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Sunday, November 15, 2026

Hanyang University ERICA researchers reported how a warming ocean is changing the base of the marine food web 

Researchers investigate regional copepod diet differences to investigate effects of climate change on marine food webs

Hanyang University Research Strategy Planning Team

How Calanus spp. diet varies geographically in a warming ocean — image:
The diet of Calanus spp. has significant geographical variations, with nitrogen fixing and heterotrophic bacteria being dominant sources in tropical and subtropical Pacific and dinoflagellates in the Pacific Arctic Ocean.
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Credit: Professor Kyung-Hoon Shin from Hanyang University, South Korea

Climate change is causing warming in the oceans, which can have significant effects on marine food webs. Rising ocean temperatures can intensify seawater stratification, a process in which ocean water forms layers of different densities that mix less readily. This can reduce the supply of nutrients to surface waters and favor smaller phytoplankton species that are better adapted to low-nutrient conditions. Phytoplankton support zooplankton, which in turn transfer energy to fish and other animals. Changes in phytoplankton communities can therefore lead to cascading effects in marine food webs.

In the western North Pacific, changes in ocean temperatures, circulation patterns, and sea-ice cover are causing changes in phytoplankton ecosystem structure. However, how contributions of different microscopic food sources to zooplankton vary across these regions, remain poorly understood.

To address this gap, a research team led by Professor Kyung-Hoon Shin from the Department of Marine Science and Convergent Technology at Hanyang University in South Korea analyzed the cosmopolitan calanoid copepod Calanus spp., a zooplankton that is a key source of food for fishes and sea birds, making it an ideal indicator of basal resource composition and nitrogen pathways. “Our objective was to quantify how nutrient sources and primary-producer communities shape zooplankton diets and nitrogen transfer pathways across the dynamic western north Pacific,” explains Prof. Shin. “To this end, we utilized a new dual-isotope approach for estimating the diet of Calanus.” Their study was made available online in Volume 12, Issue 38 of Science Advances on September 18, 2026.

The researchers sampled Calanus across the western North Pacific during summer and autumn, covering a broad region from tropical and subtropical waters, the subarctic Pacific, to the Bering Strait and southern Chukchi Sea in the Pacific Arctic Ocean. They analyzed carbon and nitrogen isotope ratios in essential amino acids from Calanus spp. tissue. These chemical signatures helped them estimate the contributions of different basal food sources and investigate the nitrogen sources supporting microalgae.

The results revealed notable geographical variations in basal diets of the copepods. In tropical and subtropical Pacific, which have strong surface stratification and low phytoplankton amounts, N2-fixing bacteria and heterotrophic bacteria accounted for 19.6 ± 5.8% and 30.6 ± 5.3%, respectively, of the basal diet. Further north, in regions of the subarctic Pacific, the contribution of N2-fixing bacteria and heterotrophic bacteria decreased, while those of eukaryotic microalgae, such as diatoms and dinoflagellates, increased. Notably, in the Bering Strait and Chukchi Sea, dinoflagellates made up more than half (54.4 ± 10.5%) of the basal diet, while the total eukaryotic microalgae contribution rose to approximately 80%.

The researchers also found that the estimated contribution of dinoflagellates was strongly correlated with the protist contribution inferred from nitrogen isotope ratios. N2 sources supporting microalgae also varied regionally: biologically fixed N2 was more dominant in the tropical Pacific, accounting for 29.2 ± 7.9% of the nitrogen source, while nitrates were the primary source in the Pacific Arctic Ocean, accounting for an estimated 91.4 ± 2.3%.

“Our results demonstrate that combining carbon and nitrogen isotope ratios in Calanus spp. is a robust framework for understanding dietary records,” remarks Prof. Shin. “Importantly, our study shows how warming-driven changes in stratification and nutrient dynamics are reshaping planktonic food webs. This will have cascading consequences for marine biodiversity, biogeochemical cycling, and ecosystem resilience.”

In summary, this study offers an innovative method to track dietary sources of zooplankton, establishing a foundation for investigating how climate change may affect marine food webs.

