The 91探花 is No. 8 on the 2025-26 U.S. News & World Report鈥檚 Best Global Universities rankings, 聽on Tuesday. The 91探花maintained its No. 2 ranking among U.S. public institutions.

The 91探花also placed in the top 10 in eight subject areas ranked by U.S. News.

Harvard University, Massachusetts Institute of Technology and Stanford University topped the list in that order. The University of Oxford is No. 4, followed by University of Cambridge, the University of California, Berkeley, University College London and the UW. Yale University and Columbia University rounded out the top 10.

鈥淯nquestionably, the 91探花is advancing discovery that saves and improves lives, promotes prosperity, makes our nation stronger and expands human knowledge for the good of all,鈥� said 91探花President Ana Mari Cauce. 鈥淚鈥檓 very proud to see this extraordinary impact recognized through this latest ranking.鈥�

The U.S. News ranking聽聽鈥斅燽ased on data and metrics provided by Clarivate 鈥� weighs factors that measure a university鈥檚 global and regional research reputation and academic research performance. For the overall rankings, this includes bibliometric indicators such as the number of publications, citations and international collaboration.

The overall Best Global Universities ranking encompasses 2,250 institutions spread across 105 countries, according to U.S. News.

Here are the 91探花fields of study that are in the top 10 in U.S. News鈥� subject rankings:

Molecular biology and genetics 鈥� No. 6

Clinical medicine 鈥� No. 6

Public, environmental and occupational health 鈥� No. 6

Microbiology 鈥� No. 7

Biology and biochemistry 鈥� No. 8 (up from 9)

Infectious diseases 鈥� No. 9

Marine and freshwater biology 鈥� No. 9

Social sciences and public health 鈥� No. 9

Horacio de la Iglesia, a 91探花professor of biology and circadian rhythms expert, was a co-author of the paper and is President of the Society for Research on Biological Rhythms.

鈥淲e all love to聽see the Huskies beat the Ducks, and appreciate the funds that these games bring to聽the UW. But, as instructors, we also聽know that student athletes always need to聽shoulder more than most students,鈥� de la Iglesia said. 鈥淢ore east-west travel and more travel time has increased this load and added a sleep disparity to聽it. Proper sleep is critical for health and we can鈥檛 let the health聽of聽our student-athletes get聽out聽of focus. As a community, it is聽our responsibility to聽guard their sleep,聽which聽will not聽only protect their health, but will聽also聽optimize their academic and athletic performance.鈥�

鈥淐ognitive abilities are best in the morning hours, complex hand-eye coordination in early afternoon, and peak muscle performance in late afternoon-early evening,鈥� de la Iglesia added.聽鈥淭herefore, the scheduling of events can favor one or the other team.鈥�

A total of 25 experts co-authored the paper, noting that while travel is essential in collegiate athletic programs it inevitably results in disruptions of academic work, poor sleep, and alterations in most other aspects of student life.

鈥淭his white paper highlights some of the potential negative health repercussions of the recent college athletic conference re-alignments.聽The effects will be particularly challenging for athletes in sports that compete multiple times per week,鈥� said Dr. Russ Van Gelder, professor and chair of the 91探花Medicine Department of Ophthalmology and a co-author on the paper.聽鈥淚 hope that affected university administrations recognize these potential repercussions and take appropriate steps to track and mitigate the effects of frequent trans-time zone travel on their students.鈥�

The 91探花Athletics program already is聽looking at efforts to mitigate the effects of additional travel upon its upcoming move to the Big Ten Conference in August 2024.

