Bioacoustics can’t fully replace ecology fieldwork, but can provide reams of data that would be extremely expensive to collect by merely sending scientists to remote areas for long stretches of time. With bioacoustic instruments, researchers must return to collect the data and swap batteries, but otherwise the technology can work uninterrupted for years. “Scaling sampling from 10, 100, [or] 1,000 sound recorders is much easier than training 10, 100, 1,000 people to go to a forest at the same time,” says Donoso.
“The need for this kind of rigorous assessment is enormous. It will never be cost-effective to have a kind of boots-on-the-ground approach,” agrees Eddie Game, the Nature Conservancy’s lead scientist and director of conservation for the Asia Pacific region, who wasn’t involved in the new research. “Even in relatively well-studied places it would be difficult, but certainly, in a tropical forest environment where that diversity of species is so extraordinary, it’s really difficult.”
A limitation, of course, is that while birds, insects, and frogs make a whole lot of noise, many species do not vocalize. A microphone would struggle to pick up the presence of a butterfly or a snake.
But no one’s suggesting that bioacoustics alone can quantify the biodiversity of a forest. As with the current experiment, bioacoustics work will be combined with the use of cameras, field researchers, and DNA collection. While this team harvested DNA directly from insects caught in light traps, others may collect environmental DNA, or eDNA, that animals leave behind in soil, air, and water. In June, for instance, a separate team showed how they used the filters at air quality stations to identify DNA that had been carried by the wind. In the future, ecologists might be able to sample forest soils to get an idea of what animals moved through the area. But while bioacoustics can continuously monitor for species, and eDNA can record clues about which ones crossed certain turf, only an ecologist can observe how those species might be interacting—who’s hunting who, for instance, or what kind of bird might be outcompeting another.
The bioacoustics data from the new study suggests that Ecuador’s forests can recover beautifully after small-scale pastures and cacao plantations are abandoned. For instance, the researchers found the banded ground cuckoo already in 30-year-old recovery forests. “Even our professional collaborators were surprised at how well the recovery forests were colonized by so-called old-growth species,” says Müller. “In comparison to Europe, they do it very quickly. So after, let’s say, 40, 50 years, it’s not fully an old-growth forest. But most of these very rare species can make use of this as a habitat, and thereby expand their population.”
This technology will also be helpful for monitoring forest recovery—to confirm, for example, that governments are actually restoring the areas they say they are. Satellite images can show that new trees have been planted, but they’re not proof of a healthy ecosystem or of biodiversity. “I think any ecologist would tell you that trees don’t make a forest ecosystem,” says Game. The cacophony of birds and insects and frogs—a thriving, complex mix of rainforest species—do.
“I think we’re just going to keep on learning so much more about what sound can tell us about the environment,” says Game, who compares bioacoustics to NASA’s Landsat program, which opened up satellite imagery to the scientific community and led to key research on climate change and wildfire damage. “It was radically transformational in the way we looked at the Earth. Sound has some similar potential to that,” he says.
No one expected the first Covid-19 vaccine to be as good as it was. “We were hoping for around 70 percent, that’s a success,” says Dr Ann Falsey, a professor of medicine at the University of Rochester, New York, who ran a 150-person trial site for the Pfizer-BioNTech vaccine in 2020.
Even Uğur Şahin, the co-founder and CEO of BioNTech, who had shepherded the drug from its earliest stages, had some doubts. All the preliminary laboratory tests looked good; having seen them, he would routinely tell people that “immunologically, this is a near-perfect vaccine.” But that doesn’t always mean it will work against “the beast, the thing out there” in the real world. It wasn’t until November 9, 2020, three months into the final clinical trial, that he finally got the good news. “More than 90 percent effective,” he says. “I knew this was a game changer. We have a vaccine.”
“We were overjoyed,” Falsey says. “It seemed too good to be true. No respiratory vaccine has ever had that kind of efficacy.”
The arrival of a vaccine before the close of 2020 was an unexpected turn of events. Early in the pandemic, the conventional wisdom was that, even with all the stops pulled, a vaccine would take at least a year and a half to develop. Talking heads often referenced that the previous fastest-ever vaccine developed, for mumps back in 1967, took four years. Modern vaccines often stretch out past a decade of development. BioNTech—and US-based Moderna, which announced similar results later the same week—shattered that conventional timeline.
Neither company was a household name before the pandemic. In fact, neither had ever had a single drug approved before. But both had long believed that their mRNA technology, which uses simple genetic instructions as a payload, could outpace traditional vaccines, which rely on the often-painstaking assembly of living viruses or their isolated parts. mRNA turned out to be a vanishingly rare thing in the world of science and medicine: a promising and potentially transformative technology that not only survived its first big test, but delivered beyond most people’s wildest expectations.
