Ingenuity is still flying on Mars. Here’s what the helicopter is up to

The Ingenuity Mars helicopter was never supposed to last this long. NASA engineers built and tested the first self-powered aircraft to fly on another planet to answer a simple question: Could the helicopter fly at all? The goal was to take five flights in 30 Martian days or break the aircraft trying.

But more than 120 Martian days past that experiment window, Ingenuity is still flying and doing things no one ever expected. The helicopter, which took its first flight on April 19, is breaking its own records for distance and speed (SN: 4/19/21). It’s helping the Perseverance rover explore Jezero crater, near an ancient river delta that may hold signs of past Martian life (SN: 2/17/21). And Ingenuity is coping with changing seasons and navigating over rough terrain, two things that the flier wasn’t designed to do.

“It’s gotten into a good groove,” says Ingenuity’s original chief engineer Bob Balaram NASA’s Jet Propulsion Lab in Pasadena, Calif. “It’s in its element and having fun.”

Here’s what Ingenuity has been up to on Mars.
Testing the limits
Ingenuity is flying farther, faster and higher than it did in its first few flights. The helicopter has lifted itself a maximum of 12 meters above the Martian surface, zipped along at up to five meters per second (about half as fast as record-setting sprinter Florence Griffith-Joyner) and covered 625 meters (about a third the length of the Kentucky Derby) in a single flight. These extremes give engineers valuable information about the limits of flying on Mars.

“We are still trying to learn lessons,” says JPL robotics engineer Teddy Tzanetos, a team leader for the Ingenuity mission. “Flight after flight, we’re learning the boundaries of performance.”
Early on, Ingenuity tested its limits in a way that the flight team really didn’t plan for. During its sixth flight on May 22, the helicopter’s navigation system suffered a glitch that made it roll and sway alarmingly.

The helicopter’s navigation software keeps track of the craft’s position by taking an image, reading the time stamp on that image and predicting what the camera should see next based on landmarks from previous photos that Ingenuity took. If the next image doesn’t match that prediction, the software corrects the helicopter’s position and velocity to match up better.

Less than a minute into the May 22 flight, a single image got lost on its way from Ingenuity’s cameras to its onboard computer. That meant that the time stamps on all subsequent images were a little off. In trying to correct what it perceived as errors, Ingenuity “went on a wild joyride,” Balaram says.

Luckily, the helicopter touched down safely within five meters of its intended landing spot. The anomaly was a blessing in disguise, Balaram says. It put the helicopter through extremes of movement — “how aggressively you can move the joystick, if you will” — that the engineers would not have asked it to do on purpose, and did perfectly fine, he says.

“It’s a serendipitous thing that we got that flight experience under our belt,” Balaram says. “We have much more confidence in the vehicle.”

Doing science
Originally, the helicopter team wanted to push the vehicle until it broke. But now the researchers are flying more cautiously and less often. That’s because the helicopter is currently supporting the Perseverance rover in doing science (SN: 4/30/21).

“We’re no longer in the Month of Ingenuity,” Tzanetos says. “We’re a small part of a much larger team.”

The helicopter has already proven its worth by telling the rover where not to go. Ingenuity’s ninth flight, on July 5, took the helicopter over a dune field called South Séítah that would have been difficult for the rover to drive through safely. Then, Ingenuity photographed some rock outcrops and raised ridges in South Séítah that had looked interesting in images taken from an orbiting spacecraft. Scientists thought those ridges could record some of the deepest water environments in the lake that filled the crater long ago.
In 3-D images from the helicopter, it turned out that those ridges did not show the layers that would have indicated that the rocks formed in deep water. The rover team decided to move on, saving Perseverance a long, arduous and potentially dangerous drive.

“They didn’t have to send the rover all the way to this particular target, and then realize, hey, this may not be the highest priority thing,” Balaram says.

Scouting for the rover has also taken Ingenuity over terrain that the helicopter wasn’t designed to understand. Ingenuity’s navigation software was programmed to assume that the ground beneath it is always flat because that was the type of terrain selected for that experimental first month of flight demonstrations.

“It was a perfectly reasonable simplification for a technology demonstration,” Balaram says. “But it was baked in. And now you’re stuck with a system with a flat ground assumption.”

When the helicopter is flying over a sloped surface, some features seem to move faster in its view than they would if the ground were flat, giving the helicopter a false sense of its motion. “The onboard navigation has no way of explaining it, except for thinking maybe I’m turning or spinning a bit,” Balaram says. The helicopter ends up veering to the side.

The team has come up with some work-arounds, such as choosing large enough landing zones that a precision landing isn’t necessary and slowing down when flying over rough terrain.

Coping with seasons
The air on Mars is notoriously thin (SN: 7/14/20). But since mid-September, the atmosphere in Jezero crater has been getting even thinner. As that part of Mars shifts from spring to summer, the air density has gone from about 1.5 percent of Earth’s at sea level, to about 1 percent.

That doesn’t sound like a big difference, but it’s enough that Ingenuity has had to spin its rotor blades faster to stay aloft. In October, the helicopter increased its rotor speed to 2,700 revolutions per minute, compared with a previous maximum of 2,537 rpm.
At that faster spin speed, the helicopter can fly for only 130 seconds at a time instead of the 170 seconds it managed before, without running the risk of the motors overheating.

