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Don’t let the name fool you. Flamboyant cuttlefish (Metasepia pfefferi) look anything but flashy most of the time. Images and videos of the marine mollusks flashing bright purple and yellow hues litter the internet, perpetuating the idea that these animals are constantly putting on a show in the wild. But a new study proves just the opposite: Flamboyant cuttlefish spend most of their time looking like a pile of mud.

“These animals have superb camouflage,” says Roger Hanlon, a marine biologist at the Marine Biological Laboratory in Woods Hole, Mass. Specialized cells and structures in their skin allow the animals to instantly morph into ostentatious patterns, as well as blend in.

Keen to see how the animals balanced flamboyance with camo in nature, Hanlon organized two field studies in a cuttlefish habitat off the coast of North Sulawesi, Indonesia. Citizen scientist divers scouted the Lembeh Strait area over eight days in 2002 and again for 11 days in 2019, being careful to eavesdrop without disturbing the animals.  Video footage collected by the team now reveals intimate details of the species’ mating practices and defensive behaviors as well as what the animals do in their downtime. Hanlon and Gwendolyn McManus, a marine biology student at Northeastern University in Boston, describe the results in the August Journal of Experimental Marine Biology and Ecology.

The solitary species slowly ambles along the seafloor, foraging in a drab region of mud and sand between coral reefs. “It’s like a moonscape or a desert,” says Hanlon. Flamboyant cuttlefish take on the color and texture of their muddy seafloor backdrop and masquerade as a lump of sand or a rock. Like some other cephalopods, these cuttlefish spend most of their time incognito, reserving their displays for special occasions: confusing a predator, courting a mate and sparring with rival suitors.

Flashing their good looks 24/7 would attract unwanted attention. But it comes in handy if their first line of defense — camouflage — fails. Then, both males and females will engage in a campaign of unpredictability. When confronted by a threat, the animal might quickly flash its colors to frighten the predator, sometimes in just 700 milliseconds. Next, it cycles through other confusing behaviors — jetting, shooting ink and reverting to camouflage — until it has eluded the enemy.

Males also show flamboyant displays to attract the ladies. After spotting a female in the distance, a male will flaunt bright colors and undulate their mantle stripes in a move called “the passing cloud.” Researchers also observed two types of gestures during this colorful routine: arm waving (reminiscent of a human bowing) and kissing (a tap on the female’s arm with his arms). “These displays are really elaborate and dynamic,” says Hanlon. “And they’re comparable to what some of the most sophisticated birds do and even some primates.”

Love triangles happen, and males sometimes guard females and fight off other males (SN: 5/12/17). In brawls, male body patterns split flirting and fighting. The side facing the female flashes the bright motif, while the side facing the male takes on an aggressive white pattern.

All of this pizzazz can put males at risk. Hanlon recalls an instance where a male swimming backward got scarfed up by a scorpion fish in the midst of his flamboyant display. “There’s the price you pay for displaying to a female not paying attention to where you’re going,” says Hanlon.

But the risk can come with reward — for some lucky guys. Eventually, a female may open her arms and mate for a quick three seconds. Figuring out exactly what flirting tactics a female uses to select her mate requires more data. “Does she focus on the male’s courtship dance? On his ‘kiss’ signal? Or on how bright his passing cloud is? It’s too soon to tell,” says Alex Schnell, a wildlife scientist at Cambridge University who was not affiliated with the study.

Males also got shot down a lot, as picky females appear largely unmoved by most of their showmanship. Of 108 kisses observed, only 20 led to something more. The observations hint that the most successful males might be the ones that worked the hardest and remained persistent.

The field observations fill in knowledge gaps about how these animals survive in the wild and contradict two previous studies in a lab and an aquarium, as well as photos and videos from scuba divers, that suggested that the animals displayed their flamboyant patterns more frequently. Looming humans, bright lights and higher density tanks may have shifted the behavior of a species that spends most of its time alone and under the radar.

In the United States, the average wait time for COVID-19 test results is about four days. Even worse, 10 percent of individuals don’t receive lab results for 10 days or more.

Quick reporting of test results helps identify infected individuals so they and anyone they potentially spread the coronavirus to can be isolated, preventing further spread of the virus.

“If you have a 14-day lag to knowing if someone is actually sick and contagious, then they’ll interact with many, many more people in that period than if you have a one-day or a six-hour or one-hour turnaround,” says Omar Abudayyeh, a bioengineer at MIT.

Abudayyeh is among the many researchers and companies racing to develop new and speedier types of diagnostic tests that circumvent clinical labs altogether. Some of these tests complete their analyses in all-in-one machines that are portable enough to be set up in schools, nursing homes and offices. Several companies are developing tests like these that can diagnose COVID-19 in 30 minutes or less, with a level of accuracy comparable to lab tests. Others are harnessing the power of the gene editor CRISPR to deliver rapid results.

And another type of test, made by Abbott Laboratories and granted emergency use authorization by the U.S. Food and Drug Administration on August 26, works more like a pregnancy test. All it requires is a test card the size of a credit card, a few drops of a reaction solution and a sample from a nasal swab. Within 15 minutes, two lines appear on the card if the sample contains the virus; one line appears if it doesn’t. 

