Over 80% of Atlantic Rainforest remnants have been impacted by human activity

Researchers estimated biodiversity and biomass losses in the biome using data from 1,819 forest inventories. In terms of carbon storage, the losses correspond to the destruction of 70,000 km² of forest

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO

Research News

 

IMAGE: BIODIVERSITY AND BIOMASS LOSSES IN THE BIOME USING DATA FROM 1,819 FOREST INVENTORIES. IN TERMS OF CARBON STORAGE, THE LOSSES CORRESPOND TO THE DESTRUCTION OF 70,000 KM² OF FOREST, REPRESENTING... view more 

CREDIT: RENATO DE LIMA/USP

A Brazilian study published (http://www.nature.com/articles/s41467-020-20217-w) in Nature Communications shows that human activities have directly or indirectly caused biodiversity and biomass losses in over 80% of the remaining Atlantic Rainforest fragments.

According to the authors, in terms of carbon storage, the biomass erosion corresponds to the destruction of 70,000 square kilometers (km²) of forest - almost 10 million soccer pitches - or USD 2.3 billion-USD 2.6 billion in carbon credits. "These figures have direct implications for mechanisms of climate change mitigation," they state in the article.

Atlantic Rainforest remnants in Brazil are strung along its long coastline. The biome once covered 15% of Brazil, totaling 1,315,460 km². Only 20% of the original area is now left. The fragments are of varying sizes and have different characteristics.

To estimate the impact of human activity on these remnants, the researchers used data from 1,819 forest inventories conducted by several research groups.

"These inventories are a sort of tree census. The researchers go into the field and choose an area to survey, typically 100 meters by 100 meters. All the trees found within this perimeter are identified, analyzed, and measured," said Renato de Lima (https://bv.fapesp.br/en/pesquisador/668300/renato-augusto-ferreira-de-lima), a researcher at the University of São Paulo's Institute of Biosciences (IB-USP) and leader of the study. "We compiled all the data available in the scientific literature and calculated the average loss of biodiversity and biomass in the fragments studied, which represent 1% of the biome. We then used statistical methods to extrapolate the results to the fragments not studied, assuming that the impact would be constant throughout the Atlantic Rainforest biome."

After identifying the tree species in a fragment, the researchers estimated the size of their seeds and also what they call the "ecological or successional group". These two factors indicate how healthy the forest is, according to Lima. "There are hardy plants that require very little in the way of local resources and can grow on wasteland, pasture, forest borders, etc. These are known as pioneer species. A Brazilian example is the Ambay pumpwood [Cecropia pachystachya]," he said.

Pioneer tree species tend to produce seeds of smaller size, but in large numbers, because each seed has such a small chance of germinating. At the opposite extreme are climax species that flourish only in favorable environments, such as Brazilwood (Paubrasilia echinata) or various species of the genus Ocotea. These trees produce larger seeds with a substantial store of nutrients.

"This kind of seed requires a heavier investment by the parent tree in terms of energy," Lima said. "Areas in which climax species are present typically support more diversified fauna, so they serve as a marker of overall forest quality. Areas in which pioneer species predominate have probably been disturbed in the recent past."

The IB-USP group set out to show how the loss of late-successional species correlated with overall biodiversity loss and also with biomass loss, which represents the reduction in the forest's capacity to store carbon and keep this greenhouse gas out of the atmosphere. They found the forest fragments studied to have 25%-32% less biomass, 23%-31% fewer tree species, and 33%-42% fewer individuals belonging to late-successional, large-seeded, and endemic species.

The analysis also showed that biodiversity and biomass erosion were lower in strictly protected conservation units, especially large ones. "The smaller the forest fragment and the larger the edge area, the easier it is for people to gain access and disturb the remnant," Lima said.

On the positive side, degraded forest areas can recoup their carbon storage capacity if they are restored. "Combating deforestation and restoring totally degraded open areas such as pasturelands have been a major focus. These two strategies are very important, but we shouldn't forget the fragments in the middle," Lima said.

According to Paulo Inácio Prado (https://bv.fapesp.br/en/pesquisador/3487/paulo-inacio-de-knegt-lopez-de-prado), a professor at IB-USP and last author of the study, restored forest remnants can attract billions of dollars in investment relating to carbon credits. "Degraded forests should no longer be considered a liability. They're an opportunity to attract investment, create jobs and conserve what still remains of the Atlantic Rainforest," he said.

Lima believes this could be an attractive strategy for landowners in protected areas of the biome. "There's no need to reduce the amount of available arable land. Instead, we should increase the biomass in forest fragments, recouping part of the cost of restoration in the form of carbon credits," he said. "There will be no future for the Atlantic Rainforest without the owners of private properties. Only 9% of the remaining forest fragments are on state-owned land."