But its next step could be even bigger. The scope of mRNA vaccines always went beyond any one disease. Like moving from a vacuum tube to a microchip, the technology promises to perform the same task as traditional vaccines, but exponentially faster, and for a fraction of the cost. “You can have an idea in the morning, and a vaccine prototype by evening. The speed is amazing,” says Daniel Anderson, an mRNA therapy researcher at MIT. Before the pandemic, charities including the Bill & Melinda Gates Foundation and the Coalition for Epidemic Preparedness Innovations (CEPI) hoped to turn mRNA on deadly diseases that the pharmaceutical industry has largely ignored, such as dengue or Lassa fever, while industry saw a chance to speed up the quest for long-held scientific dreams: an improved flu shot, or the first effective HIV vaccine.
Amesh Adalja, an expert on emerging diseases at the Johns Hopkins Center for Health Security, in Maryland, says mRNA could “make all these applications we were hoping for, pushing for, become part of everyday life.”
“When they write the history of vaccines, this will probably be a turning point,” he adds.
The race for the next generation of mRNA vaccines—targeted at a variety of other diseases—is already exploding. Moderna has over two dozen vaccine candidates in development or clinical trials; BioNTech a further eight. There are at least six mRNA vaccines against flu in the pipeline, and a similar number against HIV. Nipah, Zika, herpes, dengue, hepatitis, and malaria vaccines have all been announced. The field sometimes resembles the early stage of a gold rush, with pharma giants snapping up promising researchers for huge contracts—Sanofi paid $425 million (£307m) to partner with a small American mRNA biotech called Translate Bio in 2021, while GSK paid $294 million (£212m) to work with Germany’s CureVac. Even Moderna and BioNTech, buoyed by the success of their Covid vaccines, have started to buy up companies to help with product development.
Friction is resistance. In this case, it tells you how hard it is for something to get across the membrane. If you engineer a membrane that has less resistance to water, and more resistance to salt or whatever else you want to remove, you get a cleaner product with potentially less work.
But that model got shelved in 1965, when another group introduced a simpler model. This one assumed that the plastic polymer of the membrane was dense and had no pores through which water could run. It also didn’t hold that friction played a role. Instead, it presumed that water molecules in a saltwater solution would dissolve into the plastic and diffuse out of the other side. For that reason, this is called the “solution-diffusion” model.
Diffusion is the flow of a chemical from where it’s more concentrated to where it’s less concentrated. Think of a drop of dye spreading throughout a glass of water, or the smell of garlic wafting out of a kitchen. It keeps moving toward equilibrium until its concentration is the same everywhere, and it doesn’t rely on a pressure difference, like the suction that pulls water through a straw.
The model stuck, but Elimelech always suspected it was wrong. To him, accepting that water diffuses through the membrane implied something strange: that the water scattered into individual molecules as it passed through. “How can it be?” Elimelech asks. Breaking up clusters of water molecules requires a ton of energy. “You almost need to evaporate the water to get it into the membrane.”
Still, Hoek says, “20 years ago it was anathema to suggest that it was incorrect.” Hoek didn’t even dare to use the word “pores” when talking about reverse osmosis membranes, since the dominant model didn’t acknowledge them. “For many, many years,” he says wryly, “I’ve been calling them ‘interconnected free volume elements.’”
Over the past 20 years, images taken using advanced microscopes have reinforced Hoek and Elimelech’s doubts. Researchers discovered that the plastic polymers used in desalination membranes aren’t so dense and poreless after all. They actually contain interconnected tunnels—although they are absolutely minuscule, peaking at around 5 angstroms in diameter, or half a nanometer. Still, one water molecule is about 1.5 angstroms long, so that’s enough room for small clusters of water molecules to squeeze through these cavities, instead of having to go one at a time.
About two years ago, Elimelech felt the time was right to take down the solution-diffusion model. He worked with a team: Li Wang, a postdoc in Elimelech’s lab, examined fluid flow through small membranes to take real measurements. Jinlong He, at the University of Wisconsin-Madison, tinkered with a computer model simulating what happens at the molecular scale as pressure pushes salt water through a membrane.
Predictions based on a solution-diffusion model would say that water pressure should be the same on both sides of the membrane. But in this experiment, the team found that the pressure at the entrance and exit of the membrane differed. This suggested that pressure drives water flow through the membrane, rather than simple diffusion.
This story originally appeared onYale Environment 360and is part of theClimate Deskcollaboration.
“Thousands of sea lamprey are passed upstream [on the Connecticut River] each year. This is a predator that wiped out the Great Lakes lake-trout fishery. [Lampreys] literally suck the life out of their host fish, namely small-scale fish such as trout and salmon. The fish ladders ought to be used to diminish the lamprey.” So editorialized the Eagle-Tribune of Lawrence, Massachusetts, on December 15, 2002.
If that’s true, why this spring is Trout Unlimited—the nation’s leading advocate for trout and salmon—assisting the Town of Wilton, Connecticut, and an environmental group called Save the Sound in a project that will restore 10 miles of sea lamprey spawning habitat on the Norwalk River, which flows into Long Island Sound?
Why this summer will the first big returns from stocked Pacific lampreys—a species similar to sea lampreys—climb specially designed lamprey ramps at Columbia River dams and surge into historical spawning habitat in Oregon, Washington, and Idaho?