The gold standard

The current gold standard for accurate COVID-19 testing is PCR, or polymerase chain reaction, which can detect even tiny quantities of the virus’s genetic material, RNA (SN: 3/6/20).

The test requires collecting viral RNA directly from the patient, typically gathered using a swab inserted deep into the nasal cavity. At a clinical laboratory, the virus’s RNA is converted to DNA and then run through a specialized instrument that heats and cools that DNA to multiply copies of it, making it easier to detect. After repeating the process for around an hour, if DNA shows up, the sample is considered positive for SARS-CoV-2, the virus that causes COVID-19.

Such tests are fairly accurate. They miss some people very early in the infection or because of lab errors, producing false negatives, meaning that the test results indicate someone isn’t infected when they really are. False positives — when tests wrongly indicate an uninfected person has the virus — are rare with this type of technology. So if a PCR test indicates a person is infected, they probably do carry the virus. The main drawback is the speed. It typically takes days to get results back, and backups at labs can drag the process out for a week or two.

Some people find the nasal probe uncomfortable, so other lab tests have been developed that rely on less invasive samples. On August 15, the FDA authorized a saliva-based test, SalivaDirect, for emergency use. This isn’t the first test to detect the SARS-CoV-2 virus in saliva, which is easier to collect than samples from nasal passages. But its simplified protocol speeds up sample preparation and bypasses testing supplies that have been in short supply in recent months. SalivaDirect, however, is not a rapid test. It still requires processing by clinical laboratories, which contributes to the wait time between providing a sample and receiving results.

To develop faster tests, companies are taking a variety of approaches. Funding for some of this work comes from the Rapid Acceleration of Diagnostics initiative, or RADx, from the National Institutes of Health, which has invested $248.7 million in seven companies tackling testing challenges.

San Diego–based Mesa Biotech, for instance, received RADx funding to manufacture a PCR test that replaces an entire clinical lab with a handheld dock and a single-use cartridge. The company says the proprietary technology in its Accula test, which has already received FDA emergency use authorization, can provide a COVID-19 diagnosis in just 30 minutes.

Turning on the LAMP

Other RADx-funded companies, such as Talis Biomedical, headquartered in Menlo Park, Calif., aren’t using PCR to amplify SARS-CoV-2 viral material. The Talis One system instead uses LAMP, or loop-mediated isothermal amplification. In a typical LAMP assay, a patient’s nasal or oral swab sample is mixed with enzymes and specially designed DNA fragments, then heated to 65° Celsius to copy the viral RNA to DNA and produce many more DNA copies. With the Talis test, samples are placed in a cassette, popped into a specialized dock, and analyzed in just 30 minutes.

As opposed to an instrument that cycles between hot and cold, LAMP heats the reaction to one temperature. “You could run the reaction in a water bath,” says Nathan Tanner, a molecular biologist at New England Biolabs in Ipswich, Mass.

In general, LAMP-based diagnostic tests aren’t quite as sensitive as ones based on PCR, Tanner says, but could be used to test more people, given their simpler requirements. In one newly described LAMP testing method, a solution changes color in the presence of 100 or more SARS-CoV-2 RNA molecules. The authors, who describe the test August 12 in Science Translational Medicine, propose that the approach, which didn’t detect the lowest viral loads, would be suitable for identifying individuals with a moderate to high viral load.

Telltale proteins

A third RADx-funded test provides results in a mere 15 minutes. Rather than detecting viral RNA, the test, by Quidel, based in San Diego, detects proteins from virus particles. These viral proteins are also antigens, meaning they stimulate immune responses when they invade our bodies. Such antigen tests are similar to ones used in doctors’ offices and pharmacies to diagnose people with influenza.

Don’t confuse antigen tests with an antibody test that detects antibodies a person develops in response to an infection (SN: 4/28/20) Much like a pregnancy test, COVID-19 antigen tests use antibodies to detect the viral proteins and give a yes or no answer, says Kim Hamad-Schifferli, a bioengineer at the University of Massachusetts Boston.  

The Quidel Sofia SARS antigen test has been authorized for emergency use. Like the other RADx-funded rapid tests, it uses a dock and single-use cartridges: Instead of making a line on stick the way a pregnancy test does, the dock detects a fluorescent signal if SARS-CoV-2 proteins are present.

Abbott Laboratories’ test granted emergency use authorization August 26 also is an antigen test and, with its card-based technology, is even simpler. Abbott, based in Abbott Park, Ill., said its test was able to detect 34 of 35 COVID-19-positive patients with symptoms, or 97 percent, in initial studies.

The benefit: An antigen test doesn’t require any specialized lab instruments or enzymes. “It’s all self-contained,” Hamad-Schifferli says. Without a step to amplify viral material, however, an antigen test can be less sensitive than PCR or LAMP and result in a higher rate of false-negative results, up to 20 percent per the FDA’s emergency use authorization guidelines for antigen tests.