That would be fine if the helicopter was just going to hang around the rover in one area, Tzanetos says. But the Mars duo’s next task is a race to the long-dry river delta at the mouth of Jezero crater. The Perseverance team hopes to cover hundreds of meters each Martian day. The farthest Ingenuity has covered in a day is 625 meters, and that was with the lower spin speed.

“It’ll be challenging to keep up,” Tzanetos says.

There’s no technical reason why Ingenuity can’t make it, though, Balaram says. “It’s certainly possible that one day it just won’t wake up. Or a landing will be a failure and we’ll never hear from it again because it tipped over,” he admits. “Those are rolls of the dice, there’s nothing inevitable about those. Barring that, it should keep working for many months.”

Inspiring future fliers
Meanwhile, engineers are already dreaming of the next Martian aircraft.

“Ingenuity is very exciting, we’re breaking a lot of ground,” Tzanetos says. “The whole point of it is to be that foundation. The important thing is what comes next.”

Current blueprints include a scaled-up version of Ingenuity that could carry more equipment and work alone or with a rover, and a large hexacopter, with six rotors arranged around a central ring. A craft like that could cover more ground more quickly than a rover, traveling distances that could take Perseverance multiple years in just a few months.

A white paper submitted to the 2023–2032 planetary science and astrobiology decadal survey — a once-a-decade review of the fields’ goals and priorities — suggests several possible missions for a Mars Science Helicopter. In one, the craft could take samples of clay minerals at a site like Mawrth Vallis, a channel thought to be carved by a long-ago flood.
Mawrth was a finalist for the last two Mars rover landing sites and is a contender for the European Space Agency’s Rosalind Franklin rover, set to launch in 2022. Clays can preserve organic material on Earth, so a mission to Mawrth could search for signs of life.

A helicopter could also explore craters with water ice deposits with slopes too steep for rover wheels. And by taking measurements at several different altitudes, the helicopter could help figure out how the atmosphere exchanges gases with the ground, which could help solve the mystery of when and how Mars lost its liquid water (SN: 11/12/20). Or a helicopter could map the magnetic field of large swaths of the Martian surface, revealing when and how the Red Planet lost its molten core (SN: 2/24/20).

And whenever astronauts get around to visiting Mars, “it might be useful to have fleets of drones zipping around the skies, carrying loads or scouting ahead,” Tzanetos says. “That’s the exciting future I’m looking forward to.”

2021 research reinforced that mating across groups drove human evolution

Evidence that cross-continental Stone Age networking events powered human evolution ramped up in 2021.

A long-standing argument that Homo sapiens originated in East Africa before moving elsewhere and replacing Eurasian Homo species such as Neandertals has come under increasing fire over the last decade. Research this year supported an alternative scenario in which H. sapiens evolved across vast geographic expanses, first within Africa and later outside it.

The process would have worked as follows: Many Homo groups lived during a period known as the Middle Pleistocene, about 789,000 to 130,000 years ago, and were too closely related to have been distinct species. These groups would have occasionally mated with each other while traveling through Africa, Asia and Europe. A variety of skeletal variations on a human theme emerged among far-flung communities. Human anatomy and DNA today include remnants of that complex networking legacy, proponents of this scenario say.

It’s not clear precisely how often or when during this period groups may have mixed and mingled. But in this framework, no clear genetic or physical dividing line separated Middle Pleistocene folks usually classed as H. sapiens from Neandertals, Denisovans and other ancient Homo populations.
“Middle Pleistocene Homo groups were humans,” says paleoanthropologist John Hawks of the University of Wisconsin–Madison. “Today’s humans are a remix of those ancient ancestors.”

New fossil evidence in line with that idea came from Israel. Braincase pieces and a lower jaw containing a molar tooth unearthed at a site called Nesher Ramla date to between about 140,000 and 120,000 years ago. These finds’ features suggest that a previously unknown Eurasian Homo population lived at the site (SN Online: 6/24/21), a team led by paleoanthropologist Israel Hershkovitz of Tel Aviv University reported. The fossils were found with stone tools that look like those fashioned around the same time by Middle Easterners typically classified as H. sapiens, suggesting that the two groups culturally mingled and possibly mated.

Interactions like these may have facilitated enough mating among mobile Homo populations to prevent Nesher Ramla inhabitants and other Eurasian groups from evolving into separate species, Hershkovitz proposed.

But another report provided a reminder that opinions still vary about whether Middle Pleistocene Homo evolution featured related populations that all belonged to the same species or distinct species. Researchers studying the unusual mix of features of a roughly 146,000-year-old Chinese skull dubbed it a new species, Homo longi (SN Online: 6/25/21). After reviewing that claim, however, another investigator grouped the skull, nicknamed Dragon Man, with several other Middle Pleistocene Homo fossils from northern China.

If so, Dragon Man — like Nesher Ramla Homo — may hail from one of many closely related Homo lines that occasionally mated with each other as some groups moved through Asia, Africa and Europe. From this perspective, Middle Pleistocene Homo groups evolved unique traits during periods of isolation and shared features as a result of crossing paths and mating.
Back-and-forth migrations by Homo groups between Africa and Asia started at least 400,000 years ago, discoveries in Saudi Arabia suggest (SN: 10/9/21 & 10/23/21, p. 7). Monsoon rains periodically turned what’s now desert into a green passageway covered by lakes, wetlands and rivers, reported archaeologist Huw Groucutt of the Max Planck Institute for the Science of Human History in Jena, Germany, and colleagues. Each of five ancient lake beds identified at a Saudi site once hosted hunter-gatherers who left behind stone tools.

