Monday, February 20, 2023

Plague Trackers: Uncovering the Elusive Origins of the Black Death

By MCMASTER UNIVERSITY FEBRUARY 19, 2023

The East Smithfield plague pits, which were used for mass burials in 1348 and 1349. Credit: Museum of London Archaeology (MOLA)

The researchers analyzed over 600 genome sequences of Yersinia pestis, the bacterium responsible for causing the plague.

In an effort to gain deeper insight into the origins and spread of bubonic plague throughout history, researchers from McMaster University, the University of Sydney, and the University of Melbourne have conducted a thorough and detailed analysis of hundreds of modern and ancient genome sequences, creating the largest study of its type.

Despite significant advancements in DNA technology and analysis, the origin, evolution, and spread of the plague remain challenging to pinpoint.

The plague is responsible for the two largest and most deadly pandemics in human history. However, the ebb and flow of these, why some die out and others persist for years has confounded scientists.

In a paper published today in the journal Communications Biology, McMaster researchers use comprehensive data and analysis to chart what they can about the highly complex history of Y. pestis, the bacterium that causes plague.

The research features an analysis of more than 600 genome sequences from around the globe, spanning the plague’s first emergence in humans 5,000 years ago, the plague of Justinian, the medieval Black Death, and the current (or third) Pandemic, which began in the early 20^th century

The East Smithfield plague pits, which were used for mass burials in 1348 and 1349. Credit: Museum of London Archaeology (MOLA)

“The plague was the largest pandemic and biggest mortality event in human history. When it emerged and from what host may shed light on where it came from, why it continually erupted over hundreds of years and died out in some locales but persisted in others. And ultimately, why it killed so many people,” explains evolutionary geneticist Hendrik Poinar, director of McMaster’s Ancient DNA Centre.

Poinar is a principal investigator with the Michael G. DeGroote Institute for Infectious Disease Research and McMaster’s Global Nexus for Pandemics & Biological Threats.

The team studied genomes from strains with a worldwide distribution and of different ages and determined that Y. pestis has an unstable molecular clock. This makes it particularly difficult to measure the rate at which mutations accumulate in its genome over time, which are then used to calculate dates of emergence.

Because Y. pestis evolves at a very slow pace, it is almost impossible to determine exactly where it originated.

Humans and rodents have carried the pathogen around the globe through travel and trade, allowing it to spread faster than its genome evolved. Genomic sequences found in Russia, Spain, England, Italy, and Turkey, despite being separated by years are all identical, for example, creating enormous challenges in determining the route of transmission.

To address the problem, researchers developed a new method for distinguishing specific populations of Y. pestis, enabling them to identify and date five populations throughout history, including the most famous ancient pandemic lineages which they now estimate had emerged decades or even centuries before the pandemic was historically documented in Europe.

“You can’t think of the plague as just a single bacterium,” explains Poinar. “Context is hugely important, which is shown by our data and analysis.”

To properly reconstruct pandemics of our past, present, and future, historical, ecological, environmental, social, and cultural contexts are equally significant.

He explains that genetic evidence alone is not enough to reconstruct the timing and spread of short-term plague pandemics, which has implications for future research related to past pandemics and the progression of ongoing outbreaks such as COVID-19.

Reference: “Plagued by a cryptic clock: insight and issues from the global phylogeny of Yersinia pestis” by Katherine Eaton, Leo Featherstone, Sebastian Duchene, Ann G. Carmichael, Nükhet Varlık, G. Brian Golding, Edward C. Holmes, and Hendrik N. Poinar, 19 January 2023, Communications Biology.
DOI: 10.1038/s42003-022-04394-6

Study of Ancient Proteins Clarifies Mystery of Crocodiles’ Unique Hemoglobin

By UNIVERSITY OF NEBRASKA-LINCOLN FEBRUARY 18, 2023

A Nile crocodile swallows an impala, its reward for lying in wait beneath the water’s surface. By resurrecting the hemoglobin of ancient crocodilian ancestors, a Husker-led team has helped explain why other vertebrates failed to evolve the adaptations that allow crocs to go hours without air. Credit: Cell Press / Current Biology / Shutterstock / Scott Schrage, University of Nebraska–Lincoln

Experiments on ancient proteins reveal that mutations are more numerous and nuanced than previously believed.

