New AI method captures uncertainty in medical images

By providing plausible label maps for one medical image, the Tyche machine-learning model could help clinicians and researchers capture crucial information

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

In biomedicine, segmentation involves annotating pixels from an important structure in a medical image, like an organ or cell. Artificial intelligence models can help clinicians by highlighting pixels that may show signs of a certain disease or anomaly. 

However, these models typically only provide one answer, while the problem of medical image segmentation is often far from black and white. Five expert human annotators might provide five different segmentations, perhaps disagreeing on the existence or extent of the borders of a nodule in a lung CT image. 

“Having options can help in decision-making. Even just seeing that there is uncertainty in a medical image can influence someone’s decisions, so it is important to take this uncertainty into account,” says Marianne Rakic, an MIT computer science PhD candidate.

Rakic is lead author of a paper with others at MIT, the Broad Institute of MIT and Harvard, and Massachusetts General Hospital that introduces a new AI tool that can capture the uncertainty in a medical image. 

Known as Tyche (named for the Greek divinity of chance), the system provides multiple plausible segmentations that each highlight slightly different areas of a medical image. A user can specify how many options Tyche outputs and select the most appropriate one for their purpose.

Importantly, Tyche can tackle new segmentation tasks without needing to be retrained. Training is a data-intensive process that involves showing a model many examples and requires extensive machine-learning experience. 

Because it doesn’t need retraining, Tyche could be easier for clinicians and biomedical researchers to use than some other methods. It could be applied “out of the box” for a variety of tasks, from identifying lesions in a lung X-ray to pinpointing anomalies in a brain MRI. 

Ultimately, this system could improve diagnoses or aid in biomedical research by calling attention to potentially crucial information that other AI tools might miss. 

“Ambiguity has been understudied. If your model completely misses a nodule that three experts say is there and two experts say is not, that is probably something you should pay attention to,” adds senior author Adrian Dalca, an assistant professor at Harvard Medical School and MGH, and a research scientist in the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL).

Their co-authors include Hallee Wong, a graduate student in electrical engineering and computer science; Jose Javier Gonzalez Ortiz PhD ’23; Beth Cimini, associate director for bioimage analysis at the Broad Institute; and John Guttag, the Dugald C. Jackson Professor of Computer Science and Electrical Engineering. Rakic will present Tyche at the IEEE Conference on Computer Vision and Pattern Recognition, where Tyche has been selected as a highlight.

Addressing ambiguity

AI systems for medical image segmentation typically use neural networks. Loosely based on the human brain, neural networks are machine-learning models comprising many interconnected layers of nodes, or neurons, that process data.

After speaking with collaborators at the Broad Institute and MGH who use these systems, the researchers realized two major issues limit their effectiveness. The models cannot capture uncertainty and they must be retrained for even a slightly different segmentation task. 

Some methods try to overcome one pitfall, but tackling both problems with a single solution has proven especially tricky, Rakic says.  

“If you want to take ambiguity into account, you often have to use an extremely complicated model. With the method we propose, our goal is to make it easy to use with a relatively small model so that it can make predictions quickly,” she says.

The researchers built Tyche by modifying a straightforward neural network architecture.

A user first feeds Tyche a few examples that show the segmentation task. For instance, examples could include several images of lesions in a heart MRI that have been segmented by different human experts so the model can learn the task and see that there is ambiguity.

The researchers found that just 16 example images, called a “context set,” is enough for the model to make good predictions, but there is no limit to the number of examples one can use. The context set enables Tyche to solve new tasks without retraining.

For Tyche to capture uncertainty, the researchers modified the neural network so it outputs multiple predictions based on one medical image input and the context set. They adjusted the network’s layers so that, as data move from layer to layer, the candidate segmentations produced at each step can “talk” to each other and the examples in the context set. 

In this way, the model can ensure that candidate segmentations are all a bit different, but still solve the task.

“It is like rolling dice. If your model can roll a two, three, or four, but doesn’t know you have a two and a four already, then either one might appear again,” she says.

They also modified the training process so it is rewarded by maximizing the quality of its best prediction. 

If the user asked for five predictions, at the end they can see all five medical image segmentations Tyche produced, even though one might be better than the others. 

