Understanding rogue waves of the Eastern Mediterranean Sea

Peer-Reviewed Publication

GEORGIA INSTITUTE OF TECHNOLOGY

 

IMAGE: ROGUE WAVES CAN CAUSE COLOSSAL DAMAGE IF NOT AVOIDED. CREDIT: JOHN LUND, GETTY IMAGES view more 

CREDIT: JOHN LUND, GETTY IMAGES

The eastern Mediterranean Sea, a large basin surrounded by ancient cultural sites, is also a climatology hot spot. However, the region has received comparatively little attention when it comes to understanding the extreme sea states that produce massive and potentially catastrophic waves.

Recognizing a gap in scientific knowledge, an international team of researchers led by Francesco Fedele, associate professor in the School of Civil and Environmental Engineering at Georgia Tech, investigated potential hazards for ship navigation in the eastern Mediterranean. They looked at rogue waves, examined how they form, and analyzed the likelihood that a ship would encounter them while navigating the rough waters of intense storms. Their findings illuminate the nature of extreme waves in the Mediterranean Sea and could advance technology for rogue wave predictions and maritime navigation in extreme weather conditions.

“Imagine that at a single point in the ocean, waves are coming from many directions,” Fedele said. “There is always a chance they will meet, pile up in amplitude, and create an enormous wave. This is what we call a rogue event.”

Rogue waves have long been observed in the western Mediterranean by eyewitnesses — sometimes travelers on cruise ships — and have been known to cause structural damage and loss of lives. To examine the case of the eastern Mediterranean, Fedele teamed up with collaborators at the Technion-Israel Institute of Technology and the CAMERI Coastal and Marine Engineering Research Institute in Haifa, Israel. The team employed a novel theory of space-time wave extremes and considered the hypothetical scenarios of Israeli naval fleet ships navigating the waters of two major storms that occurred in the Mediterranean Sea in 2017 and 2018.

The researchers studied the frequency of rogue wave occurrences as encountered by an observer at a given point on the sea’s surface, such as an oil rig. The team’s statistical analysis indicated that the largest observed waves during the two major storms have similar characteristics to the catastrophic El Faro, Andrea, and Draupner rogue waves, in which the asymmetry of the waves’ crests and troughs was the dominant factor in creating rogue waves.

They discovered that, because the eastern Mediterranean basin is characterized by waves coming from all directions, rogue waves do not “steal” energy from neighboring waves or grow at their expense. This effect, known as modulational instability, has been employed in the past to understand rogue waves. But, according to Fedele, it is only relevant when waves travel in the same direction, like through a long channel, and therefore does not apply in realistic seas.

The team’s novel space-time analysis of the most intense sea states also demonstrated the ability to predict potential rogue hazards for ships of various sizes and cruise speeds navigating within the rough waters of the analyzed storms.

Fedele says a surfer can offer a useful analogy for the space-time effect of waves.  

“As we know, surfers do not wait all day at the same spot, hoping a large wave will arrive,” he said. “They swim around an area to increase their chances of encountering large waves, and they always find one. Similarly, a ship navigating waves will encounter more waves along its path, and the likelihood of coming across a rogue wave is higher than it would be for an oil rig.”

The team’s novel analysis of waves in space-time can also predict the potential of rogue hazards for ship navigation. A version of Fedele’s model has already been adopted by the National Oceanic and Atmospheric Administration for WAVEWATCH III, the national operational wave forecast model. According to Fedele, such a model can be expanded to account for ship motion and rogue hazards, and has the potential to benefit shipping companies, maritime industries, and coastal communities.

 

CITATION: Knobler, S., Liberzon, D. & Fedele, F. Large waves and navigation hazards of the Eastern Mediterranean Sea. Sci Rep 12, 16511 (2022). 

DOI: https://doi.org/10.1038/s41598-022-20355-9

About Georgia Tech

The Georgia Institute of Technology, or Georgia Tech, is one of the top public research universities in the U.S., developing leaders who advance technology and improve the human condition.

The Institute offers business, computing, design, engineering, liberal arts, and sciences degrees. Its more than 46,000 students, representing 50 states and more than 150 countries, study at the main campus in Atlanta, at campuses in France and China, and through distance and online learning.