That’s because people may produce widely varying amounts of virus, depending on how long has passed since they became infected. In most people, the coronavirus is most abundant from a couple of days after infection to about nine days into the illness (SN: 3/13/20). After that, the immune system kicks in, preventing viruses from being made. On the other hand, viral RNA can be detectable in some people for more than a month.  A negative result from an antigen test has a higher chance of being false comfort, so the FDA says that diagnosis may need to be confirmed with another type of test, like PCR.

A new kind of rapid test

Even though antigen tests typically are not as accurate as standard PCR or the new rapid tests, they could play a crucial role helping to end the pandemic — if their use becomes widespread. As of now, though, even Abbott’s 15-minute test still needs to be ordered by a doctor and performed in a health care setting, so that can provide hurdles to its use. But what if people didn’t even have to leave home to get a test?

That’s what Hamad-Schifferli and her colleagues are working on. The idea is to build a cheaper test that doesn’t involve a dedicated instrument — just a paper strip and a signal detectable by eye. Such a simple test could be used more widely by people at home. “It would be a game changer,” she says.

If COVID-19 tests are deployed widely enough, they could serve as a public health measure to identify people with high levels of SARS-CoV-2 and spreading the virus to others, even if they’re not displaying symptoms. That’s because frequent and fast tests can be used to pinpoint outbreaks as they are happening (SN: 7/1/20).  If cheap enough, these tests could be used by people daily, catching any missed detections through repeated rounds of testing.

The United States is currently testing nearly 700,000 people a day on average, based on data from August 21 through August 27. Michael Mina, however, wants to see even more tests, like “200 million tests … every day in this country.” Surveillance provided by such widespread testing “will effectively do the same thing as a vaccine” in slowing the spread of the coronavirus says Mina, an epidemiologist at the Harvard T.H. Chan School of Public Health in Boston.

But for daily, population-wide testing that could alert people when they first start transmitting the coronavirus to be adopted, a test needs to be cheap enough — for instance, under a dollar — for many people to use them frequently. Abbott said its tests would cost $5. Quidel’s test cartridges cost $23 apiece and the other RADx-funded rapid tests are likely in a similar price range. Given their higher accuracy, those tests could serve a separate purpose: to conclusively determine if an individual is infected and ensure they receive treatment.

The holy grail of tests may be one that is fast, easy, accurate and inexpensive and that could be used broadly — even by people at home. One group of scientists may be among those nearing that goal. The work is led by Abudayyeh, Jonathan Gootenberg and Feng Zhang, all bioengineers at the McGovern Institute for Brain Research at MIT. Zhang is also at the Broad Institute of MIT and Harvard University.

The team adapted an FDA-authorized test by Sherlock Biosciences in Cambridge, Mass., that uses the gene-editing tool CRISPR. All someone has to do is add a sample — either from a nasal swab or saliva — to a tube with a reaction solution, heat the tube to 60° C for an hour in a pot of water, then add a paper test strip to the tube. If two lines appear, that means SARS-CoV-2 RNA is present.

The readout relies on activity of a CRISPR enzyme, Cas12b. If SARS-CoV-2 RNA is present in the reaction, Cas12b cuts what’s called a reporter, a short piece of DNA that’s labeled on both ends. The two halves of the reporter then wick up the paper strip to different places and appear as two lines. If viral RNA isn’t present, the reporter remains intact and wicks up the strip to one place, showing up as one line.

The new test, STOPCovid, is not yet authorized for clinical use, but based on tests in a small number of patients, it identifies SARS-CoV-2 cases as well as PCR tests, the researchers reported May 8 in a preprint posted at medRxiv.org. It returns results in about an hour and would cost under $10, they say.

Unlike rapid tests relying on docks and cartridges, the STOPCovid test is uniquely designed to scale up to millions of tests per week, says Gootenberg. “There’s never been a demand for millions or tens of millions of tests per week — ever.”

Other research groups have also developed similar CRISPR-based COVID-19 tests (SN: 4/17/20).

With the development of so many new technologies to test for the coronavirus, “we’re going to come away from the epidemic with a whole new field of diagnostics,” Mina says.

As the coronavirus hit communities across the United States over the summer, four overnight camps in Maine successfully kept the virus at bay.

Of 1,022 people who attended the summer camps, which included campers and staff members, only three people tested positive for COVID-19, researchers report August 26 in the Morbidity and Mortality Weekly Report. That’s because the people who came to Maine from 41 U.S. states, Puerto Rico, Bermuda and five other countries diligently followed public health measures put in place to stop transmission, the team says.

The camps’ success, as well as others including child care programs in Rhode Island that limited coronavirus transmission, could point to a path forward for places like schools that are reopening with in-person classes in the face of the ongoing pandemic, though challenges remain.

At the camps, a combination of testing, social bubbles, social distancing, masks, quarantine and isolation prevented outbreaks.

Before arriving at camp, officials told all 642 children and 380 staff members to quarantine with their households for 10 to 14 days. Attendees were also tested for COVID-19 five to seven days prior to arrival — with the exception of 12 people who had already been previously diagnosed. Four people tested positive for the virus and isolated for 10 days at home before heading off to one of the camps, which were in session at different times from mid-June to mid-August. (Three of the four camps ran for less than 50 days and the other went on for 62 days.)

