Salmonella solution

Researchers develop rapid food-contamination test to improve safety, reduce waste and lower costs

Peer-Reviewed Publication

MCMASTER UNIVERSITY

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IMAGE: POSTDOCTORAL RESEARCH FELLOW JIUXING LI DEMONSTRATES MCMASTER UNIVERSITY'S NEW SALMONELLA TEST. view more 

CREDIT: MATTHEW CLARKE, MCMASTER UNIVERSITY

McMaster University researchers have developed a rapid and inexpensive test for Salmonella contamination in chicken and other food – one that’s easier to use than a home COVID test.

The test, described in a new paper in the journal Angewandte Chemie, could improve food safety, reduce the cost of processing fresh poultry and other foods, and help to limit broad recalls to batches that have specifically been identified as contaminated.

The researchers have shown that the test provides accurate results in an hour or less without the need for accessories or a power source, compared to today’s monitoring through lab cultures, which require at least a full day to produce results.

Once scaled up and made available commercially, the new test could be a significant boon to poultry processors, for whom Salmonella is among the most significant contamination risks. The test would also be beneficial for ensuring the safe processing of other foods that are particularly vulnerable to Salmonella, such as eggs, dairy products and ground beef.

A single major poultry processor performs tens of thousands of Salmonella lab tests each year. Reducing or even eliminating the need for overnight lab cultures would represent significant savings and make it easier to identify contamination earlier in the process.

“Anyone can use it right in the setting where food is being prepared, processed or sold,” says co-author Yingfu Li, a professor of Biochemistry and Chemical Biology who leads McMaster’s Functional Nucleic Acids Research Group. “There’s a balance between cost, convenience and need. If it’s cheap, reliable and easy, why not use it?”

Protecting the public from Salmonella is a high priority for food producers, retailers and regulators alike, since Salmonella is one of the most common and serious forms of food-borne infection, causing 155,000 deaths globally every year.

What makes the test work is a new synthetic nucleic acid molecule, developed at McMaster. For the test, the molecule is sandwiched between microscopic particles such as gold.

The test platform lines the inside of the tip of a pipette and begins to work when a liquefied sample of the food being tested is drawn inside the tube.

If Salmonella bacteria are present, they cut through the particles, allowing the molecule to escape.

When the solution is dropped onto a paper test strip, the presence of Salmonella shows as a visible shade of red, thanks to a new form of biosensor, also created by the McMaster team. The greater the concentration of Salmonella, the brighter the colour appears.

“Using these tests is easier than using a COVID test, which so many people are already doing,” says co-author Carlos Filipe, chair of McMaster’s Department of Chemical Engineering. “For this to be as effective and useful as possible, it has to be easy to use.”

The new technology has been developed with support from the non-profit research organization Mitacs, and Toyota Tsusho Canada Inc., an indirect subsidiary of Toyota Tsusho Corporation in Japan, which plans to develop the innovation for commercial use.

The research is part of an ongoing, broader effort to establish McMaster and its Global Nexus for Pandemics and Biological Threats as a centre for the development of real-time sensors, pathogen-repellent materials and other products that improve food safety.

“This is very important to us in the development of our food-testing program,” says co-author Tohid Didar, an associate professor of Mechanical Engineering and Canada Research Chair in Nano-biomaterials. “Being able to create a test that is both easy to use and which produces a readily visible color within an hour is significant.”

Li, Didar and Filipe authored the paper with postdoctoral research fellow Jiuxing Li, PhD student and Vanier Scholar Shadman Khan, and research associate Jimmy Gu.

Reducing illness and food waste aligns with Toyota Tsusho Canada’s values, explained Toyota Tsusho Canada Inc. President Grant Town.

“Our goal is to help bring proven research from the lab to the marketplace, where it can benefit society,” Town says. “Reducing the risk of illness while also cutting food waste will benefit everyone, and Toyota Tsusho Canada sees this as a great opportunity.”

  

McMaster University's new Salmonella test indicates the presence of Salmonella by producing a red dot on test paper.

