Salinity changes threaten the world's oceans and biodiversity

Insightful study with participation from the University of Konstanz warns of human-induced impacts on the marine ecosystem

Peer-Reviewed Publication

UNIVERSITY OF KONSTANZ

A thought-provoking review led by an international team of researchers reveals the critical, yet poorly studied role of salinity in a changing ocean and coastline. The study underlines how changes in salinity could have potentially devastating impacts on the vital ecosystems and describes how this might affect coastal communities. Titled "Human-induced salinity changes impact marine organisms and ecosystems", the study was published in the journal Global Change Biology. Lead author of the study is biologist Till Röthig from the Fraunhofer Institute for Molecular Biology and Applied Ecology in Giessen. Co-author Christian Voolstra is professor of genetics of adaptation in aquatic systems at the University of Konstanz.

Röthig explains: "Our work shows that salinity is the elephant in the room. While we know comparably well how changing temperatures, acidification and nutrients affect ocean and coastal ecosystems, the effects of human-induced changes in salt content, or salinity, are severely understudied – even though salt exposure levels are crucial for all kinds of organisms, including plants, animals and microorganisms".

Human activities amplify impacts
Coastal and estuarine ecosystems, known for their high productivity, are particularly vulnerable to the impacts of salinity changes. The review emphasizes that climate change-related variations in rainfall can lead to extreme flood and drought events, affecting freshwater availability and subsequently impacting these sensitive ecosystems. Moreover, the authors highlight the compounding effects of local human activities, such as changes in land use, urbanization, river regulation and terrestrial runoff, which further exacerbate the challenges faced by coastal regions.

Salinity is a central factor for many metabolic processes – marine organisms are built to live in salty environments. Salinity is also interacting with other physical and chemical properties, such as temperature and oxygen levels, and thereby shapes the physical environment of the ocean”, explains Professor Voolstra from the University of Konstanz.

The researchers warn that salinity changes are predicted to intensify alongside ocean warming, deoxygenation, nutrient enrichment and increased sediment loads due to climate change and human activity. Expansion caused by warming, freshwater addition and salinity changes contribute to sea-level rise that causes saltwater inflow in coastal and low-lying areas, disrupting ecosystem structures and functions.

Challenges need to be addressed urgently
The authors stress the urgency of addressing these salinity-related challenges to safeguard marine and coastal ecosystems and biodiversity. They highlight the vulnerability of selected habitats and their keystone members including implications of salinity changes on microorganisms, plankton, coral, mangroves, tidal marshes, macroalgae and seagrass.

"Our data show that projected salinity changes alone can lead to ecosystem collapse", Professor Voolstra points out. "Unfortunately, salinity change will not happen in a bubble, and these sensitive ecosystems will also have to cope with changes in temperature, oxygen, acidification and pollution. These interacting effects are a massive black box in terms of understanding and managing the future of our oceans and coasts".

The review provides valuable insights into the threats posed by anthropogenic salinity changes to marine and coastal ecosystems and outlines consequences for health and economy of the local communities in the oftentimes densely populated regions.

About the authors
Till Röthig, Stacey M. Trevathan-Tackett, Christian R. Voolstra, Cliff Ross, Samuel Chaffron, Paul J. Durack, Laura M. Warmuth and Michael Sweet are an interdisciplinary team of researchers from various prestigious institutions worldwide. Their collective expertise spans disciplines such as marine biology, ecology, environmental science, oceanography and climate modelling, enabling a comprehensive analysis of the impact of human-induced salinity changes on marine and coastal ecosystems.

