A hiking trail in the Sierra National Forest where a family of three and their dog were found dead two weeks ago was shut down on Aug. 28 due to “unknown hazards found in and near the Savage Lundy Trail.”
John Gerrish and Ellen Chunt went hiking with their 1-year-old daughter, Miju, and their dog, Oski, on the Savage Lundy trail early in the morning on Aug. 15, a sweltering Sunday when temperatures reached as high as 109 degrees, according to the Mariposa County Sheriff’s Office.
When Gerrish didn’t show up to his job as a software engineer on Monday, a friend reported them missing. The family was then found deceased on the trail about 1.5 miles from their vehicle on Tuesday, Aug. 17.
There is no clear cause of death for the family and autopsies have failed to turn up any clues, though toxicology reports are still pending.
Authorities have ruled out weapons and chemical hazards along the Savage Lundy trail as potentially causing their deaths, and a spokesperson for the sheriff’s office said homicide is not being considered.
“Initially, yes, when we come across a family with no apparent cause of death, there’s no smoking gun, there’s no suicide note, there’s nothing like that, we have to consider all options,” Kristie Mitchell, a spokeswoman for the Mariposa County Sheriff, previously told Fox News. “Now that we’re five days in, no, we’re no longer considering homicide as a cause of death.”
CALIFORNIA AUTHORITIES TURN TO CELLPHONE DATA, OTHER FORENSICS FOR ANSWERS IN FAMILY’S MYSTERIOUS DEATHS
The closure order will be in effect through Sept. 26, or until “conditions change” at the trail.
“As a precaution and to protect the public from unknown hazards in the area, The SNF decided to close several recreation sites, roads, and trails along the Merced River and its South Fork, until deemed safe for public use,” the U.S. Forest Service said in an advisory.
The Savage Lundy trail leads into the South Fork Merced River, which the Sierra National Forest has warned people against drinking from or swimming in due to potentially harmful algal blooms. (Google Maps)
The Savage Lundy hiking trail where the family was found ends at the South Fork Merced River.
The Sierra National Forest noted in its closure order that potentially harmful algal blooms (HABs) have been identified in the South Fork of the Merced River, and the California Department of Fish and Wildlife warned hikers in mid-July “not to swim, wade or allow their pets to enjoy the water” due to the toxic HABs.
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The U.S. Forest Service announced on Aug. 30 that all National Forests in California will be shut down through Sept. 17 in order “to better provide public and firefighter safety due to the ongoing California wildfire crisis.”
The area is the site of mid-19th century gold mines that are now abandoned and have the potential to emit toxic gases like carbon monoxide, but the sheriff’s office told Fox News last week that it has ruled out carbon monoxide poisoning.
The bodies of Jonathan Gerrish, Ellen Chung, their 1-year-old daughter, Miju, and the family dog, Oksi, were found by search and rescue workers on August 17 in a remote area of the Sierra National Forest near the south fork of the Merced River, according to the Mariposa County Sheriff’s Office. They were found on the Savage Lundy Trail.
The Sierra National Forest said it closed the area where the family was found as a precaution due to “unknown hazards found in and around the Savage Lundy Trail.”
“Designated recreation sites, roads, and trails in proximity and/or leading to this location will be off limits to public,” the national forest said in a statement Saturday. The closures are effective until September 26.
Since the closure was announced, the US Forest Service temporarily closed all national forests in California due to multiple wildfires burning in the state.
Investigators have not yet determined what led to the mysterious deaths. Autopsies on the family and a necropsy on the dog were inconclusive while toxicology results remain pending. Some results could come as early as Wednesday, Kristie Mitchell, spokesperson for the sheriff’s office, told CNN.
The only potential causes of death that have been ruled out include gunshots, or any other type of weapon, and chemical hazards specifically along the Savage Lundy Trail. Detectives have not ruled out possible toxins in areas near the trail.
Signs warning of a toxic algae bloom have been posted since mid-July along the south fork of the Merced River, in the vicinity of where the family was found. Water samples from the area — along with samples of the drinking water the family packed — have been sent to labs for testing.