Database

According to Lima, the study began during his postdoctoral research, which was supported by São Paulo Research Foundation - FAPESP (https://bv.fapesp.br/en/bolsas/145695) and supervised by Prado. The aim was to identify the key factors that determine biodiversity and biomass loss in remnants of Atlantic Rainforest. "We found human action to be a major factor," he said. "We considered activities such as logging, hunting, and invasion by exotic species, as well as the indirect effects of forest fragmentation."

The data obtained from the 1,819 forest inventories used in the research is stored in a repository called TreeCo (http://labtrop.ib.usp.br/doku.php?id=projetos:treeco:start), short for Neotropical Tree Communities. Lima developed the database during his postdoctoral fellowship and still runs it. Its contents are described in an article published in Biodiversity and Conservation (https://link.springer.com/article/10.1007/s10531-015-0953-1). It is open to other research groups interested in sharing data on Neotropical forests.

"The repository became a byproduct of my postdoctoral project, and more than ten PhD and master's candidates are using it in their research," Lima said.

###

A Brazilian study published in Nature Communications shows that human activities have directly or indirectly caused biodiversity and biomass losses in over 80% of the remaining Atlantic Rainforest fragments.

According to the authors, in terms of carbon storage, the biomass erosion corresponds to the destruction of 70,000 square kilometers (km²) of forest – almost 10 million soccer pitches – or USD 2.3 billion-USD 2.6 billion in carbon credits. “These figures have direct implications for mechanisms of climate change mitigation,” they state in the article.

Atlantic Rainforest remnants in Brazil are strung along its long coastline. The biome once covered 15% of Brazil, totaling 1,315,460 km². Only 20% of the original area is now left. The fragments are of varying sizes and have different characteristics.

To estimate the impact of human activity on these remnants, the researchers used data from 1,819 forest inventories conducted by several research groups.

“These inventories are a sort of tree census. The researchers go into the field and choose an area to survey, typically 100 meters by 100 meters. All the trees found within this perimeter are identified, analyzed, and measured,” said Renato de Lima, a researcher at the University of São Paulo’s Institute of Biosciences (IB-USP) and leader of the study. “We compiled all the data available in the scientific literature and calculated the average loss of biodiversity and biomass in the fragments studied, which represent 1% of the biome. We then used statistical methods to extrapolate the results to the fragments not studied, assuming that the impact would be constant throughout the Atlantic Rainforest biome.”

After identifying the tree species in a fragment, the researchers estimated the size of their seeds and also what they call the “ecological or successional group”. These two factors indicate how healthy the forest is, according to Lima. “There are hardy plants that require very little in the way of local resources and can grow on wasteland, pasture, forest borders, etc. These are known as pioneer species. A Brazilian example is the Ambay pumpwood [Cecropia pachystachya],” he said.

Pioneer tree species tend to produce seeds of smaller size, but in large numbers, because each seed has such a small chance of germinating. At the opposite extreme are climax species that flourish only in favorable environments, such as Brazilwood (Paubrasilia echinata) or various species of the genus Ocotea. These trees produce larger seeds with a substantial store of nutrients.

“This kind of seed requires a heavier investment by the parent tree in terms of energy,” Lima said. “Areas in which climax species are present typically support more diversified fauna, so they serve as a marker of overall forest quality. Areas in which pioneer species predominate have probably been disturbed in the recent past.”

The IB-USP group set out to show how the loss of late-successional species correlated with overall biodiversity loss and also with biomass loss, which represents the reduction in the forest’s capacity to store carbon and keep this greenhouse gas out of the atmosphere. They found the forest fragments studied to have 25%-32% less biomass, 23%-31% fewer tree species, and 33%-42% fewer individuals belonging to late-successional, large-seeded, and endemic species.

The analysis also showed that biodiversity and biomass erosion were lower in strictly protected conservation units, especially large ones. “The smaller the forest fragment and the larger the edge area, the easier it is for people to gain access and disturb the remnant,” Lima said.

On the positive side, degraded forest areas can recoup their carbon storage capacity if they are restored. “Combating deforestation and restoring totally degraded open areas such as pasturelands have been a major focus. These two strategies are very important, but we shouldn’t forget the fragments in the middle,” Lima said.

According to Paulo Inácio Prado, a professor at IB-USP and last author of the study, restored forest remnants can attract billions of dollars in investment relating to carbon credits. “Degraded forests should no longer be considered a liability. They’re an opportunity to attract investment, create jobs and conserve what still remains of the Atlantic Rainforest,” he said.