CREDIT

Matthew Clarke, McMaster University

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JOURNAL

Angewandte Chemie

DOI

10.1002/anie.202300828 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animal tissue samples

ARTICLE TITLE

A Simple Colorimetric Au-on-Au Tip Sensor with a New Functional Nucleic Acid Probe for Food-borne Pathogen Salmonella typhimurium

Why orchid bees concoct their own fragrance

Peer-Reviewed Publication

RUHR-UNIVERSITY BOCHUM

 

IMAGE: MALE OF THE ORCHID BEE EUGLOSSA DILEMMA PERFORMING TYPICAL COURTSHIP DISPLAY AT A PERCH IN A FLIGHT CAGE IN FLORIDA. THEIR SCENT POCKETS ARE LOCATED ON THE THICKENED HIND LEGS. view more 

CREDIT: THOMAS ELTZ

Male bees display a remarkable passion for collecting scents: they deposit scents from various sources in special pockets on their hind legs, thus composing their own fragrance. This behaviour has been known since the 1960s. The reason why they do it has been the subject of much speculation just as long. Researchers from Ruhr University Bochum, Germany, in collaboration with colleagues from the University of California at Davis and the University of Florida at Fort Lauderdale, have finally solved the mystery. The bee fragrance serves as a sex attractant and increases the reproductive success of the males, as the team found out after three years of experiments in flight cages. The group headed by PhD student Jonas Henske and Dr. Thomas Eltz from the Bochum Department of Animal Ecology, Evolution and Biodiversity describes their findings in the journal “Current Biology”, published online on 12 April 2023.

There’s been a lot of theorising about the purpose of the fragrance: some have suggested that it could be an attractant or a wedding gift for the females, or that the scent is used to communicate with rivals. In a previous paper, the group around Thomas Eltz had already shown that the male bees transport the fragrance out of the pockets on their hind legs during the courtship ritual. “What we didn’t know, however, was who was supposed to receive this signal,” says Eltz. “The females? Or rival males?”

The researchers pursued this question in the current project. For three years, they studied orchid bees in an experiment in Florida. In a 15 by 15 by 4 metre cage, they had two male bees each compete for a female – one with fragrance and one without. They then tracked whether the female mated and, if so, with which male.

Mating activities difficult to observe

“The mating of orchid bees is very rarely observed in the wild, and even in experiments it’s been almost impossible to get them to mate,” as Thomas Eltz describes the challenge. This is why the Bochum-based researchers and their US colleagues tried to offer the bees optimal conditions; for example, they used a particularly large cage and provided the animals with the perfect pollen plants.

For the experiment, the researchers first lured male bees to artificial scent sources, which the bees then used to create a fragrance. The scientists extracted this fragrance from the pockets on the hind legs using a microcapillary and subsequently transferred it to one of the bees that they tested in the experiment. Here, two males, which had been kept under identical conditions, competed for the favour of females.

Typical courtship behaviour with varying degrees of success

The males – with or without fragrance – displayed typical courtship behaviour. Mating occurred with 27 females, which each mated with a single mate. Male bees that had been equipped with fragrance were involved in 26 of these cases. In one case, a male reproduced that belonged to the control group, which should have been fragrance-free; however, the researchers found hints that this individual had also acquired a scent mixture – fragrance theft does occasionally occur.

In order to be able to prove beyond doubt which males had mated, Jonas Henske carried out paternity analyses. He compared the genetic make-up of the brood with that of the male bees.

“It’s become clear that the fragrance is an attractant for females and triggers mating behaviour in them,” as Thomas Eltz sums up the findings. “Our results also prove that the fragrance is probably not used as a status signal among males. Indeed, a male was not more likely to defend his courtship site when he was in possession of fragrance.”

About orchid bees

There are about 250 known species of euglossine bees that are important pollinators in the tropics of Central and South America. Many orchid species rely on male euglossine bees for pollination, which is why these insects are commonly known as orchid bees. These orchids produce specific flower scents as a reward, which are collected by the male bees. There are five different genera of orchid bees, and they can vary greatly in size and appearance. The male bees collect the scents with tufts of hair on their front legs, which they wring out into the pockets on their hind legs.

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JOURNAL

Current Biology

DOI

10.1016/j.cub.2023.03.060 

ARTICLE TITLE

Function of environment-derived male fragrances in orchid bees

Female butterflies breed despite male shortage

Peer-Reviewed Publication

UNIVERSITY OF EXETER

 

IMAGE: A MALE AND FEMALE AFRICAN MONARCH MATING view more 

CREDIT: RUTAGARAMA ET AL

Female monarch butterflies have no trouble finding a mate – even when a parasite kills most of the males, new research shows.