Once on site, the campers and staff participated in daily symptom checks and activities held largely outdoors. They also hung out in small “bubbles,” or cohorts, that ranged from five to 44 people in size and became like family during the weeks at camp, the researchers say. If people interacted with anyone outside their group, masks and social distancing were required.

“We wanted to give the kids the ability to have a family unit at camp that they didn’t need to be masked or social distanced from,” says Laura Blaisdell, a pediatrician at Maine Medical Center Research Institute in Scarborough who worked on the new report.

Attendees came to Maine via car, bus and plane, and could have been exposed to the virus after their initial test, so officials retested the 1,006 attendees who had never had COVID-19 four to nine days after their arrival.

In that round of testing, two staff members and one camper from three different camps tested positive but never developed symptoms. Their cohorts were quarantined for two weeks, but still “were able to have a camp experience … and continue to have fun and play together,” Blaisdell says. The three positive cases didn’t transmit the virus to anyone else before they were identified. They each remained isolated until they had two negative test results.

Off to camp

More than 1,000 people from 41 U.S. states, as well as Puerto Rico, Bermuda and several other countries, attended summer camps in Maine from mid-June to mid-August. The map shown here indicates which states campers and staff members came from. (No one attended from states colored white.) A fair number of people traveled from states like Texas and Florida that were hit hard over the summer (seven-day daily average rate of coronavirus infection as calculated on July 1, shown), but the camps’ public health measures prevented outbreaks. States with less than 10 cases per 100,000 population are not designated.

Camp population, by home state, and states’ COVID-19 infection rates

Some people traveled to Maine from areas where COVID-19 cases were surging over the summer, including Texas, Arizona and Florida. But rigorous testing quickly identified potential spreaders, and small cohorts allowed officials to quickly identify those most at risk of catching the virus.

In that way, “cohorting is an unsung hero of public health intervention,” Blaisdell says. 

While interventions like cohorts, social distancing and wearing masks can help reduce coronavirus transmission on their own to some extent, each method has limitations. Combining such strategies into a layered approach where people follow multiple guidelines to curb the virus’ spread, like the Maine camps did, can further protect the members of a community.

“Every public health layer is like a layer of Swiss cheese with a hole in it,” Blaisdell says. It’s the stacking of “multiple layers of cheese on top of each other that close those holes and makes for a robust [infectious] disease plan.”

By contrast, a summer camp in Georgia faced an outbreak of the virus even after requiring attendees to provide proof of a negative test before arrival. But there, campers were not required to wear masks, weren’t tested after they arrived at camp and participated in both indoor and outdoor activities (SN: 7/31/20).

Still, the isolated nature of the summer camps in Maine likely made creating a relatively COVID-19–free bubble much easier than it might be at K–12 schools or universities around the country, where people come and go and may not live on site (SN: 8/4/20). There were some staff members at the four camps in Maine who went home every day, but those people were required to wear masks at all times and social distance from other attendees. It also likely helped that the amount of coronavirus circulating in Maine was quite low while the camps were running.

What’s more, the larger the school, the harder it will probably be to make sure that public health interventions are being adhered to. “If you follow the rules, then this can absolutely be successful,” says Brian Nichols, a virologist at Seton Hall University in South Orange, N.J. But, “when you scale it up and start looking at public schools and universities, you just have to plan on the fact that some people aren’t going to follow the rules.”

Nevertheless, the success in Maine hints that containing the virus is possible with a targeted, layered approach, Blaisdell says. “As schools and colleges begin to consider opening, they need to look at their community as a bubble,” she says. “We all need to be making contracts with each other about the behaviors that we’re going to do.” 

A researcher slips stickers under some colored cups on a lazy Susan, then gives the tray a whirl. When the spinning stops, a preschooler must find the hidden stickers. Most children remember where the stickers are, but a few have to check every single cup.

The game tests working memory, which is among the set of mental skills known as executive function that can be impaired in children who faced trauma early in life.

Adversity wreaks havoc, and from there, “you have a system that responds differently,” says Megan Gunnar, a developmental psychobiologist at the University of Minnesota in Minneapolis who has spent two decades studying the impact of early-life adversity in adopted children. The focus of this work is extreme adversity, such as being orphaned, rather than everyday challenges, which might teach beneficial resilience.

A childhood characterized by hardship, negligence or abuse can also alter the neuroendocrine system that regulates how the body responds to stress. Problems in the stress response can set kids on a path toward behavior struggles along with increased risk for depression, diabetes and a host of other health problems.

But recent studies offer hints that such a difficult future may not be inevitable. As Gunnar and others have shown, impaired stress responses can return to normal during puberty, raising the possibility that imbalances created by early trauma can be erased. The research is prompting a new view of puberty as an opportunity — a chance for people who had a shaky start to reset their physiological responses to stress.