The researchers also developed a version of Tyche that can be used with an existing, pretrained model for medical image segmentation. In this case, Tyche enables the model to output multiple candidates by making slight transformations to images.

Better, faster predictions

When the researchers tested Tyche with datasets of annotated medical images, they found that its predictions captured the diversity of human annotators, and that its best predictions were better than any from the baseline models. Tyche also performed faster than most models.

“Outputting multiple candidates and ensuring they are different from one another really gives you an edge,” Rakic says.

The researchers also saw that Tyche could outperform more complex models that have been trained using a large, specialized dataset.

For future work, they plan to try using a more flexible context set, perhaps including text or multiple types of images. In addition, they want to explore methods that could improve Tyche’s worst predictions and enhance the system so it can recommend the best segmentation candidates.

This research is funded, in part, by the National Institutes of Health, the Eric and Wendy Schmidt Center at the Broad Institute of MIT and Harvard, and Quanta Computer.

###

Written by Adam Zewe, MIT News

Paper: “Tyche: Stochastic In-Context Learning for Medical Image Segmentation”

https://arxiv.org/pdf/2401.13650.pdf

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ARTICLE TITLE

“Tyche: Stochastic In-Context Learning for Medical Image Segmentation”

 

‘Branded access offers’ dilute parent brand via perceived lack of consumer commitment

UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN, NEWS BUREAU

 

IMAGE: 

 

CONSUMERS WHO HIGHLY IDENTIFY WITH A BRAND TAKE A DIM VIEW OF THE SHORT-TERM RENTING OF CONSUMER GOODS VIA “BRANDED ACCESS OFFERS,” ACCORDING TO RESEARCH CO-WRITTEN BY TIFFANY BARNETT WHITE, A PROFESSOR OF BUSINESS ADMINISTRATION AT THE UNIVERSITY OF ILLINOIS URBANA-CHAMPAIGN AND AN EXPERT IN CONSUMER-BRAND RELATIONSHIPS.

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CREDIT: PHOTO BY GIES COLLEGE OF BUSINESS

CHAMPAIGN, Ill. — Why buy when you can rent? From cars to high-end clothing, the short-term renting or sharing of consumer goods through “branded access offers” has become an increasingly popular alternative to the traditional ownership model. But such time-limited consumption may have unintended consequences for the parent brands that offer them, according to a new study co-written by a University of Illinois Urbana-Champaign expert in consumer-brand relationships.

Consumers who highly identify with a brand take a dim view of branded access offers, said Tiffany Barnett White, a professor of business administration and the Bruce and Anne Strohm Faculty Fellow at the U. of I.’s Gies College of Business.

“Brands are constantly pursuing new customers, and the leading trend is a focus on branded access offers, which was motivated by this other trend in consumption of moving away from ownership to more of a short-term rental mode,” she said. 

A concrete example would be the Zipcar model: Why spend tens of thousands of dollars on a luxury import sedan when you can rent the same vehicle for a couple hours now and then?

“In response to disruptive startups like Zipcar or Rent the Runway, established brands like H&M, Peloton and BMW have launched their own branded access offers,” said co-author Aaron J. Barnes of the University of Louisville.

“The unintended consequence of these offers that are meant to entice ‘accessors,’ however, is that doing so can seriously damage the brand image to existing customers — particularly the brand’s most hard-core adherents,” White said. “Those consumers are especially sensitive about a perceived lack of brand commitment from these new consumers who are seemingly jumping on the bandwagon.”

Despite their growing popularity, surprisingly little is known about how branded access offers affect consumer responses to brands, White said. Across four studies spanning fashion, sports and fitness goods, White and Barnes found that consumers with high group-brand connections reacted less favorably to the introduction of new access offers compared with the traditional ownership model. 

“The research shows that otherwise well-intentioned attempts by firms to entice new customers with low-commitment rental offers can backfire for those who, ironically, are most committed to the brand,” White said. “Those whose connection to the brand is based on their belief that it connects them to others shun those who want access but not commitment to the brand. Furthermore, those consumers then penalize the parent company for sharing its offerings with those whom they perceive to lack commitment.”

The perceived lack of brand commitment led to lower brand image, an unintended consequence the researchers dubbed the “accessor effect.”