 

Key facts

• Original publication: Till Röthig, et al.: Human-induced salinity changes impact marine organisms and ecosystems, Global Change Biology, 12 July 2023. DOI: 10.1111/gcb.16859
• Study warns of human-induced impacts of salinity changes on ecosystem
• Lead author of the study is Till Röthig from the Fraunhofer Institute for Molecular Biology and Applied Ecology in Giessen
• Co-author Christian Voolstra is professor of genetics of adaptation in aquatic systems at the University of Konstanz

 

Note to editors:
You can download  images here:

https://www.uni-konstanz.de/fileadmin/pi/fileserver/2023/veraenderungen_beim_salzgehalt_Bay.jpg

Caption: Salinity changes threaten the world's oceans and biodiversity.
Image: Julia Spät

https://www.uni-konstanz.de/fileadmin/pi/fileserver/2023/veraenderungen_beim_salzgehalt_Graphical.jpg

Caption: Salinity changes and their influence on ecosystem structure and function.

Increasing temperatures enhance hydrological cycling, resulting in increased meltwater and shifts in evaporation and precipitation patterns that affect global ocean salinity patterns. Local impacts, such as land use practice further modulate terrestrial runoff patterns affecting coastal ecosystems. Enhanced variation or shifts in salinity impact diversity, growth, and survival of key species. Sea level rise connected with salinization as well as ecotone shifts and trophic cascades may contribute to substantially altered ecosystem structure and functionality.

Graphic: Amy Keagy

https://www.uni-konstanz.de/fileadmin/pi/fileserver/2023/veraenderungen_beim_salzgehalt_Salinity.jpg

Caption: Figure 1. Changes in global salinity patterns and terrestrial runoff. Due to an intensified water cycle global surface salinity patterns a, have changed from 1950 to 2020 (PSS-78 70 years). Future projections from the phase 6 of the Coupled Model Intercomparison Project (CMIP6) multi-model mean under b, low (Shared Socioeconomic Pathway, SSP1-2.6), c, mid (SSP3-7.0), and d, high (SSP5-8.5) CO2 emission future scenarios (differences from the 1985-2014 historical counterpart) show strong salinity changes (PSS-78) that resemble the pattern of observed changes will continue, particularly under mid and high CO2 emission scenarios. This is in concert with changes in precipitation and the more direct anthropogenic impact, changes over land annual total runoff (%), that project increasing variations from e, low (SSP1-2.6), f, mid (SSP3-7.0), and g, high CO2 (SSP5-8.5) emission future scenarios.

Graphic: Paul J. Durack

 

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JOURNAL

Global Change Biology

DOI

10.1111/gcb.16859 

ARTICLE TITLE

Human-induced salinity changes impact marine organisms and ecosystems

2018–2022 Southern Resident killer whale presence in the Salish Sea: continued shifts in habitat usage

Peer-Reviewed Publication

PEERJ

 

IMAGE: THE SOUTHERN RESIDENT ORCA view more 

CREDIT: MONIKA WIELAND SHIELDS, ORCA BEHAVIOR INSTITUTE

Monika Wieland Shields, Director of the Orca Behavior Institute, has observed orcas in the Salish Sea, a marginal sea of the Pacific Ocean located in the Canadian province of British Columbia and the U.S. state of Washington, since 2000. She has recently published an article in the peer-reviewed Open Access journal PeerJ Life & Environment that provides crucial insights into the changing habitat usage of the critically endangered Southern Resident killer whales (Orcinus orca), shedding light on historic trends and the current status of the population in the Salish Sea. We caught up with Monika to find out more about her research and the orcas she is so passionate about.

 

Can you tell us a bit about yourself?

My name is Monika Wieland Shields and I’m the co-founder and director of the non-profit Orca Behavior Institute (OBI) based on San Juan Island, Washington, USA. We conduct non-invasive behavioral and acoustic research on two populations of killer whales that frequent the regional inland waters known as the Salish Sea: the endangered fish-eating Southern Resient killer whales and the thriving mammal-eating Bigg’s killer whales. I have been studying, photographing, writing about, and advocating for these whales for over 20 years, and am the author of the 2019 book “Endangered Orcas: The Story of the Southern Residents”.

 

Can you briefly explain the research you published in PeerJ?