As a leading technological university, Georgia Tech is an engine of economic development for Georgia, the Southeast, and the nation, conducting more than $1 billion in research annually for government, industry, and society. 

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JOURNAL

Scientific Reports

DOI

10.1038/s41598-022-20355-9 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Large waves and navigation hazards of the Eastern Mediterranean Sea

Earth’s oldest stromatolites and the search for life on Mars

New Geology Science published online ahead of print

Peer-Reviewed Publication

GEOLOGICAL SOCIETY OF AMERICA

 

IMAGE: HAND SAMPLE OF DRESSER FORMATION STROMATOLITE, SHOWING A COMPLEX LAYERED STRUCTURE FORMED OF HEMATITE, BARITE, AND QUARTZ, AND A DOMED UPPER SURFACE (DOME ARROW). view more 

CREDIT: KEYRON HICKMAN-LEWIS AND COLLEAGUES

Boulder, Colo., USA: The earliest morphological traces of life on Earth are often highly controversial, both because non-biological processes can produce relatively similar structures and because such fossils have often been subjected to advanced alteration and metamorphism. Stromatolites, layered organo-sedimentary structures reflecting complex interplays between microbial communities and their environment, have long been considered key macrofossils for life detection in ancient sedimentary rocks; however, the biological origin of ancient stromatolites has frequently been criticized. An article released Friday in the Geological Society of America journal Geology uses a range of advanced two- and three-dimensional analytical techniques to establish the biological origins of Earth’s oldest stromatolites from the 3.48-billion-year-old Dresser Formation, Pilbara, Western Australia.

Although these stromatolites have undergone severe diagenesis and weathering and preserve no organic materials, a team led by Dr. Keyron Hickman-Lewis of the Natural History Museum, London, has used optical and electron microscopy, elemental geochemistry, Raman spectroscopy, and laboratory- and synchrotron-based tomography to identify numerous characteristics indicative of a biological origin.

In addition to performing laboratory tomography of 3D stromatolitic macrostructure, the team was able to achieve the first sub-micron pixel and voxel sizes for imaging of Precambrian stromatolite microstructures via phase contrast imaging using the SYRMEP beamline at the Elettra Synchrotron, Trieste, Italy. This enabled the identification of non-uniform layer morphologies, void spaces arising from the degassing of decaying organic materials, and pillar-like vertical structures interpreted as microbial palisade structure, a common indicator of phototrophic growth.

The Dresser Formation stromatolites have been mostly replaced by hematite (iron oxide) due to recent weathering. While this renders organic geochemical analyses impossible, this composition is highly relevant for the search for life on Mars.

Sedimentary rocks at the surface of Mars have been subjected to similar pervasive oxidation and also comprise mostly iron oxides in their upper centimeters to meters. In this regard, the Dresser Formation stromatolites may be uniquely relevant materials to inform us of a precise style of biosignature preservation expected on Mars. As the Mars 2020 Perseverance rover continues its exploration of Jezero crater, we should search for morphological expressions of life resembling those identified in the Dresser Formation and prepare for advanced multi-technique analyses when Martian samples are eventually returned to Earth.

FEATURED ARTICLE
Advanced 2D-3D insights into Earth's oldest stromatolites (~3.5 Ga): Prospects for the search for life on Mars
Keyron Hickman-Lewis and colleagues
Contact: keyron.hickman-lewis@nhm.ac.uk, The Natural History Museum, Department of Earth Sciences, London, UK
URL: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G50390.1/618747/Advanced-two-and-three-dimensional-insights-into

GEOLOGY articles are online at https://geology.geoscienceworld.org/content/early/recent . Representatives of the media may obtain complimentary articles by contacting Kea Giles at the e-mail address above. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to GEOLOGY in articles published. Non-media requests for articles may be directed to GSA Sales and Service, gsaservice@geosociety.org.

https://www.geosociety.org

Undulatory laminations of the Dresser Formation stromatolites 

Optical photomicrograph (left) and EDX map (right) showing primary and replacement mineralogy in undulatory laminations of the Dresser Formation stromatolites.

CAPTION

Three-dimensional rendering of stromatolite microstructure, enabling the distribution of phases throughout the structure of the stromatolites to be visualized.