Search warrants for the family’s home and cars turned up no significant evidence. Their phones have been collected and are undergoing data extraction by the FBI.
“We know the family and friends of John and Ellen are desperate for answers, our team of Detectives are working round the clock,” Mariposa County Sheriff Jeremy Briese said in a statement. “Cases like this require us to be methodical and thorough while also reaching out to every resource we can find to help us bring those answers to them as quickly as we can.”
Family was generous, amazing, friend says
Steve Jeffe said he met the couple in San Francisco years ago, and they grew very close after each relocated to the Mariposa area.
“They were amazing people, very generous,” Jeffe told CNN. “They love their daughter very much.”
Gerrish worked for Google and had recently started a job at Snapchat, according to Jeffe, who was alerted by friends after the family didn’t return home from a day hike last month.
The family’s nanny found no one home when she arrived the following Monday morning, and after Gerrish failed to show for work, “alarm bells went off,” Jeffe said.
“They were an amazingly loving and doting family,” said Jeffe, describing the couple as beloved with a very large group of friends.
“It’s a bewildering event. There’s something so disconcerting about what happened,” said Jeffe. “Whether it was environmental or man made, it was obviously something they encountered,” Jeffe added, speculating about what may have led to their deaths.
Mitchell said the area where the family was found is popular in the spring because of its colorful wildflower blooms and is very hot at this time of year and there is little shade.
She said the family was well prepared for a day hike.
This distinct human lineage has never been found anywhere else in the world, according to new research.
The study published Wednesday in the journal Nature.
“We have discovered the first ancient human DNA in the island region between Asia and Australia, known as ‘Wallacea’, providing new insight into the genetic diversity and population history of early modern humans in this little understood part of the world,” said study coauthor Adam Brumm, a professor of archaeology at Griffith University’s Australian Research Centre for Human Evolution, via email.
The first modern humans used the Wallacea islands, mainly Indonesian islands that include Sulawesi, Lombok and Flores, as they crossed from Eurasia to the Australian continent more than 50,000 years ago, researchers believe. The exact route or how they navigated this crossing, however, is unknown.
“They must have done so using relatively sophisticated watercraft of some kind, as there were no land bridges between the islands, even during the glacial peaks of the last ice age, when global sea levels were up to 140 meters (459 feet) lower than they are today,” Brumm said.
Tools and cave paintings have suggested that humans were living on these islands by 47,000 years ago, but the fossil record is sparse and ancient DNA degrades more rapidly in the tropical climate.
However, researchers uncovered the skeleton of a female between the ages of 17 and 18 in a cave on Sulawesi in 2015. Her remains were buried in the cave 7,200 years ago. She was part of the Toalean culture, only found in a pocket of Sulawesi’s southwestern peninsula. The cave is part of an archaeological site called Leang Panninge.
“The ‘Toaleans’ is the name archaeologists have given to a rather enigmatic culture of prehistoric hunter-gatherers that lived in the forested plains and mountains of South Sulawesi between around 8,000 years ago until roughly the fifth century AD,” said Brumm via email. “They made highly distinctive stone tools (including tiny, finely crafted arrowheads known as ‘Maros points’) that are not found anywhere else on the island or in wider Indonesia.”
The young hunter-gatherer is the first largely complete and well-preserved skeleton associated with the Toalean culture, Brumm said.
Lead study author Selina Carlhoff was able to retrieve DNA from the wedge-shaped petrous bone at the base of the skull.
“It was a major challenge, as the remains had been strongly degraded by the tropical climate,” said Carlhoff, also a doctoral candidate at the Max Planck Institute for the Science of Human History in Jena, Germany, in a statement.
Secrets hiding in DNA
The work to retrieve the genetic information was well worth it.
The young woman’s DNA showed that she descended from the first wave of modern humans to enter Wallacea 50,000 years ago. This was part of the initial colonization of “Greater Australia,” or the combined ice age landmass of Australia and New Guinea. These are the ancestors of present-day Indigenous Australians and Papuans, Brumm said.