It can pogo-stick along at 50-plus miles per hour, leaping 30-odd feet in a single bound. But that platinum-medal athleticism falls by the wayside at a sub-Saharan riverside, the source of life and death for the skittish impala stilling itself for a drink in 100-degree heat.

For the past hour, a Nile crocodile has been silently lurking in the muddy river. When the apex predator strikes, its powerful jaws clamp onto the hindquarter of an unsuspecting impala with a force of 5,000 pounds. The real weapon, however, is the water itself, as the crocodile drags its prey to the deep end to drown.

The success of the croc’s ambush lies in the nanoscopic scuba tanks — hemoglobins — that course through its bloodstream, unloading oxygen from lungs to tissues at a slow but steady clip that allows it to go hours without air. The hyper-efficiency of that specialized hemoglobin has led some biologists to wonder why, of all the jawed vertebrates in all the world, crocodilians were the lone group to hit on such an optimal solution to making the most of a breath.

By statistically reconstructing and experimentally resurrecting the hemoglobin of an archosaur, the 240-million-year-old ancestor of all crocodilians and birds, the University of Nebraska–Lincoln’s Jay Storz and colleagues have gleaned new insights into that why. Rather than requiring just a few key mutations, as earlier research suggested, the unique properties of crocodilian hemoglobin stemmed from 21 interconnected mutations that litter the intricate component of red blood cells.

That complexity, and the multiple knock-on effects that any one mutation can induce in hemoglobin, may have forged an evolutionary path so labyrinthine that nature failed to retrace it even over tens of millions of years, the researchers said.

“If it was such an easy trick — if it was that easy to do, just making a few changes — everyone would be doing it,” said Storz, a senior author of the study and Willa Cather Professor of biological sciences at Nebraska.

All hemoglobin binds with oxygen in the lungs before swimming through the bloodstream and eventually releasing that oxygen to the tissues that depend on it. In most vertebrates, hemoglobin’s affinity for capturing and holding oxygen is dictated largely by molecules known as organic phosphates, which, by attaching themselves to the hemoglobin, can coax it into releasing its precious cargo.

But in crocodilians — crocodiles, alligators, and their kin — the role of organic phosphates was supplanted by a molecule, bicarbonate, that is produced from the breakdown of carbon dioxide. Because hardworking tissues produce lots of carbon dioxide, they also indirectly generate lots of bicarbonate, which in turn encourages hemoglobin to dispense its oxygen to the tissues most in need of it.

“It’s a super-efficient system that provides a kind of slow-release mechanism that allows crocodilians to efficiently exploit their onboard oxygen stores,” Storz said. “It’s part of the reason they’re able to stay underwater for so long.”

As postdoctoral researchers in Storz’s lab, Chandrasekhar Natarajan, Tony Signore, and Naim Bautista had already helped decipher the workings of the crocodilian hemoglobin. Alongside colleagues from Denmark, Canada, the United States, and Japan, Storz’s team decided to embark on a multidisciplinary study of how the oxygen-ferrying marvel came to be.

Prior efforts to understand its evolution involved incorporating known mutations into human hemoglobin and looking for any functional changes, which were usually scant. Recent findings from his own lab had convinced Storz that the approach was flawed. There were plenty of differences, after all, between human hemoglobin and that of the ancient reptilian creatures from which modern-day crocodilians evolved.

“What’s important is to understand the effects of mutations on the genetic background in which they actually evolved, which means making vertical comparisons between ancestral and descendant proteins, rather than horizontal comparisons between proteins of contemporary species,” Storz said. “By using that approach, you can figure out what actually happened.”