CREDIT

Keyron Hickman-Lewis and colleagues

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JOURNAL

Geology

DOI

10.1130/G50390.1 

ARTICLE TITLE

Advanced 2D-3D insights into Earth's oldest stromatolites (~3.5 Ga): Prospects for the search for life on Mars

ARTICLE PUBLICATION DATE

4-Nov-2022

Study highlights the complexity of dryland dynamics under a changing climate

Peer-Reviewed Publication

INDIANA UNIVERSITY-PURDUE UNIVERSITY INDIANAPOLIS SCHOOL OF SCIENCE

Professor Lixin Wang, a hydrologist in the IUPUI School of Science, recently reviewed advances in the study of dryland productivity and examined major outstanding debates on dryland responses to environmental changes in the Nature Climate Change journal. Working with a small, but diverse group of internationally recognized researchers, Wang spent more than a year examining dryland productivity and their important role in the global carbon budget.

In the review article, Wang breaks down the complexity of dryland dynamics and provides an in-depth discussion on the outstanding dryland debate regarding whether drylands are expanding under a warming climate, what are the key drivers of shifts in dryland vegetation, and the importance of hydrological processes regulating dryland ecosystems. The review article also discusses dryland agriculture, grazing, and land use change in drylands under the current and future climates.

Going forward, Wang suggests prioritizing holistic approaches to dryland management, accounting for the increase climate and anthropogenic pressures, and the associated uncertainties in the observation and prediction of dryland productivity.

Besides Wang, the research team includes Dr. Wenzhe Jiao (a former Ph.D. student in Dr. Wang’s group and currently a postdoctoral researcher at MIT) who played an instrumental role in data collection, synthesis, and virtualization, Dr. Natasha MacBean at Western University in Canada, Dr. Maria Cristina Rulli at Politecnico di Milano in Italy, Stefano Manzoni at Stockholm University in Sweden, Giulia Vico at Swedish University of Agricultural Sciences in Sweden, and Paolo D’Odorico at the University of California, Berkeley. The project was funded by a National Science Foundation grant awarded to Dr. Wang.

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JOURNAL

Nature Climate Change

DOI

10.1038/s41558-022-01499-y 

ARTICLE TITLE

Dryland productivity under a changing climate

ARTICLE PUBLICATION DATE

7-Nov-2022

Million prize at international robot competition

Team NimbRo from the University of Bonn has won the grand prize at the finals of the ANA Avatar XPRIZE competition

Grant and Award Announcement

UNIVERSITY OF BONN

 

IMAGE: AVATER ROBOT BLINDLY EXPLORES A STONE USING HAPTICS. view more 

CREDIT: PHOTO: XPRIZE FOUNDATION

Team NimbRo from the University of Bonn has won the grand prize of five million US dollars at the ANA Avatar XPRIZE competition in Long Beach (USA). The final of the competition, sponsored by the Japanese airline All Nippon Airways (ANA) and hosted by the XPRIZE Foundation, featured 17 teams from ten countries who were selected from 99 registered research groups in a multi-stage qualification process. With a total of ten million US dollars in prize money, the ANA Avatar XPRIZE competition was the most highly endowed robotics competition to date.

The Bonn team had already fully convinced the international jury at the semifinals in Miami last September, where it scored the most points. The finals now took place in Long Beach, California. The aim of the ANA Avatar XPRIZE competition was to develop robotic systems with which people can virtually put themselves to another place. This works via an operator station and an avatar robot that are connected via the Internet. The avatar robot's sensors capture the environment, which is displayed in the operator station in such a way that the user has the feeling of being in the remote location. The user’s movements are captured and transferred to the avatar robot. This enables the user to move around, handle objects, use tools and communicate intuitively through speech, facial expressions and gestures.

Intuitive usability

In the competition, the avatar systems were not controlled by the developers, but by members of an international jury. They had only a few minutes to familiarize themselves with the system. "Therefore, intuitive usability was an important objective in system design," says Prof. Dr. Sven Behnke of Team NimbRo, who heads the Autonomous Intelligent Systems group at the University of Bonn.

At the finals, there was one qualification run and two competition runs on three consecutive days. In all three runs, the jury member was able to solve all ten tasks, which formed a mission that could be set on a distant planet. Tasks included communicating with a human, operating a switch, estimating the weight of objects, using a power drill, and blindly identifying a stone by the roughness of its surface. In addition to task performance, judges also evaluated the quality of the telepresence experience.