Occupations occurred intermittently between about 400,000 and 55,000 years ago. By about 200,000 years ago, stone tools at one of the lake beds resembled those made around the same time by H. sapiens in northeastern Africa. Some of those Africans may have stopped for a bit in a green Arabia before trekking into southwestern Asia, Groucutt suggests.

Either H. sapiens or Neandertals made stone tools unearthed in the youngest lake bed. Neandertals inhabited parts of the Middle East by around 70,000 years ago and could have reached a well-watered Arabia by 55,000 years ago. If that’s what happened, Neandertals may have mated with H. sapiens already there, Groucutt speculates.

Although Arabian hookups have yet to be detected in ancient DNA, European Neandertals and H. sapiens mated surprisingly often around 45,000 years ago (SN: 5/8/21 & 5/22/21, p. 7), other scientists reported. DNA extracted from H. sapiens fossils of that age found in Bulgaria and the Czech Republic indicates that these ancient individuals possessed between about 2 percent and 4 percent Neandertal ancestry, a large amount considering H. sapiens migrants had only recently arrived in Europe.

So even after the Middle Pleistocene, networking among ancient Homo groups may have helped make us who we are today.

The cosmic ‘Cow’ may have produced a new neutron star or black hole

A cosmic flare-up called the Cow seems to have left behind a black hole or neutron star.

When the flash was spotted in June 2018, astronomers debated its origins. Now, astrophysicist DJ Pasham of MIT and colleagues have seen the first direct evidence of what the Cow left behind. “We may be seeing the birth of a black hole or neutron star,” Pasham says.

The burst’s official, random designation is AT2018cow, but astronomers affectionately dubbed it the Cow. The light originated about 200 million light-years away and was 10 times as bright as an ordinary supernova, the explosion that marks the death of a massive star.

Astronomers thought the flare-up could have been from an unusual star being eaten by a black hole or from a weird sort of supernova that left behind a black hole or neutron star (SN: 6/21/19).

So Pasham and colleagues checked the Cow for flickering X-rays, which are typically produced close to a compact object, possibly in a disk of hot material around a black hole or on the surface of a neutron star.

Flickers in these X-rays can reveal the size of their source. The Cow’s X-rays flicker roughly every 4 milliseconds, meaning the object that produces them must be no more than 1,000 kilometers wide. Only a neutron star or a black hole fits the bill, Pasham and colleagues report December 13 in Nature Astronomy.

Because the Cow’s flash was from the explosion that produced either of these objects, a preexisting black hole was probably not responsible for the burst. Pasham admits he was hoping for a black hole eating an exotic star. “I was a little bit disappointed,” he says. “But I’m more blown away that this could be direct evidence of the birth of a black hole. This is an even cooler result.”

Australian fires in 2019–2020 had even more global reach than previously thought

The severe, devastating wildfires that raged across southeastern Australia in late 2019 and early 2020 packed a powerful punch that extended far beyond the country, two new studies find.

The blazes injected at least twice as much carbon dioxide into the atmosphere as was previously thought, one team’s satellite-derived estimates revealed. The fires also sent up vast clouds of smoke and ash that wafted far to the east over the Southern Ocean, fertilizing the waters with nutrients and triggering widespread blooms of microscopic marine algae called phytoplankton, another team found. Both studies were published online September 15 in Nature.

Meteorologist Ivar van der Velde of the SRON Netherlands Institute for Space Research in Leiden and colleagues first examined carbon monoxide data collected over southeastern Australia by the satellite-based instrument TROPOMI from November 2019 to January 2020, during the worst of the fires. Then, to get new estimates of the carbon dioxide emissions attributable to the fires, the team used previously determined ratios of carbon monoxide to carbon dioxide emitted by the region’s eucalyptus forests — the predominant type of forest that was scorched in the blazes — during earlier wildfires and prescribed burns.

Van der Velde’s team estimates that the fires released from 517 trillion to 867 trillion grams of carbon dioxide to the atmosphere. “The sheer magnitude of CO2 that was emitted to the atmosphere … was much larger than what we initially thought it would be,” van der Velde says. The emissions “from this single event were significantly higher than what all Australians normally emit with the combustion of fossil fuels in an entire year.”
Previous assessments of CO2 emissions from the fires, based on estimations of burned area and biomass consumed by the blazes, calculated an average of about 275 trillion grams. Using the satellite-derived carbon monoxide data, the researchers say, dramatically improves the ability to distinguish actual emissions from the fires from other background sources of the gases, giving a more accurate assessment.

That finding has worrisome implications. The fires swiftly cut a swath through southeastern Australia’s eucalyptus forests, devastating the forests to a degree that made their rapid recovery more difficult — which in turn affects how much carbon the trees can sequester, van der Velde says (SN: 3/9/21). Fires in northern and central Australia’s dry, grassy savannas are seen as more climate neutral because the grasses can regrow more quickly, he says.

And severe fire seasons are likely to become more common in southeastern Australia with ongoing climate change. Climate change has already increased the likelihood of severe fire events such as the 2019–2020 fire season by at least 30 percent (SN: 3/4/20).

The smoke and ash from the fires also packed a powerful punch. Scientists watched in awe as the fires created a “super outbreak” of towering thunderclouds from December 29 to December 31 in 2019 (SN: 12/15/20). These clouds spewed tiny aerosol particles of ash and smoke high into the stratosphere.