So, with the help of biochemical principles and statistics, the team set out to reconstruct hemoglobin blueprints from three sources: the 240-million-year-old archosaur ancestor; the last common ancestor of all birds; and the 80-million-year-old shared ancestor of contemporary crocodilians. After putting all three of the resurrected hemoglobins through their paces in the lab, the team confirmed that only the hemoglobin of the direct crocodilian ancestor lacked phosphate binding and boasted bicarbonate sensitivity.

Comparing the hemoglobin blueprints of the archosaur and crocodilian ancestors also helped identify changes in amino acids — essentially the joints of the hemoglobin skeleton — that may have proved important. To test those mutations, Storz and his colleagues began introducing certain croc-specific mutations into the ancestral archosaur hemoglobin. By identifying the mutations that made archosaur hemoglobin behave more like that of a modern-day crocodilian, the team pieced together the changes responsible for those unique, croc-specific properties.

Counter to conventional wisdom, Storz and his colleagues discovered that evolved changes in hemoglobin’s responsiveness to bicarbonate and phosphates were driven by different sets of mutations, so that the gain of one mechanism was not dependent on the loss of the other. Their comparison also revealed that, though a few mutations were enough to subtract the phosphate-binding sites, multiple others were needed to eliminate phosphate sensitivity all together. In much the same way, two mutations seemed to directly drive the emergence of bicarbonate sensitivity — but only when combined with or preceded by other, easy-to-miss mutations in remote regions of the hemoglobin.

Storz said the findings speak to the fact that a combination of mutations might yield functional changes that transcend the sum of their individual effects. A mutation that produces no functional effect on its own might, in any number of ways, open a path to other mutations with clear, direct consequences. In the same vein, he said, those later mutations might influence little without the proper stage-setting predecessors already in place. And all of those factors can be supercharged or waylaid by the environment in which they unfold.

“When you have these complex interactions, it suggests that certain evolutionary solutions are only accessible from certain ancestral starting points,” Storz said. “With the ancestral archosaur hemoglobin, you have a genetic background that makes it possible to evolve the unique properties that we see in hemoglobins of modern-day crocodilians. By contrast, with the ancestor of mammals as a starting point, it may be that there’s some way that you could evolve the same property, but it would have to be through a completely different molecular mechanism, because you’re working within a completely different structural context.”

For better or worse, Storz said, the study also helps explain the difficulty of engineering a human hemoglobin that can mimic and approach the performance of the crocodilian.

“We can’t just say, ‘OK, it’s mainly due to these five mutations. If we take human hemoglobin and just introduce those mutations, voilà, we’ll have one with those same exact properties, and we’ll be able to stay underwater for two hours, too,’” Storz said. “It turns out that’s not the case.

“There are lots of can’t-get-there-from-here problems in the tree of life.”

Reference: “Evolution and molecular basis of a novel allosteric property of crocodilian hemoglobin” by Chandrasekhar Natarajan, Anthony V. Signore, Naim M. Bautista, Federico G. Hoffmann, Jeremy R.H. Tame, Angela Fago and Jay F. Storz, 21 December 2022, Current Biology.
DOI: 10.1016/j.cub.2022.11.049

The study was funded by the National Science Foundation and the National Institutes of Health.