A sense of safety

When the brain perceives a threat — even a temporary one such as a stressful exam or a high-stakes competition — levels of the hormone adrenaline shoot up, setting off the “fight-or-flight” reaction. Breathing and heart rate soar. Palms get sweaty. Sight and other senses sharpen. Before long, the brain sends chemical messengers to stimulate adrenal glands near the kidneys to release cortisol.

Cortisol sends sugars into the blood for quick energy. The hormone also slows digestion, immune responses, growth and other processes considered nonessential in a fight-or-flight situation.

When the threat passes, the fight-or-flight response ends, at least in a person whose stress response is working as it should. Adrenaline and cortisol levels fall, heart rate slows and other systems resume business as usual.

When Gunnar started her doctoral work in the 1970s, researchers had already mapped out the key actors in the stress response. The neuro-endocrine signals involved form the HPA axis, short for hypothalamic-pituitary-adrenal. When rodents and monkeys face early-life adversity, the HPA axis gets thrown off-kilter. As methods became available for measuring cortisol from samples of saliva — rather than having to collect blood or urine — Gunnar set out to study how the HPA axis influences the brain and behavior in humans.

From experiments with newborn babies in the mid-1980s, Gunnar showed that having a secure parent relationship is important for a healthy neuroendocrine system and helps babies deal with stressful situations, such as getting immunizations. “You can go to the doctor as a baby and get a big shot in one leg and the other leg, and you’re crying your head off … but [the HPA axis] doesn’t kick off,” Gunnar says. However, shots or no shots, if babies get separated from their parents for even a few minutes, “their HPA axis shoots up like a rocket.”

Gunnar wondered what happens if that sense of safety is disrupted longer-term. She tried studying maltreated and impoverished children, but separating the effects of early hardship from later difficulties is not easy. “The way you start out in life tends to continue,” Gunnar says. A report published last November by the U.S. Centers for Disease Control and Prevention points to the long-term consequences: Compared with their peers, adults who experienced childhood trauma are more likely to smoke, drink heavily, have dropped out of high school and develop heart disease and a host of other chronic conditions.

A trip in the mid-1990s set Gunnar on a new path to answer that tricky research question. She ventured with a research team to an orphanage in eastern Romania, where young children were raised in overcrowded, inhumane conditions. “You walk into these wards, and all of a sudden you’re mobbed by kids saying ‘Mama, mama, mama’ … reaching their arms up to get held,” says Gunnar, who had two school-age sons at the time. “It was awful. I just wanted to bring them all home.”

What she did bring back to Minnesota, along with that searing memory, was a set of small vials, each containing a saliva sample from a 2- or 3-year-old orphan. To her surprise, the children’s cortisol levels — the end product of the neuroendocrine cascade — were lower than the average toddler’s. That finding offered a window into the effects of long-term parental deprivation on stress responses.

Adoptee struggles

To single out the effects of early hardship, Gunnar needed children who had started life in deprivation but then moved into healthy, supportive environments after infancy. Such children would be the ideal human analog for all of the animal studies on early adversity, she thought. It dawned on her that this group exists: adopted orphans.

Gunnar shared her idea with members of the adoption unit at the Minnesota Department of Human Services. With the department’s support and funding, she surveyed Minnesota parents who had adopted children internationally in the 1990s, and invited families to join a university registry and participate in research.

Many parents in the study had noticed early on that their adopted children had behavioral problems. And when the youngsters came to the university lab for problem-solving and sorting tests, including the lazy Susan task and the famous marshmallow test of delayed gratification (SN: 8/4/18, p. 14), the children struggled with attention and self-regulation.

Like the Romanian orphans, these kids had lower cortisol levels than nonadopted children who had no behavioral problems. In the face of sustained hardship, which has the potential to encourage dangerously high levels of cortisol, a weak stress response — that is, producing less cortisol — could be “nature’s way of preserving the brain and body,” Gunnar speculates.

Teen-time shift

Before puberty, adopted children, who grew up with early-life trauma (gray curve), had blunted stress responses relative to kids living with biological parents (blue curve). By the time puberty ended, the adopted children showed normal cortisol patterns before, during and after a stressful task. Saliva was collected 20 minutes and 5 minutes before the task, then 5, 20, 40, 60 and 80 minutes after the task. The researchers converted the data to a logarithmic scale, which shows negative numbers. The actual cortisol levels are between 0 and 1 micrograms per deciliter.

Cortisol stress response in adopted and nonadopted children    

Source: C.E. DePasquale, B. Donzella and M.R. Gunnar/J. Child Psychol. Psychiatry 2019

Studying the adoptees over time, she found that preschoolers with low cortisol often entered kindergarten with attention problems. A blunted stress response persisted into middle childhood, even after an average of seven to eight years in a household with healthy caregiving.

That was disheartening, says Russell Romeo, a psychobiologist at Barnard College in New York City. “We’d always thought that maybe if these individuals get out of the adverse situations, they could start recalibrating their stress reactivity.”

But research Romeo had done in the mid-2000s gave Gunnar reason to think she just needed to look further down the road of the children’s lives.