鈥淲e are excited about the future of our athletic department and will continue working to optimize the student-athlete experience. While competition schedules and travel demands are yet to be determined, we have been working to identify high level, transition-related needs especially as it relates to sleep science,鈥� said Michael Dillon, 91探花Associate Athletic Director for Health and Wellness.聽鈥淲e are currently identifying a team of consultants, that will be instrumental in working with our existing staff, to guide education initiatives for our student-athletes.聽And, as always, we will continue prioritizing mental and physical health, and implementing solutions to benefit the welfare of Washington student-athletes.鈥�

The authors of the paper share recommendations to lessen the impact of jet lag, including creating event schedules that minimize the circadian differentials between the teams. Other methods include preadaptation for several days before travel or allowing sufficient time in the new location to allow circadian adjustment鈥� but they note the latter may prove difficult because it extends the length of each trip.聽Both before and after travel, management of exposure to light is important as are a variety of methods to facilitate good sleep.

This article, 鈥淭he Negative Effects of Travel on Student Athletes Through Sleep and Circadian Disruption鈥�, by H. Craig Heller and others and published in Journal of Biological Rhythms will be free to access and can be read here:

Adapted from the Society for Research on Biological Rhythms .

Contact: Victor Balta at balta@uw.edu.

Six 91探花 subjects ranked in the top 10, and atmospheric sciences maintained its position as No. 1 in the world on the聽聽list for 2023. The ranking, released at the end of October, was conducted by researchers at the ShanghaiRanking Consultancy, a fully independent organization dedicated to research on higher education intelligence and consultation.

Other 91探花subjects in the top 10 include oceanography at No. 2; public health at No. 5; biological sciences and statistics at No. 7; and clinical medicine at No. 9.

鈥淭he 91探花 is a powerhouse for research and discovery 鈥� both within and across disciplines,鈥� said 91探花President Ana Mari Cauce. 鈥淭hat research leads to cures, advances innovation in areas like climate science and transforms our understanding in ways that are critical to the future for all people and communities. We are grateful to see the impact of this vital work recognized by this esteemed organization.鈥�

This ranking takes into account more than 5,000 universities around the world in 54 subjects across natural sciences, engineering, life sciences, medical sciences and social sciences. More information about the methodology used to calculate the rankings can be found .

In 2023, the 91探花was ranked No. 18 on the group鈥檚 annual聽Academic Ranking of World Universities听濒颈蝉迟.

Note: The subject names below are general descriptions from the ranking website, and not necessarily the names of the 91探花unit ranked.

, a researcher at the 91探花Applied Physics Laboratory, appears in the film doing fieldwork on Wrangel Island, an island off the northeast coast of Russia that is home to the world’s highest concentration of polar bears. He and 91探花glaciologist will field audience questions after of the film, which focuses on the changing Arctic environment.

91探花News asked Regehr a few questions about his research studying a population of polar bears that traverse the waters between Alaska and Russia.

When do you typically go to Wrangel Island, and how long do you spend there?

I鈥檝e been leading polar bear research on Wrangel Island since 2016. I typically spend about one month there each fall, although the entire trip takes two months because the island is so remote. Unfortunately, everything has been on hold since early 2022 due to the political situation with Russia.

Who are your usual collaborators? What was it like to have a film crew with you?

The research project is a collaboration between the 91探花, the UNESCO Natural System of Wrangel Island Reserve, the U.S. government, and others. Having a film crew was fun. The only downside was that it meant keeping track of more people, to make sure they didn鈥檛 wander off and bump into a bear.

How did you come up with the technique, shown in the film, that uses a wire enclosure to collect polar bear fur for DNA analysis?

A colleague in Alaska developed the first 鈥渉air snare鈥� traps for polar bears, and then engineers here at the 91探花Applied Physics Laboratory improved the design to make the traps lightweight and collapsible. I came up with the secret polar bear sauce (it鈥檚 really old fish, old cheese and walrus blubber) that we put inside the traps as a scent attractant.

What do you wish people knew about polar bears?

Actually, I鈥檓 constantly amazed by how much the public knows about polar bears 鈥� especially kids. It鈥檚 great. But if there was one thing I鈥檇 emphasize, it鈥檚 that polar bears are directly connected to the people that live and work in the Arctic. Climate warming is rapidly changing things for both bears and humans.

Why is important to study polar bears on Wrangel Island?