In the two competition runs, NimbRo received full points here as well. In case of identical scores, execution time was the deciding factor. With just under six minutes, NimbRo was almost twice as fast here as the second-best team "Pollen Robotics" from Bordeaux (France). For the best competition performance, NimbRo received the grand prize of five million US dollars. "My fantastic team developed a powerful avatar system for the complex tasks of the competition and successfully solved all problems that arose," said Prof. Behnke.

The NimbRo avatar

The NimbRo team's avatar system was developed over three years at the Autonomous Intelligent Systems group of the Institute of Computer Science VI – Intelligent Systems and Robotics at the University of Bonn, led by Prof. Dr. Sven Behnke. The avatar robot has a human-like upper body with two arms and five-finger hands. Attached to the head are a wide-angle stereo camera, a stereo microphone, and a display on which the user's face is animated. The remote scene is visualized to the user through 3D data glasses, with the user's head movements captured and transferred to the avatar head. This allows the user to look around freely, see around obstacles and view objects from different angles, which contributes significantly to the feeling of immersion in the remote environment. Stereo audio is also transmitted alongside the live video signals.

The user feels the interaction forces of the avatar hands via force-moment sensors in the wrist. Robotic arms sense the user's hand movements and relay them to the avatar arms. Hand exoskeletons mediate the finger movements. Gripping forces are sensed by finger motor currents and transmitted to the user's fingers. Haptic sensor measurements are transferred to the user's fingertips. The avatar robot can move in all directions and turn on the spot, with direction and speed controlled by a foot controller. Orientation is provided by cameras which create an all-round view from above. The data glasses are equipped with three cameras to capture eye movements and facial expressions of the user for a live facial animation displayed on the avatar robot's head display.

Beyond this competition, avatar systems have numerous applications. These include, for example, helping people in need of assistance to manage their daily lives, telemedicine, and use in inaccessible or hazardous environments. "Avatar systems have great potential to overcome spatial separation between people and could be as widespread in a few years as video conferencing systems are today," says Prof. Behnke.

Team NimbRo of the University of Bonn 

won the top prize at the finals of the ANA Avatar XPRIZE competition (from left to right, front: Max Schwarz, Christian Lenz; back: Andre Rochow, Bastian Pätzold, Prof. Dr. Sven Behnke, Michael Schreiber and Raphael Memmesheimer.

Not the developers, but jury members, controlled the avatar systems in the competition - here from team NimbRo.

There was a mission to master, 

which could take place on a distant planet.

Photo: University of Bonn

Videos of the final competition runs by Team NimbRo from the University of Bonn:
https://youtu.be/pxblVcN606E
https://youtu.be/8AwgGSpcAe8

Information about the avatar system: https://www.ais.uni-bonn.de/nimbro/AVATAR

Information about the competition: https://www.xprize.org/prizes/avatar

Contact:

Prof. Dr. Sven Behnke
University of Bonn
Institute for Computer Science VI - Intelligent Systems and Robotics
Email: behnke@cs.uni-bonn.de

National study suggests it’s time to rethink how we treat atrial fibrillation

Early intervention with catheter cryoablation can halt disease progression, reduce risk of serious health impacts

Peer-Reviewed Publication

UNIVERSITY OF BRITISH COLUMBIA

 

IMAGE: CRYOABLATION INVOLVES GUIDING A SMALL TUBE INTO THE HEART AND INFLATING A SMALL BALLOON TO KILL PROBLEMATIC TISSUE WITH COLD TEMPERATURES. view more 

CREDIT: MEDTRONIC

A national study led by UBC researchers at the Centre for Cardiovascular Innovation is shedding light on how to more effectively treat atrial fibrillation (AF) – a common heart rhythm problem associated with increased risk of stroke and heart failure.

The study, published today in The New England Journal of Medicine, shows that early intervention with cryoballoon catheter ablation (cryoablation) is more effective at reducing the risk of serious long-term health impacts, when compared to the current first step in treatment, antiarrhythmic drugs.

