Hexbyte Glen Cove Discovered: How ladybugs stick to surfaces without losing legs at takeoff thumbnail

Hexbyte Glen Cove Discovered: How ladybugs stick to surfaces without losing legs at takeoff

Hexbyte Glen Cove

Figure 1. Ladybird beetle on a glass surface. Its white tarsal setae can be seen in contact with the surface. Credit: National Institute for Materials Science

NIMS, the University of Tokyo and the University of Kiel have jointly ascertained the tarsal adhesion mechanisms employed by ladybird beetles, which had been debated for decades.

Strong adhesives are commonly used to firmly bond materials together. Their use hinders recycling—one of our efforts to build a sustainable society—by making it more difficult to disassemble and sort waste products. Efforts are therefore underway to develop new, environmentally friendly adhesive technologies that have high bonding strength but are also easier to detach. Some scientists in biomimetics have been studying the ability of reptiles and insects to easily walk on ceilings and walls by quickly and repeatedly attaching and detaching their tarsi to and from these surfaces. This research team has been researching and developing new adhesive technologies using the efficient tarsal functions of ladybird beetles as a model. This beetle is capable of walking on glassy, smooth surfaces without slipping despite the fact that the portion of its tarsi which comes into contact with the surface is covered with rigid setae. This portion of the tarsi also secretes fluid. Based on these observations, two potential tarsal adhesion mechanisms had been proposed: a mechanism involving intermolecular forces of attraction between tarsal setae and the walking surface and another mechanism involving the of the secreted tarsal fluid. The debate over which was correct remained unresolved for 40 years.

This research team recently succeeded in measuring the thickness of the tarsal fluid layer formed between the setal tips of a ladybird beetle and the glass surface on which the beetle was placed, under the presumption that this thickness indicates the strength of the intermolecular of attraction between the tarsi and the surface. To make this measurement, the team first formed an AuPd particle layer 10 to 20 nm in thickness on the glass surface. The beetle was then placed on the coated surface and allowed to secrete tarsal fluid. The tarsal fluid was then instantaneously frozen while the beetle’s legs were still resting on the coated surface. The legs were then detached from the surface and the height of the AuPd particle layer filled with the frozen tarsal fluid was measured under a Cryo-SEM microscope. As a result, the thickness of the tarsal layer (i.e., the distance between the setal tips of the beetle and the glass ) was found to be sufficiently narrow for intermolecular forces of attraction to act effectively. The team then measured traction forces of ladybird beetles walking on the surfaces of various substrates using a combination of biomimetic and materials science techniques in order to determine the relative contributions of intermolecular forces and other adhesion forces. Intermolecular forces are known to be correlated with work of adhesion (WA), the amount of energy required to separate two connected surfaces of different materials. The correlation between WA and traction forces was therefore examined by fitting experimental data into a mathematical formula describing the relationship between these two parameters. As a result, the tarsal adhesion force of the beetle was found to be correlated with WA, indicating that intermolecular forces (i.e., van der Waals forces) are the primary force involved in the tarsal adhesion of ladybird beetles.

In future studies, the team plans to apply these results to the development of artificial structures capable of attaching and detaching themselves to and from various substrates. These structures may be used in the feet of disaster relief robots capable of traveling on various surfaces in a manner similar to ladybird beetles. They also may be integrated into devices designed to replace parts within high-precision equipment.

This research was published in the April 8, 2021 issue of Scientific Reports.



More information:
Naoe Hosoda et al, Evidence for intermolecular forces involved in ladybird beetle tarsal setae adhesion, Scientific Reports (2021). DOI: 10.1038/s41598-021-87383-9

Citation:
Discovered: How ladybugs stick to surfaces without losing legs at takeoff (2021, June 23)
retrieved 23 June 2021

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Hexbyte Glen Cove First clear view of a boiling cauldron where stars are born thumbnail

Hexbyte Glen Cove First clear view of a boiling cauldron where stars are born

Hexbyte Glen Cove

The RCW 49 galactic nebula pictured above is one of the brightest star-forming regions in the Milky Way. By analyzing the movement of carbon atoms in an expanding bubble of gas surrounding the Westerlund 2 star cluster within RCW 49, a UMD-led team of researchers have created the clearest image to date of a stellar-wind driven bubble where stars are born. Credit: NASA/JPL-Caltec/E.Churchwell (University of Wisconsin).

University of Maryland researchers created the first high-resolution image of an expanding bubble of hot plasma and ionized gas where stars are born. Previous low-resolution images did not clearly show the bubble or reveal how it expanded into the surrounding gas.

The researchers used data collected by the Stratospheric Observatory for Infrared Astronomy (SOFIA) telescope to analyze one of the brightest, most massive star-forming regions in the Milky Way galaxy. Their analysis showed that a single, expanding bubble of warm gas surrounds the Westerlund 2 and disproved earlier studies suggesting there may be two bubbles surrounding Westerlund 2. The researchers also identified the source of the bubble and the energy driving its expansion. Their results were published in The Astrophysical Journal on June 23, 2021.

“When form, they blow off much stronger ejections of protons, electrons and atoms of heavy metal, compared to our sun,” said Maitraiyee Tiwari, a postdoctoral associate in the UMD Department of Astronomy and lead author of the study. “These ejections are called , and extreme stellar winds are capable of blowing and shaping bubbles in the surrounding clouds of cold, dense gas. We observed just such a bubble centered around the brightest cluster of stars in this region of the galaxy, and we were able to measure its radius, mass and the speed at which it is expanding.”

