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Kombucha Cultures Could Be the Key to Better Water Filters

Kombucha Cultures Could Be the Key to Better Water Filters

The refreshing kombucha tea that’s all the rage these days among certain global demographics might also hold the key to affordable, environmentally sustainable living membranes for water filtration, according to a recent paper published in the American Chemical Society journal ACS ES&T Water. Experiments by researchers at Montana Technological University (MTU) and Arizona State University (ASU) showed that membranes grown from kombucha cultures were better at preventing the formation of biofilms—a significant challenge in water filtration—than current commercial membranes.

As we’ve reported previously, you need three basic ingredients to make kombucha. Just combine tea and sugar with a kombucha culture known as a SCOBY (symbiotic culture of bacteria and yeast). The culture is also known as the “mother,” tea mushroom, tea fungus, or Manchurian mushroom. (Kombucha tea is believed to have originated in Manchuria, China, or possibly Russia.)

Whatever you call it, it’s basically akin to a sourdough starter. A SCOBY is a firm, gel-like collection of cellulose fiber (biofilm), thanks to the active bacteria in the culture creating the perfect breeding ground for yeast and bacteria. Dissolve the sugar in non-chlorinated boiling water, then steep some tea leaves of your choice in the hot sugar water before discarding them.

Once the tea cools, add the SCOBY and pour the whole thing into a sterilized beaker or jar. Then cover the beaker or jar with a paper towel or cheesecloth to keep out insects, let it sit for two to three weeks, and voilà! You have your own home-brewed kombucha. A new “daughter” SCOBY will be floating right at the top of the liquid (technically known in this form as a pellicle).

Beyond its popularity as a beverage, kombucha holds promise as a useful biomaterial. For instance, scientists at MIT and Imperial College London last year created new kinds of tough “living materials” out of SCOBYs that could one day be used as biosensors. These materials could help purify water or detect damage to “smart” packing materials. The scientists couldn’t use the wild yeasts typically used in kombucha because the yeasts are difficult to modify genetically. Instead, the researchers used lab-grown yeast, specifically a strain called Saccharomyces cerevisiae, or brewer’s yeast. They combined the brewer’s yeast with a bacteria called Komagataeibacter rhaeticus (which can create a lot of cellulose) to create their “mother” SCOBY.

That team was able to engineer the cells in the yeast to produce glow-in-the-dark enzymes that could sense pollutants and then break them down after detection. One of their prototype materials senses the pollutant estradiol, while another can detect luciferase, a bioluminescent protein. Any number of other strains can be swapped out to achieve different functional properties.

And now we have the possibility of SCOBY-based water filters. According to the authors of this latest paper, contaminated drinking water has been linked to 2,000 deaths of children globally each day. Commercial polymer-based filters are compact and versatile, and they can strain off many dangerous contaminants, including bacteria, parasites, and even some viruses. However, the pores of these filters eventually become clogged, decreasing the rate of filtration and water flow, thanks to the accumulation of clays, oils, minerals, and bacterial biofilms. The latter are especially persistent and difficult to remove once they form. Scientists are developing materials, methods, and chemical treatments to combat the adhesion of biofilms to the filters. But perhaps a more promising strategy would be to focus instead on developing materials that inhibit bacterial growth. That’s where the kombucha SCOBYs come in.

Scientists Are Racing to Understand the Fury of Tonga’s Volcano

Scientists Are Racing to Understand the Fury of Tonga’s Volcano

On December 20, Hunga Tonga-Hunga Ha’apai—an underwater volcano in the South Pacific topped with a diminutive and uninhabited island—awoke from a seven-year slumber. The volcano spluttered and crackled, creating a large plume of ash. Ten-thousand miles away in England, Simon Proud, a satellite data researcher at the University of Oxford, began to monitor the twitching volcano using an array of satellites.

As 2021 ticked into 2022, what had appeared to be the beginnings of an almighty eruption seemingly calmed down. Then, early in the morning on January 14 local Tongan time, a 12-mile-high plume of ash pierced the sky. The volcano became increasingly turbulent, and hundreds of lightning discharges shot out of the maelstrom every second, bombarding the land and ocean. And one day later, in the late afternoon of January 15, satellites captured a cataclysm in action.

Back in England, when Proud woke up that day and checked his computer, he saw a tower of ash unlike anything he, or anyone else, had ever seen. Satellites had captured images of a huge column of ash that billowed out 22 miles above the island into a shadowy, tempestuous canopy 160 miles long. Rising from the canopy’s heart was a thin, transient spike of volcanic debris reaching an altitude of 34 miles—about five times the height of a cruising passenger jet. “What the heck is this?”, Proud recalls thinking. “I looked at the data, and I thought, this is so far outside anything I’ve seen before. It’s just unreal.”

