently to an object in their field of vision based on what sound the researchers broadcast into the arena. If they played to a tone at 450 hertz — the frequency at which female mosquito wings beat in these swarms — males steered toward the object. But males did not try to turn toward the object if the researchers played a tone at 700 hertz, which is closer to the frequency at which their fellow males beat their wings.

The mosquito’s perceived distance to the object also mattered. If the simulated object appeared more than three body lengths away, he would not turn toward it, even in the presence of female-like flight tones.

“The resolving power of the mosquito eye is about 1,000-fold less than the resolving power of the human eye,” said Riffell. “Mosquitoes tend to use vision for more passive behaviors, like avoiding other objects and controlling their position.”

In addition to their dramatic response to objects when hearing female flight tones, arena experiments revealed that males made a different set of subtle flight adjustments to other objects. They modified their wingbeat amplitude and frequency in response to an object in their field of view, even with no wingbeat sounds piped in through the speaker. The team hypothesized that these visually driven responses may be preparatory maneuvers to avoid an object. To learn more, they filmed male-only swarms in the laboratory. Analyses of those movements showed that males accelerated away when they neared another male.

“We believe our results indicate that males use close-range visual cues for collision avoidance within swarms,” said Gupta. “However, hearing female flight tones appears to dramatically alter their behavior, suggesting the importance of integrating sound and visual information.”

This research may demonstrate a new method for mosquito control by targeting how mosquitoes integrate auditory and visual cues. The males’ strong and consistent attraction to visual cues when they hear the female buzz may be a vulnerability that researchers can utilize while designing the next generation of mosquito traps —particularly traps for the Anopheles species, which are a major spreader of malaria pathogens.

“Mosquito swarms are a popular target for mosquito control efforts, because it really leads to a strong reduction in biting overall,” said Riffell. “But today’s measures, like insecticides, are increasingly less effective as mosquitoes evolve resistance. We need new approaches, like lures or traps, which will draw in mosquitoes with high fidelity.”

Co-authors are Antoine Cribellier, Serge Poda and Florian Muijres of Wageningen University of Wageningen University in the Netherlands and Olivier Roux of the University of Montpelier in France. Roux and Poda are also with the Health Sciences Research Institute in Burkina Faso. The research was funded by the Human Frontiers Science Program, the National Institutes of Health, the Air Force Office of Scientific Research and the French National Research Agency.

For more information, contact Riffell at jriffell@uw.edu and Gupta at saumyag@uw.edu.

For decades, scientists have known that some galaxies reside in dense environments with lots of other galaxies nearby. Others drift through the cosmos essentially alone, with few or no other galaxies in their corner of the universe.

A new study has found a major difference between galaxies in these divergent settings: Galaxies with more neighbors tend to be larger than their counterparts, which have a similar shape and mass, but reside in less dense environments. In a published Aug. 14 in the Astrophysical Journal, researchers at the 91̽��, Yale University, the Leibniz Institute for Astrophysics Potsdam in Germany and Waseda University in Japan report that galaxies found in denser regions of the universe are as much as 25% larger than isolated galaxies.

The research, which used a new machine-learning tool to analyze millions of galaxies, helps resolve a long-standing debate among astrophysicists over the relationship between a galaxy’s size and its environment. The findings also raise new questions about how galaxies form and evolve over billions of years.

“Current theories of galaxy formation and evolution cannot adequately explain the finding that clustered galaxies are larger than their identical counterparts in less dense regions of the universe,” said lead author , a 91̽��postdoctoral researcher in astronomy and with the UW’s . “That’s one of the most interesting things about astrophysics. Sometimes what the theories predict we should find and what a survey actually finds are not in agreement, and so we go back and try to modify existing theories to better explain the observations.”

Past studies that looked into the relationship between galaxy size and environment came up with contradictory results. Some determined that galaxies in clusters were smaller than isolated galaxies. Others came to the opposite conclusion. The studies were generally much smaller in scope, based on observations of hundreds or thousands of galaxies.

In this new study, Ghosh and his colleagues utilized a survey of millions of galaxies conducted using the in Hawaii. This endeavor, known as the , took high-quality images of each galaxy. The team selected approximately 3 million galaxies with the highest-quality data and used a machine learning algorithm to determine the size of each one. Next, the researchers essentially placed a circle — one with a radius of 30 million light years — around each galaxy. The circle represents the galaxy’s immediate vicinity. They then asked a simple question: How many neighboring galaxies lie within that circle?

The answer showed a clear general trend: Galaxies with more neighbors were also on average larger.