The surfaces of these expanding bubbles are made of a dense gas of ionized carbon, and they form a kind of outer around the bubbles. New stars are believed to form within these shells. But like soup in a boiling cauldron, the bubbles enclosing these star clusters overlap and intermingle with clouds of surrounding gas, making it hard to distinguish the surfaces of individual bubbles.

Tiwari and her colleagues created a clearer picture of the bubble surrounding Westerlund 2 by measuring the radiation emitted from the cluster across the entire electromagnetic spectrum, from high-energy X-rays to low-energy radio waves. Previous studies, which only radio and submillimeter wavelength data, had produced low-resolution images and did not show the bubble. Among the most important measurements was a far-infrared wavelength emitted by a specific ion of carbon in the shell.

A team led by UMD astronomers created the first clear image of an expanding bubble of stellar gas where stars are born using data from NASA’s SOFIA telescope on board a heavily modified 747 jet as seen here in this artist’s rendering. Credit: Artist Rendering by Marc Pound/UMD

“We can use spectroscopy to actually tell how fast this carbon is moving either towards or away from us,” said Ramsey Karim (M.S. ’19, astronomy), a Ph.D. student in astronomy at UMD and a co-author of the study. “This technique uses the Doppler effect, the same effect that causes a train’s horn to change pitch as it passes you. In our case, the color changes slightly depending on the velocity of the carbon ions.”

By determining whether the carbon ions were moving toward or away from Earth and combining that information with measurements from the rest of the electromagnetic spectrum, Tiwari and Karim were able to create a 3-D view of the expanding stellar-wind bubble surrounding Westerlund 2.

In addition to finding a single, stellar wind-driven bubble around Westerlund 2, they found evidence of new stars forming in the shell region of this bubble. Their analysis also suggests that as the bubble expanded, it broke open on one side, releasing hot plasma and slowing expansion of the shell roughly a million years ago. But then, about 200,000 or 300,000 years ago, another bright star in Westerlund 2 evolved, and its energy re-invigorated the expansion of the Westerlund 2 shell.

“We saw that the expansion of the bubble surrounding Westerlund 2 was reaccelerated by winds from another very massive star, and that started the process of expansion and star formation all over again,” Tiwari said. “This suggests stars will continue to be born in this shell for a long time, but as this process goes on, the new will become less and less massive.”

Tiwari and her colleagues will now apply their method to other bright star clusters and warm gas bubbles to better understand these star-forming regions of the galaxy. The work is part of a multi-year NASA-supported program called FEEDBACK.



More information:
“SOFIA FEEDBACK Survey: Exploring the Dynamics of the Stellar-wind-driven Shell of RCW 49” Astrophysical Journal (2021). DOI: 10.3847/1538-4357/abf6ce

Citation:
First clear view of a boiling cauldron where stars are born (2021, June 23)
retrieved 23 June 2021
from https://phys.org/news/2021-06-view-cauldron-stars-born.html

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part may be reproduced without the written permission. The content is provided for information purposes only.

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Hexbyte Glen Cove Putting makeup on spiders does not change their chances of being eaten by a predator thumbnail

Hexbyte Glen Cove Putting makeup on spiders does not change their chances of being eaten by a predator

Hexbyte Glen Cove

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Hexbyte Glen Cove Turtle carcasses wash ashore in Sri Lanka after ship fire thumbnail

Hexbyte Glen Cove Turtle carcasses wash ashore in Sri Lanka after ship fire

Hexbyte Glen Cove

A Sri Lankan policeman looks at a dead turtle that washed ashore in Colombo, Sri Lanka, June 10, 2021. Carcasses of nearly a hundred turtles believed to have been killed due to heat and chemical poisoning from a fire-ravaged ship that sank off while transporting chemicals have been washed to Sri Lanka’s ashore in recent weeks, raising fears of a severe marine disaster. Credit: AP Photo/ Krishan Kariyawasam

Nearly a hundred carcasses of turtles with throat and shell damage, as well as a dozen dead dolphins and a blue whale, have washed ashore in Sri Lanka since a container ship burned and sank, raising fears of a severe marine disaster.

Ecologists believe the deaths were directly caused by the fire and release of hazardous chemicals while the Singapore-flagged X-Press Pearl burned for 12 days and sank last week off Sri Lanka’s main port in the capital Colombo. Government officials, however, said these causes were “provisionally” confirmed and the investigation was continuing.

The fire started on the ship on May 20 and dead marine species started washing ashore days later.

A ship manifest seen by The Associated Press said 81 of the ship’s nearly 1,500 containers held “dangerous” goods.

The Sri Lankan navy believes the blaze was caused by its chemical cargo, most of which was destroyed in the fire. But debris including burned fiberglass and tons of plastic pellets have severely polluted the surrounding waters and a long stretch of the island nation’s famed beaches.

Post-mortem analysis on the carcasses are being performed at five government-run laboratories and separately by the Government Analysts Department, said an official of the wildlife department who spoke on condition of anonymity as the official was not authorized to speak to the media.