One of my long-term projects at OBI is tracking the shifting habitat usage of Southern Resident killer whales. Their seasonal usage of the Salish Sea has changed dramatically since their endangered listing in 2005, correlating with shifts in their preferred prey. This study provides an update on daily whale occurrence from 2018-2022 showing that these shifts are continuing to occur.

 

What did you discover and where?

The focus of this study is the inland waters of Washington State and British Columbia, a region known as the Salish Sea. This study shows that historic Southern Resident habitat use of this area has essentially reversed: they used to be most abundant here from May through September, but now occur more in the fall and winter months while their spring and summer presence has declined dramatically.

 

What was significant about your findings?

Protecting habitats is a key component of endangered species recovery, but to be biologically meaningful, any geographic or temporal protection zones need to overlap in space and time with how the target species is currently using the habitat, rather than based on historic trends. Both Canada and the US have implemented regional and seasonal protection measures aimed at supporting population recovery, but it is important that they are regularly updated to reflect shifting habitat usage by the Southern Residents. This study fills that data gap by demonstrating how these endangered orcas are utilizing the Salish Sea over the last 5 years and how that has shifted from previous trends.

Read the full article 2018–2022 Southern Resident killer whale presence in the Salish Sea: continued shifts in habitat usage published in PeerJ Life & Environment.

The Southern Resident orca

CREDIT

Monika Wieland Shields, Orca Behavior Institute

Monika Wieland Shields, Orca Behavior Institute

CREDIT

Katya McMullen

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JOURNAL

PeerJ

DOI

10.7717/peerj.15635 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

2018–2022 Southern Resident killer whale presence in the Salish Sea: continued shifts in habitat usage

Reinhart Koselleck Project for TUD Chemist Jan J. Weigand: 

Sustainable Chemistry and Phosphorus Recycling

Grant and Award Announcement

TECHNISCHE UNIVERSITÄT DRESDEN

 

IMAGE: PORTRAIT PROFESSOR JAN J. WEIGAND view more 

CREDIT: AK WEIGAND

Recently, the team led by chemist Prof. Jan J. Weigand announced a significant breakthrough in phosphorus chemistry. In a publication in Nature Synthesis, they introduced an innovative and simple method for producing phosphorus-based chemicals without the use of hazardous intermediates such as white phosphorus.

In the next step, the team aims to expand the range of phosphorus-based chemicals that can be produced using this novel method, thereby enabling a direct and more sustainable access to a variety of platform chemicals. Phosphorus and its compounds are indispensable in our daily lives – their application in fertilizers alone is crucial and contributes significantly to feeding the world's population. Out of the globally mined 190 million tons of raw phosphorus per year, 80 percent is processed into fertilizers. However, the current wasteful handling of this essential elements leads to the depletion of natural and available phosphorus reserves on Earth. As a result, phosphate rock and elemental phosphorus have been included in the list of critical raw materials. Projections suggest that global reserves could be depleted within 100 years. "For these reasons, the development of new and innovative chemical methods in the phosphorus value chain is urgently needed. The issue of phosphorus recovery through truly suitable large-scale recycling processes for valuable phosphorus compounds will become significantly more challenging in the future," explains Dr. Kai Schwedtmann, a key member of Jan J. Weigand's team and co-inventor of the patents underlying this project.

In a highly exploratory project, Prof. Weigand's team aims to explore electrochemical methods for recycling phosphorus-based chemicals in an efficient circular process. "In our blueprint for a modern sustainable phosphorus chemistry, we are investigating systematic and progressively atom- and energy-efficient pathways for the deoxygenation of phosphoric acid and recycled phosphorus resources such as phosphoric acid and struvite from sewage sludge treatment or lithium iron phosphate from battery recycling. An extension of this approach is the synthesis of various hexafluorophosphate (PF6) salts, starting from highly problematic substances like uranium hexafluoride (UF6), which contains one of the key anions, PF6-, for battery electrolytes," explains Prof. Weigand, Chair of Inorganic Molecular Chemistry at TUD.