Some females carry a parasite called Spiroplasma that kills all their male offspring, meaning highly infected populations have very few males.

But the new study – by the universities of Exeter, Rwanda and Edinburgh, and the Dian Fossey Gorilla Fund – found females mated about 1.5 times on average, regardless of how many males were around.

The male proportion dropped below 10% in some cases, but it appears the remaining hard-working males managed to breed with most of the available females.

10-20% of females remained unmated, only slightly higher than the expected average in a population with plenty of males (5-10%).

“It was an inspiring and powerful experience working along with an international team of experts and advancing our knowledge of monarchs, which will shape my future career path towards research-based conservation,” said first author Vincent Rutagarama, a student at the University of Rwanda.

Professor Richard ffrench-Constant, from the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall, said: “It seems that monarch butterflies are very good at finding each other and mating.

“The proportion of males in butterfly populations fluctuates through the year, but we found consistent evidence of female breeding success all year round.”

Dr Ian Gordon, of the University of Rwanda, said this breeding success might explain how the male-killing parasite can be successfully transmitted in a population where males are rare.

“The irony is that if the entire population was infected, monarch butterflies – also known as African queens – would produce no more princes, and the parasite would die out along with the butterflies,” Dr Gordon said.

“Further research is now needed, to find out why some monarch butterflies remain uninfected, and therefore able to produce healthy male offspring.

“Future research could also explain why the male-killing parasite is currently confined to a sub-section of the East African ‘contact zone’ (where prevailing winds converge, bringing flying insects together).”

Professor ffrench-Constant said other butterfly species have evolved resistance to parasites like Spiroplasma, so monarchs – which are very numerous and widespread – are unlikely to be at risk.

However, several years of severe drought in East Africa have caused a food crisis for humans and damaged biodiversity and ecosystems.

“We hope the monarch butterfly could become a symbol of conservation across Africa,” Professor ffrench-Constant said.

“Monarchs live in savanna habitats. When there is rain, they thrive. When there is no rain, there are no butterflies, no cattle and no food for humans.

“The future of the monarch butterfly is tied to that of the continent, and humanity must tackle the climate and environment crisis to secure that future.”

In butterflies and moths, successful breeding involves the transfer of a “spermatophore” from the male to the female. Spermatophores remain detectable after breeding. 

In this study, carried out at one site in Rwanda and another in Kenya, male-female ratios were regularly counted and 10 randomly selected females were dissected each month to count spermatophores.

The research was funded by the National Geographic Society, Cleveland Metroparks Zoo and the Dian Fossey Gorilla Fund.

The paper, published in the journal Ecology and Evolution, is entitled: “The African Queen find mates when males are rare.”

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JOURNAL

Ecology and Evolution

DOI

10.1002/ece3.9956 

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

African Queens find mates when males are rare

Temperature, drought influencing movement of Plains bison

Findings could guide management of Great Plains icon

Peer-Reviewed Publication

UNIVERSITY OF NEBRASKA-LINCOLN

 

IMAGE: PLAINS BISON GRAZE BENEATH THE MOON OF AN OKLAHOMA SKY. A RECENT ANALYSIS OF GPS-TRACKED HERDS IN THE STATE FOUND THAT THE ONCE-ENDANGERED MAMMAL RESPONDS TO TEMPERATURE AND SEVERE DROUGHT IN WAYS THAT SHOULD INFORM ITS LONG-TERM MANAGEMENT. view more 

CREDIT: DENIZ BERTUNA / ANTHONY COOK

It epitomizes the Great Plains in spirit and in form: a 2,000-pound tank on hooves, cloaked in shaggy winter-tested coat, capped by horns acting as warning and weapon.

Even its scientific name, Bison bison bison, seems to conjure an echo worthy of its majesty. Still, the implacable profile of the Plains bison — the national mammal of the United States and largest on the continent — belies the vulnerability in its history, which saw its legions decimated from tens of millions to just a few hundred in the span of a few colonial centuries.