Lima believes this could be an attractive strategy for landowners in protected areas of the biome. “There’s no need to reduce the amount of available arable land. Instead, we should increase the biomass in forest fragments, recouping part of the cost of restoration in the form of carbon credits,” he said. “There will be no future for the Atlantic Rainforest without the owners of private properties. Only 9% of the remaining forest fragments are on state-owned land.”

Database

According to Lima, the study began during his postdoctoral research, which was supported by FAPESP and supervised by Prado. The aim was to identify the key factors that determine biodiversity and biomass loss in remnants of Atlantic Rainforest. “We found human action to be a major factor,” he said. “We considered activities such as logging, hunting, and invasion by exotic species, as well as the indirect effects of forest fragmentation.”

The data obtained from the 1,819 forest inventories used in the research is stored in a repository called TreeCo, short for Neotropical Tree Communities. Lima developed the database during his postdoctoral fellowship and still runs it. Its contents are described in an article published in Biodiversity and Conservation. It is open to other research groups interested in sharing data on Neotropical forests.

“The repository became a byproduct of my postdoctoral project, and more than ten PhD and master’s candidates are using it in their research,” Lima said.

###

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 http://www.fapesp.br/en and visit FAPESP news agency at http://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.

POSTMODERN PARACELUS ALCHEMY 

'Miracle poison' for novel therapeutics

Researchers prove they can engineer botulinum toxin proteins to find new targets with high selectivity, a critical advance toward potential new treatments for everything from neuroregeneration to cytokine storm

HARVARD UNIVERSITY

Research News

 

IMAGE: ENGINEERED BOTULINUM TOXIN COULD LEAD TO NEW TREATMENTS FOR A RANGE OF MALADIES, INCLUDING NERVE AND BRAIN DAMAGE, MUSCLE INJURY, AND RAMPANT INFLAMMATION. view more 

CREDIT: THE LIU LAB

When people hear botulinum toxin, they often think one of two things: a cosmetic that makes frown lines disappear or a deadly poison.

But the "miracle poison," as it's also known, has been approved by the F.D.A. to treat a suite of maladies like chronic migraines, uncontrolled blinking, and certain muscle spasms. And now, a team of researchers from Harvard University and the Broad Institute have, for the first time, proved they could rapidly evolve the toxin in the laboratory to target a variety of different proteins, creating a suite of bespoke, super-selective proteins called proteases with the potential to aid in neuroregeneration, regulate growth hormones, calm rampant inflammation, or dampen the life-threatening immune response called cytokine storm.

"In theory, there is a really high ceiling for the number and type of conditions where you could intervene," said Travis Blum, a postdoctoral researcher in the Department of Chemistry and Chemical Biology and first author on the study published in Science. The study was the culmination of a collaboration with Min Dong, an associate professor at the Harvard Medical School, and David Liu, the Thomas Dudley Cabot Professor of the Natural Sciences, a Howard Hughes Medical Institute Investigator, and a core faculty member of the Broad Institute.

Together, the team achieved two firsts: They successfully reprogrammed proteases--enzymes that cut proteins to either activate or deactivate them--to cut entirely new protein targets, even some with little or no similarity to the native targets of the starting proteases, and to simultaneously avoid engaging their original targets. They also started to address what Blum called a "classical challenge in biology": designing treatments that can cross into a cell. Unlike most large proteins, botulinum toxin proteases can enter neurons in large numbers, giving them a wider reach that makes them all the more appealing as potential therapeutics.

Now, the team's technology can evolve custom proteases with tailor-made instructions for which protein to cut. "Such a capability could make 'editing the proteome' feasible," said Liu, "in ways that complement the recent development of technologies to edit the genome."

Current gene-editing technologies often target chronic diseases like sickle cell anemia, caused by an underlying genetic error. Correct the error, and the symptoms fade. But some acute illnesses, like neurological damage following a stroke, aren't caused by a genetic mistake. That's where protease-based therapies come in: The proteins can help boost the body's ability to heal something like nerve damage through a temporary or even one-time treatment.

Scientists have been eager to use proteases to treat disease for decades. Unlike antibodies, which can only attack specific alien substances in the body, proteases can find and attach to any number of proteins, and, once bound, can do more than just destroy their target. They could, for example, reactivate dormant proteins.

"Despite these important features, proteases have not been widely adopted as human therapeutics," said Liu, "primarily because of the lack of a technology to generate proteases that cleave protein targets of our choosing."