And it turns out that the oldest genome traced to the Wallacea islands revealed something else: previously unknown ancient humans.
She also shares ancestry with a separate and distinct group from Asia who likely arrived after the colonization of Greater Australia — because modern Indigenous Australians and Papuans don’t share ancestry with this group, Brumm said.
“Previously, it was thought that the first time people with Asian genes entered Wallacea was around 3,500 years ago when Austronesian-speaking farmers from Neolithic Taiwan swept down through the Philippines and into Indonesia,” he said.
“It suggests that there might have been a distinct group of modern humans in this region that we really had no idea about up until now, as archaeological sites are so scarce in Wallacea and ancient skeletal remains are rare.”
No descendents of this lineage remain.
Her genome included another trace of an enigmatic and extinct group of humans: Denisovans. The handful of fossils signifying that these early humans ever existed are largely from Siberia and Tibet.
“The fact that their genes are found in the hunter-gatherers of Leang Panninge supports our earlier hypothesis that the Denisovans occupied a far larger geographical area” than previously understood, said study coauthor Johannes Krause, a professor of archaeogenetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, in a statement.
But when her DNA was compared with that of other hunter-gatherers who lived west of Wallacea at the same time, their DNA didn’t contain any traces of Denisovan DNA.
“The geographic distribution of Denisovans and modern humans may have overlapped in the Wallacea region. It may well be the key place where Denisova people and the ancestors of indigenous Australians and Papuans interbred,” said study coauthor Cosimo Posth, a professor at the University of Tübingen’s Senckenberg Centre for Human Evolution and Palaeoenvironment in Frankfurt, Germany, in a statement.
Researchers don’t know what happened to the Toalean culture, and this latest discovery is one piece of the puzzle as they try to understand the ancient genetic history of humans in southeast Asia. Brumm hopes that more ancient DNA from the Toalean people can be recovered to reveal its diversity “and its wider ancestral story.”
A dose of the Pfizer-BioNTech COVID-19 vaccine is administered at the Sheba Medical Center near Tel Aviv, Israel.Credit: Jack Guez/AFP/Getty
Many vaccines have been shown to provide strong protection against COVID-19. Now growing evidence finds that they also substantially reduce the risk of passing on the virus SARS-CoV-2 — crucial information for governments making decisions about how best to control the pandemic.
However, the studies were done before the highly-transmissible Delta variant became prevalent – and scientists say it may be more easily spread by vaccinated people than earlier variants.
Two studies1,2 from Israel, posted as preprints on 16 July, find that two doses of the vaccine made by pharmaceutical company Pfizer, based in New York City, and biotechnology company BioNTech, based in Mainz, Germany, are 81% effective at preventing SARS-CoV-2 infections. And vaccinated people who do get infected are up to 78% less likely to spread the virus to household members than are unvaccinated people. Overall this adds up to very high protection against transmission, say researchers.
The studies reflect population-level trends, say researchers. “It’s good news,” says Natalie Dean, a biostatistician at Emory University in Atlanta, Georgia. “But it’s not quite good enough,” she notes, because it means that vaccinated people can still occasionally spread the infection.
And the highly transmissible Delta variant is a major source of uncertainty. The Israeli studies and others are based on the circulation of earlier variants, in particular Alpha, but research suggests that vaccines offer slightly reduced protection against Delta.
Robust estimates
The studies “help us understand why cases were falling in most highly vaccinated populations before the emergence of the Delta variant”, says Marm Kilpatrick, an infectious-disease researcher at the University of California, Santa Cruz. “If that variant hadn’t arisen and spread, it’s likely that case burdens would be very, very low in many countries” with high rates of vaccination, he says.
The studies provide robust estimates for various aspects of transmission that had previously been inferred through multiple studies, says Kilpatrick.
The first study1, co-authored by researchers in Israel and France, looked at transmission in 210 households of infected people who worked at the Sheba Medical Center near Tel Aviv, which is Israel’s largest hospital. The data come from between December 2020 and April 2021 — a time when a massive vaccination drive in Israel was competing with a surge in cases driven by Alpha.