Conservation efforts have pushed its number back to roughly 20,000, and its status from endangered to near-threatened. But a recent study led by the University of Nebraska–Lincoln’s Nic McMillan hints that the ongoing conservation of the Plains bison will demand accounting for the climate — especially the number of scorching days and powdery landscapes — it encounters moving forward.

McMillan and colleagues at Oklahoma State University have found GPS-backed evidence that temperature and extreme drought can drive movement among herds of Plains bison. Continued increases in both, combined with the fact that most bison herds are now confined to fractions of the land they once roamed, could pose challenges to managing the iconic species, McMillan said.

“When we think about reintroducing bison or any large animal to a landscape, the landscape that the animal is inhabiting is potentially a lot smaller than it was historically,” said McMillan, assistant professor of agronomy and horticulture at Nebraska. “In 1491, if there was a drought in northeastern Montana, the bison had the entire Great Plains to escape that drought. They could move as far as they needed to.

“In this time when we’re seeing more extremes — more of those extreme air temperatures, more of those extreme droughts — we probably need to rethink how these landscapes are structured, and whether or not they’re actually meeting the fundamental physiological needs of these animals.”

The team reached its conclusions after analyzing the movement data of 33 Plains bison from two disparate sites in Oklahoma: the Wichita Mountains Wildlife Refuge in the southwestern part of the state, and the Tallgrass Prairie Preserve near its northern border. Each of the bison wore GPS-equipped collars that tracked their location every 12 minutes over multiple years, yielding a total of 715,344 measurements. Pairing that data with temperature, rainfall, wind and other variables recorded by nearby weather stations, plus drought-revealing moisture readings of the soils at both sites, allowed the team to search for links between bison movement and weather.

Air temperature explained variations in bison movement better than any other factor the researchers analyzed. When the temperature ranged from a few degrees below zero to 83 degrees Fahrenheit, bison movement increased 92.5% for every 18-degree rise, so that movement nearly doubled when the temperature rose from, say, 65 degrees to 83 degrees. Above that threshold — from 83 degrees through at least 112, the highest recorded temperature — an 18-degree increase instead corresponded to a 48.5% decrease in movement.

The temperature-related increase in movement hints that the Plains bison were in search of grasses that grew better amid the greater heat, the team said, especially given that bison get the majority of their water from foraging. The reduced movement in the face of excessive heat, meanwhile, suggests that they rested and cooled themselves in places where standing water and the shade of nearby trees prevented the equivalent of heat stroke.

“When you consider (that) this is the first study of Plains bison across multiple herds — and then we find the same relationship across herds, in two very different landscapes — that’s a big deal,” said McMillan, who noted that the trend also paralleled a study of wood bison in Canada.

In looking for potential effects of drought, the team turned to sensors that measured soil moisture at two depths: 5 centimeters, where dryness indicates moderate drought, and 25 centimeters, where it signifies severe drought. Though bison seemed mostly unaffected by the former case, reinforcing that they can tolerate moderate drought by taking up water through vegetation, they moved substantially more when contending with the severe drought that struck Oklahoma in the early 2010s.

“There’s a lot of (prior) research that suggests that bison are basically drought-proof,” said McMillan, who also holds an appointment with the School of Natural Resources. “They’re like these tanks out on the prairie that don’t need anything. They can just take whatever comes, and no big deal. At least, that’s the dogma in the reintroduction world.

“So I think this is really interesting, because we show that, hey, they still are not immune to drought. They have this potential threshold where they can’t handle it.”

‘I was just hooked’

Back when bison blanketed the Great Plains, they served not just as a vital food source and cultural touchstone for Indigenous peoples but also a species that many others, animal and plant, relied on for survival, McMillan said. Following the dwindling of their population and eventual relocation to protected areas, Plains bison may or may not serve the same ecological purposes they once did. Regardless, McMillan said their place in the history of the continent and country should be preserved in the animals themselves.

“They’re incredibly culturally important and represent the cultural identity for all of the Plains tribes, at a minimum,” McMillan said. “But they also represent one of the most charismatic animals that we have in North America. So they’re really important for our identity as a country and all the people who live here.”