And why, when the canal at Turners Falls on the Connecticut River is drawn down in September, will the Connecticut River Conservancy, Fort River Watershed Association, and the Biocitizen environmental school rescue stranded sea lamprey larvae?
The answer is ecological awakening—the gradual realization that, if the whole of nature is good, no part can be bad. In their native habitat, marine lampreys are “keystone species” supporting vast aquatic and terrestrial ecosystems. They provide food for insects, crayfish, fish, turtles, minks, otters, vultures, herons, loons, ospreys, eagles, and hundreds of other predators and scavengers. Lamprey larvae, embedded in the stream bed, maintain water quality by filter feeding; and they attract spawning adults from the sea by releasing pheromones. Because adults die after spawning, they infuse sterile headwaters with nutrients from the sea. When marine lampreys build their communal nests, they clear silt from the river bottom, providing spawning habitat for countless native fish, especially trout and salmon.
Environmental consultant Stephen Gephard, formerly Connecticut’s anadromous-fish chief, calls lampreys “environmental engineers” as important to native ecosystems as beavers.
Marine lampreys, our elders by some 340 million years, depend on cold, free-flowing freshwater for spawning. They are boneless, jawless, eel-like fish with fleshy fins. They extract body fluids from other fish via tooth-studded suction disks. Both sea lampreys and Pacific lampreys are widely reviled because they are perceived as “ugly” and because sea lampreys decimated indigenous fish in the upper Great Lakes when they gained access to those waters via human-built canals, most likely the Welland Canal that bypassed Niagara Falls. Once there, they nearly wiped out valuable commercial and sport fisheries for lake trout (the largest char species, not a true trout like rainbows, cutthroats, and browns).
By the 1960s, nonnative sea lampreys had reduced the annual commercial take of lake trout in the upper Great Lakes from about 15 million pounds to half a million pounds. In 1955, Canada and the United States established the Great Lakes Fisheries Commission, which controls lampreys with barriers, traps, and a remarkably selective larvae poison called TFM. Lamprey control costs $15 to $20 million a year; and without it, ongoing lake-trout recovery would be impossible, and populations of all other sport fish would crash.
The plastics industry has long hyped recycling, even though it is well aware that it’s been a failure. Worldwide, only 9 percent of plastic waste actually gets recycled. In the United States, the rate is now 5 percent. Most used plastic is landfilled, incinerated, or winds up drifting around the environment.
Now, an alarming new study has found that even when plastic makes it to a recycling center, it can still end up splintering into smaller bits that contaminate the air and water. This pilot study focused on a single new facility where plastics are sorted, shredded, and melted down into pellets. Along the way, the plastic is washed several times, sloughing off microplastic particles—fragments smaller than 5 millimeters—into the plant’s wastewater.
Because there were multiple washes, the researchers could sample the water at four separate points along the production line. (They are not disclosing the identity of the facility’s operator, who cooperated with their project.) This plant was actually in the process of installing filters that could snag particles larger than 50 microns (a micron is a millionth of a meter), so the team was able to calculate the microplastic concentrations in raw versus filtered discharge water—basically a before-and-after snapshot of how effective filtration is.
Their microplastics tally was astronomical. Even with filtering, they calculate that the total discharge from the different washes could produce up to 75 billion particles per cubic meter of wastewater. Depending on the recycling facility, that liquid would ultimately get flushed into city water systems or the environment. In other words, recyclers trying to solve the plastics crisis may in fact be accidentally exacerbating the microplastics crisis, which is coating every corner of the environment with synthetic particles.
“It seems a bit backward, almost, that we do plastic recycling in order to protect the environment, and then end up increasing a different and potentially more harmful problem,” says plastics scientist Erina Brown, who led the research while at the University of Strathclyde.
“It raises some very serious concerns,” agrees Judith Enck, president of Beyond Plastics and a former US Environmental Protection Agency regional administrator, who wasn’t involved in the paper. “And I also think this points to the fact that plastics are fundamentally not sustainable.”
The Association of Plastic Recyclers, an international group that represents the industry, did not respond to a request for comment.
The good news is that filtration makes a difference: Without it, the researchers calculated that this single recycling facility could emit up to 6.5 million pounds of microplastic per year. Filtration got it down to an estimated 3 million pounds. “So it definitely was making a big impact when they installed the filtration,” says Brown. “We found particularly high removal efficiency of particles over 40 microns.”
But a critical caveat is that the team only tested for microplastics down to 1.6 microns. Plastic particles can get way smaller—like nanoplastics that are tiny enough to enter individual cells—and they grow much more numerous as they do. So this is likely a significant underestimate. And these researchers were finding a lot of particularly small particles. In two of the sample points, approximately 95 percent of the microplastics were under 10 microns, and 85 percent were under 5 microns. “It completely shocked me just how tiny the majority of them were,” says Brown. “But we easily could have found so many smaller than that.”
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