A stray dog stands amid the waves as decomposed remains of a turtle lies on a beach polluted following the sinking of a container ship that caught fire while transporting chemicals off Kapungoda, outskirts of Colombo, Sri Lanka, Monday, June 21, 2021. X-Press Pearl, a Singapore-flagged ship sank off on Thursday a month after catching fire, raising concerns about a possible environmental disaster. Credit: AP Photo/Eranga Jayawardena

“Provisionally, we can say that these deaths were caused by two methods—one is due to burns from the heat and secondly due to chemicals. These are obvious,” said Anil Jasinghe, secretary of the environment ministry.

He refrained from giving an exact cause, saying “post-mortem analysis are still being conducted.”

Thushan Kapurusinghe of the Turtle Conservation Project blamed the fire and chemicals the ship carried for killing the turtles.

With over three decades experience on turtle conservation, Kapurusinghe said the dead turtles had oral, cloacal and throat bleeding and “specific parts of their carapace have burns and erosion signs.”

The sea off Sri Lanka and its coastline are home to five species of turtles that regularly come to lay eggs. March to June is the peak season for turtle arrivals.

  • Sri Lankan wild life workers remove decomposed remains of a turtle lies on a beach polluted following the sinking of a container ship that caught fire while transporting chemicals off Kapungoda, outskirts of Colombo, Sri Lanka, Monday, June 21, 2021. X-Press Pearl, a Singapore-flagged ship sank off on Thursday a month after catching fire, raising concerns about a possible environmental disaster. Credit: AP Photo/Eranga Jayawardena
  • Sri Lankan wild life workers prepare to remove decomposed remains of a turtle lies on a beach polluted following the sinking of a container ship that caught fire while transporting chemicals off Kapungoda, outskirts of Colombo, Sri Lanka, Monday, June 21, 2021. X-Press Pearl, a Singapore-flagged ship sank off on Thursday a month after catching fire, raising concerns about a possible environmental disaster. Credit: AP Photo/Eranga Jayawardena
  • Sri Lankan wild life workers prepare to remove decomposed remains of a turtle lies on a beach polluted following the sinking of a container ship that caught fire while transporting chemicals off Kapungoda, outskirts of Colombo, Sri Lanka, Monday, June 21, 2021. X-Press Pearl, a Singapore-flagged ship sank off on Thursday a month after catching fire, raising concerns about a possible environmental disaster. Credit: AP Photo/Eranga Jayawardena

Lalith Ekanayake, a marine and coastal ecologist, suspects, based on the nature of the fire and amount of chemicals, that “at least 400 turtles may have died and their carcasses may have sunk in the sea or drifted to the deep sea.”

Sri Lanka plans to claim compensation from X-Press Feeders, the ship’s owner, and already have submitted an interim claim of $40 million.



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Turtle carcasses wash ashore in Sri Lanka after ship fire (2021, June 22)
retrieved 22 June 2021
from https://phys.org/news/2021-06-turtle-carcasses-ashore-sri-lanka.html

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Hexbyte Glen Cove Australia fights UN downgrade of Great Barrier Reef health thumbnail

Hexbyte Glen Cove Australia fights UN downgrade of Great Barrier Reef health

Hexbyte Glen Cove

This aerial photos shows the Great Barrier Reef in Australia on Dec. 2, 2017. Australia said Tuesday, June 22, 2021, it will fight a recommendation for the Great Barrier Reef to be listed as in danger of losing its World Heritage values due to climate change, while environmentalists have applauded the U.N. World Heritage Committee’s proposal.Credit: Kyodo News via AP

Australia said Tuesday it will fight against plans to downgrade the Great Barrier Reef’s World Heritage status due to climate change, while environmentalists have applauded the U.N. World Heritage Committee’s proposal.

The committee said in a draft report on Monday that “there is no possible doubt” that the network of colorful corals off Australia’s northeast coast was “facing ascertained danger.”

The report recommends that the world’s most extensive coral reef ecosystem be added to UNESCO’s List of World Heritage in Danger, which includes 53 sites, when the World Heritage Committee considers the question in China in July.

The listing could shake Australians’ confidence in their government’s ability to care for the natural wonder and create a role for UNESCO headquarters in devising so-called “corrective measures,” which would likely include tougher action to reduce Australia’s greenhouse gas emissions.

Any downgrade of the reef’s World Heritage status could reduce tourism revenue that the natural wonder generates for Australia because fewer tourists would be attracted to a degraded environment and dead coral.

Reef cruise operators said the report was wrong and that tourists continued to be awed by dazzling coral and multicolored fish. But some tourists said the reef had seemed more colorful during visits decades ago.

Environment Minister Sussan Ley said she and Foreign Minister Marise Payne had called UNESCO Director-General Audrey Azoulay to express the government’s “strong disappointment” and “bewilderment” at the proposal.

Australia, which is one of 21 countries on the committee, will oppose the listing, Ley said.

“This decision was flawed. Clearly there were politics behind it,” Ley told reporters. “Clearly those politics have subverted a proper process and for the World Heritage Committee to not even foreshadow this listing is, I think, appalling.”

The network of 2,500 reefs covering 348,000 square kilometers (134,000 square miles) has been World Heritage-listed since 1981.

But its health is under increasing threat from and rising ocean temperatures.

The report found the site had suffered significantly from coral bleaching events caused by unusually warm ocean temperatures in 2016, 2017 and last year.