“By treating patients with cryoablation right from the start, we see fewer people advancing to persistent, more life-threatening forms of atrial fibrillation,” says Dr. Jason Andrade, an associate professor of medicine at UBC and director of Heart Rhythm Services at Vancouver General Hospital. “In the short term, this can mean less recurrences of arrhythmia, improved quality of life and fewer visits to the hospital. In the long run, this can translate into a reduced risk of stroke and other serious heart problems.”

Cryoablation is a minimally invasive procedure that involves guiding a small tube into the heart to kill problematic tissue with cold temperatures. Historically, the procedure has been reserved as a secondary treatment when patients don’t respond to antiarrhythmic drugs.

“This study adds to the growing body of evidence that early intervention with cryoablation may be a more effective initial therapy in the appropriate patients,” says Dr. Andrade.

Early intervention halts disease progression

AF affects approximately three per cent of the population, or more than one million Canadians.

While the condition starts as an isolated electrical disorder, each recurring incident can cause electrical and structural changes in the heart that can lead to longer-lasting events known as persistent AF (episodes lasting more than seven continuous days).

“Atrial fibrillation is like a snowball rolling down a hill. With each atrial fibrillation episode there are progressive changes in the heart, and the heart rhythm problem gets worse,” explains Dr. Andrade.

The new findings, stemming from a multi-site clinical trial, show that cryoablation can stop this snowball effect.

For the trial, the pan-Canadian research team enrolled 303 patients with AF at 18 sites across Canada. Half of the patients were randomly selected to receive antiarrhythmic drugs, while the other half were treated with cryoablation. All patients received an implantable monitoring device that recorded their cardiac activity throughout the study period.

After three years, the researchers found that patients in the cryoablation group were less likely to progress to persistent AF compared to patients treated with antiarrhythmic drugs. Over the follow-up period, the cryoablation patients also had lower rates of hospitalization and experienced fewer serious adverse health events that resulted in death, functional disability or prolonged hospitalization.

Addressing the root cause

Because cryoablation targets and destroys the cells that initiate and perpetuate AF, the researchers say it can lead to longer-lasting benefits.

“With cryoablation, we’re treating the cause of the condition, instead of using medications to cover-up the symptoms,” says Dr. Andrade. “If we start with cryoablation, we may be able to fix atrial fibrillation early in its course.”

The new study builds on a previous paper in which Dr. Andrade and his team demonstrated that cryoablation was more effective than antiarrhythmic drugs at reducing the short-term recurrence of atrial fibrillation.

The researchers say that more effective early interventions would benefit patients as well as the health care system. Currently, costs associated with the provision of atrial fibrillation-associated care are estimated at 2.5 per cent of overall annual health care expenditures. Those costs are expected to rise to four per cent within the next two decades.

“The evidence shows increasingly that it’s time to rethink how we approach the treatment of atrial fibrillation. With effective early intervention, we can keep people healthy, happy, and out of hospital, which would be a tremendous benefit for patients and their families, and also our entire health system.”

Interview language(s): English

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JOURNAL

New England Journal of Medicine

DOI

10.1056/NEJMoa2212540 

METHOD OF RESEARCH

Randomized controlled/clinical trial

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Progression of Atrial Fibrillation after Cryoablation or Drug Therapy

ARTICLE PUBLICATION DATE

7-Nov-2022

COI STATEMENT

https://www.nejm.org/doi/suppl/10.1056/NEJMoa2212540/suppl_file/nejmoa2212540_disclosures.pdf

Sea urchins keep on trucking while other marine life languishes in the Florida Keys

Peer-Reviewed Publication

FLORIDA MUSEUM OF NATURAL HISTORY

 

IMAGE: ONE OF THE MOST EXTENSIVE SURVEYS OF ECHINOIDS YET CONDUCTED IN THE FLORIDA KEYS SUGGESTS THAT SAND DOLLARS, HEART URCHINS AND SEA BISCUIT POPULATIONS HAVE REMAINED STABLE FOR THE LAST SEVERAL DECADES. view more 

CREDIT: IMAGES FROM GRUN AND KOWALEWSKI, 2022

In the summer of 2020, Florida Museum researchers Tobias Grun and Michał Kowalewski dove into the shallow waters off the coast of the Florida Keys and scoured the ocean floor for sea urchins. Telltale tracks and dimples in the sediment alerted them to the presence of sand dollars, sea biscuits and heart urchins concealed just beneath the surface.