But Liu has a technological ace in his pocket: PACE (which stands for phage-assisted continuous evolution). A Liu lab invention, the platform rapidly evolves novel proteins with valuable features. PACE, Liu said, can evolve dozens of generations of proteins a day with minimal human intervention. Using PACE, the team first taught so-called "promiscuous" proteases--those that naturally target a wide swath of proteins--to stop cutting certain targets and become far more selective. When that worked, they moved on to the bigger challenge: Teaching a protease to only recognize an entirely new target, one outside its natural wheelhouse.

"At the outset," said Blum, "we didn't know if it was even feasible to take this unique class of proteases and evolve them or teach them to cleave something new because that had never been done before." ("It was a moonshot to begin with," said Michael Packer, a previous Liu lab member and an author on the paper). But the proteases outperformed the team's expectations. With PACE, they evolved four proteases from three families of botulinum toxin; all four had no detected activity on their original targets and cut their new targets with a high level of specificity (ranging from 218- to more than 11,000,000-fold). The proteases also retained their valuable ability to enter cells. "You end up with a powerful tool to do intracellular therapy," said Blum. "In theory."

"In theory" because, while this work provides a strong foundation for the rapid generation of many new proteases with new capabilities, far more work needs to be done before such proteases can be used to treat humans. There are other limitations, too: The proteins are not ideal as treatments for chronic diseases because, over time, the body's immune system will recognize them as alien substances and attack and defuse them. While botulinum toxin lasts longer than most proteins in cells (up to three months as opposed to the typical protein lifecycle of hours or days), the team's evolved proteins might end up with shorter lifetimes, which could diminish their effectiveness.

Still, since the immune system takes time to identify foreign substances, the proteases could be effective for temporary treatments. And, to side-step the immune response, the team is also looking to evolve other classes of mammalian proteases since the human body is less likely to attack proteins that resemble their own. Because their work on botulinum toxin proteases proved so successful, the team plans to continue to tinker with those, too, which means continuing their fruitful collaboration with Min Dong, who not only has the required permission from the Centers for Disease Control (CDC) to work with botulinum toxin but provides critical perspective on the potential medical applications and targets for the proteases.

"We're still trying to understand the system's limitations, but in an ideal world," said Blum, "we can think about using these toxins to theoretically cleave any protein of interest." They just have to choose which proteins to go after next.

###

Salmon scales reveal substantial decline in wild salmon population & diversity

Researchers from Simon Fraser University analyzed 100-year-old salmon scales to assess the health of wild salmon populations

SIMON FRASER UNIVERSITY

Research News

 

IMAGE: THE COLLECTION OF 100-YEAR-OLD WILD SALMON SCALES FROM THE SKEENA RIVER. view more 

CREDIT: MICHAEL PRICE

The diversity and numbers of wild salmon in Northern B.C. have declined approximately 70 per cent over the past century, according to a new Simon Fraser University study.

Researchers drawing on 100-year-old salmon scales report that recent numbers of wild adult sockeye salmon returning to the Skeena River are 70 per cent lower than 100 years ago. Wild salmon diversity in the Skeena watershed has similarly declined by 70 per cent over the last century.

The research undertaken by Simon Fraser University (SFU) and Fisheries and Oceans Canada was published today in the Journal of Applied Ecology.

The research team applied modern genetic tools to salmon scales collected from commercial fisheries during 1913-1947 to reconstruct historical abundance and diversity of populations for comparison with recent information.

The analysis revealed that Canada's second largest salmon watershed - the Skeena River - once hosted a diverse sockeye salmon portfolio composed of many populations that fluctuated from year to year, yet overall remained relatively stable. However, the Skeena sockeye portfolio has largely eroded over the last century, such that it now is dominated by a single population that primarily is supported by artificial production from spawning channels.

"Our study provides a rare example of the extent of erosion of within-species biodiversity over the last century of human influence," says Michael Price, an SFU PhD candidate and lead author. "That loss in abundance and diversity from wild populations has weakened the adaptive potential for salmon to survive and thrive in an increasingly variable environment influenced by climate change."

Life-cycle diversity also has shifted: populations are migrating from freshwater at an earlier age, and spending more time in the ocean.

"Rebuilding a diversity of abundant wild populations - that is, maintaining functioning portfolios - should help ensure that important salmon watersheds like the Skeena are robust to global change," says John Reynolds, co-author, SFU professor, and Tom Buell BC Leadership Chair in Aquatic Conservation.

This research can help inform status assessments and rebuilding plan discussions for threatened salmon populations by expanding our understanding of historical diversity and production potential.

CAPTION

Wild sockeye salmon in the river.