The U.S. and Russia share a polar bear population, most of which ends up on Wrangel Island each fall to wait for the sea ice to reform. I鈥檝e tagged a bear in Alaska in April, and then stood 10 feet from that same bear on Wrangel Island in October. Polar bears don鈥檛 recognize political boundaries, so it’s critical that the U.S. and Russia work together to conserve these awesome animals.

Previously, Regehr also worked on the BBC series , narrated by David Attenborough, where he appears in episode 6. That series is available on Amazon Prime and Google TV.

For more information, contact Regehr at eregehr@uw.edu.

Many of us are familiar with the hummingbirds that visit feeders, plants and gardens around us. But these small creatures are unusual in the ways they push the limits of biology, says , 91探花assistant professor biology and curator of ornithology at the . He and his students study hummingbirds and other birds that drink nectar.聽

鈥淚 think what really caught my attention is their personality 鈥� how they can be so fierce and so bold despite being so tiny,鈥� said Rico-Guevara.

Some of the smallest of all bird species are hummingbirds, and they are unique in the way they fly. They produce 鈥渓ift鈥� with the forward and backward motion of their wings, enabling them to hover in place for long periods of time, something no other bird can do. A giant hummingbird beats its wings around 10-15 times a second while some bee hummingbirds beat their wings over 100 times a second during hovering displays, using an incredible amount of energy. Hummingbirds have tiny legs and perch when they can, but their speedy metabolism requires them to visit flowers thousands of times and eat 1-3 times their weight daily in floral nectar. These pollinators also eat spiders, a good source of protein. To rest, they are one of few bird species that go into a sleep-like state called 鈥渢orpor,鈥� in which their metabolic functions slow to a minimum; while active, their heart beats around 600-1200 times a minute.

Hummingbirds have evolved so that they are well matched to the flowers they feed from. Their beaks can be long or short, curved down or even tilted slightly upwards to make them efficient at accessing nectar from specific blooms, and, perhaps, useful in fighting. They have become fast and nimble to out-maneuver other animals and insects for nectar, and hovering allows them to access the openings of hard-to-reach flowers.

Hummingbirds are fiercely protective of their food and will chase other birds away from flowers. They fly in front of each other and vocalize to scare each other off. Some hummingbirds will use their claws or bill to poke each other or pluck feathers. They鈥檝e even been known to peck larger birds like falcons or crows, inspiring Aztecs to use hummingbirds as a warrior symbol. During breeding season, males court females with flashy displays of chirping, singing and aerobatics. Hummingbirds can make sounds with their tails and wings and learn new songs throughout their lives.

鈥淚t鈥檚 a circus,鈥� said Rico-Guevara. 鈥淭heir behavior is extremely rich.鈥�

Advances in high-speed photography and lenses have made it possible to see bird activity that wasn鈥檛 possible a decade ago. Rico-Guevara has used slow-motion video to document the way that hummingbirds gather and swallow nectar, using a long, split tongue that flattens and springs open when it touches liquid, filling with nectar. describes how space inside the bill fills with nectar as the tongue is wrung out; then the tongue base rakes the nectar as it retracts. Pumping action through the flexible bill helps move the nectar towards the throat. These discoveries reveal a set of coordinated movements that are different and far more complex than what was previously believed 鈥� that hummingbirds drank by moving liquid through their tongues or bills using capillary action, much the way liquid will naturally move up a small glass tube.

鈥淚t鈥檚 all really complicated, and it鈥檚 happening up to 20 times a second,鈥� said Rico-Guevara.

鈥淚t鈥檚 way more intricate than is known for any other bird.鈥�

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

The 91探花 rose from No. 7 to No. 6 on the聽, released on Tuesday. The 91探花maintained its No. 2 ranking among U.S. public institutions.

U.S. News also ranked several subjects, and the 91探花placed in the top 10 in 10 subject areas, including immunology (No. 4), molecular biology and genetics (No. 5) and clinical medicine (No. 6).