Aerosols from the fires also traveled eastward through the lower atmosphere, ultimately reaching the Southern Ocean where they triggered blooms of phytoplankton in its iron-starved waters. Geochemist Weiyi Tang, now at Princeton University, and colleagues analyzed aerosols from the fires and found the particles to be rich in iron, an important nutrient for the algae. By tracing the atmospheric paths of the cloud of ash and smoke across the ocean, the team was able to link the observed blooms — huge patches of chlorophyll detected by satellite — to the fires.
Researchers have long thought that fires can trigger ocean blooms, particularly in the Southern Ocean, under the right conditions, says marine biogeochemist Joan Llort, now at the Barcelona Supercomputing Center and a coauthor on the study. But this research marks the most direct observation ever made of such an event — in part because it was such a massive one, Llort says.

Large ocean blooms are “yet another process which is potentially being modified by climate change,” says biogeochemist Nicolas Cassar of Duke University, also a coauthor on the study.

One of the big questions to emerge from the study, Cassar adds, is just how much carbon these phytoplankton may have ultimately removed from the atmosphere as they bloomed. Some of the carbon that the algae draw out of the air through photosynthesis sinks with them to the seafloor as they die. But some of it is quickly respired back to the atmosphere, muting any mitigating effect that the blooms might have on the wildfire emissions. To really assess what role the algae play, he says, would require a rapid-response team aboard an ocean vessel that could measure these chemical processes as they are happening.

The sheer size of this wildfire-triggered bloom — “larger than Australia itself” — shows that “wildfires have the potential to increase marine productivity by very large amounts,” says Douglas Hamilton, a climate scientist at Cornell University who was not connected with the study.

“The impact of fires on society is not straightforward,” Hamilton adds. The same smoke that can cause severe health impacts when inhaled “is also supplying nutrients to ecosystems and helping support marine food webs.” What this study demonstrates, he adds, is that to understand how future increases in fire activity might help shape the future of marine productivity “it is crucial that we monitor the impacts closely now.”

Rice feeds half the world. Climate change’s droughts and floods put it at risk

under a midday summer sun in California’s Sacramento Valley, rice farmer Peter Rystrom walks across a dusty, barren plot of land, parched soil crunching beneath each step.

In a typical year, he’d be sloshing through inches of water amid lush, green rice plants. But today the soil lies naked and baking in the 35˚ Celsius (95˚ Fahrenheit) heat during a devastating drought that has hit most of the western United States. The drought started in early 2020, and conditions have become progressively drier.

Low water levels in reservoirs and rivers have forced farmers like Rystrom, whose family has been growing rice on this land for four generations, to slash their water use.

Rystrom stops and looks around. “We’ve had to cut back between 25 and 50 percent.” He’s relatively lucky. In some parts of the Sacramento Valley, depending on water rights, he says, farmers received no water this season.

California is the second-largest U.S. producer of rice, after Arkansas, and over 95 percent of California’s rice is grown within about 160 kilometers of Sacramento. To the city’s east rise the peaks of the Sierra Nevada, which means “snowy mountains” in Spanish. Rice growers in the valley below count on the range to live up to its name each winter. In spring, melting snowpack flows into rivers and reservoirs, and then through an intricate network of canals and drainages to rice fields that farmers irrigate in a shallow inundation from April or May to September or October.

If too little snow falls in those mountains, farmers like Rystrom are forced to leave fields unplanted. On April 1 this year, the date when California’s snowpack is usually at its deepest, it held about 40 percent less water than average, according to the California Department of Water Resources. On August 4, Lake Oroville, which supplies Rystrom and other local rice farmers with irrigation water, was at its lowest level on record.
Not too long ago, the opposite — too much rain — stopped Rystrom and others from planting. “In 2017 and 2019, we were leaving ground out because of flood. We couldn’t plant,” he says. Tractors couldn’t move through the muddy, clay-rich soil to prepare the fields for seeding.

Climate change is expected to worsen the state’s extreme swings in precipitation, researchers reported in 2018 in Nature Climate Change. This “climate whiplash” looms over Rystrom and the other 2,500 or so rice producers in the Golden State. “They’re talking about less and less snowpack, and more concentrated bursts of rain,” Rystrom says. “It’s really concerning.”

Farmers in China, India, Bangladesh, Indonesia, Vietnam — the biggest rice-growing countries — as well as in Nigeria, Africa’s largest rice producer — also worry about the damage climate change will do to rice production. More than 3.5 billion people get 20 percent or more of their calories from the fluffy grains. And demand is increasing in Asia, Latin America and especially in Africa.

To save and even boost production, rice growers, engineers and researchers have turned to water-saving irrigation routines and rice gene banks that store hundreds of thousands of varieties ready to be distributed or bred into new, climate-resilient forms. With climate change accelerating, and researchers raising the alarm about related threats, such as arsenic contamination and bacterial diseases, the demand for innovation grows.

“If we lose our rice crop, we’re not going to be eating,” says plant geneticist Pamela Ronald of the University of California, Davis. Climate change is already threatening rice-growing regions around the world, says Ronald, who identifies genes in rice that help the plant withstand disease and floods. “This is not a future problem. This is happening now.”
Saltwater woes
Most rice plants are grown in fields, or paddies, that are typically filled with around 10 centimeters of water. This constant, shallow inundation helps stave off weeds and pests. But if water levels suddenly get too high, such as during a flash flood, the rice plants can die.