Between August and April of the following year, Grun and Kowalewski visited 27 sites along a 20-mile stretch of coast near Long Key. By the time they finished, their sea urchin survey was among the most extensive conducted in the region for the last several decades, and their results offer a bit of good news.

The researchers published an analysis of their survey last week in the journal PeerJ, which shows the number and diversity of sand dollars, sea biscuits and heart urchins appears to have remained relatively stable since researchers began keeping tabs on their populations in the 1960s.

“It was a pleasant surprise to find that they’re still widespread and abundant,” said study co-author Kowalewski, the Florida Museum Thompson Chair of Invertebrate Paleontology. “The Florida Keys are heavily impacted by human activity, with fishing, tourism and diving all occurring on a massive scale. On top of that, coastal ecosystems are subject to climate change, increasingly strong hurricanes and escalating stressors resulting from continuous urban development.”

Sea urchins are essential for healthy marine ecosystems

Sea urchins are echinoderms, the name derived from a mix of Greek and Latin meaning “spiny skin.” They’re closely related to starfish, brittle stars, sea lilies and sea cucumbers, and they include two types: regular and irregular.

Sea urchins of the first type are spherical in shape and covered in a formidable network of spines, giving them the appearance of medieval morning stars. Each spine can be pointed in the direction of a threat and provides a measure of protection as they graze on algae in open seagrass meadows, mangrove shoals and coral reefs.

Irregular echinoids, which include sand dollars, sea biscuits and heart urchins, are the unsung Roombas of the seafloor. Unlike their prickly surface-dwelling relatives, most sand dollars and sea biscuits are burrowers, with short, locomotive spines they use to crawl and deposit food in grooves along their skin, which run like conveyer belts directly to their mouths. Others, such as the cake urchin (Meoma ventricosa), simply scoop up anything in their path.

As they tunnel their way through sand, silt and mud in an endless quest for food, they clean, ventilate and enrich the sediment, making it more hospitable to other organisms.

By changing the landscape, they function as ecosystem engineers, explained lead author Grun, a postdoctoral researcher at the Florida Museum. “They’re essential for maintaining healthy environments. They feed on detritus and help oxygenate the sediment, which allows microorganisms to degrade waste,” he said.

There are also a lot of them. In certain areas, irregular urchins can be among the most abundant animals by volume on the seafloor. This is especially true in the Gulf of Mexico and Caribbean Sea, where dozens of species inhabit sprawling shelf platforms.

Sand dollars and heart urchins stand the test of time in deteriorating environments

Despite their importance and abundance, sea urchins are often given short shrift when it comes to marine surveys. In the denuded Florida Keys, considerable effort has been extended to document the decline of coral, fish, seagrass and manatees, but only a handful of widescale sea urchin surveys have been carried out over the last 60 years.

According to a 2020 report by the National Oceanic and Atmospheric Administration, Florida’s coral reefs have become impaired in recent decades due to a combination of factors. Increased global temperatures have resulted in six mass coral bleaching events in South Florida since 1987, and in 2014, an outbreak of stony coral tissue loss disease was reported on reefs near Miami. The disease has spread every year since and now affects the entirety of Florida’s barrier reef, from Martin County in central Florida to the furthest tip of the Florida Keys.

Delicate seagrass meadows are additionally reeling from the combined effects of climate change, pollution and the reduced influx of freshwater from the Everglades; Florida’s mangrove forests are at risk from increasingly intense tropical weather events; and a 2022 study determined that, of 15 grouper and snapper species popular among recreational fisheries, 85% were being harvested past the point of sustainability in the Florida Keys.  

Given the paucity of available data on sea urchins, it was unclear how their populations may have fared amid the degradation of the surrounding ecosystems.

“One of the reasons we conduct these surveys is to get a better numerical understanding of how important and abundant these organisms are because right now, that documentation is spotty,” Kowalewski said.

Grun and Kowalewski caution that this survey offers only a small snapshot of sea urchin diversity in the Florida Keys. But if their results are at all indicative of nearby benthic habitats, then sand dollars, sea biscuits and heart urchins seem to have mostly evaded the negative consequences of environmental change.

Irregular urchins were present at the majority (63%) of surveyed sites, from sheltered seagrass meadows along the coastline to deeper mudflats on the far side of the barrier reef. When they found living urchins, they often noted the waferlike discs of dead individuals disintegrating in the sediment, a sign that populations may have persisted in place for multiple generations.