In another ranking out this week, Times Higher Education World University Rankings 2023 by Subject, six subject areas at the 91探花placed in the top 25.

鈥淎s a global public research university, the UW鈥檚 mission is to create and accelerate change for the public good,鈥� 91探花President Ana Mari Cauce said. 鈥淚鈥檓 proud that these rankings reflect the outstanding and wide-ranging work of our faculty, staff and students to expand knowledge and discovery that is changing people鈥檚 lives for the better, particularly in the health sciences.鈥�

The U.S. News ranking 鈥斅� based on Web of Science data and metrics provided by Clarivate Analytics InCites 鈥� weighs factors that measure a university鈥檚 global and regional research reputation and academic research performance. For the overall rankings, this includes bibliometric indicators such as publications, citations and international collaboration.

The overall Best Global Universities ranking, now in its ninth year, encompasses the top 2,000 institutions spread across 90 countries, according to U.S. News.聽American universities make up eight of the top 10 spots.

Here are all the top 10 91探花rankings in U.S. News鈥� subject rankings:

• Immunology 鈥� No. 4
• Molecular biology and genetics 鈥� No. 5
• Clinical medicine 鈥� No. 6
• Geosciences 鈥� No. 7
• Infectious diseases 鈥� No. 7
• Public, environmental and occupational health 鈥� No. 7
• Social sciences and public health 鈥� No. 7
• Biology and biochemistry 鈥� No. 8
• Microbiology 鈥� No. 10

In the rankings, UW鈥檚 programs in these areas placed in the top 25:

• : No. 15
• (includes agriculture and forestry, biological sciences, veterinary science and sport science): No. 16
• (includes medicine, dentistry and other health subjects): No. 17
• (includes communication and media studies, politics and international studies 鈥� including development studies, sociology and geography): No. 18
• (includes mathematics and statistics, physics and astronomy, chemistry, geology, environmental sciences, and Earth and marine sciences): No. 19
• (includes education, teacher training, and academic studies in education): No. 23

The subject tables employ the same used in the overall聽; however, the methodology is recalibrated for each subject, with the weightings changed to suit the individual fields.

Scientists have documented a previously unknown subpopulation of polar bears living in Southeast Greenland. The polar bears survive with limited access to sea ice by hunting from freshwater ice that pours into the ocean from Greenland鈥檚 glaciers. Because this isolated population is genetically distinct and uniquely adapted to its environment, studying it could shed light on the future of the species in a warming Arctic.

鈥淲e wanted to survey this region because we didn鈥檛 know much about the polar bears in Southeast Greenland, but we never expected to find a new subpopulation living there,鈥� said lead author , a polar scientist at the 91探花鈥檚 Applied Physics Laboratory. 鈥淲e knew there were some bears in the area from historical records and Indigenous knowledge. We just didn鈥檛 know how special they were.鈥�

The , published in the June 17 issue of Science, combines seven years of new data collected along the southeastern coast of Greenland with 30 years of historical data from the island鈥檚 whole east coast. The remote Southeast region had been poorly studied because of its unpredictable weather, jagged mountains and heavy snowfall. The newly collected genetic, movement and population data show how these bears use glacier ice to survive with limited access to sea ice.

鈥淧olar bears are threatened by sea ice loss due to climate change. This new population gives us some insight into how the species might persist into the future,鈥� said Laidre, who is also a 91探花associate professor of aquatic and fishery sciences. 鈥淏ut we need to be careful about extrapolating our findings, because the glacier ice that makes it possible for Southeast Greenland bears to survive is not available in most of the Arctic.鈥�

The genetic difference between this group of bears and its nearest genetic neighbor is greater than that observed for any of the 19 previously known polar bear populations.

鈥淭hey are the most genetically isolated population of polar bears anywhere on the planet,鈥� said co-author , a professor and geneticist at the University of California, Santa Cruz and investigator at the Howard Hughes Medical Institute. 鈥淲e know that this population has been living separately from other polar bear populations for at least several hundred years, and that their population size throughout this time has remained small.鈥�

Part of the reason the population is so isolated, researchers believe, is that the bears are hemmed in on all sides: by the sharp mountain peaks and massive Greenland Ice Sheet to the west, the open water of the Denmark Strait to the east, and by the fast-flowing East Greenland coastal current that poses a hazard offshore.