Jan J. Weigand is also a member of the international expert pool at the Center for Transformation of Chemistry (CTC) and emphasizes the significance of this project in the context: "The vision of the CTC to transform the chemical industry towards a sustainable circular economy is of central importance. Our research aims to develop innovative solutions that are closely aligned with the goals of the CTC, focusing on the sustainable use of resources and the reduction of environmental impacts. We are proud to contribute our expertise to this groundbreaking project and make a significant contribution to the transformation of the chemical industry, particularly in the field of phosphorus chemistry and recycling."

The German Research Foundation (DFG) supports this ambitious endeavor for the next five years through a Reinhart Koselleck Project, named after the German historian Reinhart Koselleck (1923-2006). This funding provides exceptional scientists with the opportunity to carry out highly innovative and positively risk-prone projects.

‘Taboo’ & ‘crazy:’ researchers examine mental health stigmas on the border

Peer-Reviewed Publication

UNIVERSITY OF TEXAS AT EL PASO

 

IMAGE: FROM LEFT TO RIGHT: FORMER AND CURRENT GRADUATE RESEARCH ASSISTANTS BRITTANY OCHOA AND KAREN KWON; ASSISTANT PROFESSOR JASON MALLONEE, D.S.W.; AND GRADUATE RESEARCH ASSISTANT ROSA ESCALANTE LOPEZ. CIUDAD JUÁREZ IS IN THE BACKGROUND. view more 

CREDIT: THE UNIVERSITY OF TEXAS AT EL PASO

EL PASO, Texas (July 13, 2023) — Hispanic adults with mental health conditions are 17 percent less likely to receive treatment than their non-Hispanic white counterparts. But what causes this disparity and how can we fix it?

That was a question recently posed by Jason Mallonee, D.S.W., an assistant professor in the Department of Social Work at The University of Texas at El Paso. 

“There’s a higher likelihood of unresolved mental health conditions in this community and we wanted to try to understand that,” Mallonee explained. “What stops someone from seeking help or engaging in services and then, what could help someone?”

To answer his questions, Mallonee and a team of graduate research assistants went straight to the source, studying the mental health perspectives of Hispanics living along the U.S.-Mexico border in El Paso, Texas. The findings, published in the journal Frontiers in Public Health, reveal the pervasive stigmas surrounding mental health in the Hispanic culture and how social workers may help more community members seek treatment.

To conduct the study, 25 participants were recruited from an El Paso food pantry called the Kelly Center for Hunger Relief.

“What I have found in my research is that people who have a difficult time meeting their basic needs also have a higher likelihood of unresolved mental health conditions,” Mallonee explained. 

Participants were recruited by agency staff and assigned into smaller groups. Rose Escalante Lopez, who graduated with a master’s degree in social work at UTEP this spring, conducted focused, in-person discussions in both Spanish and English. Mallonee, who currently serves as the president of the Board of Directors for the Kelly Center for Hunger Relief, did not participate in the recruitment or focus groups to minimize a conflict of interest. 

Small group discussions ranged from an hour to an hour-and-a-half long each and Escalante Lopez posed multiple questions to understand mental health perceptions and potential barriers to seeking help.

The responses were striking and it surprised Escalante Lopez just how taboo mental health is in the community. Statements from participants included:

• “In the Latino community, everyone refuses to see a psychologist because they are not crazy…”
• “When they hear mental illness, they already think they have a bad brain.”
• “Something very taboo, something that is not needed if you are a man. You are a man and you do not need help so they can control your mind.”
• “Shame, fear, rejection, or that people will say or speak ill of me…”

“Listening to some of the participants’ experiences with mental health or a relative’s experience, it was surprising to hear how they were taught to suppress emotions,” Escalante Lopez said. “Even though today there is a better acceptance of mental health after the COVID-19 pandemic, the stigma around it continues to be a barrier to seek services.”