***

Reference
DOI: 10.1126/sciadv.aed3966

About Hanyang University ERICA
Hanyang University ERICA (Education Research Industry Cluster at Ansan) is a prominent research-focused campus established in 1979 in Ansan, South Korea. ERICA offers undergraduate and graduate programs. ERICA is renowned for its active industry-university cooperation, offering students hands-on experience through partnerships with various industries. This ensures that graduates are well-prepared to meet societal needs and excel in their respective fields. With state-of-the-art facilities and a supportive learning environment, Hanyang University ERICA empowers students to pursue their passions and contribute meaningfully to society, staying true to the university's founding philosophy of "Love in Deed and Truth."
Website: https://www.hanyang.ac.kr/web/eng/erica-campus1

About the Author
Prof. Kyung-Hoon Shin is currently a Professor at the Department of Marine Science and Convergence Engineering and a Director of the Global Science Research Center for Marine Material Cycle Processes at Hanyang University. His research group is developing approaches to assess organic biogeochemical cycles and marine food web structure through compound-specific isotope technology for advanced ocean science and environmental ecology. Prof. Shin’s group is also developing lipid biomarker analytical skills and their applications for carbon cycle and nitrogen source identification in marine and environmental science. Prof. Shin has served as Vice President of the Korean Academy of Marine Science and has been a Distinguished Fellow of the Academy since 2021.

Journal

Science Advances

DOI

10.1126/sciadv.aed3966

Method of Research

Observational study

Subject of Research

Animals

Article Title

Dietary records in cosmopolitan copepod Calanus spp. revealed large contribution of dinoflagellates in subarctic Pacific

New online listening experience invites public into the underwater world of dolphins

The newly launched Sarasota Bay Listening Network (SBLN) website connects the public with the sounds of the bay and a long-term resident bottlenose dolphin community

Brookfield Zoo

Sarasota Bay Listening Network station equipment exterior. — image:
The Sarasota Bay Listening Network (SBLN) uses hydrophones (underwater microphones) at 20 shore-based listening stations to continuously record underwater sounds in and around the Sarasota Bay estuary. The network has collected more than 500,000 hours of acoustic recordings since 2017, capturing sounds of bottlenose dolphins, manatees, fish and invertebrates, along with vessel traffic, weather and other features of the bay soundscape.
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Credit: Photos/video taken by Brookfield Zoo Chicago’s Sarasota Dolphin Research Program under National Marine Fisheries Service Scientific Research Permits.

Brookfield, IL—What does Sarasota Bay sound like beneath the surface? A new interactive website from Brookfield Zoo Chicago’s Sarasota Dolphin Research Program (SDRP), developed by Loggerhead Instruments Inc., gives anyone, anywhere, the opportunity to listen beneath the surface and get to know the marine life of the bay in a new way—through sound, the same sense dolphins rely on to navigate their environment and connect with the world around them.

The website brings the Sarasota Bay Listening Network (SBLN) to the public. Led by SDRP, SBLN is a collaborative passive acoustic monitoring program that uses hydrophones (underwater microphones) at 20 shore-based listening stations to continuously record underwater sounds in and around the Sarasota Bay estuary. The network has collected more than 500,000 hours of acoustic recordings since 2017, capturing sounds of bottlenose dolphins, manatees, fish and invertebrates, along with vessel traffic, weather and other features of the bay soundscape.

Visitors can click through a map of the bay, listen live to underwater audio and get to know individual dolphins. The website features profiles for more than 100 individuals that can be acoustically identified by the SBLN in near-real time via their individually-specific signature whistle “names.” The profiles include recent acoustic detections that can be viewed and listened to, photos, fun facts, links to relatives’ profiles and a map showing where individuals have recently been detected. Drawing on decades of SDRP research, the new SBLN website opens a more personal window into marine life.

SBLN is one of two underwater acoustic monitoring networks that form the Sarasota Passive Acoustic Listening Stations (PALS) Network. Its sister acoustic network, the Sarasota Coast Acoustic Network (SCAN), listens for acoustically tagged sharks, rays, fish and gastropods. Together, SBLN and SCAN provide valuable information about animal ranging patterns, habitat use and behavior, as well as insights into the health of the broader ecosystem. Visitors to the SBLN website can see summaries of SCAN species detections at 14 SBLN stations where SCAN acoustic receivers are also deployed.

“Sarasota Bay is a thriving ecosystem, and listening to its soundscapes allows us to follow wildlife over time and understand how animals respond to red tides, vessel traffic and other changes,” said Dr. Katie McHugh, director of SDRP. “Those insights help guide conservation decisions. By sharing these sounds online, we are giving people a new way to experience the bay and connect with its wildlife.”