The second study2, co-authored by researchers in Israel and the United States, was based on a retrospective analysis of data from about 66,000 multiperson households with at least one infected member, collected by Maccabi Healthcare Services, a large health-care provider based in Tel Aviv, Israel, between June 2020 and March 2021.
Both studies found that two doses of the Pfizer–BioNTech vaccine were 81% effective at preventing infections. Those who did get infected were also less likely to pass the infection to household members than were unvaccinated individuals.
The first study saw a drop of 78%, and the second 41%, in reduction of infectiousness — with the large difference in numbers perhaps explained by the fact that the estimates are based on a very small number of vaccinated people who were infected and then infected others.
Reduce infectiousness
Nevertheless, “both papers provide good evidence of a substantial reduction in infectiousness,” says Elizabeth Halloran, a biostatistician at the Fred Hutchinson Cancer Research Center in Seattle, Washington.
While the studies provide an insight into transmission within households, the protection could be even higher outside the home, where people might be exposed to smaller doses of virus, notes Kilpatrick.
Although most of the benefit is because vaccines prevent infection in the first place, “the fact that they also reduce the infectiousness of breakthrough cases is important and reassuring”, says Virginia Pitzer, an infectious-diseases modeller at Yale School of Public Health in New Haven, Connecticut, and co-author of one of the Israel studies2.
The results correspond well with studies conducted elsewhere. One analysis3 of some 365,000 households in the United Kingdom, published on 23 June, estimated that individuals infected with SARS-CoV-2 were 40–50% less likely to spread the infection if they had received at least one dose of the Pfizer–BioNTech vaccine or that developed by the University of Oxford, UK, and pharmaceutical company AstraZeneca, based in Cambridge, UK, at least three weeks previously
A study4 from Finland, posted as a preprint on 10 July, found that spouses of infected health-care workers who had received a single dose of the Pfizer–BioNTech vaccine or that produced by Moderna in Cambridge, Massachusetts, were 43% less likely to get infected than were spouses of unvaccinated health workers.
Confounding factor of Delta
But studies on Alpha and other variants cannot be easily generalized to Delta, says Steven Riley, an infectious-diseases researcher at Imperial College London.
So far, there are no published data on how vaccines affect infections and infectiousness with Delta, but a UK study5 published on 21 July shows that the Pfizer–BioNTech and Oxford–AstraZeneca vaccines both protect slightly less well against symptomatic disease caused by Delta than against that caused by Alpha. This could also mean a drop in how well they protect against transmission of Delta, but there is still a lot of uncertainty, says Dean.
Unpublished preliminary data from Israel’s Ministry of Health show that Delta could chip away at some of the reduction in transmission provided by the Pfizer–BioNTech vaccine. And case numbers have risen sharply in Israel following Delta’s arrival, despite more than 60% of the population being fully vaccinated. This hints at what might happen elsewhere, say researchers.
Even if vaccines are just as effective at preventing infections with Delta as with earlier variants, if Delta is more infectious, transmission in households could still increase, says Dean.
A study6 from China, posted as a preprint on 12 July, found that the concentration of viral particles — a proxy for infectiousness — in people infected with Delta was roughly 1,000 times that in people infected with the original strain of SARS-CoV-2.
Delta’s increased infectiousness could mean that the proportion of people in a population who need to be vaccinated to bring the pandemic under control will be larger than would have been required with earlier variants.
Most of the viruses were previously unknown to humans, study finds.
Scientists who study glacier ice have found viruses nearly 15,000 years old in two ice samples taken from the Tibetan Plateau in China. Most of those viruses, which survived because they had remained frozen, are unlike any viruses that have been cataloged to date.
The findings, published on July 20, 2021, in the journal Microbiome, could help scientists understand how viruses have evolved over centuries. For this study, the scientists also created a new, ultra-clean method of analyzing microbes and viruses in ice without contaminating it.