Australian Environment Minister Sussan Ley, left, speaks to the media during a press conference at Parliament House in Canberra, Tuesday, June 22, 2021. Australia said on Tuesday it will fight a draft recommendation to list the Great Barrier Reef as a World Heritage site in danger after a United Nations body called for more government action on climate change. Credit: Lukas Coch/AAP via AP

Australian Marine Conservation Society environmental consultant Imogen Zethoven welcomed the committee’s recognition that “Australia hasn’t done enough on climate change to protect the future of the reef.”

The reef would become the first site to be added to the List of World Heritage in Danger primarily for climate change reasons, Zethoven said.

“It would be a very significant step for the World Heritage Committee to make this decision and one that we really hope that it does make because it will open up a lot of potential change,” she said.

Richard Leck, a spokesman for the environmental group WWF, said listing the reef as in-danger would be “a real shock” to many Australians.

In 2014, Australia was warned that an “in danger” listing was being considered rather than being proposed for immediate action.

Australia had time to respond by developing a long-term plan to improve the reef’s health called the Reef 2050 Plan.

The committee said this week that plan “requires stronger and clearer commitments, in particular towards urgently countering the effects of climate change.”

Ley said climate change policy debate should be restricted to the U.N. Framework Convention on Climate Change.

“I know … that climate change is the biggest threat to the and in no way am I stepping away from that recognition and countries including European countries have got strong views about what policies different countries should have on climate change and I understand that as well, but this is not the convention in which to have those conversations,” Ley said, referring to the Convention Concerning the Protection of the World Cultural and Natural Heritage.

Observers say the swearing in on Tuesday of new Deputy Prime Minister Barnaby Joyce, who opposes action on climate change that increases prices, signals Australia is likely to set less ambitious targets for reducing greenhouse gas emissions.

Terry Hughes, director of the Australian Research Council’s Center for Excellence in Coral Reef Studies, said Australia’s refusal to commit to a net zero carbon emissions target by 2050 made the country a “complete outlier.”

“This draft decision from UNESCO is pointing the finger at Australia and saying: ‘If you’re serious about saving the Great Barrier Reef, you need to do something about your policies,'” Hughes told Australian Broadcasting Corp.



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Australia fights UN downgrade of Great Barrier Reef health (2021, June 22)
retrieved 22 June 2021
from https://phys.org/news/2021-06-australia-downgrade-great-barrier-reef.html

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Hexbyte Glen Cove Engineers examine urban cooling strategies using reflective surfaces thumbnail

Hexbyte Glen Cove Engineers examine urban cooling strategies using reflective surfaces

Hexbyte Glen Cove

Credit: Unsplash/CC0 Public Domain

If you’ve ever been in a city’s central core in the middle of summer, you know the heat can be brutal—and much hotter than in the surrounding region.

Temperatures in cities tend to be several degrees warmer than in its , a phenomenon called the Urban Heat Island (UHI) effect. Many cities have been observed to be 2-4ºC warmer than the countryside in virtually every inhabited continent. This phenomenon occurs because , especially pavements, absorbs a lot of heat as compared to natural vegetated surfaces. This heat pollution causes higher air conditioning and water costs, while also posing a public health hazard.

One mitigation strategy called gray infrastructure involves the modification of impermeable surfaces (walls, roofs, and pavements) to counter their conventional heating effect. Typical urban surfaces have a solar reflectance (albedo) of 0.20, which means they reflect just 20 percent of sunlight and absorb as much as 80 percent. By contrast, reflective concrete and coatings can be designed to reflect 30-50 percent or more. Cities like Los Angeles have already used reflective coatings on major streets to combat heat pollution, although the solution can be expensive to implement -wide.

Researchers at the University of Pittsburgh Swanson School of Engineering used a Computational Fluid Dynamics model to find ways to decrease cost and increase usage of cooler surfaces. The paper, published in the journal Nature Communications, examined the possibility of applying cooler surfaces to just half the surfaces in a city.

“This could be an effective solution if the surfaces selected were upstream of the dominant wind direction,” said lead author Sushobhan Sen, postdoctoral associate in the Department of Civil and Environmental Engineering. “A ‘barrier’ of cool surfaces preemptively cools the warm air, which then cools the rest of the city at a fraction of the cost. On the other hand, if the surfaces are not strategically selected, their effectiveness can decline substantially.”

This research gives and civil engineers an additional way to build resilient and sustainable infrastructure using .

“It’s important for the health of the planet and its people that we find a way to mitigate the heat produced by urban infrastructure,” said coauthor Lev Khazanovich, the department’s Anthony Gill Chair Professor of Civil and Environmental Engineering. “Strategically placed reflective surfaces could maximize the mitigation of heat pollution while using minimal resources.”

The paper, titled “Limited application of reflective surfaces can mitigate urban heat pollution,” was coauthored by Sen and Khazanovich.