Striking the right balance between too much and too little water can be a struggle for many rice farmers, especially in Asia, where over 90 percent of the world’s rice is produced. Large river deltas in South and Southeast Asia, such as the Mekong River Delta in Vietnam, offer flat, fertile land that is ideal for farming rice. But these low-lying areas are sensitive to swings in the water cycle. And because deltas sit on the coast, drought brings another threat: salt.

Salt’s impact is glaringly apparent in the Mekong River Delta. When the river runs low, saltwater from the South China Sea encroaches upstream into the delta, where it can creep into the soils and irrigation canals of the delta’s rice fields.

“If you irrigate rice with water that’s too salty, especially at certain [growing] stages, you are at risk of losing 100 percent of the crop,” says Bjoern Sander, a climate change specialist at the International Rice Research Institute, or IRRI, who is based in Vietnam.

In a 2015 and 2016 drought, saltwater reached up to 90 kilometers inland, destroying 405,000 hectares of rice paddies. In 2019 and 2020, drought and saltwater intrusion returned, damaging 58,000 hectares of rice. With regional temperatures on the rise, these conditions in Southeast Asia are expected to intensify and become more widespread, according to a 2020 report by the Economic and Social Commission for Asia and the Pacific.

Then comes the whiplash: Each year from around April to October, the summer monsoon turns on the faucet over swaths of South and Southeast Asia. About 80 percent of South Asia’s rainfall is dumped during this season and can cause destructive flash floods.

Bangladesh is one of the most flood-prone rice producers in the region, as it sits at the mouths of the Ganges, Brahmaputra and Meghna rivers. In June 2020, monsoon rains flooded about 37 percent of the country, damaging about 83,000 hectares of rice fields, according to Bangladesh’s Ministry of Agriculture. And the future holds little relief; South Asia’s monsoon rainfall is expected to intensify with climate change, researchers reported June 4 in Science Advances.
A hot mess
Water highs and lows aren’t the entire story. Rice generally grows best in places with hot days and cooler nights. But in many rice-growing regions, temperatures are getting too hot. Rice plants become most vulnerable to heat stress during the middle phase of their growth, before they begin building up the meat in their grains. Extreme heat, above 35˚ C, can diminish grain counts in just weeks, or even days. In April in Bangladesh, two consecutive days of 36˚ C destroyed thousands of hectares of rice.

In South and Southeast Asia, such extreme heat events are expected to become common with climate change, researchers reported in July in Earth’s Future. And there are other, less obvious, consequences for rice in a warming world.

One of the greatest threats is bacterial blight, a fatal plant disease caused by the bacterium Xanthomonas oryzae pv. oryzae. The disease, most prevalent in Southeast Asia and rising in Africa, has been reported to have cut rice yields by up to 70 percent in a single season.

“We know that with higher temperature, the disease becomes worse,” says Jan Leach, a plant pathologist at Colorado State University in Fort Collins. Most of the genes that help rice combat bacterial blight seem to become less effective when temperatures rise, she explains.

And as the world warms, new frontiers may open for rice pathogens. An August study in Nature Climate Change suggests that as global temperatures rise, rice plants (and many other crops) at northern latitudes, such as those in China and the United States, will be at higher risk of pathogen infection.

Meanwhile, rising temperatures may bring a double-edged arsenic problem. In a 2019 study in Nature Communications, E. Marie Muehe, a biogeochemist at the Helmholtz Centre for Environmental Research in Leipzig, Germany, who was then at Stanford University, showed that under future climate conditions, more arsenic will infiltrate rice plants. High arsenic levels boost the health risk of eating the rice and impair plant growth.
Arsenic naturally occurs in soils, though in most regions the toxic element is present at very low levels. Rice, however, is particularly susceptible to arsenic contamination, because it is grown in flooded conditions. Paddy soils lack oxygen, and the microbes that thrive in this anoxic environment liberate arsenic from the soil. Once the arsenic is in the water, rice plants can draw it in through their roots. From there, the element is distributed throughout the plants’ tissues and grains.

Muehe and her team grew a Californian variety of rice in a local low-arsenic soil inside climate-controlled greenhouses. Increasing the temperature and carbon dioxide levels to match future climate scenarios enhanced the activity of the microbes living in the rice paddy soils and increased the amount of arsenic in the grains, Muehe says. And importantly, rice yields diminished. In the low-arsenic Californian soil under future climate conditions, rice yield dropped 16 percent.

According to the researchers, models that forecast the future production of rice don’t account for the impact of arsenic on harvest yields. What that means, Muehe says, is that current projections are overestimating how much rice will be produced in the future.

Managing rice’s thirst
From atop an embankment that edges one of his fields, Rystrom watches water gush from a pipe, flooding a paddy packed with rice plants. “On a year like this, we decided to pump,” he says.

Able to tap into groundwater, Rystrom left only about 10 percent of his fields unplanted this growing season. “If everybody was pumping from the ground to farm rice every year,” he admits, it would be unsustainable.

One widely studied, drought-friendly method is “alternate wetting and drying,” or intermittent flooding, which involves flooding and draining rice paddies on one- to 10-day cycles, as opposed to maintaining a constant inundation. This practice can cut water use by up to 38 percent without sacrificing yields. It also stabilizes the soil for harvesting and lowers arsenic levels in rice by bringing more oxygen into the soils, disrupting the arsenic-releasing microbes. If tuned just right, it may even slightly improve crop yields.