“These glaciers were formed gradually, and along with dust and gases, many, many viruses were also deposited in that ice,” said Zhi-Ping Zhong, lead author of the study and a researcher at The Ohio State University Byrd Polar and Climate Research Center who also focuses on microbiology. “The glaciers in western China are not well-studied, and our goal is to use this information to reflect past environments. And viruses are a part of those environments.”
The researchers analyzed ice cores taken in 2015 from the Guliya ice cap in western China. The cores are collected at high altitudes – the summit of Guliya, where this ice originated, is 22,000 feet above sea level. The ice cores contain layers of ice that accumulate year after year, trapping whatever was in the atmosphere around them at the time each layer froze. Those layers create a timeline of sorts, which scientists have used to understand more about climate change, microbes, viruses and gases throughout history.
Researchers determined that the ice was nearly 15,000 years old using a combination of traditional and new, novel techniques to date this ice core.
When they analyzed the ice, they found genetic codes for 33 viruses. Four of those viruses have already been identified by the scientific community. But at least 28 of them are novel. About half of them seemed to have survived at the time they were frozen not in spite of the ice, but because of it.
Researchers determined that the ice was nearly 15,000 years old using a combination of traditional and new, novel techniques to date this ice core.
When they analyzed the ice, they found genetic codes for 33 viruses. Four of those viruses have already been identified by the scientific community. But at least 28 of them are novel. About half of them seemed to have survived at the time they were frozen not in spite of the ice, but because of it.
Yao Tandong, left, and Lonnie Thompson, right, process an ice core drilled from the Guliya Ice Cap in the Tibetan Plateau in 2015. The ice held viruses nearly 15,000 years old, a new study has found. Credit: Image courtesy Lonnie Thompson, The Ohio State University
“These are viruses that would have thrived in extreme environments,” said Matthew Sullivan, co-author of the study, professor of microbiology at Ohio State and director of Ohio State’s Center of Microbiome Science. “These viruses have signatures of genes that help them infect cells in cold environments – just surreal genetic signatures for how a virus is able to survive in extreme conditions. These are not easy signatures to pull out, and the method that Zhi-Ping developed to decontaminate the cores and to study microbes and viruses in ice could help us search for these genetic sequences in other extreme icy environments – Mars, for example, the moon, or closer to home in Earth’s Atacama Desert.”
Viruses do not share a common, universal gene, so naming a new virus – and attempting to figure out where it fits into the landscape of known viruses – involves multiple steps. To compare unidentified viruses with known viruses, scientists compare gene sets. Gene sets from known viruses are cataloged in scientific databases.
Those database comparisons showed that four of the viruses in the Guliya ice cap cores had previously been identified and were from virus families that typically infect bacteria. The researchers found the viruses in concentrations much lower than have been found to exist in oceans or soil.
The researchers’ analysis showed that the viruses likely originated with soil or plants, not with animals or humans, based on both the environment and the databases of known viruses.
The study of viruses in glaciers is relatively new: Just two previous studies have identified viruses in ancient glacier ice. But it is an area of science that is becoming more important as the climate changes, said Lonnie Thompson, senior author of the study, distinguished university professor of earth sciences at Ohio State and senior research scientist at the Byrd Center.
“We know very little about viruses and microbes in these extreme environments, and what is actually there,” Thompson said. “The documentation and understanding of that is extremely important: How do bacteria and viruses respond to climate change? What happens when we go from an ice age to a warm period like we’re in now?”
Reference: “Glacier ice archives nearly 15,000-year-old microbes and phages” by Zhi-Ping Zhong, Funing Tian, Simon Roux, M. Consuelo Gazitúa, Natalie E. Solonenko, Yueh-Fen Li, Mary E. Davis, James L. Van Etten, Ellen Mosley-Thompson, Virginia I. Rich, Matthew B. Sullivan and Lonnie G. Thompson, 20 July 2021, Microbiome. DOI: 10.1186/s40168-021-01106-w
This study was an interdisciplinary effort between Ohio State’s Byrd Center and its Center for Microbiome Science. The 2015 Guliya ice cores were collected and analyzed as part of a collaborative program between the Byrd Polar and Climate Research Center and the Institute of Tibetan Plateau Research of the Chinese Academy of Sciences, funded by the U.S. National Science Foundation and the Chinese Academy of Sciences. Funding also came from the Gordon and Betty Moore Foundation and the U.S. Department of Energy.