“This is really about the penalizing of these brands for inviting people into this inner circle of consumers, into settings when they are clearly not adhering to the intragroup dynamics,” White said. “And it’s the hard-core brand adherents who are holding it against these latecomers, the bandwagon consumers. You can imagine what happens with sports brands, for example, when a whole segment of consumers is seen as less loyal than the die-hard fans. They’re looked at as the party crashers. Well, you can apply that to all sorts of consumer goods.”

The reason why brands, even prestigious brands, have these access offers is because of concerns that “startup sharing services will eat their lunch from a profitability standpoint,” White said. “Big brands want to play in this space, but at what cost? They need to do it in a way that gives them some sort of control because, after all, it’s their brand that’s on the line.”

To mitigate the “accessor effect,” White and Barnes say that businesses should communicate that consumers can access goods in longer rather than shorter rental periods, as the perception of a longer commitment to a brand sends a better signal to its long-time adherents, according to the paper. 

“The accessor effect occurs because consumers who really identify with a brand are particularly sensitive to accessors’ perceived lack of brand commitment,” White said. “So if you’re a brand and you want to mitigate that effect, you really have to, essentially, blur the signal. We know that branded access offers signal a lack of commitment to ownership of that brand. So whatever brands can do to add noise to that signal is helpful for attenuating the effect.”

For example, in one of the four studies, the perceived brand commitment of college basketball fans was gauged as higher when brand accessors were only allowed to return team-branded jerseys two weeks rather than two days after the season ended.

“Again, we’re blurring the signal with this longer rental period,” White said. “It’s a signal that you’re more committed to the brand if you rent this jersey for longer because you’re still going to stick by this team — and by extension, this brand — even after the party has ended.

“Now, that doesn’t necessarily signal one’s commitment to the brand forever, it just blurs the commitment, which, in turns, reduces brand dilution. So it’s this middle-ground mechanism where you don’t do it in a way that weakens the parent brand quite as much.”

The paper was published by the Journal of the Academy of Marketing Science.

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JOURNAL

Journal of the Academy of Marketing Science

DOI

10.1007/s11747-024-01006-z 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

“The accessor effect: How (and for whom) renters’ lack of perceived brand commitment dilutes brand image”

 

University of Ottawa team’s work could help supercharge Canada’s biomanufacturing capacity

The study proposes a large-scale workflow to produce natural killer cells and extracellular vesicles for cancer research & therapeutics

UNIVERSITY OF OTTAWA

A team of uOttawa Faculty of Medicine researchers have developed a path to a biomanufacturing process that could potentially transform how Canada generates immunotherapeutic materials – specifically natural killer cells and extracellular vesicles (EVs) – to fuel tomorrow’s novel cancer treatments.

How does it work? Their proof-of-concept study focuses on using a hollow-fiber bioreactor – a type of high-density cell culture system that’s bundled in a small cartridge containing thousands of semipermeable fibers. The team’s method detailed in the Journal of Extracellular Vesicles would allow scientists to generate a continuous flow of cell-derived immunotherapeutics without compromising the materials’ quality and anti-cancer characteristics.

This could significantly boost the feasibility of setting up cost-effective biomanufacturing production systems here in Canada, according to Dr. Jessie Lavoie, one of the study’s senior authors. 

Dr. Lavoie says cell and EV therapies require large amounts of high-quality materials for pre-clinical and clinical investigation – and access to low-cost and continuous closed systems is crucial for meeting these requirements.

“Drug innovators in Canada are driven by scientists in academic centers and small biotechnology companies, making it imperative to have efficient and cost-effective solutions,” says Dr. Lavoie, an adjunct professor at the uOttawa Faculty of Medicine and a research scientist at Health Canada.

This proof-of-concept study is just the latest work from the uOttawa Faculty of Medicine establishing new horizons in EVs and immunotherapy research. In recent years, the Faculty’s broad research community has emerged as a true innovator in this dynamic area, making new discoveries with potentially broad impact.

Dr. Lisheng Wang, a professor in the Faculty’s Department of Biochemistry, Microbiology, and Immunology and the study’s other senior author, says the biomanufacturing workflow detailed in the Journal of Extracellular Vesicles could prove to be a game changer down the line since it can potentially offer new options for drug developers exploring cost-effective ways to develop and advance innovative therapies.