According to Grun, it’s hard to pinpoint exactly why sea urchins have remained unaffected, but he suspects the relative disregard people have for them might play a role. “These sea urchins are neither of commercial nor of recreational interest, and their sandy habitats are not often visited by fishers or divers,” he said.

Whether sea urchins in the Florida Keys will carry on unscathed as temperatures continue to rise and oceans become increasingly acidic remains an open question.

“We’re planning on looking more into the environmental factors that affect sea urchins, such as sediment and water composition, over the next years,” he said, stressing that the amount known about sea urchins is dwarfed by what’s left to be discovered. “We’re entering a new arena of research in which we’d really like to drive home the importance of these organisms and highlight their role as ecosystem engineers.”  

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JOURNAL

PeerJ

DOI

10.7717/peerj.14245 

ARTICLE TITLE

Spatial distribution, diversity, and taphonomy of clypeasteroid and spatangoid echinoids of the central Florida Keys

Neuron function is altered by the widely used anesthetic propofol

Rensselaer researchers found that propofol decreases intracellular transport

Peer-Reviewed Publication

RENSSELAER POLYTECHNIC INSTITUTE

 

IMAGE: DR. MARVIN BENTLEY view more 

CREDIT: RENSSELAER POLYTECHNIC INSTITUTE

Propofol is the most commonly used drug to induce general anesthesia. Despite its frequent clinical application, it is poorly understood how propofol causes anesthesia.

In a new study published in Molecular Biology of the Cell, a team of Rensselaer Polytechnic Institute researchers identified a previously unknown propofol effect in neurons. The study found that propofol exposure impacted the process by which neurons transport proteins, biomolecules that perform most cellular functions, to the cell surface.

Almost all animal cells, including human cells, are highly compartmentalized and rely on efficient movement of protein material between compartments. Proteins are moved from their site of synthesis to the location at which they perform their function in small carriers called “vesicles.” This transport must be efficient and highly specific to maintain cellular organization and function.

The research team was led by Dr. Marvin Bentley, an assistant professor in the Department of Biological Sciences, whose laboratory studies vesicle transport in neurons. Neurons are particularly reliant on vesicle transport because axons — which are often organized in nerve bundles — can span distances of up to 1 meter in humans. Errors in vesicle transport have been linked to neurodevelopmental and neurodegenerative diseases such as Alzheimer’s and Parkinson’s.

This new study found that propofol affects a family of proteins called kinesins. Kinesins are small “motor proteins” that move vesicles on tiny filaments called microtubules.

Dr. Bentley’s team observed that vesicle movement of two prominent kinesins, Kinesin-1 and Kinesin-3, was substantially reduced in cells exposed to propofol. The team then showed that propofol-induced transport delays led to a significant decrease of protein delivery to axons.

“The mechanism by which propofol works is not fully understood,” Bentley said. “What we discovered was unexpected: propofol altered the trafficking of vesicles in live neurons.”

Overall, the research contributes significantly to our understanding of how propofol works. Most studies that address the anesthetic mechanism of propofol have been focused on its interaction with an ion channel called the GABAA receptor, which inhibits neurotransmission when activated.

This new study demonstrates that vesicle transport is an additional mechanism that may be important for propofol’s anesthetic effect. Discovery of this new propofol effect has important applications for human health and may lead to the development of better anesthetic drugs.

“By using state-of-the-art live cell imaging technologies, Dr. Bentley’s team has furthered our understanding of the mechanism of action of a widely used drug that is already impacting human health on a daily basis,” said Curt M. Breneman, Dean of the School of Science. “Dr. Bentley’s research may pave the way for the development of related compounds that use these same mechanisms to target debilitating neurodegenerative diseases.”

In addition to Dr. Bentley, the study was co-authored by Dr. Susan P. Gilbert, Head of the Department of Biological Sciences at Rensselaer, and doctoral students Madeline Frank and Alec T. Nabb.

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JOURNAL

Molecular Biology of the Cell

DOI

10.1091/mbc.E22-07-0276 

SUBJECT OF RESEARCH

Cells

ARTICLE TITLE

Propofol attenuates kinesin-mediated axonal vesicle transport and fusion