Necrophagy by insects in Oculudentavis and other lizard body fossils preserved in Cretaceous amber

Scientific Reports volume 13, Article number: 2907 (2023) Cite this article

When a vertebrate carcass begins its decay in terrestrial environments, a succession of different necrophagous arthropod species, mainly insects, are attracted. Trophic aspects of the Mesozoic environments are of great comparative interest, to understand similarities and differences with extant counterparts. Here, we comprehensively study several exceptional Cretaceous amber pieces, in order to determine the early necrophagy by insects (flies in our case) on lizard specimens, ca. 99 Ma old. To obtain well-supported palaeoecological data from our amber assemblages, special attention has been paid in the analysis of the taphonomy, succession (stratigraphy), and content of the different amber layers, originally resin flows. In this respect, we revisited the concept of syninclusion, establishing two categories to make the palaeoecological inferences more accurate: eusyninclusions and parasyninclusions. We observe that resin acted as a “necrophagous trap”. The lack of dipteran larvae and the presence of phorid flies indicates decay was in an early stage when the process was recorded. Similar patterns to those in our Cretaceous cases have been observed in Miocene ambers and actualistic experiments using sticky traps, which also act as “necrophagous traps”; for example, we observed that flies were indicative of the early necrophagous stage, but also ants. In contrast, the absence of ants in our Late Cretaceous cases confirms the rareness of ants during the Cretaceous and suggests that early ants lacked this trophic strategy, possibly related to their sociability and recruitment foraging strategies, which developed later in the dimensions we know them today. This situation potentially made necrophagy by insects less efficient in the Mesozoic. details

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Necrophagy by insects in Oculudentavis and other lizard body fossils preserved in Cretaceous amber | Scientific Reports (nature.com)

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“Shocking Findings” – Painstaking Study of 50-Plus Years of Seafloor Sediment Cores Has Surprise Payoff

By RICE UNIVERSITY FEBRUARY 18, 2023

A schematic depiction of the burial and deep subduction of organic carbon. Credit: R. Dasgupta/Rice University

Rising global temperatures are leading to a decrease in the amount of organic carbon being deposited in the ocean floor.

An international group of researchers meticulously collected data from over 50 years of oceanic scientific drilling expeditions to carry out a groundbreaking study of organic carbon that sinks to the ocean floor and is drawn deep into the earth.

According to their study, published recently in the journal Nature, global warming may result in a decrease in the burial of organic carbon and a rise in the amount of carbon released back into the atmosphere. This is due to the potential effect of higher ocean temperatures in boosting the metabolic rates of bacteria.

Researchers from Rice University, Texas A&M University, the University of Leeds, and the University of Bremen analyzed data from drilled cores of muddy seafloor sediments that were gathered during 81 of the more than 1,500 shipboard expeditions mounted by the International Ocean Discovery Program (IODP) and its predecessors.

Their study provides the most detailed accounting to date of organic carbon burial over the past 30 million years, and it suggests scientists have much to learn about the dynamics of Earth’s long-term carbon cycle.

The JOIDES Resolution is a scientific research vessel operated by Texas A&M University for the International Ocean Discovery Program that drills into the ocean floor to collect and study core samples. Credit: International Ocean Discovery Program

“What we’re finding is that burial of organic carbon is very active,” said study co-author Mark Torres of Rice. “It changes a lot, and it responds to the Earth’s climatic system much more than scientists previously thought.”

The paper’s corresponding author, Texas A&M oceanographer Yige Zhang, said, “If our new records turn out to be right, then they’re going to change a lot of our understanding about the organic carbon cycle. As we warm up the ocean, it will make it harder for organic carbon to find its way to be buried in the marine sediment system.”

Mark Torres is an assistant professor in Rice University’s Department of Earth, Environmental, and Planetary Sciences. Credit: Tommy LaVergne/Rice University

Carbon is the main component of life, and carbon constantly cycles between Earth’s atmosphere and biosphere as plants and animals grow and decompose. Carbon can also cycle through the Earth on a journey that takes millions of years. It begins at tectonic subduction zones where the relatively thin tectonic plates atop oceans are dragged down below thicker plates that sit atop continents. Downward diving oceanic crust heats up as it sinks, and most of its carbon returns to the atmosphere as carbon dioxide (CO2) from volcanoes

Scientists have long studied the amount of carbon that gets buried in ocean sediments. Drilled cores from the ocean floor contain layers of sediments laid down over tens of millions of years. Using radiometric dating and other methods, researchers can determine when specific sediments were laid down. Scientists can also learn a lot about past conditions on Earth by studying minerals and microscopic skeletons of organisms trapped in sediments.