Each discussion was recorded and then analyzed to identify overarching themes. In addition to identifying the need for mental health to be normalized, the researchers noticed dissatisfaction and distrust of current mental health services.

“Someone reported a two-year waitlist to get in to see a psychologist,” Mallonee said. “Another commented on how providers turn over so quickly that you have a new therapist every few months, so then you’re going through your story again and again.”

Mallonee added, “They told us how they always get these ‘Mental Health Resource Lists’ with numbers to call for help, but when they call, no one answers or returns the calls. Those are all things that are going to turn someone off from seeking help.”

Armed with these perspectives, Mallonee has just kicked off an evidence-based mental health program in El Paso called ‘Pensamientos y Platicas’ or ‘Thoughts and Talks.’

The four-week program is facilitated by UTEP social work students and is intended to normalize conversations around mental health and help those with mental health conditions cope and create a plan to manage their condition and seek treatment when needed.

Mallonee is excited to see the program’s impact. 

He said, “We took the recommendations from the focus groups and built this program from scratch while incorporating best practices.”

###

About The University of Texas at El Paso 

The University of Texas at El Paso is America’s leading Hispanic-serving University. Located at the westernmost tip of Texas, where three states and two countries converge along the Rio Grande, 84% of our 24,000 students are Hispanic, and half are the first in their families to go to college. UTEP offers 169 bachelor’s, master’s, and doctoral degree programs at the only open-access, top-tier research university in America.

 

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JOURNAL

Frontiers in Public Health

DOI

10.3389/fpubh.2023.1134076 

ARTICLE TITLE

“Something very taboo”: a qualitative exploration of beliefs, barriers, and recommendations for improving mental health care and access for Hispanic adults in the Paso del Norte U.S.-Mexico border region

Disclaimer: AAAS and EurekAler

Mandatory EU financial disclosure increases frequency and quality of M&A deals, says study

Peer-Reviewed Publication

CITY UNIVERSITY LONDON

Forcing private firms to disclose their financial statements leads to more mergers and acquisitions (M&As) and better deals, according to a new paper published by a researcher from Bayes Business School (formerly Cass). 

The paper, which has been published in the Review of Financial Studies, found that financial disclosure increases M&A activity by reducing information friction in the market for corporate control. 

Following the implementation of the 2003 European Commission (EC) directive on financial reporting, the study shows the positive spillovers associated with this regulation, counteracting the common view that M&A deals are value-destroying in nature.  

Assessing M&As 

M&As are large and risky investment decisions for firms. Particularly when the potential target is a private company, the scarcity of available information is bound to be a hurdle for a potential acquirer.  

To explore how the EU directive affected M&A deals, the researchers compiled detailed data from Zephyr, a comprehensive database on mergers and acquisitions. This approach yielded 40,321 deals from 12 countries completed between 2001 and 2012, which they complemented with target’s financials following the completion of the deal. 

Key findings from the research show: 

• M&As of private targets increased with the enactment of the disclosure regulation. Consistent with the view that more extensive disclosure of financial information reduces the information friction faced by the potential acquirers, they also discovered that mandatory reporting intensity is positively correlated with M&A activity, even when accounting for different ways to measure M&A activity. 
   

• Using data on the targets after an acquisition, the researchers found that more mandated disclosures in the industry lead to higher growth rates (measured by total assets) in the target after the acquisition, but not necessarily better performance. Conversely, an increase in target-specific disclosure requirements is associated with greater growth and improved performance post-deal. This suggests that firm-specific information is the key driver of synergistic deals, while industry-specific information may not necessarily help achieve the best match between acquirer and target. 

Effects of mandatory disclosure 

Co-author Dr Francisco Urzúa, Reader in Finance at Bayes Business School (formerly Cass), said: 

“Our study shows that more deals take place following the implementation of mandatory reporting in the EU, but not only that, targets that are disclosing thanks to this regulation improve their performance after the acquisition. That is, there are more and better deals taking place thanks to it.  