More information:
Sushobhan Sen et al, Limited application of reflective surfaces can mitigate urban heat pollution, Nature Communications (2021). DOI: 10.1038/s41467-021-23634-7

Citation:
Engineers examine urban cooling strategies using reflective surfaces (2021, June 22)
retrieved 22 June 2021
from https://phys.org/news/2021-06-urban-cooling-strategies-surfaces.html

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Hexbyte Glen Cove Proliferation of electric vehicles based on high-performance, low-cost sodium-ion battery thumbnail

Hexbyte Glen Cove Proliferation of electric vehicles based on high-performance, low-cost sodium-ion battery

Hexbyte Glen Cove

Graphical abstract. Credit: Korea Institute of Science and Technology (KIST)

Various automobile companies are preparing to shift from internal combustion (IC) engine vehicles to electric vehicles (EVs). However, due to higher cost, EVs are not as easily accessible to consumers; hence, several governments are subsidizing EVs to promote sales. For EV costs to compete with those of IC engine vehicles, their batteries, which account for about 30% of their cost, must be more economical than IC-based vehicles.

The Korea Institute of Science and Technology (KIST) has announced that Dr. Sang-Ok Kim’s team at the Center for Energy Storage Research had developed a novel, high-performance, economical anode material for use in sodium-ion secondary batteries, which are more cost-effective than . This novel material can store 1.5 times more electricity than the graphite anode used in commercial lithium-ion batteries and its performance does not degrade even after 200 cycles at very fast charging/discharging rates of 10 A/g.

Sodium is over 500 times more abundant in the Earth’s crust than lithium; hence, sodium-ion batteries have drawn considerable attention as the next-generation secondary battery because it is 40% cheaper than lithium-ion batteries. However, compared to lithium ions, sodium ions are larger and, thus, cannot be stored as stably in graphite and silicon, which are widely used as anodes in such batteries. Hence, the development of a novel, high-capacity anode material is necessitated.

The KIST research team used molybdenum disulfide (MoS2), a metal sulfide that has garnered interest as a candidate for large-capacity anode materials. MoS2 can store a large amount of electricity, but cannot be used because of its high electrical resistance and structural instability that occur during battery operation. However, Dr. Sang-Ok Kim’s team overcame this problem by creating a ceramic nano-coating layer using silicone oil, which is a low-cost, eco-friendly material. Through the simple process of mixing the MoS2 precursor with silicone oil and heat-treating the mixture, they could produce a stable heterostructure with low resistance and enhanced stability.

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Hexbyte Glen Cove New cause found for intensification of oyster disease thumbnail

Hexbyte Glen Cove New cause found for intensification of oyster disease

Hexbyte Glen Cove

Panel A shows the original form of the Dermo parasite Perkinsus marinus, with black arrows indicating typical Dermo cells and the white arrow a dividing form, all infecting connective tissues deep inside an oyster. Panel B shows the new form of the parasite, much smaller, with the arrow indicating a mass of dozens of Dermo cells inside a single oyster blood cell, and primarily infecting the lining of the stomach and gut. Credit: R. Carnegie/VIMS.

A new paper in Scientific Reports led by researchers at William & Mary’s Virginia Institute of Marine Science challenges increased salinity and seawater temperatures as the established explanation for a decades-long increase in the prevalence and deadliness of a major oyster disease in the coastal waters of the mid-Atlantic.

Dr. Ryan Carnegie, the paper’s lead author, says “We present an entirely new lens through which we can view our last 35 years of history in the Chesapeake Bay region. We now know the great intensification of Dermo disease in the 1980s wasn’t simply due to drought. It was more fundamentally due to the emergence of a new and highly virulent form of Perkinsus marinus, the parasite that causes Dermo.”

In an unusual twist, the team’s evidence suggests that transformation of this native parasite was in response to evolutionary pressures brought by the impacts of another, non-native oyster parasite known as MSX, first seen in Bay waters in 1959. Dermo’s mid-80s rise in virulence, along with decades of overharvesting, habitat destruction, and the earlier devastation of MSX, brought the Bay’s traditional oyster fishery to a historic low.

Carnegie says his team’s findings can help better manage the Bay’s modern oyster industry, which is now on the upswing due to disease-resistant aquaculture strains, reef restoration, and limits on the wild harvest. “The lesson,” he says, “is that pathogens like P. marinus are highly dynamic, and our disease surveillance must be attentive to any changes that may occur. This includes the emergence of more virulent strains, or variants that may have different forms or life histories than we expect. Management should be continually tuned to any changes in disease dynamics.”

The team’s findings also give scientists and fishery managers a better understanding of the “rock-bottom” era for Bay oysters between the late 1980s and early 2000s. “The oysters reached this level of devastation not because they were unable to deal with Dermo after decades, if not centuries or millennia, of exposure,” says Carnegie. “They hit rock bottom because they were challenged with a brand-new form of the parasite, and needed time to adapt. And now they are adapting, which is key to the oyster’s recent recovery in the region.”

Along with Carnegie, the paper’s other authors are the late Susan Ford of Haskin Shellfish Research Laboratory at Rutgers University; Peter Kingsley-Smith of the South Carolina Department of Natural Resources; and Rita Crockett, Lydia Bienlien, Lúcia Safi, Laura Whitefleet-Smith, and Eugene Burreson of VIMS. Funding for the study comes from the VIMS Foundation A. Marshall Acuff, Sr., Memorial Endowment for Oyster Disease Research.

The sharp transition from the original form of Dermo (light blue) to contemporary (dark blue) in Chesapeake Bay (A), South Carolina (B), and New Jersey (C). Weighted prevalence in the Virginia panel is a conventional measure of Dermo disease in oyster populations, and shows that the change in Dermo’s form in Virginia coincided with the increase in Dermo prevalence within Bay oysters. Credit: © R. Carnegie/VIMS.