Before starting the fieldwork, the team spent two years soliciting input and gathering information from polar bear subsistence hunters in East Greenland. Hunters participated throughout the study, contributing their expertise, and providing harvest samples for genetic analysis.

The satellite tracking of adult females shows that, unlike most other polar bears that travel far over sea ice to hunt, Southeast Greenland bears are homebodies. They walk on ice inside protected fjords or scramble up mountains to reach neighboring fjords over the Greenland Ice Sheet. Half of the 27 tracked bears accidentally floated an average of 120 miles (190 kilometers) south on small ice floes caught in the East Greenland coastal current, but then hopped off and walked back north on land to their home fjord.

鈥淚n a sense, these bears provide a glimpse into how Greenland鈥檚 bears may fare under future climate scenarios,鈥� Laidre said. 鈥淭he sea ice conditions in Southeast Greenland today resemble what鈥檚 predicted for Northeast Greenland by late this century.鈥�

Southeast Greenland bears have access to sea ice for only four months, between February and late May. Sea ice provides the platform that most of the Arctic鈥檚 roughly 26,000 polar bears use to hunt seals. But polar bears can鈥檛 fast for eight months. For two-thirds of the year, the Southeast Greenland polar bears rely on a different strategy: They hunt seals from chunks of freshwater ice breaking off the Greenland Ice Sheet.

鈥淭he marine-terminating glaciers in Southeast Greenland are a fairly unique environment,鈥� said co-author , deputy lead scientist at the National Snow and Ice Data Center. 鈥淭hese types of glaciers do exist in other places in the Arctic, but the combination of the fjord shapes, the high production of glacier ice and the very big reservoir of ice that is available from the Greenland Ice Sheet is what currently provides a steady supply of glacier ice.鈥�

The fact that bears can survive here suggests that marine-terminating glaciers, and especially those regularly calving ice into the ocean, could become small-scale climate refugia 鈥� places where some polar bears could survive as sea ice on the ocean鈥檚 surface declines. Similar habitats exist at marine-terminating glaciers on other parts of Greenland鈥檚 coast and the island of Svalbard, a Norwegian territory located east of Greenland.

鈥淓ven with rapid changes happening on the ice sheet, this area in Greenland has the potential to continue to produce glacial ice, with a coast that may looks similar to today, for a long time,鈥� Moon said.

The authors estimate that there are roughly a few hundred bears in Southeast Greenland, similar to other small populations. Body measurements suggest that adult females are smaller than in most regions. They also have fewer cubs, which may reflect the challenge of finding mates in the complex landscape of fjords and mountains. Laidre cautioned, however, that longer-term monitoring is needed to know the future viability of Southeast Greenland bears and to understand what happens to polar bear subpopulations as they become increasingly cut off from the rest of the Arctic by declining sea ice.

鈥淚f you鈥檙e concerned about preserving the species, then yes, our findings are hopeful 鈥� I think they show us how some polar bears might persist under climate change,鈥� Laidre said. 鈥淏ut I don鈥檛 think glacier habitat is going to support huge numbers of polar bears. There鈥檚 just not enough of it. We still expect to see large declines in polar bears across the Arctic under climate change.鈥�

The government of Greenland will decide on any protection and management measures. The International Union for Conservation of Nature, which helps oversee protected species, is responsible for determining whether Southeast Greenland bears are internationally recognized as a separate population, the 20th in the world.