They resonate with McMillan on another frequency, too. As the son of a plant biologist and ecologist who hosted a national TV show that aired on PBS, the South Carolina native tagged along with his father on a visit to Nebraska when he was 15. That visit, and the vistas he took in from atop the badlands of western Nebraska, would kindle his “profound attachment” to bison and help set the course of his career.

“We came to the Great Plains, and I was just hooked,” he said. “I never thought about anything else after that. I never necessarily originally envisioned myself being a scientist or studying bison as a scientist, but I was just always fascinated by how they exist on the landscape, bringing them back — that really emotional story. So for me, it’s very personal.”

McMillan said he hopes the team’s findings can inform the management of Plains bison in places like Yellowstone National Park, which houses the largest wild herd of the species. Those findings, he said, make the case for paying attention to what the animal’s behavior is telling ecologists and conservationists. Though the size and natural beauty of national parks and other protected areas may seem to offer everything the Plains bison could need, the fact that the animals still attempt to leave would seem to suggest otherwise.

And if the heat and extreme drought that apparently encourage Plains bison to move are only becoming more commonplace, then the space that was once considered sufficient may no longer be, McMillan said. That issue could be compounded by the fact that ensuring the diversity of their habitat — that they have access to grasslands, but also trees, and also standing water — appears to become even more important as that habitat shrinks.

“Then it’s an ethical question for us,” McMillan said. “Are we really being ethical if we’re forcing these animals to live in a landscape that may not actually be suited for them into the future? Whether bison were in Yellowstone historically is irrelevant to the likelihood that they can persist there into the future. Because today is completely and fundamentally different than yesterday.”

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JOURNAL

Ecology and Evolution

DOI

10.1002/ece3.9586 

Saving declining amphibians through genetics - newly funded Morris Animal Foundation and Revive & Restore projects lay the foundation for genomic approaches to amphibian conservation

Grant and Award Announcement

MORRIS ANIMAL FOUNDATION

 

IMAGE: HARLEQUIN FROGS ARE AMONG THE AMPHIBIANS IN DECLINE view more 

CREDIT: REPTILES4ALL

DENVER/April 17, 2023 – Morris Animal Foundation and Revive & Restore recently announced the funding of five new projects building genomic tools for amphibian conservation. The projects are an important first step toward species preservation and provide compelling examples of genomics in action.

 

“Amphibian populations are declining at an alarming rate around the world,” said Dr. Kathy Tietje, Chief Program Officer at Morris Animal Foundation. “These newly funded projects will leverage advanced genomic approaches to create new conservation strategies.”

 

Amphibians have existed on Earth for more than 300 million years, but today the International Union for Conservation of Nature (IUCN) estimates at least one-third of known amphibian species are threatened with extinction. Major threats to amphibians include habitat loss and degradation, and the infectious disease chytridiomycosis. Managed populations of amphibians have become the only hope for many species facing imminent extinction, making genetic rescue technologies a critical component of current and future recovery efforts.

 

“Amphibians face monumental conservation challenges, and we need new tools to help bring these species back from the brink,” said Dr. Bridget Baumgartner, Director of Research & Development at Revive & Restore. “The selected projects have important conservation applications today, and lay the foundation for future genomic technologies that can help rescue amphibian populations.”

 

The selected projects are part of the Wild Genomes program, an initiative to develop applied genomics tools for wildlife conservation. To help stem the loss of amphibians globally, Morris Animal Foundation and Revive & Restore created a special call for Wild Genomes proposals focused on amphibian species. More than 30 proposals from around the world were submitted for funding consideration. Projects were selected for ecological significance, strategic conservation value and/or evolutionary significance.

 

Genomic tools, like genome sequencing, cell culturing and biobanking, are standard practice in agriculture and human medicine. However, these technologies have rarely been applied in wildlife conservation. Through their portfolio of Wild Genomes projects, Morris Animal Foundation and Revive & Restore help introduce conservation biologists to genomic tools and showcase their potential for the protection and restoration of wildlife.

 

Morris Animal Foundation will fund two of the projects and Revive & Restore will fund three. The projects are slated to begin this year. 

 

Morris Animal Foundation grant recipients and their topics are:

• Dr. David Weisrock, University of Kentucky - Use a top-down genomic approach to develop a cost-effective molecular toolkit for the conservation of an endangered newt (Laotriton laoensis).
• Dr. Andrea Schreier, University of California, Davis - Enable rapid field detection of the amphibian fungal pathogen Batrachochytrium dendrobatidis using a CRISPR-based SHERLOCK assay.