But the water-saving benefits of this method are greatest when it is used on highly permeable soils, such as those in Arkansas and other parts of the U.S. South, which normally require lots of water to keep flooded, says Bruce Linquist, a rice specialist at the University of California Cooperative Extension. The Sacramento Valley’s clay-rich soils don’t drain well, so the water savings where Rystrom farms are minimal; he doesn’t use the method.

Building embankments, canal systems and reservoirs can also help farmers dampen the volatility of the water cycle. But for some, the solution to rice’s climate-related problems lies in enhancing the plant itself.
Better breeds
The world’s largest collection of rice is stored near the southern rim of Laguna de Bay in the Philippines, in the city of Los Baños. There, the International Rice Genebank, managed by IRRI, holds over 132,000 varieties of rice seeds from farms around the globe.

Upon arrival in Los Baños, those seeds are dried and processed, placed in paper bags and moved into two storage facilities — one cooled to 2˚ to 4˚ C from which seeds can be readily withdrawn, and another chilled to –20˚ C for long-term storage. To be extra safe, backup seeds are kept at the National Center for Genetic Resources Preservation in Fort Collins, Colo., and the Svalbard Global Seed Vault tucked inside a mountain in Norway.

All this is done to protect the biodiversity of rice and amass a trove of genetic material that can be used to breed future generations of rice. Farmers no longer use many of the stored varieties, instead opting for new higher-yield or sturdier breeds. Nevertheless, solutions to climate-related problems may be hidden in the DNA of those older strains. “Scientists are always looking through that collection to see if genes can be discovered that aren’t being used right now,” says Ronald, of UC Davis. “That’s how Sub1 was discovered.”
The Sub1 gene enables rice plants to endure prolonged periods completely submerged underwater. It was discovered in 1996 in a traditional variety of rice grown in the Indian state of Orissa, and through breeding has been incorporated into varieties cultivated in flood-prone regions of South and Southeast Asia. Sub1-wielding varieties, called “scuba rice,” can survive for over two weeks entirely submerged, a boon for farmers whose fields are vulnerable to flash floods.

Some researchers are looking beyond the genetic variability preserved in rice gene banks, searching instead for useful genes from other species, including plants and bacteria. But inserting genes from one species into another, or genetic modification, remains controversial. The most famous example of genetically modified rice is Golden Rice, which was intended as a partial solution to childhood malnutrition. Golden Rice grains are enriched in beta-carotene, a precursor to vitamin A. To create the rice, researchers spliced a gene from a daffodil and another from a bacterium into an Asian variety of rice.

Three decades have passed since its initial development, and only a handful of countries have deemed Golden Rice safe for consumption. On July 23, the Philippines became the first country to approve the commercial production of Golden Rice. Abdelbagi Ismail, principal scientist at IRRI, blames the slow acceptance on public perception and commercial interests opposed to genetically modified organisms, or GMOs (SN: 2/6/16, p. 22).

Looking ahead, it will be crucial for countries to embrace GM rice, Ismail says. Developing nations, particularly those in Africa that are becoming more dependent on the crop, would benefit greatly from the technology, which could produce new varieties faster than breeding and may allow researchers to incorporate traits into rice plants that conventional breeding cannot. If Golden Rice were to gain worldwide acceptance, it could open the door for new genetically modified climate- and disease-resilient varieties, Ismail says. “It will take time,” he says. “But it will happen.”

Climate change is a many-headed beast, and each rice-growing region will face its own particular set of problems. Solving those problems will require collaboration between local farmers, government officials and the international community of researchers.

“I want my kids to be able to have a shot at this,” Rystrom says. “You have to do a lot more than just farm rice. You have to think generations ahead.”

50 years ago, chemical pollutants were linked to odd animal behavior

For fish and other underwater life, a sensitivity to chemicals plays the same role as the sense of smell does for land animals.… [Researchers] have been studying the subtle ways this delicate fish-communication system can be disrupted by pollutants…. One study examined the effects of kerosene pollution on the behavior of lobsters…. The experiments demonstrate that chemical communication interference takes place at extremely low dilutions.

Update
Chemical pollution — from sewage and agricultural runoff to pharmaceutical waste — muddles aquatic animals’ senses with potentially dire effects, decades of research has shown. A chemical used to treat sewage seems to limit some fish species’ abilities to form schools, making the fish vulnerable to predators (SN: 10/27/07, p. 262). Drug-tainted waters can have a variety of effects on fish, including suppressing their appetites (SN: 12/20/08, p. 15). A plastic chemical also appears to confuse senses: Its scent can lure sea turtles into eating plastic debris (SN: 3/28/20, p. 14).

How AI can help forecast how much Arctic sea ice will shrink

In the next week or so, the sea ice floating atop the Arctic Ocean will shrink to its smallest size this year, as summer-warmed waters eat away at the ice’s submerged edges.

Record lows for sea ice levels will probably not be broken this year, scientists say. In 2020, the ice covered 3.74 million square kilometers of the Arctic at its lowest point, coming nail-bitingly close to an all-time record low. Currently, sea ice is present in just under 5 million square kilometers of Arctic waters, putting it on track to become the 10th-lowest extent of sea ice in the area since satellite record keeping began in 1979. It’s an unexpected finish considering that in early summer, sea ice hit a record low for that time of year.

The surprise comes in part because the best current statistical- and physics-based forecasting tools can closely predict sea ice extent only a few weeks in advance, but the accuracy of long-range forecasts falters. Now, a new tool that uses artificial intelligence to create sea ice forecasts promises to boost their accuracy — and can do the analysis relatively quickly, researchers report August 26 in Nature Communications.