HERE COMES SPRING COVID GARDENING

Pioneering research reveals gardens are secret powerhouse for pollinators

UNIVERSITY OF BRISTOL

Research News

 

IMAGE: RESIDENTIAL GARDENS UNDERPIN THE URBAN NECTAR SUPPLY, AND MANY CAN BE EXTREMELY RICH IN FLOWERING PLANTS. view more 

CREDIT: NICHOLAS TEW

Home gardens are by far the biggest source of food for pollinating insects, including bees and wasps, in cities and towns, according to new research.

The study, led by the University of Bristol and published today in the Journal of Ecology, measured for the first time how much nectar is produced in urban areas and discovered residential gardens accounted for the vast majority - some 85 per cent on average.

Results showed three gardens generated daily on average around a teaspoon of Nature's ambrosia, the unique sugar-rich liquid found in flowers which pollinators drink for energy. While a teaspoon may not sound much to humans, it's the equivalent to more than a tonne to an adult human and enough to fuel thousands of flying bees. The more bees and fellow pollinators can fly, the greater diversity of flora and fauna will be maintained.

Ecologist Nicholas Tew, lead author of the study, said: "Although the quantity and diversity of nectar has been measured in the countryside, this wasn't the case in urban areas, so we decided to investigate.

"We expected private gardens in towns and cities to be a plentiful source of nectar, but didn't anticipate the scale of production would be to such an overwhelming extent. Our findings highlight the pivotal role they play in supporting pollinators and promoting biodiversity in urban areas across the country."

The research, carried out in partnership with the universities of Edinburgh and Reading and the Royal Horticultural Society, examined the nectar production in four major UK towns and cities: Bristol, Edinburgh, Leeds, and Reading. Nectar production was measured in nearly 200 species of plant by extracting nectar from more than 3,000 individual flowers. The extraction process involves using a fine glass tube. The sugar concentration of the nectar was quantified with a refractometer, a device which measures how much light refracts when passing through a solution.

"We found the nectar supply in urban landscapes is more diverse, in other words comes from more plant species, than in farmland and nature reserves, and this urban nectar supply is critically underpinned by private gardens," said Nicholas Tew, who is studying for a PhD in Ecology.

CAPTION

Even balconies and window boxes in densely urban regions can provide food for pollinators.

CREDIT

Nicholas Tew

"Gardens are so important because they produce the most nectar per unit area of land and they cover the largest area of land in the cities we studied."

Nearly a third (29 per cent) of the land in urban areas comprised domestic gardens, which is six times the area of parks, and 40 times the area of allotments.

"The research illustrates the huge role gardeners play in pollinator conservation, as without gardens there would be far less food for pollinators, which include bees, wasps, butterflies, moths, flies, and beetles in towns and cities. It is vital that new housing developments include gardens and also important for gardeners to try to make sure their gardens are as good as possible for pollinators," Nicholas Tew explained.

"Ways to do this include planting nectar-rich flowers, ensuring there is always something in flower from early spring to late autumn, mowing the lawn less often to let dandelions, clovers, daisies and other plant flowers flourish, avoiding spraying pesticides which can harm pollinators, and avoiding covering garden in paving, decking or artificial turf."

Dr Stephanie Bird, an entomologist at the Royal Horticultural Society, which helped fund the research, said: "This research highlights the importance of gardens in supporting our pollinating insects and how gardeners can have a positive impact through their planting decisions. Gardens should not be seen in isolation - instead they are a network of resources offering valuable habitats and provisions when maintained with pollinators in mind."

CAPTION

One way to help pollinators (even in a small garden) is to allow part of your lawn to grow into meadow.

CREDIT

Paper

'Quantifying nectar production by flowering plants in urban and rural landscapes' by N.E.Tew et al in Journal of Ecology

Notes to editors

A range of images, including caption and credit details, can be found here:

https://drive.google.com/drive/folders/1P8BZDDB7Ry1UW5RxASd2KihVypQpMotf?usp=sharing

Nicholas Tew is available for interview. For interview requests and any other related enquiries, please email: Nicholas.tew@bristol.ac.uk and/or Victoria.tagg@bristol.ac.uk

New shape-changing 4D materials hold promise for morphodynamic tissue engineering

Shape-changing scaffold for tissue engineering

UNIVERSITY OF ILLINOIS AT CHICAGO

Research News

IMAGE: THE 4D MATERIAL CHANGES SHAPE IN RESPONSE TO WATER. THE GREY SIDE OF THE MATERIAL IN THE IMAGE ABSORBS WATER FASTER THAN THE BLUE SIDE, CAUSING IT TO BEND INTO... view more 

CREDIT: YU BIN LEE

New hydrogel-based materials that can change shape in response to psychological stimuli, such as water, could be the next generation of materials used to bioengineer tissues and organs, according to a team of researchers at the University of Illinois Chicago.