 

Revive & Restore grant recipients and their topics are:

• Dr. Danté Fenolio, San Antonio Zoo Center for Conservation and Research - Complete a reference genome for the Chile Mountains false toad (Telmatobufo venustus) to help develop a national conservation plan for this species and other false toads endemic to Chile.
• Dr. Tao T. Nguyen, Institute of Genome Research, Hanoi, Vietnam - Sequence the unusually large and complex genome of the Vietnamese crocodile newt (Tylototriton vietnamensis) to provide a resource for scientists and inform conservation of the species.
• Dr. Sarah Fitzpatrick, Michigan State University - Develop a reference genome for the Andean Jambato harlequin frog (Atelopus ignescens) to characterize a recent genetic bottleneck and improve recovery of a species once thought to be extinct.

 

 

About Morris Animal Foundation
Morris Animal Foundation’s mission is to bridge science and resources to advance the health of animals. Founded in 1948 and headquartered in Denver, it is one of the largest nonprofit animal health research organizations in the world, funding more than $149 million in nearly 3,000 critical studies to date across a broad range of species. Learn more at morrisanimalfoundation.org.

 

About Revive & Restore

Revive & Restore is the leading wildlife conservation organization promoting the incorporation of biotechnologies into standard conservation practice. The Sausalito, California nonprofit was formed in 2012 with the idea that 21st century biotechnology can and should be used to enhance genetic diversity, build disease resistance, and facilitate adaptation. Its mission is to enhance biodiversity through the genetic rescue of endangered and extinct species. Learn more at reviverestore.org.

 

 

Media Contacts:

Annie Mehl (Morris Animal Foundation)

Marmee Manack (Revive & Restore) 

Less ice, fewer calling seals

Peer-Reviewed Publication

ALFRED WEGENER INSTITUTE, HELMHOLTZ CENTRE FOR POLAR AND MARINE RESEARCH

 

IMAGE: A WEDDELL SEAL IN ANTARTICA view more 

CREDIT: ALFRED WEGENER INSTITUTE / JOACHIM PLOETZ

For several years, a team of researchers from the Alfred Wegener Institute used underwater microphones to listen for seals at the edge of the Antarctic. Their initial findings, just released in the journal Frontiers in Ecology and the Environment, indicate that sea-ice retreat has had significant effects on the animals’ behaviour: when the ice disappears, areas normally full of vocalisations become very quiet.

When the sea ice vanishes, Antarctic seals become silent. This is the main conclusion of a new article just published by Dr Ilse van Opzeeland’s research group. The biologist is currently working at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) and the Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB). For the study, she and her team analysed audio recordings from an underwater microphone that automatically recorded the vocalisations of marine mammals like seals and whales. “What’s unique about our study is that, for the first time, we were able to assess recordings covering eight years and all four Antarctic seal species,” says lead author Dr Irene Roca, biologist at HIFMB and AWI at that time and currently working at the Université du Québec en Outaouais (Canada). “This allowed us to observe the seals’ behaviour over an extended timeframe and to compare individual years.”

Among the data on the years 2007 to 2014, the turn of the year 2010/2011 particularly stands out. Back then, the research area, located in the Southern Ocean near the AWI’s Neumayer Station III, was virtually ice-free: less than ten percent of the usually frozen waters had ice cover. As the recordings from the underwater microphones show, there were far fewer seals in these waters at the time than in the other seven years. Antarctic seals need sea ice, because it’s where they give birth and nurse their young. This takes place during spring and summer in the Southern Hemisphere, from October to January. Normally, there is extensive ice cover at this time of year, offering the seals ideal conditions for giving birth. But in the 2010/2011 season, the ice virtually disappeared. Since the experts had only installed one underwater microphone in the area, it remains unclear whether the seals migrated during the season, and if so, where to. “However, our underwater recordings clearly show that there were far fewer calling seals than usual in the observed waters,” says Irene Roca. This applies, she claims, to all seal species native to the region: the crabeater seal, Weddell seal, leopard seal and Ross seal.