Evidence for a more virulent Dermo parasite

Dermo disease results when the eastern oyster Crassostrea virginica is infected by the protozoan parasite Perkinsus marinus. Infected oysters grow more slowly, exhibit poorer body condition, and reproduce less successfully than their healthy counterparts. Severe infections lead to oyster death and release of into the surrounding water, potentially infecting other nearby oysters as they filter water for food. The disease does not affect people who eat the shellfish.

Native to the Gulf Coast, Dermo was first recorded in the Chesapeake Bay in 1949, though it had likely been there far longer. Prior to the 1980s, it typically occurred as a chronic disease that killed about 30% of oysters annually, mostly older animals that had been exposed to the parasite for several years. But, says Carnegie, “around 1986, Dermo suddenly became an acute and profoundly destructive disease capable of killing more than 70% of host oysters within months of infection.” The increased virulence of the Perkinsus parasite persists today.

Because the parasite’s infectiousness is known to increase with higher salinity, scientists initially attributed the mid-1980s spike in Dermo’s virulence to a multi-year drought that had struck the mid-Atlantic around that time, raising coastal salinities as freshwater input from rivers decreased. Increasing seawater temperatures also promote increased Dermo disease, and ocean warming has been blamed for the northward increase in Dermo’s range since the 1980s. As time passed, however, Carnegie and other researchers began to realize that salinity and temperature alone did not fully explain the lasting increase in Dermo infections and associated oyster mortality along the East Coast.

“We began to ask why more protracted and intense droughts in earlier years, before the 1980s, hadn’t produced a similar intensification of disease,” says Carnegie, “and why subsequent wet periods didn’t return the parasite to the low levels of infection characteristic of earlier years.”

Motivated by these questions, Carnegie and colleagues compared samples from modern Bay oysters with samples taken in 1960 and stored at VIMS, using paper-thin tissue slices glued onto slides for viewing under a microscope. Finding striking and unexpected differences, they then took a comprehensive look at more than 8,000 tissue samples collected from oysters in Chesapeake Bay, South Carolina, and New Jersey between 1960 and 2018.

“Our analysis,” says Carnegie, “clearly showed that a new parasite variant emerged between 1983 and 1990, concurrent with the historical mid-80s outbreaks of Dermo.” Changes included a shift in the infection site—from deeper connective tissues to the lining of the digestive tract—changes in reproductive strategy, and a sharp decrease in cell size. In Chesapeake Bay, they found the most pronounced change between oysters sampled in 1985 and 1986, when the modern variant increased in frequency from 22% to 99% of observations.

Dr. Ryan Carnegie (L) of the Virginia Institute of Marine Science and postdoctoral research associate Lúcia Safi collect oysters from the waters of the Chesapeake Bay as part of their long-term study of Dermo disease. Credit: © P. Richardson/VIMS.

“The picture that emerges,” says Carnegie, “is the rise of a virulent new form of the Dermo parasite Perkinsus along the mid-Atlantic coast in the mid-80s, which dispersed from there and supplanted a form that previously had been widely distributed in Atlantic estuaries. While changes in pathogen virulence have been documented in other systems, the scope of changes we’ve seen, and their rapid spread across a wide area, is unusual.”

“Our work underscores the importance of long-term environmental monitoring,” he adds. “Without that, and the maintenance of associated natural history collections, this new perspective wouldn’t have been possible.”

Evolutionary pressures

The type of changes observed in the Dermo parasite suggest they represent a novel but predictable response to the devastating impacts of MSX, the disease caused by the non-native parasite Haplosporidium nelsoni, which was first reported in Bay waters in 1959. MSX killed more than 90% of Virginia’s farmed oysters by 1961, and slashed the harvest of planted oysters from 3,347,170 bushels in 1959 to 361,792 bushels by 1983, an estimated loss of 1.8 billion animals. This decrease was likely compounded by simultaneous losses from wild populations.

A parasite that quickly kills its host effectively destroys its own home. Over evolutionary time scales, natural selection thus often leads to an equilibrium between a native parasite and its host, marked by the type of minor, long-term Perkinsus infections and low rates of Dermo mortality historically observed in Chesapeake Bay oysters.

But when a new parasite arrives on the scene, that evolutionary balance may shift. Carnegie and his team speculate that the devastating arrival of the non-native, MSX parasite in Bay waters drastically disrupted the long-established equilibrium between Dermo and Crassostrea, directly leading to the new, more virulent form of the disease.

“A huge reduction in oyster abundance—like that caused by the arrival of MSX—would severely impact a parasite such as P. marinus that depends entirely on a single host,” says Carnegie. As evidence, he notes that Perkinsus declined sharply in abundance beginning in 1959; recent theoretical modeling underscores the possibility that an increase in parasite virulence could be a consequence of such reduction in host resources.

“The changes we saw in the Dermo parasite are likely adaptive with regard to the reduced oyster abundance and longevity it faced after rapid establishment of Haplosporidium nelsoni and MSX in 1959,” says Carnegie. “Our findings, we hypothesize, illustrate a novel ecosystem response to a marine parasite invasion: an increase in virulence in a native parasite.” An intriguing possibility is that the changes the researchers observed may represent a shortening of the Perkinsus life cycle, as it adapted to oysters with shorter life spans due to mortality from MSX.