The individual dolphin experience is made possible by more than 56 years of collaborative research on Sarasota Bay’s resident bottlenose dolphin community and a long-term archive of signature-whistle recordings called the Sarasota Dolphin Whistle Database (SDWD). The SDWD is a unique resource managed by long-time SDRP collaborators at Woods Hole Oceanographic Institution (USA), Aarhus University (Denmark), University of St Andrews (Scotland) and Cetacean Communication Research (USA).

“Sound is central to how dolphins experience the world. They whistle, click and buzz as they navigate, communicate and hunt. Each dolphin develops a signature whistle as a calf and keeps it throughout life, creating an individually learned call that functions much like a name,” explained McHugh. “By matching those whistles to validated recordings collected through decades of SDRP research, we can identify individual dolphins and learn more about how they use Sarasota Bay.”

SBLN offers a level of individual dolphin identification not available through other passive acoustic monitoring platforms. A machine-learning tool identifies possible signature whistle matches by comparing with known signature whistles from the SDWD. Researchers continue to review and refine the system as more data becomes available, supporting broader efforts to automate individual dolphin identification while maintaining human review of the detections.

Future website updates are expected to expand the number of individual dolphins represented and add more ways to interpret the bay’s broader soundscape, including noise from vessel traffic. As the network’s capabilities grow, the website will offer an even deeper dive into the marine life of Sarasota Bay.

The Sarasota Bay Listening Network website is now available at sbln.sarasotadolphin.org. More information about the Sarasota Dolphin Research Program is available at sarasotadolphin.org.

# # #

Media Note: B-roll, photos and corresponding credit requirements for media use are available for download here. Journalists interested in interviews with the SDRP team and its collaborators should contact Zoo PR Director Julianne Olivo at julianne.olivo@brookfieldzoo.org or 708-688-8351.

About Brookfield Zoo Chicago: Connect. Care. Conserve.
Since 1934, Brookfield Zoo Chicago has been a global leader in animal well-being and conservation, inspiring conservation leadership by connecting people with wildlife and nature. The Zoo is a private nonprofit organization that operates on 235 acres of land owned by the Forest Preserves of Cook County and is home to more than 3,500 animals representing over 500 species—including many of Earth’s most endangered. Brookfield Zoo Chicago was the first zoo in the world to be Humane Certified™ by the American Humane Society for the care and welfare of its animals, and is an accredited member of the Association of Zoos and Aquariums, the Alliance of Marine Mammal Parks and Aquariums, and ArbNet. For more information, visit brookfieldzoo.org or follow @BrookfieldZoo on Instagram, Facebook and Threads. 

About the Sarasota Dolphin Research Program
The Sarasota Dolphin Research Program, operated by Brookfield Zoo Chicago, conducts the world’s longest-running study of a wild dolphin population. Since 1970, the program has conducted research on the resident bottlenose dolphin community in Sarasota Bay, Florida, providing critical insights into dolphin behavior, health, life history, social structure, ecology, and conservation. For more information, visit sarasotadolphin.org.

Subject of Research

Animals

The Sarasota Bay Listening Network is a new interactive website from Brookfield Zoo Chicago’s Sarasota Dolphin Research Program (SDRP) that gives anyone, anywhere, the opportunity to listen beneath the surface and get to know the marine life of the bay in a new way—through sound, the same sense dolphins rely on to navigate their environment and connect with the world around them.

Credit

Brookfield Zoo Chicago's Sarasota Bay Research Program

Parrots' vibrant feathers are susceptible to bacterial attack

New study overturns previous research and shows that the most vibrantly colored parrot feathers are highly susceptible to being broken down by bacteria

Princeton University

Macaws in flight — image:

Two Red-and-green Macaws (*Ara chgloropterus*) in flight. Princeton biologists tested whether the psittacofulvin pigments in parrot feathers protected the feathers against damage caused by bacteria.
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Credit: Octavio Campos Salles

Flashy birds, from peacocks to parrots, have inspired a long tradition of using animal colors to study evolution. Colorful plumage often functions as a signal—for example, to attract a mate. Alternatively, drab colors can be used for camouflage. However, color can have functions beyond signaling and camouflage. This is because pigments, the molecules embedded in feather tissues to produce a broad range of colors, can also influence other aspects of feathers, ranging from mechanical strength to thermoregulatory properties. For example, melanin, a pigment that creates dark colors in many animals, has been shown to make feathers physically stronger. Melanin has also been shown to reduce the damage caused by bacteria that feed on keratin proteins, the building blocks of feathers. Beyond melanin, could the pigments responsible for vivid colors also have such non-signaling functions? New work led by Princeton University biologists sheds light on this question.