High time for change

Romeo was studying rats to see if stress affects adolescent and adult brains differently. In one set of experiments, he subjected adult rats and prepubescent rats to acute stress — 30 minutes trapped inside a wire mesh container — and recorded their levels of corticosterone (the rat version of cortisol) before, during and after the confinement. Both groups produced similar hormone spikes when stressed, but in the juvenile rats, levels took much longer to return to normal.

When Romeo observed how the animals reacted to extended periods of stress — 30 minutes of restraint each day for seven days — the pattern was different. After the animals were released from the restraints, stress hormones surged higher in young rats than in adults. But the rats that were near puberty returned to baseline more quickly than the older animals. Taken together, Romeo’s studies suggested that neuroendocrine stress responses get shaped during puberty to emerge differently in adulthood.

In earlier work, researchers at McGill University in Montreal showed that moving adolescent rats into “enriched” environments — larger cages with more toys and cagemates — could reset stress responses that had been thrown out of whack by early-life trauma.

These findings heartened Gunnar. “Maybe I should be looking at puberty,” she thought. It could be a time to recalibrate.

Closer to normal

During a stressful activity (giving a speech, for example), saliva cortisol levels rose temporarily and returned to normal in those children who lived with their biological parents. Children who were adopted after starting life in an orphanage (an early-life trauma), had blunted cortisol responses during stages 1 to 2 of puberty. But at the tail end of puberty, stages 4 and 5, adopted children’s stress responses normalized.

Stages of puberty and cortisol stress reaction

Source: M.R. Gunnar et al/PNAS 2019

So her team invited 280 7- to 14-year-olds — 122 children adopted from institutions and 158 from socioeconomically comparable biological families — into the lab to complete two stressful tasks. One involved challenging mental math. For the second task, each child prepared a five-minute speech introducing themselves to a new class of students. The children were told that their speech, given in front of a video camera and a mirror, would be rated by judges. Some kids spoke with confidence, while others looked nervous. “We did have one who burst into tears,” Gunnar says. But “we don’t torture them. If we think they’re too nervous, we help them quit.”

Before and after the speech and math tasks, researchers collected saliva samples from each child to measure cortisol levels. Participants’ pubertal status was assessed on a 1-to-5 scale: Stage 1 meant no noticeable body changes and stage 5 meant sexual maturation was complete.

Among kids in early puberty (stages 1–2), adopted kids had blunted cortisol levels before and after the tasks compared with children who lived with their biological parents. This result confirmed Gunnar’s previous research on preschool-aged international adoptees. In the late puberty group (stages 4–5), cortisol patterns looked similar for adopted and nonadopted kids.

To confirm HPA recalibration had occurred within the same child, rather than just comparing across age groups, Gunnar and colleagues brought participants in for the same tests one and two years later, for a total of three annual sessions.

The results, reported in the Nov. 26 Proceedings of the National Academy of Sciences, show the body can recalibrate its response to stressors during puberty. In other words, something happens in puberty — but not earlier in childhood — that allows the brain to shift back to normal stress responses that had been skewed by early trauma.

Matthew Duggan, a therapist in Long Beach, Calif., who specializes in childhood and adolescence, is encouraged by the findings and thinks they could apply to a wide range of children who have trouble managing their emotions and connecting with others because caretakers abused or ignored them early in life. There may be “a window … where things might be able to change,” Duggan says. “And we have some data here to suggest that at a biological level, that is a possibility. For me, that’s really hopeful to see.”

Duggan says Gunnar’s study would have been even more useful if it had assessed participants’ behavior change — for example, by interviewing parents, teachers or the adolescents themselves.

How might puberty combine with better caregiving and support to reshape neuroendocrine stress responses? Romeo speculates that it stems from the fact that the hypothalamus and other brain areas, such as the prefrontal cortex, that control our reactions to stress are among the regions that rewire and strengthen connections during adolescence.

Whether those changes in the stress response will ultimately harm or help a young person is hard to predict, Gunnar says. Mental health and resilience emerge from an ever-changing combination of genes and life experiences — some of which set the body awry early on. But adolescence could potentially erase some of the damage, her research shows. Gunnar and others hope to reveal more of the underlying biology behind the reboot.

Is there a sweet spot for early adversity?

Hardships early in life can mean a difficult road ahead. But some small amount of stress may help kids build mental toughness to handle the stresses of everyday life, such as big exams or performances (SN: 6/8/19, p. 12).

“We learn to handle stress by handling stress,” says Megan Gunnar, a developmental psychobiologist at the University of Minnesota in Minneapolis.

Early-life stress affects later resilience

Groups of lab monkeys exposed to mild or moderate stress (yellow and red dots) showed lower anxiety later than animals exposed to no stress (blue) or heavy stress (black and white).

Source: K.J. Parker et al/Scientific Reports 2019

If a stressful experience shows “the world is tough but we can deal with it, perhaps with the help of family and friends,” she says, “we are tougher the next time.” On the other hand, feeling crushed by an intense stressor, such as abuse or a parent’s death, can impart a sense of helplessness that leaves young people “fearful of it happening again,” Gunnar says.