There could be many reasons why. Perhaps densely clustered galaxies are simply larger when they first form, or are more likely to undergo efficient mergers with close neighbors. Perhaps dark matter — that mysterious substance that makes up most of the matter in the universe, yet cannot be detected directly by any current means – plays a role. After all, galaxies form within individual “halos” of dark matter and the gravitational pull from those halos plays a critical role in how galaxies evolve.

“Theoretical astrophysicists will have to perform more comprehensive studies using simulations to conclusively establish why galaxies with more neighbors tend to be larger,” said Ghosh. “For now, the best we can say is that we’re confident that this relationship between galaxy environment and galaxy size exists.”

Utilizing an incredibly large dataset like the Hyper Suprime-Cam Subaru Strategic Program helped the team reach a clear conclusion. But that’s only part of the story. The novel machine learning tool they used to help determine the size of each individual galaxy also accounted for inherent uncertainties in the measurements of galaxy size.

“One important lesson we had learned prior to this study is that settling this question doesn’t just require surveying large numbers of galaxies,” said Ghosh. “You also need careful statistical analysis. A part of that comes from machine learning tools that can accurately quantify the degree of uncertainty in our measurements of galaxy properties.”

The machine learning tool that they used is called GaMPEN — or Galaxy Morphology Posterior Estimation Network. As a doctoral student at Yale, Ghosh led development of GaMPEN, which was unveiled in papers published in and in the Astrophysical Journal. The tool is freely available online and could be adapted to analyze other large surveys, said Ghosh.

Though this new study focuses on galaxies, it also forecasts the types of research — centered on complex analyses of incredibly large datasets — that will soon take astronomy by storm. When a generation of new telescopes with powerful cameras, including the in Chile, come online, they will collect massive amounts of data on the cosmos every night. In anticipation, scientists have been developing new tools like GaMPEN that can utilize these large datasets to answer pressing questions in astrophysics.

“Very soon, large datasets will be the norm in astronomy,” said Ghosh. “This study is a perfect demonstration of what you can do with them — when you have the right tools.”

Co-authors on the study are , professor of physics and of astronomy at Yale; , a research fellow with the Leibniz Institute; , associate professor at Waseda University; , a Yale professor of astronomy; , professor of physics and of astronomy at Yale; , a doctoral student at Yale; and , professor of astronomy at the 91̽��and faculty member in the DiRAC Institute and the . The research was funded by NASA, the Yale Graduate School of Arts & Sciences, the John Templeton Foundation, the Charles and Lisa Simonyi Fund for Arts and Sciences, the Washington Research Foundation and the 91̽��eScience Institute.

For more information, contact Ghosh at aritrag@uw.edu.

UPDATE (Aug. 2, 2024): A previous version of this story misstated Paul Kinahan’s name.

Fifteen faculty members at the 91̽�� have been elected to the Washington State Academy of Sciences. They are among 36 scientists and educators from across the state . Selection recognizes the new members’ “outstanding record of scientific and technical achievement, and their willingness to work on behalf of the academy to bring the best available science to bear on issues within the state of Washington.”

Twelve 91̽��faculty members were selected by current WSAS members. They are:

• , associate professor of epidemiology, of health systems and population health, and of child, family and population health nursing, who “possesses the rare combination of scientific rigor and courageous commitment to local community health. Identifying original ways to examine questions, and seeking out appropriate scientific methods to study those questions, allow her to translate research to collaborative community interventions with a direct impact on the health of communities.”
• , the Shauna C. Larson endowed chair in learning sciences, for “his work in the cultural basis of scientific research and learning, bringing rigor and light to multiculturalism in science and STEM education through STEM Teaching Tools and other programs.”
• , professor of psychiatry and behavioral sciences, “for her sustained commitment to community-engaged, science-driven practice and policy change related to the prevention of suicide and the promotion of mental health, with a focus on providing effective, sustainable and culturally appropriate care to people with serious mental illness.”
• , the David and Nancy Auth endowed professor in bioengineering, who has “charted new paths for 30-plus years. Her quest to deeply understand protein folding/unfolding and the link to amyloid diseases has propelled her to pioneer unique computational and experimental methods leading to the discovery and characterization of a new protein structure linked to toxicity early in amyloidogenesis.”
• , professor of environmental and occupational health sciences, of global health, and of emergency medicine, who is “a global and national leader at the intersection of climate change and health whose work has advanced our understanding of climate change health effects and has informed the design of preparedness and disaster response planning in Washington state, nationally and globally.”
• , professor of bioengineering and of radiology, who is “recognized for his contributions to the science and engineering of medical imaging systems and for leadership in national programs and professional and scientific societies advancing the capabilities of medical imaging.”
• , the Donald W. and Ruth Mary Close professor of electrical and computer engineering and faculty member in the 91̽��Clean Energy Institute, who is “recognized for his distinguished research contributions to the design and operation of economical, reliable and environmentally sustainable power systems, and the development of influential educational materials used to train the next generation of power engineers.”
• , senior vice president and director of the Vaccine and Infectious Disease Division at the Fred Hutchinson Cancer Center, the Joel D. Meyers endowed chair of clinical research and of vaccine and infectious disease at Fred Hutch, and 91̽��professor of medicine, who is “is recognized for her seminal contributions to developing validated laboratory methods for interrogating cellular and humoral immune responses to HIV, TB and COVID-19 vaccines, which has led to the analysis of more than 100 vaccine and monoclonal antibody trials for nearly three decades, including evidence of T-cell immune responses as a correlate of vaccine protection.”
• , professor of political science and the Walker family professor for the arts and sciences, who is a specialist “in environmental politics, international political economy, and the politics of nonprofit organizations. He is widely recognized as a leader in the field of environmental politics, best known for his path-breaking research on the role firms and nongovernmental organizations can play in promoting more stringent regulatory standards.”
• , the Ballmer endowed dean of social work, for investigations of “how inequality, in its many forms, affects health, illness and quality of life. He has developed unique conceptual frameworks to investigate how race, ethnicity and immigration are associated with health and social outcomes.”
• , professor of chemistry, who is elected “for distinguished scientific and community contributions to advancing the field of electron paramagnetic resonance spectroscopy, which have transformed how researchers worldwide analyze data.”
• , professor of bioengineering and of ophthalmology, whose “pioneering work in biomedical optics, including the invention of optical microangiography and development of novel imaging technologies, has transformed clinical practice, significantly improving patient outcomes. Through his numerous publications, patents and clinical translations, his research has helped shape the field of biomedical optics.”

Three new 91̽��members of the academy were selected by virtue of their previous election to one of the National Academies. They are:

• , professor of atmospheric and climate science, who had been elected to the National Academy of Sciences “for contributions to research and expertise in atmospheric radiation and cloud processes, remote sensing, cloud/aerosol/radiation/climate interactions, stratospheric circulation and stratosphere-troposphere exchanges and coupling, and climate change.”
• , the Bartley Dobb professor for the study and prevention of violence in the Department of Epidemiology and a 91̽��professor of pediatrics, who had been elected to the National Academy of Medicine “for being a national public health leader whose innovative and multidisciplinary research to integrate data across the health care system and criminal legal system has deepened our understanding of the risk and consequences of firearm-related harm and informed policies and programs to reduce its burden, especially among underserved communities and populations.”
• , division chief of general pediatrics at Seattle Children’s Hospital and a 91̽��professor of pediatrics, who had been elected to the National Academy of Medicine “for her leadership in advancing child health equity through scholarship in community-partnered design of innovative care models in pediatric primary care. Her work has transformed our understanding of how to deliver child preventive health care during the critical early childhood period to achieve equitable health outcomes and reduce disparities.”

In addition, Dr. , president and director of the Fred Hutchinson Cancer Center and of the Cancer Consortium — a partnership between the UW, Seattle Children’s Hospital and Fred Hutch — was elected to the academy for being “part of a research effort that found mutations in the cell-surface protein epidermal growth factor receptor (EGFR), which plays an important role in helping lung cancer cells survive. Today, drugs that target EGFR can dramatically change outcomes for lung cancer patients by slowing the progression of the cancer.”

the Boeing-Egtvedt endowed professor and chair in aeronautics and astronautics, will join the board effective Sept. 30. Morgansen was elected to WSAS in 2021 “for significant advances in nonlinear methods for integrated sensing and control in engineered, bioinspired and biological flight systems,” and “for leadership in cross-disciplinary aerospace workforce development.” She is currently director of the Washington NASA Space Grant Consortium, co-director of the 91̽��Space Policy and Research Center and chair of the AIAA Aerospace Department Chairs Association. She is also a member of the WSAS education committee.

“I am excited to serve on the WSAS board and work with WSAS members to leverage and grow WSAS’s impact by identifying new opportunities for WSAS to collaborate and partner with the state in addressing the state’s needs,” said Morgansen.

The new members to the Washington State Academy of Sciences will be formally inducted in September.