Drs Lavoie and Wang say employing hollow-fibre bioreactors are promising for biomanufacturing EVs at scale, yielding far more material than conventional flask-based methods.

When choosing a bioreactor system, the team considered systems that would be affordable for most laboratories, including academic centers which are big drivers in the development of cell therapy products in Canada. Ultimately, they chose the hollow-fiber bioreactor from Fiber Cell Systems.

The collaborative research was launched by Drs Lavoie and Wang in 2021. The work was led by Frederic St-Denis Bissonnette, a PhD candidate at the uOttawa Faculty of Medicine who is co-supervised by Drs Lavoie and Wang at the Department of Biochemistry, Microbiology, and Immunology (BMI).

Funding from Canada’s Genomics Research and Development Initiative and the CIHR and NSERC agencies allowed the researchers from the University of Ottawa and Health Canada to complete this study.

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JOURNAL

Journal of Extracellular Vesicles

DOI

10.1002/jev2.12387 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Cells

ARTICLE TITLE

A clinically relevant large-scale biomanufacturing workflow to produce natural killer cells and natural killer cell-derived extracellular vesicles for cancer immunotherapy

PSYCHIATRY REPLACES THE CONFESSIONAL

Most patients treated by public psychiatric outpatient clinics are women aged 45 on average

In Brazil, researchers analyzed data for 8,384 clinical appointments that took place in a two-year period at Hospital de Base in São José do Rio Preto and found the situation to be similar to those in publicly-funded psychiatric outpatient clinics

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO

More than 75% of the patients treated at the psychiatric outpatient clinic of Hospital de Base in São José do Rio Preto, São Paulo state (Brazil), are women with a mean age of 45 and suffering from sadness, anxiety and irritability, according to a study reported in the journal Frontiers in Psychiatry. The findings, which are compatible with data in the Brazilian and global literature, draw attention to the importance of diagnosing and treating mental disorders, and can help formulate public policy for the healthcare sector.

“The reality observed in São José do Rio Preto is similar to the situation in psychiatric outpatient clinics belonging to the public health service on the regional and national levels,” said Gerardo Maria de Araújo Filho, a professor in the Department of Neurological Sciences, Psychiatry and Medical Psychology at the São José do Rio Preto Medical School (FAMERP) and coordinator of the study, which was funded by FAPESP via two projects (20/09891-9 and 21/11939-2).

Mental disorders are lowering the quality of life and impairing work capacity with increasing frequency worldwide. They affect 20% of the adult population in Brazil, according to the Ministry of Health; they are severe and persistent in 3% of cases, and due to alcohol and drug abuse in 6%. In addition, 12% require continuous or recurring care. Nevertheless, only 2.3% of the annual budget of the SUS (Sistema Único de Saúde, Brazil’s national health service) is allocated to the treatment of mental illness.

“Improving the identification of clinical and epidemiological characteristics is a key step to establish more efficient protocols, develop public policy, and promote improvements in services,” Araújo said.

The group of researchers led by Araújo analyzed electronic medical records for 8,384 clinical appointments that took place between March 2019 and March 2021 at the psychiatric outpatient clinic of São José do Rio Preto’s Hospital de Base, which offers multidisciplinary treatment for psychiatric patients in the northwest of São Paulo state and serves as the public referral service for 2 million inhabitants of 102 municipalities in the region.

The analysis showed that the patients concerned were mostly female, averaging 45 years of age, and diagnosed with generalized anxiety. The most frequently recorded symptoms were sadness, anxiety and irritability. The most prescribed medications were selective serotonin reuptake inhibitors (SSRIs), a class of antidepressants, such as sertraline.

“We found most to be housewives suffering quite badly from depression and anxiety, and this once again raises the issue of women’s cumulative roles and functions. It’s also important to note that this is a high-risk group for mental disorders inasmuch as the victims of domestic violence are women more often than men,” Araújo said.

“Another key point is that women more often seek medical and psychological care than men, who mostly hide any mental health problems they may have, not least via alcohol and drugs,” said Cinara Cássia Brandão, a professor in the Department of Molecular Biology at FAMERP and a co-author of the article.