In a new paper published in the journal Advanced Functional Materials, the research team -- led by Eben Alsberg, the Richard and Loan Hill Professor of Biomedical Engineering -- that developed the substances show that the unique materials can curl into tubes in response to water, making the materials good candidates for bioengineering blood vessels or other tubular structures.

In nature, embryonic development and tissue healing often involve a high concentration of cells and complex architectural and organizational changes that ultimately give rise to final tissue morphology and structure.

For tissue engineering, traditional techniques have involved, for example, culturing biodegradable polymer scaffolds with cells in biochambers filled with liquid nutrients that keep the cells alive. Over time, when provided with appropriate signals, the cells multiply in number and produce new tissue that takes on the shape of the scaffold as the scaffold degrades. For example, a scaffold in the shape of an ear seeded with cells capable of producing cartilage and skin tissue may eventually become a transplantable ear.

However, a geometrically static scaffold cannot enable the formation of tissues that dynamically change shape over time or facilitate interactions with neighboring tissues that change shape. A high density of cells is also typically not used and/or supported by the scaffolds.

"Using a high density of cells can be advantageous in tissue engineering as this enables increased cell-cell interactions that can promote tissue development," said Alsberg, who also is professor of orthopaedics, pharmacology and mechanical and industrial engineering at UIC.

Enter 4D materials, which are like 3D materials, but they change shape when they are exposed to specific environmental cues, such as light or water. These materials have been eyed by biomedical engineers as potential new structural substrates for tissue engineering, but most currently available 4D materials are not biodegradable or compatible with cells.

To take advantage of the promise of 4D materials for bioengineering applications, Alsberg and colleagues developed novel 4D materials based on gelatin-like hydrogels that change shape over time in response to the addition of water and are cell-compatible and biodegradable, making them excellent candidates for advanced tissue engineering. The hydrogels also support very high cell densities, so they can be heavily seeded with cells.

In the paper, the researchers describe how exposure to water causes the hydrogel scaffolds to swell as the water is absorbed. The amount of swelling can be tuned by, for example, changing aspects of the hydrogel material such as its degradation rate or the concentration of cross-linked polymers -- strands of protein or polysaccharide in this case -- that comprise the hydrogels. The higher the polymer concentration and crosslinking, the less and more slowly a given hydrogel will absorb water to induce a change in shape.

The researchers found that by layering hydrogels with different properties like a stack of paper, the difference in water absorption between the layers will cause the hydrogel stack to bend into a 'C' shaped conformation. If the stack bends enough, a tubular shape is formed, which resembles structures like blood vessels and other tubular organs.

They also found that it is possible to calibrate the system to control the timing and the extent of shape change that occurred. The researchers were able to embed bone marrow stem cells into the hydrogel at very high density -- the highest density of cells ever recorded for 4D materials -- and keep them alive, a significant advance in bioengineering that has practical applications.

In the paper, the researchers described how the shape-changing cell-laden hydrogel could be induced to become bone- and cartilage-like tissues. 4D bioprinting of this hydrogel was also implemented to obtain unique configurations to achieve more complex 4D architectures.

"Using our bilayer hydrogels, we can not only control how much bending the material undergoes and its temporal progression, but because the hydrogels can support high cell densities, they more closely mimic how many tissues form or heal naturally," said Yu Bin Lee, a biomedical engineering postdoctoral researcher and first author on the paper. "This system holds promise for tissue engineering, but may also be used to study the biological processes involved in early development."

###

UIC's Oju Jeon, Sang Jin Lee, Aixiang Ding and Derrick Wells are co-authors on the paper.

This research was supported by grants from the National Institutes of Health's National Institute of Arthritis And Musculoskeletal and Skin Diseases (R01AR069564, R01AR066193) and the National Institute of Biomedical Imaging and Bioengineering (R01EB023907).

Bearded seals are loud -- but not loud enough

Vocal threshold may hamper survival of this Arctic species

CORNELL UNIVERSITY

Research News

 

IMAGE: BEARDED SEAL ON ICE view more 

CREDIT: MICHAEL CAMERON, NOAA

Ithaca, NY-- During mating season, male bearded seals make loud calls to attract a mate--even their "quiet" call could still be as ear-rattling as a chainsaw. Bearded seals have to be loud to be heard over the cacophony of their equally loud brethren. And, increasingly, the noise humans make is adding to the underwater din and could have serious consequences. A study conducted by the Cornell Lab of Ornithology's Center for Conservation Bioacoustics (CCB) aims to understand how resilient bearded seals can be to changes in ambient underwater noise. The results are published in Proceedings of the Royal Society: Biological Science.