The AWI experts’ research area lies roughly 2,000 kilometres south of Cape Town in the Weddell Sea. The coastal region in the eastern Weddell Sea is considered particularly relevant, as it is home to all four Antarctic seal species and several species of whale. Scientists believe the region is so appealing because it offers plentiful food and (normally) good ice conditions for the seals. Accordingly, the AWI team finds its observations from the 2010/2011 season troubling: if in future, the sea-ice cover varies to such an extent more frequently due to climate change, the region will offer the seals a less reliable option as breeding ground. In this context, the SEA ICE PORTAL recently reported that the past eight years were all characterised by below-average sea-ice extents in the Antarctic and that an all-time low was reached in February 2023.

The experts can’t yet say exactly how the lack of sea ice could affect seal populations, because we still know too little about the four species in question. From better studied Arctic ringed seals, it is known that this species requires sea ice with thick snow cover, which it uses to make tiny caves for its young. Studies have shown that many Arctic ringed seal pups die when there is too little sea ice and snow. “I surmise that the low-ice years also have an effect on Antarctic seals’ reproduction – not only in terms of the young’s survival, but possibly also the adults’ mating behaviour or other aspects,” says project coordinator Ilse van Opzeeland.

She feels the acoustic data from the eight years represents a unique asset. Normally, gathering data on seals is extremely difficult, as they can only be counted from vessels or helicopters – and the observational radius is relatively small. Moreover, neither vessels nor helicopters can be used to seamlessly observe entire ocean regions or to continuously monitor them. In contrast, underwater “listening posts” can keep tabs on extensive regions round the clock. In addition, since sounds travel farther underwater than in the air, depending on how loud their vocalisations are, some marine fauna can be detected from several kilometres away. Unfortunately, the AWI’s Perennial Acoustic Observatory in the Antarctic Ocean (PALAOA) was recently broke away from the coast together with a calving glacier. A new underwater microphone is slated for installation on the coast in the upcoming Antarctic season, starting at the end of this year.

Original publication:

Irene T. Roca, Lars Kaleschke, Ilse Van Opzeeland: Sea ice anomalies affect the acoustic presence of Antarctic pinnipeds in their breeding areas, Frontiers in Ecology and the Environment (2023). DOI: 10.1002/fee.2622

Information for editorial offices:

You can find printable image in the online version of this press release at: https://www.awi.de/en/about-us/service/press/single-view/weniger-eis-weniger-rufende-robben.html

Your contact persons are:

Dr Ilse van Opzeeland, phone: +49(0) 471 4831-1169; email: ilse.van.opzeeland@awi.de
Dr Irene T. Roca, email: irene.rocatorrecilla@uqo.ca

In the press office of the Alfred Wegener Institute, Folke Mehrtens will support you (phone: +49(0) 471 4831-2007, E-Mail: media@awi.de).

Follow the Alfred Wegener Institute on Twitter (https://twitter.com/AWI_Media), Instagram (https://www.instagram.com/awiexpedition/) and Facebook (www.facebook.com/AlfredWegenerInstitute).

The Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) conducts research in the Arctic, Antarctic and oceans of the high and mid-latitudes. It coordinates polar research in Germany and provides major infrastructure to the international scientific community, such as the research icebreaker Polarstern and stations in the Arctic and Antarctica. The Alfred Wegener Institute is one of the 18 research centres of the Helmholtz Association, the largest scientific organisation in Germany.

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JOURNAL

Frontiers in Ecology and the Environment

DOI

10.1002/fee.2622 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Sea ice anomalies affect the acoustic presence of Antarctic pinnipeds in their breeding areas

New approach estimates long-term coastal cliff loss

Peer-Reviewed Publication

STANFORD UNIVERSITY

 

IMAGE: RAILROAD TRACKS NEXT TO THE BEACH IN DEL MAR, CALIFORNIA. CREDIT: TRAVIS CLOW. view more 

CREDIT: CREDIT: TRAVIS CLOW

In parts of California’s iconic mountainous coasts, breathtaking beauty is punctuated by brusque signs warning spectators to stay back from unstable cliffs. The dangers of coastal erosion are an all-too-familiar reality for the modern residents of these communities. Now, with a new tool, researchers are bringing historical perspective to the hotly debated topic of how to manage these disappearing coastlines.