IceNet, a sea ice forecasting system developed by the British Antarctic Survey, or BAS, is “95 percent accurate in forecasting sea ice two months ahead — higher than the leading physics-based model SEAS5 — while running 2,000 times faster,” says Tom Andersson, a data scientist with BAS’s Artificial Intelligence lab. Whereas SEAS5 takes about six hours on a supercomputer to produce a forecast, IceNet can do the same in less than 10 seconds on a laptop. The system also shows a surprising ability to predict anomalous ice events — unusual highs or lows — up to four months in advance, Andersson and his colleagues found.
Tracking sea ice is crucial to keeping tabs on the impacts of climate change. While that’s more of a long game, the advanced notice provided by IceNet could have more immediate benefits, too. For instance, it could give scientists the lead time needed to assess, and plan for, the risks of Arctic fires or wildlife-human conflicts, and it could provide data that Indigenous communities need to make economic and environmental decisions.

Arctic sea ice extent has steadily declined in all seasons since satellite records began in 1979 (SN: 9/25/19). Scientists have been trying to improve sea ice forecasts for decades, but success has proved elusive. “Forecasting sea ice is really hard because sea ice interacts in complex ways with the atmosphere above and ocean below,” Andersson says.
Existing forecast tools put the laws of physics into computer code to predict how sea ice will change in the future. But partly due to uncertainties in the physical systems governing sea ice, these models struggle to produce accurate long-range forecasts.

Using a process called deep learning, Andersson and his colleagues loaded observational sea ice data from 1979 to 2011 and climate simulations covering 1850 to 2100 to train IceNet how to predict the state of future sea ice by processing the data from the past.

To determine the accuracy of its forecasts, the team compared IceNet’s outputs to the observed sea ice extent from 2012 to 2020, and to the forecasts made by SEAS5, the widely cited tool used by the European Centre for Medium-Range Weather Forecasts. IceNet was as much as 2.9 percent more accurate than SEAS5, corresponding to a further 360,000 square kilometers of ocean being correctly labeled as “ice” or “no ice.”

What’s more, in 2012, a sudden crash in summer sea ice extent heralded a new record low extent in September of that year. In running through past data, IceNet saw the dip coming months in advance. SEAS5 had inklings too but its projections that far out were off by a few hundred thousand square kilometers.

“This is a significant step forward in sea ice forecasting, boosting our ability to produce accurate forecasts that were typically not thought possible and run them thousands of times faster,” says Andersson. He believes it’s possible that IceNet has better learned the physical processes that determine the evolution of sea ice from the training data while physics-based models still struggle to understand this information.

“These machine learning techniques have only begun contributing to [forecasting] in the last couple years, and they’ve been doing amazingly well,” says Uma Bhatt, an atmospheric scientist at the University of Alaska Fairbanks Geophysical Institute who was not involved in the new study. She also leads the Sea Ice Prediction Network, a group of multidisciplinary scientists working to improve forecasting.

Bhatt says that good seasonal ice forecasts are important for assessing the risk of Arctic wildfires, which are tied strongly to the presence of sea ice (SN: 6/23/20). “Knowing where the sea ice is going to be in the spring could potentially help you figure out where you’re likely to have fires — in Siberia, for example, as soon as the sea ice moves away from the shore, the land can warm up very quickly and help set the stage for a bad fire season.”

Any improvement in sea ice forecasting can also help economic, safety and environmental planning in northern and Indigenous communities. For example, tens of thousands of walruses haul out on land to rest when the sea ice disappears (SN: 10/2/14). Human disturbances can trigger deadly stampedes and lead to high walrus mortality. With seasonal ice forecasts, biologists can anticipate rapid ice loss and manage haul-out sites in advance by limiting human access to those locations.

Still, limitations remain. At four months of lead time, the system was about 91 percent accurate in predicting the location of September’s ice edge.IceNet, like other forecasting systems, struggles to produce accurate long-range forecasts for late summer due, in part, to what scientists call the “spring predictability barrier.” It’s crucial to know the condition of the sea ice at the start of the spring melting season to be able to forecast end-of-summer conditions.

Another limit is “the fact that the weather is so variable,” says Mark Serreze, director of the National Snow and Ice Data Center in Boulder, Colo. Though sea ice seemed primed to set a new annual record low at the start of July, the speed of ice loss ultimately slowed due to cool atmospheric temperatures. “We know that sea ice responds very strongly to summer weather patterns, but we can’t get good weather predictions. Weather predictability is about 10 days in advance.”

Dog DNA reveals ancient trade network connecting the Arctic to the outside world

Ancient Arctic communities traded with the outside world as early as 7,000 years ago, DNA from the remains of Siberian dogs suggests.

Analysis of the DNA shows that Arctic pups thousands of years ago were interbreeding with other dogs from Europe and the Near East, even while they and their owners were living in one of the most remote places on Earth. Along with previous archaeological finds, these results suggest that Siberians long ago were connected to a vast trade network that may have extended as far as the Mediterranean and the Caspian Sea, researchers report in the Sept. 28 Proceedings of the National Academy of Sciences.

Dogs have been valuable commodities in the Arctic for the last 9,500 years and have been used for sledding, hunting, herding reindeer, clothing and food. Because the region is remote, scientists thought local dogs — and their owners — had been completely isolated from the rest of the world for much of that time, an idea supported by the fact that ancient Siberians didn’t exchange much DNA with people outside of the region, says Tatiana Feuerborn, an archaeologist at the University of Copenhagen.