Jaws dropped across the world. The explosion that produced the ash cloud, one estimated to be equivalent to 10 million tons of TNT, unleashed 25,000 times more energy than the lethal blast in the Lebanese capital Beirut in August 2020. The Tonga eruption is easily one of the largest explosions this century. And it didn’t stop there.

“Then there was the shockwave,” says Mike Cassidy, a volcanologist at the University of Oxford. It emanated from the volcanic blast at 600 miles per hour and caused pressure spikes on the other side of the planet. “No-one’s ever seen that before.” Within 20 minutes of the explosion, four-foot tsunami waves cascaded over Tongatapu, the archipelagic Kingdom of Tonga’s main island. By the time minor tsunami waves hit Japan and the western shorelines of the Americas, ash had already smothered multiple Tongan islands, killing off agriculture, polluting water supplies, disrupting electrical infrastructure, and cutting off roads and runways. The submarine communication cable connecting the archipelago to the rest of the world was damaged, severing the nation’s international phone and internet services. It likely won’t be repaired for several weeks.

Volcanologists couldn’t believe what they were witnessing. No matter which metric you picked, this was an astonishing, terrible eruption. And as suddenly as the volcanic violence dwindled, a global detective story began. What series of geologic events created such a devastating eruption? And what research needs to be done to crack the case?

The general mechanisms of volcanic eruptions are broadly known. But the catastrophic explosion on January 15 needs a more thorough examination and, ultimately, a novel explanation. When Hunga Tonga-Hunga Ha’apai erupted, Shane Cronin, a volcanologist at the University of Auckland in New Zealand, had the same reaction as everyone else, volcanologist or not: holy shit.

Global Ship Traffic Could Imperil the Antarctic’s Biosecurity

Global Ship Traffic Could Imperil the Antarctic’s Biosecurity

Right now, the Antarctic and the waters around it are surprisingly free of invasive species. According to new research, however, that situation might change in the not-too-distant future, thanks to a shocking level of connectivity with ports across the world. Ships can accidentally carry a large array of marine life, which can in turn colonize new places (like the world’s polar south), outcompete native life, and generally wreak havoc on an ecosystem. New research has traced the paths of the various research vessels, tourist ships, and fishing boats that chug along through the icy waters of the Antarctic.

According to Arlie McCarthy, a researcher in the University of Cambridge’s Department of Zoology and the British Antarctic Survey, these watercraft all carry with them a risk of unwanted visitors. And the visitors may have more chances to relocate than we once thought.

“We know from other cold areas in the world, including the Arctic, that things growing on the hulls of ships absolutely do get transported from place to place, and it is one of the major sources of marine introductions around the world,” McCarthy told Ars. “We also know that ships going into Antarctica do have things growing on them. What we didn’t know until this point was good detail on where those ships go.”

McCarthy’s research suggests that there are 1,581 ports around the world with connections to the Antarctic. These are ports from which at least one ship traveled to the region, defined as south of -60 degrees latitude, as set by the Antarctic Treaty. To determine this, she and her team looked at shipping data from Lloyd’s List Intelligence, an old and reliable source of maritime data, port call data, and raw satellite data. It allowed her to track ship activity from between 2014 and 2018.

“They are connected in some way to Antarctica,” McCarthy said, referring to the ports. This means that myriad species such as crabs, barnacles, and algae from a huge number of places could end up in the area. As global shipping increases—and as researchers and tourists continue to head into these waters—the odds of invasive species taking hold grows as well. There’s also a concern about the movement of some species from the North to the South Pole, potentially on tourist or research ships. Species from the Arctic would likely be adapted to cold and could thrive in the chilly Antarctic better than species brought in from somewhere south of the equator.

Antarctic waters are mostly free of invasive marine species—there are some invasive grasses and insects—and the ocean is more isolated than many other oceans. That’s due largely to the neighboring Southern Ocean, which has currents that circle around Antarctica. They’re particularly strong and form a kind of barrier. “Anything coming on ocean currents from oceans farther north, they can be deflected away from Antarctica rather than actually crossing into the Southern Ocean. They stop most things that come in on water currents,” McCarthy said, adding that seals and whales are capable of traversing these currents, even as mussels, barnacles, and algae are often blocked.

Because the region is so cold, many of the organisms that call it home are living more or less at the edge of what is physiologically possible. There is less food than elsewhere, and many of the creatures have adapted very specialized behaviors to survive, so invasive species could cause more damage than they do in a place where there is more food and warmth. For instance, some Antarctic lifeforms have developed polar gigantism, meaning that they grow large, live slow, and die old. Smaller, faster, and quicker-reproducing species from elsewhere—assuming they can survive in the Antarctic—may outcompete the original inhabitants.