鈥淧reserving the genetic diversity of polar bears is crucial going forward under climate change,鈥� Laidre said. 鈥淥fficially recognizing these bears as a separate population will be important for conservation and management.鈥�

This research was funded by NASA, the U.S. National Science Foundation, the government of Denmark; the government of Greenland; the UW; the University of Oslo; the Leo Model Foundation and the Vetlesen Foundation. Other co-authors are Eric Regehr, Benjamin Cohen and Harry Stern at the UW; Megan Supple, Christopher Vollmers and Russ Corbett-Detig at UC Santa Cruz; Erik Born, Fernando Ugarte, Peter Hegelund and Carl Isaksen at the Greenland Institute of Natural Resources; Oystein Wiig at the University of Oslo; Jon Aars at the Norwegian Polar Institute; Rune Dietz and Christian Sonne at Arhus University in Denmark; Geir Akse, a helicopter pilot in Norway; and David Paetkau at Wildlife Genetics International in Canada.

Modern cetaceans 鈥� which include dolphins, whales and porpoises 鈥� are well adapted for aquatic life. They have blubber to insulate and fins to propel and steer. Today鈥檚 cetaceans also sport a unique type of nasal passage: It rises at an angle relative to the roof of the mouth 鈥� or palate 鈥� and exits at the top of the head as a blowhole.

This is an apt adaptation for an air-breathing animal at home in the water. Yet as embryos, the cetacean nasal passage starts out in a position more typical of mammals: parallel to the palate and exiting at the tip of the snout, or rostrum. Cetacean experts have long puzzled over how the nasal passage switches during embryonic and fetal development from a palate-parallel pathway to an angled orientation terminating in a blowhole.

鈥淭he shift in orientation and position of the nasal passage in cetaceans is a developmental process that鈥檚 unlike any other mammal,鈥� said , a postdoctoral researcher at the 91探花 School of Dentistry. 鈥淚t鈥檚 an interesting question to see what parts remain connected, what parts shift orientation and how might they work together through a developmental process to bring about this change.鈥�

New research by Roston and , a professor of biology at Duke University, is shedding light on this process. By measuring anatomical details of embryos and fetuses of pantropical spotted dolphins, they determined the key anatomical changes that flip the orientation of the nasal passage up. Their findings, July 19 in the Journal of Anatomy, are an integrative model for this developmental transition for cetaceans.

鈥淲e discovered that there are three phases of growth, primarily in the head, that can explain how the nasal passage shifts in orientation and position,鈥� said lead author Roston, who began this study as a doctoral student at Duke.

The three phases of growth are:

1. Initially parallel, the roof of the mouth and the nasal passage become separated as the area between them grows into a triangular shape. This phase begins during embryonic development after the face starts forming, which, for the pantropical spotted dolphin, is in the first two months after fertilization.
2. The snout grows longer at an angle to the nasal passage, further separating the nostrils from the tip of the snout. This phase begins later in fetal development and may continue even after birth.
3. The skull folds backward, and the head and body become more aligned. This rotates the nasal passage up so that it becomes nearly vertical relative to the body axis. This phase begins in late embryonic development and continues through fetal development.

鈥淲hile the nose moves to the top of the head, many of the important angular changes are actually in the bottom, or base, of the skull. That鈥檚 not necessarily something you鈥檇 expect to find!鈥� said Roston.

The three phases of growth do not unfold in a step-by-step process, but instead overlap with each other temporally, Roston said. They represent distinct developmental transformations that, put together, shift the nasal passage to the top of the head.

Roston and Roth developed this model using anatomical data obtained by photographs and CT scans of 21 embryonic and fetal pantropical spotted dolphin specimens held by the Smithsonian Institution鈥檚 National Museum of Natural History and the Natural History Museum of Los Angeles County. The specimens represented a wide range of embryonic and fetal development.

For comparison, they obtained data from eight fin whale fetuses, also at the National Museum of Natural History, and found significant differences between them and the pantropical spotted dolphin. In fin whales, the skull folded in a region in the back of the skull, near where the skull joins with the vertebral column. In the pantropical spotted dolphin, the folding is centered near the middle of the skull.