In a 2010 study, researchers surveyed 2,398 U.S. adults to understand how pain and stress affect resilience. Participants answered questions about their mental health and overall well-being, and indicated whether they had experienced cumulative lifetime adversities, including a serious illness or divorce in the family. The upshot: People who faced some adversity reported less distress and more life satisfaction compared with those who either experienced heavy adversity or sailed through childhood with ease.

Experiments in monkeys suggest that this is more than a correlation. A team led by David Lyons, a behavioral neuroscientist at Stanford University, reported causal evidence last November in Scientific Reports. Since it can be unethical to randomly assign humans to stressful conditions, the team tested the effects of varying “doses” of stress in squirrel monkeys that had not yet reached puberty.

The monkeys in the control group enjoyed a typical lab life — housed in a cage with mom and siblings, plus plenty of water, food and toys. A second group faced a mild stressor — one hour of separation from siblings once daily for 10 days. The stress dose went up a notch for the third group, which had daily separation from siblings and no access to mom during that hour. Two additional groups experienced daily separation from mother and siblings, plus an injection as an additional stressor.

Ten weeks later, each monkey was moved with its mother to an unfamiliar cage. The researchers assessed the monkeys’ willingness to let go of mom and explore the new digs. The team also analyzed blood levels of the stress hormone cortisol before and after the time spent in the new cage. On the whole, monkeys in the groups that faced one or two stressors clung less to their mothers and more readily explored their new surroundings — showing less anxiety — than both the no-stress and the two high-stress groups.

Cortisol patterns also reflected this trend: Cortisol levels were closer to normal in monkeys exposed to mild or moderate stress than in monkeys from the other groups.

Growing up healthy means “learning how to deal with mild challenge and change,” Lyons says.

August 2020 has been a devastating month across large swaths of the United States: As powerful Hurricane Laura barreled into the U.S. Gulf Coast on August 27, fires continued to blaze in California. Meanwhile, farmers are still assessing widespread damage to crops in the Midwest following an Aug. 10 “derecho,” a sudden, hurricane-force windstorm.

Each of these extreme weather events was the result of a particular set of atmospheric — and in the case of Laura, oceanic — conditions. In part, it’s just bad luck that the United States is being slammed with these events back-to-back-to-back. But for some of these events, such as intense hurricanes and more frequent wildfires, scientists have long warned that climate change has been setting the stage for disaster.

Science News takes a closer look at what causes these kinds of extreme weather events, and the extent to which human-caused climate change may be playing a role in each of them.

California wildfires

A “dry lightning” storm, which produced nearly 11,000 bursts of lightning between August 15 and August 19, set off devastating wildfires in across California. To date, these fires have burned more than 520,000 hectares.

That is “an unbelievable number to say out loud, even in the last few years,” says climate scientist Daniel Swain, of the Institute of the Environment and Sustainability at UCLA.

The storm itself was the result of a particular, unusual set of circumstances. But the region was already primed for fires, the stage set by a prolonged and record-breaking heat wave in the western United States — including one of the hottest temperatures ever measured on Earth, at Death Valley, Calif. — as well as extreme dryness in the region (SN: 8/17/20). And those conditions bear the fingerprints of climate change, Swain says.

The extreme dryness is particularly key, he adds. “It’s not just incremental; it absolutely matters how dry it is. You don’t just flip a switch from dry enough to burn to not dry enough to burn. There’s a wide gradient up to dry enough to burn explosively.”

Both California’s average heat and dryness have become more severe due to climate change, dramatically increasing the likelihood of extreme wildfires. In an Aug. 20 study in Environmental Research Letters, Swain and colleagues noted that over the last 40 years, average autumn temperatures increased across the state by about 1 degree Celsius, and statewide precipitation dropped by about 30 percent. That, in turn, has more than doubled the number of autumn days with extreme fire weather conditions since the early 1980s, they found.

Although fall fires in California tend to be more wind-driven, and summertime fires more heat-driven, studies show that the fingerprint of climate change is present in both, Swain says. “A lot of it is very consistent with the long-term picture that scientists were suggesting would evolve.”

Though the stage had been set by the climate, the particular trigger for the latest fires was a “dry lightning” storm that resulted from a strange confluence of two key conditions, each in itself rare for the region and time of year. “’Freak storm’ would not be too far off,” Swain says.

The first was a plume of moisture from Tropical Storm Fausto, far to the south, which managed to travel north to California on the wind and provide just enough moisture to form clouds. The second was a small atmospheric ripple, the remnants of an old thunderstorm complex in the Sonoran Desert. That ripple, Swain says, was just enough to kick-start mixing in the atmosphere; such vertical motion is the key to thunderstorms. The resulting clouds were stormy but very high, their bases at least 3,000 meters aboveground. They produced plenty of lightning, but most rain would have evaporated during the long dry journey down.

Possible links between climate change and the conditions that led to such a dry lightning storm would be “very hard to disentangle,” Swain says. “The conditions are rare to begin with, and not well modeled from a weather perspective.”

But, he adds, “we know there’s a climate signal in the background conditions that allowed that rare event to have the outcome it did.”

Midwest derecho

On August 10, a powerful windstorm with the ferocity of a hurricane traveled over 1,200 kilometers in just 14 hours, leaving a path of destruction from eastern South Dakota to western Ohio.