The analysis also showed a predominance of women (78.86%) with anxiety and depressive disorders in the generalized anxiety group. However, schizophrenia was frequent among the men (59%), as were delusional disorder (57.89%), alcohol abuse (70%), and illicit substance abuse (60%).

Mean disease and treatment duration were about 15 and 9 years respectively for men and women taken together. For women only, the means were 14 and 9 years, while for men they were 18 and 8 years.

The diagnosis with the longest mean duration of illness was bipolar affective disorder (hypomanic episode, a less severe form of mania characterized by elevated mood with enhanced sociability, initiative and energy), lasting about 29 years. Moderate depressive episodes were the shortest, lasting about 10 years.

With regard to prescribed drugs, the mean was four per patient at the last visit. The highest means were for patients with bipolar affective disorder, current manic episode with psychotic symptoms, and organic delusional disorder.

Protective network

According to the researchers, besides analyzing the profile of these patients to contribute to public policy and help establish more specific treatment protocols, the study also highlights the importance of public outpatient clinics that specialize in mental health.

“They provide the care needed by low-income patients, who wouldn’t get it anywhere else. This type of service is extremely important as part of the national mental health policy,” Araújo said.

“It’s also necessary to provide follow-up support for mental health patients via a psychosocial care network with all relevant specialties. This network should be jointly operated by municipalities, states and the federal government.”

About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.

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JOURNAL

Frontiers in Psychiatry

DOI

10.3389/fpsyt.2024.1274192 

ARTICLE TITLE

Clinical and epidemiological profile of patients with mental disorders in a specialized outpatient clinic and its role in the psychosocial care network

 

Climate: Increased threat to coastlines from concurrent heatwaves and sea level rises

SCIENTIFIC REPORTS

Concurrent occurrences of heatwaves and extreme short-term sea level rises at the same coastal locations significantly increased between 1998 and 2017 when compared to the preceding twenty years, reports a study published in Communications Earth & Environment. The study also suggests that these events may be five times more likely to occur between 2025 and 2049 under a modelled high emissions scenario.

A so-called ‘concurrent heatwave and extreme sea level’ (CHWESL) event is when a heatwave and an extreme short-term sea level rise occur at the same coastal location over the same time period. Although they can pose a serious threat to coastal communities, there has so far been little research into the characteristics and occurrences of these events.

Shuo Wang and Mo Zhou investigated CHWESL events worldwide between 1979 and 2017 and projected future events between 2025 and 2049 under a high emissions climate scenario (the IPCC’s SSP5-8.5 scenario). The authors only included events occurring in the extended summer season, spanning May to September in the Northern Hemisphere, and November to March in the Southern Hemisphere.

The authors found that approximately 88% of the world’s coastlines experienced a CHWESL event during the period 1979 – 2017. Approximately 39% of coastlines recorded a significant increase in the total duration of CHWESL conditions experienced over a year during the period 1998 – 2017 compared to during 1979 – 1998, with tropical regions more likely to experience a greater increase. The authors also found a significant association between heatwave intensity and the probability of a CHWESL event occurring, with a 1% increase in heatwave intensity associated with an approximately 2% increase in the probability of a CHWESL event occurring. From their projections, the authors suggest that global coastal areas could experience on average 38 days of CHWESL conditions each year between 2025 and 2049, an increase of 31 days compared to the historical period of 1989 – 2013.

The authors conclude that CHWESL events could pose a significant threat to coastal communities, particularly from the risks of excess heat to human health. They note that countries in tropical areas are likely to be the most severely affected, and that many of these countries are low or middle-income countries which may struggle to cope with the effects. The authors argue that effective risk mitigation strategies urgently need to be developed to increase preparedness for these extreme events.

***

Springer Nature is committed to boosting the visibility of the UN Sustainable Development Goals and relevant information and evidence published in our journals and books. The research described in this press release pertains to SDG 13 (Climate Action). More information can be found here.

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JOURNAL

Communications Earth & Environment

DOI

10.1038/s43247-024-01274-1 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

The risk of concurrent heatwaves and extreme sea levels along the global coastline is increasing

ARTICLE PUBLICATION DATE

11-Apr-2024

JAMA NETWORK

Physician empathy and chronic pain outcomes

About The Study: In this study that included 1,470 adults with chronic low back pain, physician empathy was associated with better outcomes over 12 months. Greater efforts to cultivate and improve physician empathy appear warranted. 