Using a model that incorporates measurements of the amount of time coastal cliffs and their remnant deposits were exposed at the Earth’s surface, Stanford researchers found that the rate of cliff erosion in the past 100 years is similar to that of the past 2,000 years. The proof-of-concept, published in the Journal of Geophysical Research: Earth Surface April 17, opens the possibility of using this new approach to understand the long-term history of coastal cliff erosion, or retreat, in other parts of the state. The work was conducted in Del Mar, California, a beach town in San Diego County with infrastructure atop its coastal bluffs.

“In this particular location, these cliff erosion rates have been the same for thousands of years, so we shouldn’t expect them to get lower,” said senior study author Jane Willenbring, an associate professor of Earth and planetary sciences at the Stanford Doerr School of Sustainability. “If anything, we should expect them to be higher in the future.”

Del Mar is among locations that are critically important for understanding cliff retreat. Homes are situated up to 70 feet above its beach, in addition to public infrastructure. A major railroad between Los Angeles and San Diego runs atop the coastal bluffs, where cliff failures have resulted in several derailments in modern history, as well as rock fall events that led to closures in recent years.

“I think this study bolsters the thinking that we should do something about cliff retreat sooner rather than later,” said lead study author Travis Clow, PhD ’22.

A natural laboratory

The study area was ideal for the researchers’ methodology because the Del Mar beach features a narrow shore platform, the bedrock where tidepools are typically found. Using nine samples of bedrock, the co-authors measured concentrations of the chemical isotope beryllium-10 that track landform exposure to cosmic radiation from space. The data were compared with cliff retreat rates from recent studies based on aerial photography, showing that coastal erosion rates have remained relatively constant over the past two millennia – at about 2 to 5 inches per year.

“One of the advantages of this technique is that it gives you information at the time scales that are relevant for factors like sea-level rise,” Willenbring said. “Our tool estimates retreat over time periods that include multiple major storms or atmospheric rivers that don’t happen very often, but are critical in forming the coastline.”

The researchers’ approach explores the influence of different factors, including wave impacts and weathering that occur at the shore platform and the cliff interface.

“It does more than just spit out a retreat rate,” said Clow, who processed the samples in Willenbring’s lab and measured them at the Center for Accelerator Mass Spectrometry at Lawrence Livermore National Laboratory (LLNL). “It also allows us to have a relative assessment of what might be driving cliff retreat over longer periods of time.”

Jane Willenbring sampling shore platform bedrock in Del Mar with a hammer and chisel. 

(Image credit: Travis Clow)

When rock becomes air

On sandy coasts, like those spanning much of the eastern U.S., beaches are shaped by waves that pull sand out to the ocean, then re-deposit it on land with the coming and going of the tides. But with rocky coastlines like those along California, once a cliff erodes into the ocean, it cannot be replaced, Willenbring said. Instead, it’s as if the rock becomes air.

Willenbring was surprised to learn through this research that over half of all coastlines on Earth are eroding like California’s. The scope of the problem, which will be exacerbated by sea-level rise in the next century, presents an opportunity for using this new technique in other areas.

“There are plenty of other places in California and the Pacific Northwest where active erosion of coastal rocky cliffs is happening, and we hope to use this technique in a wide variety of environments,” Clow said.

Knowledge of cliff retreat in the U.S. is about 50 years behind research on the impacts of erosion and storms on sandy beaches, according to Willenbring – and that makes her excited about contributing to fundamental science in this field.

“No one had even looked at how the beach width correlated with the rate of cliff retreat in California,” Willenbring said. “There are a lot of open questions about what drives coastal erosion, and now we have a new tool to be able to address some of them.”

Additional study co-authors are from the Scripps Institution of Oceanography at the University of California, San Diego; the Center for Accelerator Mass Spectrometry at LLNL; and Imperial College London. The research was supported by LLNL, the California Department of Parks and Recreation, and the U.S. Army Corps of Engineers.

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JOURNAL

Journal of Geophysical Research Earth Surface

DOI

10.5281/zenodo.5645478 

ARTICLE TITLE

Late Holocene cliff retreat in Del Mar, CA revealed from shore platform 10Be concentrations and numerical modeling

ARTICLE PUBLICATION DATE

17-Apr-2023

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