But previous archaeological evidence — including the discovery of glass beads and other foreign goods entombed alongside 2,000-year-old dogs near the Yamal Peninsula in Russia — suggested that these communities were trading with other cultures beyond the Arctic.
After reading about the archaeological evidence in the news, Feuerborn wanted to see if she could use remains from the 2,000-year-old dogs and others from around Siberia to reveal whether an ancient trade network existed.

Dogs rarely wander far from their humans, meaning researchers can “use dogs to understand human movement, like migrations and even trade interactions,” says Kelsey Witt, a geneticist at Brown University in Providence, R.I., who was not involved in the study. For instance, archaeologists have used ancient dog DNA to push back the arrival date of people in the Americas (SN: 3/1/21).
In the new study, Feuerborn and colleagues analyzed DNA from the remains of 49 Siberian dogs, ranging from 11,000-year-old bone fragments to fur hoods used by Arctic explorers at the turn of the 20th century. The team found that Siberian dogs — unlike their owners — began mixing with other dog populations from the Eurasian steppes, the Near East and even Europe as far back as 7,000 years ago.

The result suggests that Siberians did bring in dogs from the outside world, Feuerborn says. This trade network could have helped transmit new ideas and technologies, such as metalworking, to the Arctic, and may have facilitated Siberian society’s transition from foraging to reindeer herding in the last 2,000 years.

“Dogs are a piece of our past,” Feuerborn says. “By looking at them, we can learn something about ourselves.”

Here’s what the next 10 years of space science could look like

The Astronomy and Astrophysics Decadal Survey is basically a sneak preview of the next 10 years of U.S. space science. Every decade, experts assembled by the National Academies of Sciences, Engineering and Medicine collect input from astronomers nationwide to recommend a prioritized list of projects to policy makers and federal agencies. Past to-do lists have been topped by specific big-ticket items, such as the James Webb Space Telescope and the Nancy Grace Roman Space Telescope (SN: 10/6/21; SN: 8/13/10). But this year, astronomers are shaking things up.

The latest decadal survey, which charts the course for U.S. astronomy and astrophysics from 2022 to 2032, recommends that NASA create a new program to develop several major space telescopes at a time. Investing early in multiple mission concepts could curb the risk of individual missions becoming too unwieldy and expensive, according to the report released November 4.

“These are super important recommendations,” says Scott Gaudi, an astronomer at the Ohio State University who wasn’t on the National Academies committee that compiled the report. “They really focus the direction of astronomy in the United States — and sort of by extension the rest of the world, because we have lots of international partnerships.”

The proposed multi-mission program would reshape how major space missions are planned. In the past, “you would pick a priority, you’d build it, you’d launch it, and then you would think about what the next priority was,” says Jonathan Fortney, an astrophysicist at the University of California, Santa Cruz and a member of the survey committee.
But space telescopes are getting more ambitious, complex and expensive, Fortney says. The one-at-a-time model doesn’t work so well when a single mission can take decades from blueprint to blastoff.

Having several big projects in the works offers a bit of insurance. If researchers work on one mission for a few years and realize that the technology isn’t there to make it fly on time, NASA could switch gears and send another telescope to space first, Fortney says. Developing multiple missions in parallel could also shrink the long wait time between launches.

“I’m so excited by that. It’s like the best possible outcome,” Gaudi says. This setup could boost confidence that big space missions can stay on budget and on schedule, he adds, after the large cost overruns and delays that have mired the long-awaited James Webb Space Telescope. “It is a really new way of approaching things, and one that’s really needed to advance astronomy into the next few decades.”

The first mission in the new program, according to the survey report, should be a space telescope that views the universe in infrared, optical and ultraviolet wavelengths, filling a gap left by other instruments. The Hubble Space Telescope mainly looks at optical and ultraviolet light, while the James Webb telescope will primarily see the universe in infrared.
With a light-collecting area more than twice as wide as Hubble’s, this newfangled observatory could glimpse planets in other star systems that are a tenth of a billionth as bright as their stars, and could tease out the specific wavelengths of light, or spectra, given off by exoplanets. The telescope could also observe stars, galaxies and other celestial objects. With an estimated price tag of $11 billion, the telescope would be slated to launch in the early 2040s.

Five years after starting work on that first flagship mission, NASA should begin developing both a far-infrared mission and an X-ray mission, each costing an estimated $3 billion to $5 billion, the survey recommends.

A far-infrared window into the universe could help astronomers study how water behaves in forming planetary systems, Fortney says. A successor to NASA’s 22-year-old Chandra X-ray Observatory could reveal new details of galaxy evolution, supermassive black hole behavior and other energetic phenomena (SN: 7/25/19).

On the ground, astronomers’ highest priorities, according to the decadal survey, are continuing to build two major optical observatories, the Giant Magellan Telescope in Chile and the Thirty Meter Telescope in Hawaii — though the latter project has faced controversy (SN: 8/5/20).

The survey also notes that it is time to replace the Very Large Array in New Mexico and the Very Long Baseline Array of telescope dishes scattered across the United States. The proposed successor to these world-class radio observatories is the Next-Generation Very Large Array, which would be 10 times as sensitive.

Fortney is optimistic that NASA and other federal agencies will make the decadal survey’s top-ranked priorities a reality. “The record has been quite good, in terms of the most prominent recommendations being born out,” he says. “I have really high confidence that these things really will happen.”