More information:
Ryan B. Carnegie et al, A rapid phenotype change in the pathogen Perkinsus marinus was associated with a historically significant marine disease emergence in the eastern oyster, Scientific Reports (2021). DOI: 10.1038/s41598-021-92379-6

Citation:
New cause found for intensification of oyster disease (2021, June 18)
retrieved 21 June 2021
from https://phys.org/news/2021-06-intensification-oyster-disease.html

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Hexbyte Glen Cove The 27.5-million-year cycle of geological activity thumbnail

Hexbyte Glen Cove The 27.5-million-year cycle of geological activity

Hexbyte Glen Cove

Credit: New York University

Geologic activity on Earth appears to follow a 27.5-million-year cycle, giving the planet a ‘pulse,’ according to a new study published in the journal Geoscience Frontiers.

“Many geologists believe that geological events are random over time. But our study provides statistical evidence for a common , suggesting that these geologic events are correlated and not random,” said Michael Rampino, a geologist and professor in New York University’s Department of Biology, as well as the study’s lead author.

Over the past five decades, researchers have proposed cycles of major geological events—including and mass extinctions on land and sea—ranging from roughly 26 to 36 million years. But early work on these correlations in the was hampered by limitations in the age-dating of geologic events, which prevented scientists from conducting quantitative investigations.

However, there have been significant improvements in radio-isotopic dating techniques and changes in the geologic timescale, leading to new data on the timing of past events. Using the latest age-dating data available, Rampino and his colleagues compiled updated records of major geological events over the last 260 million years and conducted new analyses.

The team analyzed the ages of 89 well-dated major geological events of the last 260 million years. These events include marine and land extinctions, major volcanic outpourings of lava called flood-basalt eruptions, events when oceans were depleted of oxygen, sea-level fluctuations, and changes or reorganization in the Earth’s tectonic plates.

They found that these global geologic events are generally clustered at 10 different timepoints over the 260 million years, grouped in peaks or pulses of roughly 27.5 million years apart. The most recent cluster of was approximately 7 million years ago, suggesting that the next of major geological activity is more than 20 million years in the future.

The researchers posit that these pulses may be a function of cycles of activity in the Earth’s interior—geophysical processes related to the dynamics of plate tectonics and climate. However, similar cycles in the Earth’s orbit in space might also be pacing these events.

“Whatever the origins of these cyclical episodes, our findings support the case for a largely periodic, coordinated, and intermittently catastrophic geologic record, which is a departure from the views held by many geologists,” explained Rampino.



More information:
Michael R. Rampino et al, A pulse of the Earth: A 27.5-Myr underlying cycle in coordinated geological events over the last 260 Myr, Geoscience Frontiers (2021). DOI: 10.1016/j.gsf.2021.101245

Citation:
The 27.5-million-year cycle of geological activity (2021, June 18)
retrieved 21 June 2021
from https://phys.org/news/2021-06-million-year-geological.html

This document is subject to copyright. Apart from any fa

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Hexbyte Glen Cove Storm expected to be another blow to Gulf Coast businesses thumbnail

Hexbyte Glen Cove Storm expected to be another blow to Gulf Coast businesses

Hexbyte Glen Cove

This GOES-16 GeoColor satellite image taken Friday, June 18, 2021, at 11 a.m. EDT, and provided by NOAA, shows a tropical weather system in the Gulf of Mexico. Officials ordered a floodgate and locks system closed in southeast Louisiana and readied sandbags in Mississippi and Alabama as a broad, disorganized tropical weather system began spinning bands of rain and brisk wind across the northern Gulf of Mexico coast Friday. Credit: NOAA via AP

A weekend that was supposed to be filled with celebrations of Juneteenth and Father’s Day has turned dreary in coastal Louisiana and Mississippi, where an unpredictable tropical weather system has brought wind, heavy rain and fears of flooding to a region where some have sandbags still left over from last year’s record-breaking hurricane season.

With virus restrictions loosened and summer near, across the Gulf Coast—everyone from restaurateurs to swamp boat operators—had been anticipating an influx of tourist cash after a year of lost revenue due to the coronavirus pandemic and relentless storms. But those hopes have been dimmed by the storm.

“My biggest concern is that it drives away a busy weekend, and may just end up being a lot of rain,” said Austin Sumrall, the owner and chef at the White Pillars Restaurant and Lounge in Biloxi, Mississippi. He had 170 reservations on his books for Sunday, but was concerned some patrons would cancel. “We saw, especially last year, the rug can get jerked out from under you pretty quickly,” he said.

The storm churning northward in the Gulf of Mexico was expected to move inland early Saturday. It’s likely to dump anywhere from 5 inches (13 centimeters) to 10 inches (25 centimeters) of rain along parts of the Gulf Coast—even 15 inches (38 centimeters) in isolated areas, according to forecasters at the National Hurricane Center.

A worker moves water tricycles off the beach in Biloxi, Miss., as a tropical system approaches on Friday, June 18, 2021. Forecasters predict a tropical system will bring heavy rain, storm surge and coastal flooding to the U.S. Gulf Coast. The poorly organized disturbance was located Friday morning about 255 miles south of Morgan City, Louisiana. Credit: Margaret Baker/The Sun Herald via AP

A tropical storm warning extended from Morgan City, Louisiana, to the Okaloosa-Walton County line in the Florida Panhandle. Coastal surge flooding was possible and flash flood watches extended along the coast from southeast Louisiana into the Florida Panhandle and well inland into Mississippi, Alabama and into parts of central and northern Georgia.