Scientists at University of California San Francisco have detected 109 chemicals in a study of pregnant women, including 55 chemicals never before reported in people and 42 “mystery chemicals,” whose sources and uses are unknown.
The chemicals most likely come from consumer products or other industrial sources. They were found both in the blood of pregnant women, as well as their newborn children, suggesting they are traveling through the mother’s placenta.
The study was published on March 16, 2021, in Environmental Science & Technology.
“These chemicals have probably been in people for quite some time, but our technology is now helping us to identify more of them,” said Tracey J. Woodruff, PhD, a professor of obstetrics, gynecology and reproductive sciences at UCSF.
A former U.S. Environmental Protection Agency scientist, Woodruff directs the Program on Reproductive Health and the Environment (PRHE) and the Environmental Research and Translation for Health (EaRTH) Center, both at UCSF.
“It is alarming that we keep seeing certain chemicals travel from pregnant women to their children, which means these chemicals can be with us for generations,” she said.
The scientific team used high-resolution mass spectrometry (HRMS) to identify human-made chemicals in people.
But, while these chemicals can be tentatively identified using chemical libraries, they need to be confirmed by comparing them to the pure chemicals produced by manufacturers that are known as “analytical standards.” And manufacturers do not always make these available.
Recently, for example, chemical manufacturer Solvay stopped providing access to a chemical standard for one perfluorooctanoic acid (PFAS) compound that has emerged as a replacement for phased-out PFAS compounds. The researchers have been using this chemical standard to evaluate the presence and the toxicity of the replacement PFAS.
“These new technologies are promising in enabling us to identify more chemicals in people, but our study findings also make clear that chemical manufacturers need to provide analytical standards so that we can confirm the presence of chemicals and evaluate their toxicity,” said co-lead author Dimitri Panagopoulos Abrahamsson, PhD, a postdoctoral fellow with UCSF’s PRHE.
The 109 chemicals researchers found in the blood samples from pregnant women and their newborns are found in many different types of products. For example, 40 are used as plasticizers, 28 in cosmetics, 25 in consumer products, 29 as pharmaceuticals, 23 as pesticides, three as flame retardants, and seven are PFAS compounds, which are used in carpeting, upholstery and other applications. The researchers say it’s possible there are also other uses for all of these chemicals.
The researchers report that 55 of the 109 chemicals they tentatively identified appear not to have been previously reported in people:
1 is used as a pesticide (bis(2,2,6,6-tetramethylpiperidini-4-y) decanedioate)
2 are PFASs (methyl perfluoroundecanoate, most likely used in the manufacturing of non-stick cookware and waterproof fabrics; 2-perfluorodecyl ethanoic acid)
10 are used as plasticizers (e.g. Sumilizer GA 80 – used in food packaging, paper plates, small appliances)
2 are used in cosmetics
4 are high production volume (HPV) chemicals
37 have little to no information about their sources or uses (e.g., 1-(1-Acetyl-2,2,6,6-tetramethylpiperidin-4-yl)-3-dodecylpyrrolidine-2,5-dione, used in manufacturing fragrances and paints—this chemical is so little known that there is currently no acronym—and (2R0-7-hydroxy-8-(2-hydroxyethyl)-5-methoxy-2-,3-dihydrochromen-4-one (Acronym: LL-D-253alpha), for which there is limited to no information about its uses or sources
“It’s very concerning that we are unable to identify the uses or sources of so many of these chemicals,” Woodruff said. “EPA must do a better job of requiring the chemical industry to standardize its reporting of chemical compounds and uses. And they need to use their authority to ensure that we have adequate information to evaluate potential health harms and remove chemicals from the market that pose a risk.”