“There are two isotopes of carbon — carbon-12 and carbon-13,” said Torres, an assistant professor in Rice’s Department of Earth, Environmental and Planetary Sciences. “The difference is just one neutron. So carbon-13 is just a bit heavier.

“But life is lazy, and if something’s heavier — even that tiny bit — it’s harder to move,” Torres said. “So life prefers the lighter isotope, carbon-12. And if you grow a plant and give it CO2, it will actually preferentially take up the lighter isotope. That means the ratio of carbon-13 to -12 in the plant is going to be lower — contain less 13 — than in the CO2 you fed the plant.”

For decades scientists have used isotopic ratios to study the relative amounts of inorganic and organic carbon that was undergoing burial at specific points in Earth’s history. Based on those studies and computational models, Torres said scientists have largely believed the amount of carbon undergoing burial had changed very little over the past 30 million years

Zhang said, “We had this idea of using the actual data and calculating their organic carbon burial rates to come up with the global carbon burial. We wanted to see if this ‘bottom-up’ method agreed with the traditional method of isotopic calculations, which is more ‘top down.’”

The job of compiling data from IODP expeditions fell to study first author, Ziye Li of Bremen, who was then a visiting student in Zhang’s lab at A&M.

Zhang said the study findings were shocking.

“Our new results are very different — they’re the opposite of what the isotope calculations are suggesting,” he said.

Zhang said this is particularly the case during a period called the mid-Miocene, about 15 million years ago. Conventional scientific wisdom held that a large amount of organic carbon was buried around this interval, exemplified by the organic-rich “Monterey Formation” in California. The team’s findings suggest instead that the smallest amount of organic carbon was buried during this interval over the last 23 million years or so.

He described the team’s paper as the beginning of a potentially impactful new way to analyze data that may aid in understanding and addressing climate change.

“It’s people’s curiosity, but I also want to make it more informative about what’s going to happen in the future,” Zhang said. “We’re doing several things quite creatively to really use paleo data to inform us about the present and future.”

Reference: “Neogene burial of organic carbon in the global ocean” by Ziye Li, Yi Ge Zhang, Mark Torres and Benjamin J. W. Mills, 4 January 2023, Nature.
DOI: 10.1038/s41586-022-05413-6

The study was funded by the American Chemical Society’s Petroleum Research Fund. On behalf of the National Science Foundation, Texas A&M has served as the science operator of the IODP drill ship JOIDES Resolution for the past 36 years as part of the largest federal research grant currently managed by the university.

Climate change disrupts the distribution of marine species

ByAndrei Ionescu

02-17-2023

Earth.com staff writer

A new modeling study published in the journal Global Change Biology has found that, if climate change continues at the current pace, most of marine species will lose significant amounts of their suitable habitat ranges by 2100.

“Ocean’s biodiversity changes faster than in terrestrial ecosystems. To be able to protect marine species and with them all the marine resources that humans depend on, it is important to understand where and how marine species communities may change,” explained study co-lead author Irene Roca, a biologist at the Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB).

While many marine species have already started shifting their distributional ranges due to global warming, estimating what marine biodiversity will look like in the future is challenging, particularly since previous studies have focused solely on temperature as the main environmental factor leading to future changes in biodiversity.

Now, the scientists examined occurrence data of over 33,500 marine species and took into consideration seven environmental factors, including water depth, water temperature, salinity, and oxygen concentrations. Based on this data, they estimated whether and where these species are likely to occur in the future in the case of three different CO2 emissions scenarios.

The analysis revealed that species’ core habitat ranges – the marine areas in which chances are higher than 50 percent that a species occurs based on its preferred environmental conditions – may not only shift but also considerably decline in a high emissions scenario.