"We wanted to know whether bearded seals would call louder when their habitat grew noisy from natural sound sources," says CCB postdoctoral research associate Michelle Fournet who led the study. "The goal was to determine if there was a 'noise threshold' beyond which seals either couldn't-or wouldn't-call any louder in order to heard. By identifying this naturally occurring threshold, we can make conservation recommendations about how loud is too loud for human activities.'

From spring through early summer, the under-ice habitat near Utqiagvik, Alaska, is flooded with the vocalizations of male bearded seals--a sound that can be best described as "otherworldly." These elaborate vocalizations are essential for bearded seal reproduction, but in the rapidly changing Arctic soundscape, where noise from industrial activities is predicted to dramatically increase in the next 15 years, bearded seals may need to adjust their calling behavior if they are going to be heard above the noise generated by ships and commercial activities. But the bearded seals can only do so much.

Fournet and colleagues listened to thousands of recorded bearded seal vocalizations from Arctic Alaska spanning a two-year period. Each call was carefully measured and compared to the concurrent ambient noise conditions. What they found is that bearded seals do call louder as their underwater acoustic habitat gets noisier, but there is an upper limit to this behavior. As expected, when ambient noise gets too high, bearded seals are no longer able to compensate in order to be heard. As a result, as ambient noise conditions increase, the distance over which individuals can be detected goes down.

CAPTION

Bearded seal

Bearded seal [audio] | EurekAlert! Science News

"Given that these are reproductive calls, it is likely that the seals are already calling as close to as loudly as possible-the males very much want to be heard by the females," Fournet says. "So, it is unsurprising that there is an upper limit. I'm grateful that we have been able to identify that limit so we can make responsible management choices moving forward."

While this work has intrinsic conservation value, a major impetus for pursuing this research is the value of bearded seals-or ugruk in the Inupiaq language-to Alaska Native communities in the high Arctic. Bearded seals are at the center of subsistence and cultural activities in Inupiaq communities. Threats to bearded seals are by extension threats to the communities that rely on them.

"This work never would have happened without the insight and guidance of Arctic communities," Fournet says. "It was their energy that led the Cornell Lab to place hydrophones in the water. It is our job to continue listening."

###

Reference: Michelle E. H. Fournet, Margherita Silvestri, Christopher W. Clark, Holger Klinck, and Aaron N. Rice. Limited vocal compensation for elevated ambient noise in bearded seals: implications for an industrializing Arctic Ocean. Proceedings of the Royal Society B. February 2021.

Study finds human-caused North Atlantic right whale deaths are being undercounted

As recent sightings of entangled whales raise alarm, scientists say annual counts of right whale carcasses do a poor job of indicating true death toll

NEW ENGLAND AQUARIUM

Research News

 

IMAGE: CATALOG #3522 SWIMS OFF THE COAST OF GEORGIA IN 2006 WITH FRESH PROPELLER CUTS ON HIS BACK. HE WAS NEVER SEEN AGAIN AND IS PRESUMED DEAD DUE TO THESE INJURIES. view more 

CREDIT: NEW ENGLAND AQUARIUM, COLLECTED UNDER NOAA PERMIT #655-1652-01

A study co-authored by scientists at the New England Aquarium has found that known deaths of critically endangered North Atlantic right whales represent a fraction of the true death toll. This comes as the death of a calf and recent sightings of entangled right whales off the southeastern United States raise alarm.

The study, published this month in Conservation Science and Practice, analyzed cryptic mortality of right whales. Cryptic mortality refers to deaths resulting from human activities that do not result in an observed carcass. The study's authors combined data on whale encounters, animal health, serious injuries, and necropsies from the North Atlantic Right Whale Consortium Identification Database curated by the New England Aquarium with the serious injury and mortality database held by the National Marine Fisheries Service. The scientists concluded that known deaths of the critically endangered species accounted for only 36% of all estimated death from 1990 to 2017.

"Our work has shown that 83% of identified right whales have been entangled one or more times in fishing gear, and an increasing number of these events result in severe injuries or complex entanglements that the whales initially survive. But we know their health becomes compromised and they eventually succumb and sink upon death," said Amy Knowlton, senior scientist with the Aquarium's Anderson Cabot Center for Ocean Life.

The study--led by Richard Pace and Rob Williams and co-authored by Knowlton, New England Aquarium Associate Scientist Heather Pettis, and Aquarium Emeritus Scientist Scott Kraus--determined that several factors interact to cause undercounting of human-caused mortalities of marine mammals. First, in order for a human-caused mortality to be determined, a whale carcass must float or strand, be detected before decomposition or scavenging occurs, be evaluated to determine cause of death, and then have that result reported. In the absence of any of these steps, information about the cause of mortality can easily be lost.