Reference: “Suspect Screening, Prioritization, and Confirmation of Environmental Chemicals in Maternal-Newborn Pairs from San Francisco” by Aolin Wang, Dimitri Panagopoulos Abrahamsson, Ting Jiang, Miaomiao Wang, Rachel Morello-Frosch, June-Soo Park, Marina Sirota and Tracey J. Woodruff, 16 March 2021, , Environmental Science & Technology. DOI: 10.1021/acs.est.0c05984
Authors: Joining Woodruff and Panagopoulos Abrahamsson in the study were Aolin Wang and Marina Sirota, of UCSF; Ting Jiang, Miamiao Wang and June-Soo Park of the California Environmental Protection Agency; and Rachel Morello-Frosch of UC Berkeley.
Funding: This study was funded by NIH/NIEHS grant numbers P30- 870 ES030284, UG3OD023272, UH3OD023272, P01ES022841, 871 R01ES027051 and by the U.S. EPA grant number 872 RD83543301.
The menagerie of bacterial and fungal species living among us is ever growing – and this is no exception in low-gravity environments, such as the International Space Station (ISS).
Researchers from the United States and India working with NASA have now discovered four strains of bacteria living in different places in the ISS – three of which were, until now, completely unknown to science.
Three of the four strains were isolated back in 2015 and 2016 – one was found on an overhead panel of the ISS research stations, the second was found in the Cupola, the third was found on the surface of the dining table; the fourth was found in an old HEPA filter returned to Earth in 2011.
All four of the strains belong to a family of bacteria found in soil and freshwater; they are involved in nitrogen fixation, plant growth, and can help stop plant pathogens. Basically, good bacteria to have around if you’re growing things.
You might wonder what such soil bacteria were doing all the way up on the ISS, but the astronauts living on the space station have been growing small amounts of food for years, so it’s unsurprising that we’ve found plant-related microbes aboard.
One of the strains – the HEPA-filter find – was identified as a known species called Methylorubrum rhodesianum. The other three were sequenced and found to all belong to the same, previously unidentified species, and the strains were named IF7SW-B2T, IIF1SW-B5, and IIF4SW-B5.
The team, lead by University of Southern California geneticist Swati Bijlani, has proposed calling the new species Methylobacterium ajmalii after Ajmal Khan, a renowned Indian biodiversity scientist. This new find is also closely related to an already known species called M. indicum.
“To grow plants in extreme places where resources are minimal, isolation of novel microbes that help to promote plant growth under stressful conditions is essential,” two of the team, Kasthuri Venkateswaran and Nitin Kumar Singh from NASA’s JPL, explained in a press statement.
Considering we already know that these microbes can survive the harsh conditions of the ISS, the team put the four strains through genetic analysis to look for genes that could be used to help promote plant growth.
“The whole genome sequence assembly of these three ISS strains reported here will enable the comparative genomic characterization of ISS isolates with Earth counterparts in future studies,” the team writes in their study.
“This will further aid in the identification of genetic determinants that might potentially be responsible for promoting plant growth under microgravity conditions and contribute to the development of self-sustainable plant crops for long-term space missions in future.”
The researchers found that one of the ISS strains – IF7SW-B2T – had promising genes involved in plant growth, including a gene for an enzyme essential for cytokinin, which promotes cell division in roots and shoots.
There’s much more research to be done here – the researchers acknowledge that they’ve barely scratched the surface of microbial diversity on the space station. Around 1,000 samples have already been collected on the ISS, but are still awaiting a trip back to Earth.
Just imagine the exciting space-faring microbes we are yet to discover!
The research has been published in Frontiers in Microbiology.
In the awful wake of an oil spill, it’s typically the smallest of organisms who do most of the cleaning up. Surprisingly, scientists know very little about the tools these tiny clean-up crews have at their disposal.
But now, thanks to a new study, researchers have uncovered a whole new cycle of natural hydrocarbon emissions and recycling facilitated by a diverse range of tiny organisms – which could help us better understand how some microbes have the power to clean up the mess an oil spill leaves in the ocean.