Besides habitat loss, the preferred habitat area of a variety of species will be disrupted. “Especially along the equator, our model projections revealed areas which are ill-suited for most marine species, for instance because of high temperatures,” Roca said.

According to the researchers, fragmented habitats will lead to diminished population sizes which can threaten many species with extinction (although new species could also develop in changed climatic conditions). Another significant problem is that different species can keep up with changing environmental conditions to varying degrees, thus leading to a restructuring of food webs and changes in the relationship between habitat-forming species such as coral and their inhabitants.

“Even though our model does not account for such interspecific interactions, the results provide valuable clues on how differently marine environments and communities are likely to change depending on the future CO2 emission scenarios,” said study co-lead author Dorothee Hodapp, a marine ecologist at HIFMB.

Understanding this high risk of critical reorganization of marine life will pose further challenges to conservation efforts. “We need to think ahead and work on effectively implementing the recent international agreements on biodiversity protection,” Hodapp concluded.

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By Andrei Ionescu, Earth.com Staff Writer

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

Satellite Tracking Data Paints A First Picture Of Antarctic Blue Whales

By Sam Helmy

Scientists have released the finding of satellite tracking data of two Antarctic blue whales.

The creatures are the only two to ever have satellite tracking tags attached. The feat was achieved by Dr. Virginia Andrews-Goff back in 2013 and, to this day, is the only case of tags being attached to these majestic creatures.

The data shows that these creatures are capable of covering great distances at great speeds. The animals seem to have a traveling speed of around 4.2km per hour/~2.6 miles per hour and a foraging/feeding speed of around 2.5kph/~1.55mph.

The data also showed that the animals covered incredible distances, with them coving 1390km/~864mi in 13 days and a massive 5550km/~3449mi in 74 days. This ability makes them even harder to protect since they are difficult to find and can circumnavigate Antarctica in one feeding season.

According to Dr. Andrews-Goff:

“This is a unique data set that was incredibly challenging to get, and, unfortunately, for 10 years no-one has been able to generate more data. We know very little about the movement and distribution of Antarctic blue whales, where they migrate, where they forage and breed, and we don’t understand the threats they might face as they recover from whaling.”

While discussing the enormous distances covered by the animals, Dr. Andrews-Goff added:

“The two whales did entirely different things, but what became obvious is that these animals can travel really quickly. If you consider how far and fast these animals moved, protecting the broader population against potential threats will be tricky because they could potentially circumnavigate Antarctica within a single feeding season. It looks like the whales might hang around in one area to feed and then move quickly to another area and hang around there for another feed. There may be certain areas that are better feeding grounds than others. From a management perspective, it would be good to understand what is it that makes these areas important?”

You can find the original research here.

Marine Ecosystems Cannot Be Restored By Marine Reserves Alone

By Sam Helmy
1 day ago

A recent study has found that marine reserves or protected marine areas cannot restore marine ecosystems on their own.

While they play a crucial role in restoring ecosystems and are an important policy component, they cannot do the job by themselves.

Researchers from the Biodiversity Research Institute (IRBio) at the University of Barcelona, working with scientists from the Group of Ecosystem Oceanography (GRECO) at the Oceanographic Center of the Balearic Islands published their latest work in the ICES Journal of Marine Science.

According to the article’s first signature, Lluís Cardona, from IRBio:

“This study shows that with only the small-scale marine reserves, it is not enough to conserve the functionality of marine ecosystems. In areas with an intense fishing pressure, both professional and recreational, exploited areas have more influence on small reserves.”

He added:

“Marine reserves favor the recovery of species such as the dusky grouper, but not other highly mobile and large species such as sharks, dolphins and seals. Even species such as the sea bass have problems recovering in Galicia’s marine reserves. The lack of these species is what prevents the emergence of differences in food webs between reserves and areas open to fishing, in the Mediterranean and the Atlantic, beyond the recovery of the biomass of some sedentary species … reducing the impact on highly mobile and large species in the areas that are open to fishing, since marine reserves alone can do little to protect these species.”