Authors: John C. Licciardone, D.O., M.S., M.B.A., of the University of North Texas Health Science Center at Fort Worth, is the corresponding author. 

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/ 

(doi:10.1001/jamanetworkopen.2024.6026)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

#  #  #

Embed this link to provide your readers free access to the full-text article This link will be live at the embargo time http://jamanetwork.com/journals/jamanetworkopen/fullarticle/10.1001/jamanetworkopen.2024.6026?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=041124

About JAMA Network Open: JAMA Network Open is an online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication. 

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JOURNAL

JAMA Network Open

 

Tropical coral-infecting parasites discovered in cold marine ecosystems

UNIVERSITY OF BRITISH COLUMBIA

 

IMAGE: 

UNIVERSITY OF BRITISH COLUMBIA BOTANISTS HAVE DISCOVERED PARASITES THOUGHT ONLY TO INFECT TROPICAL CORAL REEFS IN COLD MARINE ECOSYSTEMS. C. CALIFORNICA THAT TESTED POSITIVE FOR CORALLICOLIDS.

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CREDIT: PATRICK KEELING, UNIVERSITY OF BRITISH COLUMBIA.

Parasites thought only to infect tropical coral reefs have been discovered in a large variety of creatures in cold marine ecosystems along the Northeast Pacific, according to new research from University of British Columbia botanists.

The finding, published today in Current Biology, greatly expands the range of corallicolids, suggesting the parasites infect a range of organisms related to coral, like sea anemones and other cold-water marine invertebrates, around the world. 

“This highlights significant blind spots in our strategies designed to sample microbial biodiversity,” says University of British Columbia biodiversity researcher Dr. Patrick Keeling, senior author on the study. “It has implications for the way we sample, measure and interpret environmental diversity, because our current approaches are clearly missing an important and potentially massive fraction of that diversity.”

Corallicolids were thought to be only associated with coral reefs based on hundreds of millions of environmental sequences—samples from soil, seawater or air, rather than directly from animals that live in the same environments. But Dr. Keeling and his team had suspicions that the way microbial diversity is surveyed in environmental sequences might be biased against certain kinds of parasites. 

Luck also had a bit to do with the discovery. After discovering corallicolids in tropical reefs in 2019, subsequent COVID travel restrictions essentially forced Dr. Keeling’s team to cast their parasite nets closer to home—initially at a dock on Galiano Island, one of the southern Gulf Islands off the coast of British Columbia.

They collected 325 samples from nine species of cold-water anthozoans from non-coral reef environments at five locations in coastal British Columbia, Canada. The sampling covered a diverse range of anthozoans from cold water in temperate marine environments. Samples were screened for corallicolid infection using polymerase chain reaction—a laboratory nucleic acid amplification technique—and sequencing of nuclear small subunit rRNA. 

While the parasites are correlate with coral mortality during bleaching events, it’s unclear what exact impact corallicolids have on corals—or any of the other organisms—they infect.

“It’s possible that Corallicolids have different effects depending on who they’re infecting,” says UBC researcher Morelia Trznadel, the first author of the paper. “The parasite lineages we found in our study seem to ‘jump’ between hosts quite frequently, and while they’ve already been linked to poorer responses during coral bleaching, we don’t know if they’re equally harmful to all hosts.”

In the future the researchers want to expand sampling to include potential hosts further north along the Pacific coast—including newly discovered deep-water reefs. 

This work was supported by the Gordon and Betty Moore Foundation and the Hakai Institute. 
 

University of British Columbia botanists have discovered parasites thought only to infect tropical coral reefs in cold marine ecosystems. A high magnification image of two corallicolid cells in a membrane.

CREDIT

Dr. Sam Livingston, University of British Columbia.

University of British Columbia botanists have discovered parasites thought only to infect tropical coral reefs in a large variety of creatures in cold marine ecosystems—including the white plumose anemone.

University of British Columbia botanists have discovered parasites thought only to infect tropical coral reefs in a large variety of creatures in cold marine ecosystems—including the white plumose anemone.

CREDIT

Patrick Keeling, University of British Columbia.