Louisiana swamp tour boat captain Darrin Coulon spent Friday securing boats to docks, having already canceled popular weekend tours.

“I’m sure the area’s going to have some flooding,” Coulon lamented.

Dealing with is nothing new for Coulon, who said he jokingly tells people he’s from the “cone of uncertainty,” referring to a term that forecasters use.

In Louisiana, the threat came a month after spring storms and flooding that were blamed for five deaths, and as parts of the state continued a slow recovery from a brutal 2020 . That included Tropical Storm Cristobal that opened the season last June, hurricanes Laura and Delta that devastated southwest Louisiana, and Hurricane Zeta that downed trees and knocked out power for days in New Orleans in October.

Residents in low-lying areas of Hancock County move their vehicles, lawn mowers, ATVs and boats to higher ground in Waveland, Miss., as a tropical system approaches Friday, June 18, 2021. Forecasters predict a tropical system will bring heavy rain, storm surge and coastal flooding to the U.S. Gulf Coast. The poorly organized disturbance was located Friday morning about 255 miles south of Morgan City, Louisiana. Credit: Justin Mitchell/The Sun Herald via AP

The latest storm, moving north toward Louisiana, carried tropical storm-force sustained winds of 45 mph (72 kph) but forecasters said it couldn’t be classified as a tropical storm because it lacked a single, well-defined center.

“I hope it just gets in and gets out,” said Greg Paddie, manager of Tacky Jack’s, a restaurant at Alabama’s Orange Beach.

Paddie said the restaurant still has sandbags left over from its preparations for last year’s Hurricane Sally. That September storm, blamed for two deaths, threw ships onto dry land and knocked out power to hundreds of thousands of people in Alabama and in the Florida Panhandle.

Disappointment was evident in the voice of Seneca Hampton, an organizer of the Juneteenth Freedom Festival in Gautier, on the Mississippi Gulf Coast. He spent weeks arranging food trucks, vendors, a bounce house, face painting and free hamburgers and hot dogs for the event. It was highly anticipated because last year’s was canceled due to the pandemic and because of Juneteenth’s new designation as a federal holiday.

  • Clouds from Tropical Storm Claudette form on Highway 90 Beaches in Pass Christian, Miss., Friday, June 18, 2021. City of Pass Christian has declared state of emergency for potential severe weather. Credit: Hunter Dawkins/The Gazebo Gazette via AP
  • A man takes a photo of waves crashing into what once was a dock for a ferry that transported people from Bay St. Louis to Pass Christian, Miss., as a tropical system moves toward the Mississippi Coast on Friday, June 18, 2021. Forecasters predict a tropical system will bring heavy rain, storm surge and coastal flooding to the U.S. Gulf Coast. The poorly organized disturbance was located Friday morning about 255 miles south of Morgan City, Louisiana. Credit: Justin Mitchell/The Sun Herald via AP
  • National Hurricane Center director Ken Graham, left, speaks during a news conference along with Sen. Rick Scott, R-Fla.,Tuesday, June 1, 2021, at the center in Miami. Tuesday marks the start of the 2021 Atlantic hurricane season which runs to Nov. 30. Credit: AP Photo/Wilfredo Lee
  • Senator Rick Scott, R-Fla., right, speaks during a news conference after having toured the National Hurricane Center with director Ken Graham, left, Tuesday, June 1, 2021, at the center in Miami. Tuesday marks the start of the 2021 Atlantic hurricane season which runs to Nov. 30. Credit: AP Photo/Wilfredo Lee
  • Senator Rick Scott, R-Fla., speaks during a news conference after having toured the National Hurricane Center, Tuesday, June 1, 2021, in Miami. Tuesday marks the start of the 2021 Atlantic hurricane season which runs to Nov. 30. Credit: AP Photo/Wilfredo Lee

“It’s something that means a lot to people, and there were people that were bummed out, like ‘I already had in my mind I was coming out there to celebrate,'” said Hampton.

The Gautier event was postponed until next month. A Juneteenth event in Selma, Alabama, was postponed until August.

By Friday evening, storm clusters were dumping rain up to 4 inches (10 centimeters) an hour along parts of the Louisiana and Mississippi coasts, said Benjamin Schott, meteorologist in charge at the National Weather Service office in Slidell, Louisiana. Radar showed more heavy rain moving ashore over Alabama and the Florida Panhandle. The National Hurricane Center said the system was about 40 miles (65 kilometers) south-southeast of Morgan City, Louisiana, on Friday night, moving north at 10 mph (17 kph).

Mexico, while getting rain from the storm in the Gulf, also was threatened by a in the Pacific. Tropical Storm Dolores formed Friday with landfall expected on its west-central coast Saturday evening, possibly near hurricane strength, according to the National Hurricane Center.



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Citation:
Storm expected to be another blow to Gulf Coast businesses (2021, June 19)
retrieved 19 June 2021
from https://phys.org/news/2021-06-storm-gulf-coast-businesses.html

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part may be reproduced without the written permission. The content is provided for information purposes only.

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