You can find the original research here.

A Lifeline for Corals: How Better Access to Sunlight Can Save the Reefs

By PENN STATE FEBRUARY 19, 2023

Penn State researchers analyzed the productivity and biodiversity in the world’s symbiotic coral communities and found that the maintenance of water optical quality in coral reefs is fundamental to protecting coral biodiversity and preventing reef degradation. Credit: Tomás López-Londoño / Penn State

New research at Penn State suggests that when preserving the world’s coral reefs, both above and below the surface activity is equally important.

A recent study published in the journal Scientific Reports found that maintaining water clarity in coral reefs is crucial for preserving coral biodiversity and avoiding reef degradation. The study analyzed the productivity and biodiversity of the world’s symbiotic coral communities

“Coral reefs are one of the most biodiverse ecosystems on Earth,” said Tomás López-Londoño, a postdoctoral scholar at Penn State and lead author on the study. “To better understand that diversity, we looked at the role sunlight plays in the symbiotic relationship between coral and the algae that provide the oxygen for its survival. We found that underwater light intensity plays a critical role in the energy expended by the coral’s symbiotic algae to maintain its photosynthetic activity.”

The findings, although novel, are hardly a revelation, he explained. Science has long shown that sunlight is the major source of energy for virtually all biochemical reactions that sustain life on Earth, but sunlight’s impact had not yet been fully understood in coral, he said.

“What’s new here is we developed a model that provides a mechanistic explanation for the biodiversity patterns in coral,” said López-Londoño. “Central to that explanation is water clarity, meaning that preserving the underwater light climate should be a priority for coral reef conservation. It’s as vital as pollution mitigation, limiting ocean acidification, and reducing thermal stress.”

The researchers studied coral grown in an aquarium, simulating depth and gradations of sunlight, to develop a mathematical model that describes the association between the depth‐dependent variation in photosynthetic energy to corals and gradients of species diversity.

They then tested the model on existing published data, comparing reefs with contrasting water clarity and biodiversity patterns in hotspots of marine biodiversity across the globe. The team’s productivity‐biodiversity model explained between 64% and 95% of the depth‐related variation in coral species richness, indicating that much of the variation in species richness with depth is driven by changes in exposure to sunlight.

“The model is very elegant in that it takes into consideration only two things,” said Roberto Iglesias-Prieto, Penn State professor of biology and co-author on the study. “It looks at productivity, the potential that an alga has to extract energy from the sun, and the cost of living, the cost of the repair of the photosynthetic machinery. It’s a very simple notion and we found it explains the existing empirical data.”

Running their model against global data sets, the researchers found that variation in sunlight-supported algal energy supply plays an important role in the spatial variation of species diversity within coral communities. The results show that highly productive submarine environments, with plentiful access to sunlight, are a vital safeguard against the risk of species extinction from demographic and environmental changes.

The findings offer a new tactic for reef conservation: preserving the clarity of the water. The researchers found that “the maintenance of water optical quality in coral reefs is fundamental to protect coral biodiversity and prevent reef degradation.”

“We tend to react reflexively against large-scale threats like ocean acidification and thermal stress from climate change,” said Iglesias-Prieto. “We say ‘this is a serious issue, but what can I really do locally?’ In the case of mitigating optical pollution, the answer is ‘everything.’”

He explained that communities can protect the clarity of the local seawater by reducing the sedimentation and pollution associated with human development — and anyone can participate in that work.

“Unlike so much of the environmental threats that corals face, this is something that can and should be managed locally,” said Iglesias-Prieto.

Reference: “Photosynthetic usable energy explains vertical patterns of biodiversity in zooxanthellate corals” by Tomás López-Londoño, Kelly Gómez-Campo, Xavier Hernández-Pech, Susana Enríquez and Roberto Iglesias-Prieto, 2 December 2022, Scientific Reports.
DOI: 10.1038/s41598-022-25094-5

The work was supported by Penn State startup funds.