Parrots are hailed for their colorful plumage, yet psittacofulvins, the pigments primarily responsible for their brilliant colors, have remained somewhat of a mystery. Most birds use carotenoid pigments to produce bright red, yellow, orange and pink plumage. But not parrots. They evolved psittacofulvins, a group of pigments found in no other animals on the planet, to produce the same hues typically made by carotenoids in other birds. Why did parrots evolve a unique coloration system? A pioneering study in 2010 offered an answer, proposing that psittacofulvins might protect feathers from keratin-eating bacteria. Because feathers have so many functions, ranging from flight and thermoregulation to signaling and camouflage, susceptibility to bacteria-induced damage could have major effects on fitness. If psittacofulvins protected feathers from bacterial degradation, it might explain why these pigments—and their resulting colors—evolved in parrots. Using a relatively small sample of parrot feathers and the bacteria Bacillus licheniformis, which is ubiquitous in wild birds, the 2010 study found that red feathers, which have high concentrations of psittacofulvins, were resistant to bacterial attack, similar to black feathers.

In a new study published in the Journal of Experimental Biology, Ali et al. (2026) revisit the hypothesis that psittacofulvins protect parrots from microbial damage, but with a broader range of feathers from more species. The research team sampled thousands of parrot feathers, placing them in a solution inoculated with B. licheniformis. When these bacteria feed on feathers, small proteins are released into the surrounding liquid medium—making it possible to quantify the amount of feather breakdown that has occurred. By using the feathers of closely related parrot species, the researchers could control for variation in feather properties that would otherwise affect their findings. The least degraded feathers were black feathers, which was expected given their high melanin content. However, red, orange, yellow, and green feathers, all of which contain psittacofulvins, broke down the most, while feathers lacking psittacofulvins—blue, white, black and grey—fared substantially better. Given the results of the 2010 study, these results were unexpected.

“We thought psittacofulvins would combine with melanin to protect feathers,” explained lead author and former Princeton graduate student, Jarome R. Ali, “so our findings were entirely unanticipated”. Ali, now a postdoctoral researcher at New York University, continued, “The red feathers should have been intact, but they had totally fallen apart, while other colors, like blue, seemed mostly unbothered. We think our results may differ from those previously reported because we relied on a broader array of parrot feathers, which we sampled quite extensively. Parrots often seem to break the rules. In retrospect, we shouldn’t be surprised that they surprised us.”

Why do psittacofulvins provide such meek protection? The researchers suggest that incorporating psittacofulvins into the feather keratin could slightly destabilize its structure, making it susceptible to the enzymes bacteria use to break it down. Such a trade-off would have interesting evolutionary implications. “Our results suggest that the pressures favoring the evolution of the vibrant colors in parrots outweigh the potential negative effects of bacterial degradation,” said the senior author Mary Caswell Stoddard, professor of ecology and evolutionary biology at Princeton. “In other words, beauty over bacteria: parrots are often red, orange, yellow and green even though these colors are quite susceptible to bacterial attack.”

Alternatively, psittacofulvins might have some as-yet undiscovered role, in addition to producing beautiful colors. For example, their chemical structure is similar to some known antimicrobial and antifungal compounds and could protect feathers from microorganisms other than the B. licheniformis tested in this study. “Our findings really highlight the array of factors influencing feather coloration. It's not just about being bright," said Alexander Downie, postdoctoral researcher at the Max Planck Institute for Evolutionary Anthropology and former Princeton University graduate student. The authors say that whether bacteria actually pose a serious threat to feathers in the wild is an important area for future research. Ali ended, “This beauty and the bacteria story motivates us to ask new and exciting questions. Parrots have much to teach us about evolution and the natural world. I can’t wait to learn more from them.”

Two Red-and-green Macaws (Ara chloropterus). Princeton biologists tested whether the psittacofulvin pigments in parrot feathers protected the feathers against damage caused by bacteria

Credit

Octavio Campos Salles