The storm was what’s known as a derecho, roughly translating to “straight ahead.” These storms have winds rivaling the strength of a hurricane or tornado, but push forward in one direction instead of rotating. By definition, a derecho produces sustained winds of at least 93 kilometers per hour (similar to the fury of tropical storm-force winds), nearly continuously, for at least 400 kilometers. Their power is equally devastating: The August derecho flattened millions of hectares of crops, uprooted trees, damaged homes, flipped trucks and left hundreds of thousands of people without power.

The Midwest has had many derechos before, says Alan Czarnetzki, a meteorologist at the University of Northern Iowa in Cedar Falls. What made this one significant and unusual was its intensity and scale — and, Czarnetzki notes, the fact that it took even researchers by surprise.

Derechos originate within a mesoscale convective system — a vast, organized system of thunderclouds that are the basic building block for many different kinds of storms, including hurricanes and tornadoes. Unlike the better-known rotating supercells, however, derechos form from long bands of swiftly moving thunderstorms, sometimes called squall lines. In hindsight, derechos are easy to recognize. In addition to the length and strength conditions, derechos acquire a distinctive bowlike shape on radar images; this one appeared as though the storm was aiming its arrow eastward.

But the storms are much more difficult to forecast, because the conditions that can lead them to form can be very subtle. And there’s overall less research on these storms than on their more dramatic cousins, tornadoes. “We have to rely on situational awareness,” Czarnetzki says. “Like people, sometimes you can have an exceptional storm arise from very humble origins.”

Derecho radar

The August 10 derecho, seen in radar images here as it moved across the Midwest (times are CDT) had a distinctive curved shape on radar, like a bow poised to shoot an arrow eastward. In some places, the storm had sustained winds of about 160 kilometers per hour, comparable to the wind strength of a Category 3 hurricane.

The Aug. 10 derecho was particularly long and strong, with sustained winds in some places of up to 160 kilometers per hour (100 miles an hour). Still, such a strong derecho is not unheard of, Czarnetzki says. “It’s probably every 10 years you’d see something this strong.”

Whether such strong derechos might become more, or less, common due to climate change is difficult to say, however. Some anticipated effects of climate change, such as warming at the planet’s surface, could increase the likelihood of more and stronger derechos by increasing atmospheric instability. But warming higher in the atmosphere, also a possible result of climate change, could similarly increase atmospheric stability, Czarnetzki says. “It’s a straightforward question with an uncertain answer.”

Atlantic hurricanes

Hurricane Laura roared ashore in Louisiana in the early morning hours of August 27 as a Category 4 hurricane, with sustained winds of about 240 kilometers per hour (150 miles per hour). Just two days earlier, the storm had been a Category 1. But in the mere 24 hours from August 25 to August 26, the storm rapidly intensified, supercharged by warm waters in the Gulf of Mexico.

The Atlantic hurricane season is already setting several new records, with the National Oceanographic and Atmospheric Administration predicting as many as 25 named storms, the most the agency has ever anticipated (SN: 8/7/20).

At present, 2005 still holds the record for the most named storms to actually form in the Atlantic in a given season, at 28 (SN: 8/22/18). But 2020 may yet surpass that record. By August 26, 13 named storms had already formed in the Atlantic, the most ever before September.

The previous week, researchers pondered whether another highly unusual set of circumstances might be in the offing. As Laura’s track shifted southward, away from Florida, tropical storm Marco appeared to be on track to enter the Gulf of Mexico right behind it. That might have induced a type of physical interaction known as a Fujiwhara effect, in which a strong storm might strengthen further as it absorbs the energy of a lesser storm. In perhaps a stroke of good luck in the midst of this string of weather extremes, Marco dissipated instead.

As Hurricane Laura approached landfall, the U.S. National Hurricane Center warned that “unsurvivable” storm surges of up to five meters could inundate the Gulf Coast in parts of Texas and Louisiana. Storm surge is the height to which the seawater level rises as a result of a storm, on top of the normal tidal level.

It’s impossible to attribute the fury of any one storm to climate change, but scientists have observed a statistically significant link between warmer waters and hurricane intensity. Warm waters in the Atlantic Ocean, the result of climate change, juiced up 2017’s hurricanes, including Irma and Maria, researchers have found (SN: 9/28/18).

And the Gulf of Mexico’s bathlike waters have notably supercharged several hurricanes in recent years. In 2018, for example, Hurricane Michael intensified rapidly before slamming into the Florida panhandle (SN: 10/10/18). And in 2005, hurricanes Katrina and Rita did the same before making landfall (SN: 9/13/05).

As for Laura, one contributing factor to its rapid intensification was a drop in wind shear as it spun through the Gulf.  Wind shear, a change in the speed and/or direction of winds with height, can disrupt a storm’s structure, robbing it of some of its power.  But the Gulf’s warmer-than-average waters, which in some locations approached 32.2° C (90° Fahrenheit), were also key to the storm’s sudden strength. And, by warming the oceans, climate change is also setting the stage for supercharged storms, scientists say.