“Our empirical results support the argument that mandatory disclosure of financial information facilitates the identification of new deal opportunities, ultimately leading to more M&A activity and better-performing acquisitions.  

“In many countries around the world, including Canada and the United States, private firms face essentially no financial reporting requirements. An important normative question is whether some level of mandatory disclosure – maybe limited to the largest private firms – should be required. After all, private firms in the US employ about two-thirds of total US employees. The findings in this paper point to a clear benefit from introducing some mandatory disclosure requirements for the largest private firms.” 

“Mandatory Financial Disclosure and M&A Activity” by Marcelo Ortiz (Universitat Pompeu Fabra); Caspar David Peter (Erasmus University); Francisco Urzúa I (Bayes Business School, City, University of London); and Paolo F. Volpin (Drexel University) has been published in Review of Financial Studies. 

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JOURNAL

Review of Financial Studies

DOI

10.1093/rfs/hhad052 

ARTICLE TITLE

Mandatory Financial Disclosure and M&A Activity

 Friday, 14 July 2023 – SHARK AWARENESS DAY

Discover white sharks and more in 3D! Cutting-edge, interactive shark and ray displays bring the ocean to life

New interactive models on the Save Our Seas Foundation’s (SOSF’s) World of Sharks website, and for the SOSF Shark Education Centre’s technology for young learners, bring to life the evolution and adaptions of sharks and rays – in 3D!

Business Announcement

SAVE OUR SEAS FOUNDATION

 

IMAGE: THE ADVANCED TECHNIQUES USED TO RENDER THE MODEL SHARKS ENSURE THEY ARE NOT ONLY TRUE TO FORM BUT ALSO REPRESENT GENUINE MOVEMENT IN THE ANIMATIONS. view more 

CREDIT: PHOTO: BYRON DILKES RENDERED IMAGE: DIGITAL LIFE PROJECT AT THE UNIVERSITY OF MASSACHUSETTS AMHERST USA

For release on Friday, 14 July 2023 – SHARK AWARENESS DAY

Have you ever wondered how many kinds of sharks there are? Which is the biggest shark or the fastest? For these answers and lots more, the Save Our Seas Foundation’s (SOSF’s) World of Sharks website is the one-stop shop for shark information. Designed to provide scientifically accurate information in an engaging format, World of Sharks is where you can find infographics, podcast episodes, species cards and topic pages covering everything you’ve ever wanted to know about sharks and rays.

“We wanted World of Sharks to be the ultimate shark FAQ – created to answer all the questions people want to ask about sharks and rays,” says SOSF CEO Dr James Lea. “Through engaging and accessible content, we hope to grow a repository of fascinating shark facts that people can trust.”

And now, with this latest addition, the website will host interactive 3D white shark and manta ray models designed by the Digital Life Project at the University of Massachusetts (UMASS) in collaboration with the SOSF.

“I was really wanting to create something 3D and interactive, where visitors to the World of Sharks can explore in an engaging way that highlights the unique physiology and evolution of sharks and rays and demystifies their unique adaptations,” explains Jade Schultz, content manager for the SOSF. 

The Digital Life team, led by Professor Duncan Irschick, in collaboration with CG artist Johnson Martin and UMASS Amherst undergraduates Emma Hsiao and Braedon Fedderson, used media provided by the SOSF and data and open-access images to reconstruct these 3D shark species.

The interactive biology models enable website users to learn about different elements of shark and ray physiology. For instance, just allowing the cursor to hover over key features will bring up information on everything from how manta rays filter feed and why they are under threat to facts about how scientists use sharks’ dorsal fins to identify individuals in a population. The 3D models are open access, and free to view and download for non-profit use. 

Although concerted efforts by researchers and educators are turning the tide for sharks and rays, significant challenges remain. More than one-third of these species are under threat of extinction, which means we still have much work to do to change misconceptions, banish misinformation and empower people with useful information so that they can also participate in conservation. 