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JOURNAL

Current Biology

DOI

10.1016/j.cub.2024.03.026 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Coral-infecting parasites in cold marine ecosystems

ARTICLE PUBLICATION DATE

11-Apr-2024

A study conducted off the coast of Biscay shows that cold-affinity algae species are gradually being replaced by warm-affinity ones

A study conducted off the coast of Biscay shows that cold-affinity algae species are gradually being replaced by warm-affinity ones

UNIVERSITY OF THE BASQUE COUNTRY

 

IMAGE: 

(ALGAE). THE RISE IN SEA SURFACE TEMPERATURE HAS A GREATER IMPACT ON SHALLOW MACROALGAE COMMUNITIES.

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CREDIT: 2 (ALGAE). AUTHOR: MARINE BENTHOS RESEARCH GROUP, UPV/EHU.

The temperature of our planet is rising rapidly. Ninety per cent of the excess heat generated has been absorbed by the sea and, as a result, the surface temperature of the oceans has risen significantly. In this context, immobile and temperature-sensitive organisms are particularly vulnerable.  

In addition, there are places where the warming of the sea is more significant than in others. For example, off the Basque coast there has been a 0.23 °C increase in sea temperature per decade, compared with a global increase of 0.15 °C. Faced with this situation, the UPV/EHU's Marine Benthos Research Group explored how macroalgae communities in a coastal area off Biscay have been affected by warming. Together with the Blanes Centre for Advanced Research, the group investigated the changes that have taken place over the last 40 years. “It is important to study how macroalgae communities respond to temperature increases in order to preserve marine biodiversity, as they play essential roles in ecosystems,” said biologist Olatz Arriaga-Telleria.  

One of the main conclusions drawn is the increase in warm-affinity species in the macroalgae communities off the Basque coast due to the increase in temperature, while cold-affinity ones are becoming less numerous. This has led to profound transformations in community structure, as the species that have declined the most, such as Gelidium corneum, are structuring, i.e. they create three-dimensional environments that provide refuge for a wide variety of organisms. What is more, they provide suitable habitats for other algae, fish, invertebrates, etc., where food and protection from predators, among other things, can be found. “We did not detect other species that are replacing these important ecological functions while the structuring species are in decline, which signifies a degradation of the communities,” Arriaga explained. The warm-affinity species that have proliferated are smaller and more simple in morphological terms.  

Resilience of macroalgae communities 

The research has also shown that macroalgae communities respond very quickly to changes in sea temperature. This can be deduced from the data over the last decade. In fact, the temperature increase has not been homogeneous over the 40 years analysed. While the general trend has been upward, the most recent period (2014-2020) investigated saw warmer temperatures. Arriaga explained that “this has allowed us to study what the short-term response of the macroalgae communities is like; we saw that over these 6 years the presence of structuring species at great depths, which had been lost, has partially recovered, while some warm-affinity species have decreased”.  

Although the resilience displayed by the macroalgae gives rise to some hope, the research team stresses it does not look as if sea temperature control will be taking place right away. And given that temperature is the main cause of structural transformations in macroalgae communities, the team does not envisage an easy future. So they regard continuing the research and increasing the frequency of monitoring as essential: “This would help to better understand the behaviour of the macroalgae communities and to take proactive measures to protect the habitats of vulnerable species.” One example could be to identify the areas with the potential to become climate refugia. They are working to find solutions before the situation becomes irreversible. 

Additional information 

Olatz Arriaga-Tellería is a biologist and is writing up her PhD thesis with a grant from the Basque Government in the Department of Plant Biology and Ecology at the Faculty of Science and Technology of the UPV/EHU. She belongs to the Marine Benthos Research Group, which studies the impacts of climate change and pollution on macroalgae communities. 

Bibliographical reference 

O. Arriaga, P. Wawrzynkowski, N. Muguerza, I. Díez, J.M. Gorostiaga, E. Quintano, M.A. Becerro The thermal journey of macroalgae: Four decades of temperature-induced changes in the southeastern Bay of Biscay Marine Environmental Research DOI: 10.1016/j.marenvres.2024.106351 

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JOURNAL

Marine Environmental Research

DOI

10.1016/j.marenvres.2024.106351 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Rising sea surface temperatures have led to profound changes in macroalgae communities

ARTICLE PUBLICATION DATE

9-Apr-2024