The model Roston and Roth developed could inform how scientists view cetacean evolution. These creatures began to evolve from a four-legged, land-dwelling mammalian ancestor, which had a nasal passage parallel to the palate, more than 50 million years ago. As cetaceans evolved, the blowhole gradually migrated from the tip of the snout to the back of the snout, and then gradually up to the top of the skull.

In addition, the two species represent different branches of the cetacean family tree that diverged more than 30 million years ago. Dolphins 鈥� along with porpoises, orcas, sperm whales and beaked whales 鈥� are odontocetes, commonly known as toothed whales. Fin whales are from a group called the baleen whales, named for their distinct feeding apparatus.

鈥淚鈥檓 struck by two interesting discoveries that emerged from this work,鈥� said Roth. 鈥淎lthough they both develop blowholes, there are key differences between a baleen and a toothed whale in how they reorient their nasal passages during development. Moreover, surprisingly, accompanying the processes of developing upwardly oriented nostrils there are profound changes within the braincase.鈥�

In the future, examining more species from both lineages could indicate whether all baleen and toothed whales differ in this manner, Roston said.

鈥淭his model gives us a hypothesis for the developmental steps that had to occur to make that anatomical transformation happen, and will serve as a point of comparison for additional studies of growth and development in whales, dolphins and porpoises,鈥� said Roston.

The research was funded by Duke University. Roston has also been supported by the National Institutes of Health.

For more information, contact Roston at rroston@uw.edu and Roth at vlroth@duke.edu.

How plants will fare as carbon dioxide levels continue to rise is a tricky problem and, researchers say, especially vexing in the tropics. Some aspects of plants鈥� survival may get easier, some parts will get harder, and there will be species winners and losers. The resulting shifts in vegetation will help determine the future direction of climate change.

To explore the question, a study led by the 91探花 looked at how tropical forests, which absorb large amounts of carbon dioxide, might adjust as CO2 continues to climb. Their results show that multiple changes occurring in plants鈥� leaves and competition between species could preserve these ecosystems鈥� ability to absorb carbon dioxide from the atmosphere. The resulting was published Jan. 16 in the journal Global Biogeochemical Cycles.

鈥淥ur findings suggest that plants with some types of responses, like making their leaves thicker, will ultimately grow better in tropical forests than their competitors,鈥� said senior author , a 91探花associate professor of atmospheric sciences and of biology. 鈥淚f these better-growing plants become more common in the forest, the total rates of water and carbon exchange could stay closer to what they are now.鈥�

A previous study by Swann鈥檚 group showed that tropical plants leaves鈥� becoming thicker as CO2 climbs would worsen climate change, because thicker leaves might also be smaller. Plants would then capture less sunlight for photosynthesis, absorb less carbon dioxide from the air and emit less water vapor, all exacerbating the heating due to climate change.

The new work expands the scope of this question to include competition between plant species, and the ratio of carbon and nitrogen in their leaves. Higher carbon dioxide in the atmosphere makes it a bit easier for plants to photosynthesize. But if nitrogen can鈥檛 keep up, the plant becomes less efficient at producing energy.

鈥淎lthough it is observed to happen, the verdict is still out on why exactly plants grow thicker leaves under high CO2,鈥� Swann said. The new modeling study suggests an explanation: 鈥淭hicker leaves can concentrate the nitrogen so that photosynthesis rates per area of leaf are high.鈥�

The authors ran simulations for , a forested tropical island in Panama where the model had been well tested against conditions on the ground. The simulations included one or two species of broad-leaf evergreen tropical trees, such as wild cashew and Ecuador laurel. The trees were programmed to have various responses to the higher carbon dioxide and could compete with one another for space.

Trees that were programmed to have more carbon relative to nitrogen in their leaves became less efficient at photosynthesis, which helps them to grow, and emitted less water vapor, which helps trees stay cool. But tree species whose leaves also thickened were better at absorbing carbon and producing water vapor, helping them to grow tall and stay cool, and could also outcompete their neighbors.