Additionally, a number of right whales have been observed entangled or injured from vessel strikes and never seen again. This suggests they died and their carcasses were not discovered.

"We have long known that the number of detected right whale carcasses does not align with the number of whales that disappear from the sightings records," Pettis said. "Since 2013 alone, we have documented 40 individual right whales seen with severe injuries resulting from vessel strikes and entanglements that disappeared following their injury. This study allowed us to quantify just how underrepresented true right whale mortalities are when we rely on observed carcasses alone."

The estimated population number for North Atlantic right whales stands at just over 350 whales. Right whales are one of the most endangered large whale species in the world, facing serious ongoing threats from vessels and fishing gear. Just in the past month, a right whale calf died in an apparent vessel strike and two right whales have been spotted entangled in fishing gear. A sport fishing boat hit and killed the calf in the calving grounds off the Florida coast on February 12. The calf was the first born to Infinity (Catalog #3230), who also suffered injuries consistent with a vessel strike. Catalog #1803, a 33-year-old male, was seen badly entangled off the coast of Georgia and Florida in mid-January, and on February 18, Cottontail (Catalog #3920) was sighted entangled and emaciated off the Florida coast. Cottontail, an 11-year-old male, was first seen entangled in southern New England last fall. In both cases, disentanglement efforts were not successful and these whales will likely die.

"These serious entanglements are preventable with regulatory changes and a commitment from the fishing industry and the U.S. and Canadian governments to do more to address this threat," said Knowlton.

For 40 years, the Aquarium's Right Whale Research Program has extensively studied this critically endangered species. Scientists focus on solutions-based work, collaborating with fishermen on new techniques to reduce deadly entanglements in fishing gear, facilitating communication across the maritime industry to reduce vessel strikes, and working with lawmakers locally, nationally, and internationally to develop science-based protections for the whales.

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UM scientists achieve breakthrough in culturing corals and sea anemones cells

UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE & ATMOSPHERIC SCIENCE

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IMAGE: POCILLOPORA DAMICORNIS FROM SABOGA ISLAND, PANAMA GROWING IN THE CNIDARIAN IMMUNITY LAB AT THE ROSENSTIEL SCHOOL view more 

CREDIT: MIKE CONNELLY

MIAMI--Researchers have perfected the recipe for keeping sea anemone and coral cells alive in a petri dish for up to 12 days. The new study, led by scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, has important applications to study everything from evolutionary biology to human health.

Cnidarians are emerging model organisms for cell and molecular biology research. Yet, successfully keeping their cells in a laboratory setting has proved challenging due to contamination from the many microorganisms that live within these marine organisms or because the whole tissue survive in a culture environment.

UM cell biologist Nikki Traylor-Knowles and her team used two emerging model organisms in developmental and evolutionary biology--the starlet sea anemone (Nematostella vectensis) and cauliflower coral (Pocillopora damicornis)--to find more successful way to grow these cell cultures in a laboratory setting.

James Nowotny, a recent UM graduate mentored by Traylor-Knowles at the time, tested 175 cell cultures from the two organisms and found that their cells can survive for on average 12 days if they receive an antibiotic treatment before being cultured.

"This is a real breakthrough," said Traylor Knowles, an assistant professor of marine biology and ecology at the UM Rosenstiel School. "We showed that if you treat the animals beforehand and prime their tissues, you will get a longer and more robust culture to study the cell biology of these organisms."

"This is the first time that individual cells from all tissues of coral or sea anemones were shown to survive in cell culture for over 12 days," said Nowotny, who is currently a graduate student at the University of Maryland.

There are over 9,000 species in the phylum Cnidaria, which includes jellyfish, sea anemones, corals, Hydra, and sea fans. Due to several special unique attributes such as radial symmetry, a stinging cell known as a nematocyte and two-dermal cell layer, there is growing interest in using these animals to study key aspects of animal development.

"We can also now grow coral cells and use them in experiments that will help improve our understanding of their health in a very targeted way," said Traylor-Knowles.

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The study, titled "Novel Methods to Establish Whole-Body Primary Cell Cultures for the Cnidarians Nematostella vectensis and Pocillopora damicornis," was published in the Feb. 18 issue of the journal Scientific Reports. The authors include: Nikki Traylor-Knowles, James Nowotny and Michael Connelly from the UM Rosenstiel School. The study was funded through the National Science Foundation (award # 1951826) and Revive and Restore Catalyst Science Fund.