Feb 19 (Reuters) – Russia sank a damaged space cargo ship in the Pacific Ocean after it undocked from the International Space Station, Interfax news service reported on Sunday, citing the Roscosmos space agency.

“The Progress MS-21 (ship) was deorbited, entered the atmosphere and collapsed. Unburned elements of its structure fell in the non-navigational area of the South Pacific Ocean” on Saturday, the space agency was quoted as saying in a statement.

Roscosmos reported loss of pressure in the ship on Feb. 11. Investigations into the incident have delayed the launch of craft to take two Russian cosmonauts and an American astronaut back from the space station to as late as March 10 from a previous plan to launch on Monday.

(Reporting by Lidia Kelly in Melbourne;)

Russia has two leaky space station ships. One is about to burn up over the ocean

Meanwhile, an astronaut and two cosmonauts wait for a return ride to Earth.

By Elisha Sauers on February 18, 2023

A Russian spacecraft spewed coolant into space in December. A second Russian cargo ship sprung a leak two months later. Credit: NASA Screen Grab

> Science > Space

Russia will dispose of a leaky supply ship that had been docked at the International Space Station this weekend, allowing it to burn up over the Pacific Ocean, according to NASA.

Managers of the Russian space agency Roscosmos decided to bring the Progress 82 cargo capsule back with an engine burn scheduled at 10:15 p.m. ET Saturday. They made the decision after undocking the ship Friday night to get a better look at its radiator.

No astronauts will be aboard the deorbiting spacecraft, as it's not intended for passengers. NASA said the ship is loaded with trash

SEE ALSO: The space station sprung a leak. NASA and Russia just revealed why.

The sendoff follows the discovery of a coolant leak onboard the spacecraft on Feb. 11(Opens in a new tab), making it the second Russian spacecraft to spring a leak at the space station over the past two months.

A Soyuz capsule for carrying humans also suffered a coolant leak in Dec. 2022, leaving three crew members without a return ride. After an investigation into the first leak, Russian and U.S. space officials believed a micrometeoroid smaller than a sharpened pencil tip had caused the puncture, not a manufacturing defect. The coolant seeping into space, caught on live video(Opens in a new tab), was intended to keep the cabin at a comfortable temperature.

But officials have not yet elaborated on the culprit of the cargo ship leak.

"The entire NASA and Roscosmos team have continued to work together to investigate the cause of this situation, and we will continue to do so," said Jeff Arend, manager of NASA's space station engineering office, during an unrelated news conference Friday. "We'll know more in the coming days." "We'll know more in the coming days."

Roscosmos investigated a coolant leak onboard a spacecraft that was intended to send an astronaut and two cosmonauts home in March 2023. Credit: NATALIA KOLESNIKOVA / AFP Via Getty Images

Both agencies previously determined the leaky crew capsule would be unfit to bring three men home. NASA astronaut Frank Rubio(Opens in a new tab) and Russian cosmonauts Sergey Prokopyev and Dmitri Petelin, who arrived at the space station in Sept. 2022, were supposed to be at the Earth-orbiting laboratory for six months, with a return trip set for March.

But it hasn't been clear when they will fly home.

Despite the Russia-Ukraine war and geopolitical tensions between Russia and the United States, the two nations' space agencies have continued to work collaboratively at the space station.

Joel Montalbano, NASA's space station program manager, said in January that the crew had taken the news well that their return ride was still TBD, were excited to be doing research in space, and were prepared to stay a full year if necessary.

"I may have to fly some more ice cream to reward them," he said then.

Earlier on Saturday, Roscosmos said it wants to launch an empty ship for the marooned crew on Feb. 24, according to news wire reports(Opens in a new tab). A state commission has to approve the new date, according to an Agence France-Presse report on Saturday.

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