“Just two types of marine cyanobacteria are adding up to 500 times more hydrocarbons to the ocean per year than the sum of all other types of petroleum inputs to the ocean, including natural oil seeps, oil spills, fuel dumping and run-off from land,” said Earth scientist Connor Love from the University of California, Santa Barbara (UCSB).
But unlike more familiar human contributions of hydrocarbons into our ocean, this isn’t a one-way, local dump.
These hydrocarbons, primarily in the form of pentadecane (nC15), are spread across 40 percent of Earth’s surface, and other microbes feast on them. They’re constantly being cycled in such a way that Love and colleagues estimate only around 2 million metric tonnes are present in the water at any one time.
“Every two days you produce and consume all the pentadecane in the ocean,” Love explained.
(Luke Thompson, Chisholm Lab/Nikki Watson, MIT)
Above: A species of the globally distributed marine cyanobacteria, Prochlorococcus.
Today, humanity’s hydrocarbon footprints can be found in most aspects of our surroundings. We emit these molecules composed of only carbon and hydrogen atoms in many ways – the bulk through extraction and use of fossil fuels, but also from plastics, cooking, candles, painting, and the list goes on.
So it probably shouldn’t be a huge surprise that traces of our own emissions drowned out our ability to see the immense hydrocarbon cycle that naturally occurs in our oceans.
It took Love and colleagues some effort to clearly identify this global cycle for the first time.
Far from most human sources of hydrocarbons, in the nutrient-poor North Atlantic subtropical waters, the team had to position the ship they sampled from to face the wind, so the diesel fuel that also contains pentadecane did not contaminate the seven study sites. No one was permitted to cook, smoke or paint on deck during collections.
“I don’t know if you’ve ever been on a ship for an extended period of time, but you paint every day,” explained Earth scientist David Valentine from UCSB. “It’s like the Golden Gate Bridge: You start at one end and by the time you get to the other end it’s time to start over.”
Back on land, the researchers were able to confirm the pentadecane in their seawater samples were of biological origin, by using a gas chromatograph.
Analysing their data, they found concentrations of pentadecane increased with greater abundance of cyanobacteria cells, and the hydrocarbon’s geographic and vertical distribution were consistent with these microbe’s ecology.
Cyanobacteria Prochlorococcus and Synechococcus are responsible for around a quarter of the global ocean’s conversion of sunlight energy into organic matter (primary production) and previous laboratory cultivation revealed they produce pentadecane in the process.
Valentine explains the cyanobacteria likely use pentadecane as a stronger component for highly curved cellular membranes, like those found in chloroplasts (the organelle that photosynthesise).
The cycle of pentadecane in the ocean also follows the diel cycling of these cyanobacteria – their vertical migration in the water in response to changes of light intensity throughout a day.
Together, these findings suggest the cyanobacteria are indeed the source of the biological pentadecane, which is then consumed by other microorganisms that produce the carbon dioxide the cyanobacteria then use to continue the cycle.
Love’s team identified dozens of bacteria and surface-dwelling archaea that bloomed in response to the addition of pentadecane in their samples.
So they then tested to see if the hydrocarbon-consuming microbes could also break down petroleum. The researchers added a petroleum hydrocarbon to samples increasingly closer to areas with active oil seepage, in the Gulf of Mexico.
Unfortunately, only the sea samples from areas already exposed to non-biological hydrocarbons contained microbes that bloomed in response to consuming these molecules.
DNA tests showed genes thought to encode proteins that can degrade these hydrocarbons differed between the microbes, with a contrast evident between those that ate biological hydrocarbons and those that devoured the petroleum-sourced ones.
“We demonstrated that there is a massive and rapid hydrocarbon cycle that occurs in the ocean, and that it is distinct from the ocean’s capacity to respond to petroleum input,” said Valentine.
The researchers have begun sequencing the genomes of the microbes in their sample to further understand the ecology and physiology of the creatures involved in Earth’s natural hydrocarbon cycle.
“I think [these findings reveal] just how much we don’t know about the ecology of a lot of hydrocarbon-consuming organisms,” said Love.
This research was published in Nature Microbiology.