“The key to all our understanding of sharks – why they do what they do and what is needed to help them recover – relies on there being a foundation of basic, reliable life history information,” says Dr Lea.

The SOSF has a strong legacy of using communication and storytelling to do this, but this most recent commission with innovators from UMASS harnesses the power of creative design and technological advancement. The World of Sharks makes the reach for this kind of information global, but the SOSF is also excited to present very detailed and accurate information at the local scale.

Young visitors to the SOSF Shark Education Centre (SOSF-SEC) in Cape Town, South Africa, have an incredible opportunity to explore the rocky shores nearby in the Dalebrook marine protected area. This kind of in-person experience is irreplaceable, but to dive deeper into the reaches offshore requires technological wizardry and creative flair. A new website for the SOSF-SEC will host a diversity of 3D sharks that are found in False Bay, the largest bay in southern Africa. Children who would never otherwise dip below the waves to see these sharks will now be able to watch, for example, an endemic (found nowhere else in the world) catshark curl into a defensive doughnut-shape. Whether on iPads in the centre or at home online, learners can marvel at the most amazing feats of the sharks that live on their doorstep. Simulating behaviours like spyhopping in white sharks and demonstrating how sharks move in their environment give children an immersive experience, regardless of whether they have access to the ocean.

Still in the throes of the brainstorming and development that will expand these tools to their full potential, the director of the SOSF-SEC, Dr Clova Mabin, enthuses, “We also think that it might be possible to use the tools as a teaching aid in the classroom, to simulate field work. Learners could view them on the iPads and potentially take various measurements, comparing them across the different species.”

Sharks have special pores in their skin, known as the Ampullae of Lorenzini - that allows them to detect electrical signals. Each pore is filled with a highly conductive gel, which carries weak electrical signals from the surrounding seawater to a receptor cell.

CREDIT

Photo © Byron Dilkes

Discover great white sharks an [VIDEO] | 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Animals

Detecting spoiled food with LEDs

Perovskite-modified LEDs reveal rot in fruit and veg before it is visible

Peer-Reviewed Publication

WILEY

A team of researchers has developed new LEDs which emit light simultaneously in two different wavelength ranges, for a simpler and more comprehensive way to monitor the freshness of fruit and vegetables. As the team write in the journal Angewandte Chemie, modifying the LEDs with perovskite materials causes them to emit in both the near-infrared range and the visible range, a significant development in the contact-free monitoring of food.

Perovskite crystals are able to capture and convert light. Being simple to produce and highly efficient, perovskites are already used in solar cells but are also being intensively researched for suitability in other technologies. Angshuman Nag and his team at the Indian Institute of Science Education and Research (IISER) in Pune, India, are now proposing a perovskite application in LED technology that could simplify the quality control of fresh fruit and vegetables.

Without light converters, LEDs would emit light in rather narrow light bands. To cover the whole range of white light produced by the sun, the diodes in “phosphor-converted” (pc) LEDs are coated with luminescent substances. Nag and his team have used a double emission coating with the purpose to produce pc-LEDs that emit both white (“normal”) light and also a strong band in the near-infrared range (NIR).

To make the dual-emission pc-LED, they applied a double perovskite doped with bismuth and chromium. Part of the bismuth component emits warm white light and another part transfers energy to the chromium component, de-exciting it and causing an additional emission in the NIR range, the researchers found out.

NIR is already used in the food industry to examine freshness in fruit and vegetables. Nag and PhD student Sajid Saikia, first author of the paper, explain their idea: "Food contains water, which absorbs the broad near-infrared emission at around 1000 nm. The more water that is present [due to rotting], the greater the absorption of near-infrared radiation, yielding darker contrast in an image taken under near-infrared radiation. This easy, non-invasive imaging process can estimate the water content in different parts of food, assessing its freshness."