鈥淥ur work suggests that by shifting which plants are growing in the forest there may be less dire consequences of higher CO2 than other studies have suggested,鈥� Swann said. 鈥淭here is a lot we still don鈥檛 know about how plants are responding to climate change 鈥� this work really sets up some best guesses about which plants will grow best in future tropical forests that we can test with more observations.鈥�

This research was funded by the National Science Foundation and the U.S. Department of Energy. Lead author was 91探花graduate student Marlies Kovenock; co-authors are Charles Koven and Ryan Knox at Lawrence Berkeley National Laboratory; and Rosie Fisher at the National Center for Atmospheric Research.

For more information, contact Swann at aswann@uw.edu.

World leaders are currently updating the laws for international waters that apply to most of the world’s ocean environment. This provides a unique opportunity, marine scientists argue this week, to introduce new techniques that allow protected zones to shift as species move under climate change.

In an in the Jan. 17 issue of Science, researchers make the case for the United Nations to include mobile marine protected areas in the U.N. Convention on the Law of the Sea, or UNCLOS, now being updated since its last signing in 1982.

“Animals obviously don’t stay in one place 鈥� a lot of them use very large areas of the ocean, and those areas can move in time and space,” said lead author , an assistant professor at the 91探花 Bothell who studies migratory marine animals. “As climate change happens, if we make boundaries that are static in place and time, chances are that the animals we are trying to protect will be gone from those places.”

Former President Barack Obama, former President George W. Bush and actor Leonardo DiCaprio are well-known proponents of protecting large regions of the ocean environment in marine protected areas, or MPAs. But even these huge swaths of protected ocean aren’t enough to conserve highly mobile species, like sea turtles, whales, sharks and seabirds that can travel across entire oceans in search of food and breeding grounds.

Climate change will further complicate things, the authors argue. As species, habitats and ecological communities shift, established protected areas might no longer work.

“In the context of climate change, the way that we have been applying things in the past is not likely to work into the future,” Maxwell said. “Species will increasingly need protection, and we will need to apply more dynamic and innovative tools to be effective.鈥�

Maxwell’s research uses tags that transmit to satellites to track sea turtles, seabirds and other marine species’ movements from space 鈥� a new technology that is just beginning to be applied to real-time protection of marine species. Only in the past 10 to 15 years, she said, have countries started to incorporate such tools into management, combining satellite tags on animals, GPS tracking of ships and ocean modeling to create rules that adjust to the situation, a technique known as dynamic management.

“Until we could implement this type of management and show that it’s feasible, people didn’t quite believe that it was possible,” Maxwell said. “But as we know more about where animals are going in space and time, we can use that information to better protect them.”

Several nations now use dynamic management strategies within the 200 nautical miles from shore that they fish exclusively, Maxwell said. A few countries also use dynamic management strategies farther from shore, for boats registered to their countries.

The program, for instance, asks U.S. fishing boats to voluntarily avoid waters north of Hawaii at the surface temperatures preferred by loggerhead and leatherback sea turtles, to reduce the unintended capture of the endangered animal. In Australia, longline fishing boats bypass fishing in international waters when and where models predict the presence of the southern bluefin tuna, a commercially valuable and endangered species that’s managed through a quota system.

“New technology is making this dynamic approach to ocean conservation possible, at the same time that climate change is making it necessary,” Maxwell said.

With the newly published article, the authors encourage the international community to adopt this emerging management strategy and urge its widespread use in international waters, which cover some two-thirds of the planet’s oceans.

“We hope the language in the United Nations treaty could be changed to explicitly include mobile marine protected areas and dynamic management, so that those become options to protect the largest parts of the ocean going forward,” Maxwell said.

Co-authors are at the International Union for Conservation of Nature; , a research scientist at Stony Brook University and former 91探花Bothell postdoctoral researcher; and at Stanford University. In addition to support from their home institutions, the authors received funding from the Alfred P. Sloan Foundation, the Gallifrey Foundation and the Pew Charitable Trusts.

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For more information, contact Maxwell at smmax@uw.edu.