Using these modified pc-LEDs to examine apples or strawberries, the team observed dark spots that were not visible in standard camera images. Illuminating the food with both white and NIR light revealed normal coloring that could be seen by the naked eye, as well as those parts which were starting to rot, but not yet visibly so.

Saikia and Nag envision a compact device for simultaneous visual and NIR food inspection, although the two detectors, one for visible light and one for NIR light, could make such an instrument costly for common applications. On the other hand, the researchers emphasize that the pc LEDs are easy to produce without any chemical waste or solvents and short-term costs could be more than recovered by the long service life and scalability of this novel dual-emitting pc-LED device.

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About the Author

Angshuman Nag is an Associate Professor of Chemistry at IISER Pune, India. His group develops novel semiconductors with favorable optoelectronic properties such as defect-free nanocrystals, lead-free metal halide perovskites, semiconductors with luminescent, plasmonic, and magnetic properties, and surface-engineered nanocrystals.

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JOURNAL

Angewandte Chemie International Edition

DOI

10.1002/anie.202307689 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Broad Dual Emission by Codoping Cr3+ (d→d) and Bi3+ (s→p) in Cs2Ag0.6Na0.4InCl6 Double Perovskite

Analogous to algae: scientists move toward engineering living matter by manipulating movement of microparticles

Breakthrough uses lasers to mimic biological and meteorological systems

Peer-Reviewed Publication

NEW YORK UNIVERSITY

 

IMAGE: AI IMPRESSION OF ORBITING PARTICLE SPUN BY A ROTATING LIGHT BEAM. view more 

CREDIT: MATAN YAH BEN ZION

A team of scientists has devised a system that replicates the movement of naturally occurring phenomena, such as hurricanes and algae, using laser beams and the spinning of microscopic rotors. 

The breakthrough, reported in the journal Nature Communications, reveals new ways that living matter can be reproduced on a cellular scale.

“Living organisms are made of materials that actively pump energy through their molecules, which produce a range of movements on a larger cellular scale,” explains Matan Yah Ben Zion, a doctoral student in New York University’s Department of Physics at the time of the work and one of the paper’s authors. “By engineering cellular-scale machines from the ground up, our work can offer new insights into the complexity of the natural world.”  

The research centers on vortical flows, which appear in both biological and meteorological systems, such as algae or hurricanes. Specifically, particles move into orbital motion in the flow generated by their own rotation, resulting in a range of complex interactions. 

To better understand these dynamics, the paper’s authors, who also included Alvin Modin, an NYU undergraduate at the time of the study and now a doctoral student at Johns Hopkins University, and Paul Chaikin, an NYU physics professor, sought to replicate them at their most basic level. To do so, they created tiny micro-rotors—about 1/10th the width of a strand of human hair—to move micro-particles using a laser beam (Chaikin and his colleagues devised this process in a previous work).

The researchers found that the rotating particles mutually affected each other into orbital motion, with striking similarities to dynamics observed by other scientists in “dancing” algae—algae groupings that move in concert with each other. 

In addition, the NYU team found that the spins of the particles reciprocate as the particles orbit. 

“The spins of the synthetic particles reciprocate in the same fashion as that observed in algae—in contrast to previous work with artificial micro-rotors,” explains Ben Zion, now a researcher at Tel Aviv University. “So we were able to reproduce synthetically—and on the micron scale—an effect that is seen in living systems.”

“Collectively, these findings suggest that the dance of algae can be reproduced in a synthetic system, better establishing our understanding of living matter,” he adds.

The research was supported by grants from the Department of Energy (DE-SC0007991, SC0020976). 

DOI: 10.6084/m9.figshare.22294690

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JOURNAL

Nature Communications

DOI

10.6084/m9.figshare.22294690 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Hydrodynamic spin-orbit coupling in asynchronous optically driven micro-rotors

ARTICLE PUBLICATION DATE

11-Jul-2023