The World Was Cooler in 2021 Than 2020. That’s Not Good News

The World Was Cooler in 2021 Than 2020. That’s Not Good News

Today NASA and NOAA dropped their annual analysis of global temperatures: Last year was tied with 2018 as the sixth-hottest ever, but cooler than 2020. A good sign, right? Yeah, no. Not in the least.

“It’s easy to want to focus on that year-to-year variability,” says Bridget Seegers, an oceanographer at NASA. “But it’s important to look at the trend: The last eight years were the eight hottest on record.”

To calculate global temperatures, the two agencies pull data from weather stations all over the world, plus measurements taken from ships and buoys in the ocean. Other groups like Berkeley Earth, a nonprofit research organization, do the same with their own somewhat different methodology. But the analyses are nearly identical in their findings. As you can see in the graph below, which compares results from Berkeley Earth, NOAA, NASA, and two other groups in Europe, the global average temperature might have been lower in 2021 than 2020, but it’s still soaring. 

graph showing a rise in global warming from 1850 to 2021
Illustration: Berkeley Earth

One reason for cooler temperatures in 2021 was likely La Niña, a band of cold water in the Pacific. It’s the product of strong trade winds that scour the ocean, pushing the top layer of water toward Asia, causing deeper, colder waters to rush to the surface to fill the void. This in turn influences the atmosphere, for instance changing the jet stream above the United States and leading to more hurricanes in the Atlantic. The sea itself cools things off by absorbing heat from the atmosphere.

The Covid-19 pandemic may have had an additional influence, but not in the way you might think. As the world locked down in 2020, fewer emissions went into the sky, including aerosols that typically reflect some of the sun’s energy back into space. “If you take them away, you make the air cleaner, then that’s a slight warming impact on the climate,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, during a Thursday press conference announcing the findings. But as economic activity ramped back up in 2021, so did aerosol pollution, contributing again to that cooling effect. The 2021 temperature drop “may be possibly due to a resumption of activity that produces aerosols in the atmosphere,” Schmidt said. 

graph

NASA’s data on rising temperatures over the decades

Illustration: NASA/NOAA

(The pandemic-based drop in carbon dioxide production didn’t have a cooling effect. Human civilization produces so much of the planet-warming gas every year, and it persists so long in the atmosphere, that the pandemic didn’t even register as a blip.)

How Body Farms and Human Composting Can Help Communities

How Body Farms and Human Composting Can Help Communities

Spade began her investigations as a master’s student in Architecture with her thesis, “A place for the urban dead.” Seeking to replicate the process of livestock composting for humans, she invested a decade of research and fundraising into the Urban Death Project, followed by the opening of Recompose in 2020. Her intention was to not only develop a sustainable system but also engage community members in the transformation of their loved one’s body to soil.

Legislation for human composting has been introduced in Delaware, Hawaii, Maine, Massachusetts, and New York. A similar bill in California received bipartisan support but was shelved in August 2021. In some states, such as New York, the Catholic Church has opposed natural organic reduction, calling the process “more appropriate for vegetable trimmings and eggshells than for human bodies.” But this religious resistance hasn’t halted the legislation, especially in light of funeral homes overwhelmed with bodies waiting for both cremation and burial during Covid-19.

Another company in Washington, Return Home, provides human composting in a facility that’s open to the public, with a 74-person vessel capacity.

“It’s about reclaiming our ability to say goodbye to our loved ones,” said CEO Micah Truman. “There’s a man who comes to sit each morning and brings two cups of coffee, one for his wife in the vessel and one for him. Given the choice, people want to engage, and it makes all the difference in the world.”

During my visit to the Forest lab at Western Carolina University, Zejdlik emphasized the potential of composting, especially since many people think burial and cremation are their only choices: “Animals in agriculture are composted all the time,” she said. “And if human composting takes off, it could be phenomenal.” She noted the environmental benefits in urban areas with a scarcity of green spaces for burial grounds, where land is a resource that needs conserving.

Human composting isn’t yet available in North Carolina, where I live, but support has grown in a range of states since its legalization in Washington in 2019. In many municipalities, restrictive codes around composting pose the initial obstacles to the relatively new process of natural organic reduction. Yet as soon as human composting became legal in Colorado in September 2021, the Natural Funeral constructed vessels for body composting and began offering the service as an addition to green burial and aquamation, which uses water and lye for cremation instead of flames.

“We’re about to have our fourth person placed in a Chrysalis Vessel,” said Karen van Vuuren, cofounder of the Natural Funeral in Boulder. She explained that they named the vessel after a builder named Chris, who helped construct the container that would transform bodies into soil.

“The first person placed into the vessel was a hard loss,” van Vuuren said, “He was a young person. But the family was able to place handwritten notes on the body and lift him into the vessel to return to the earth.”

In a world where 100 companies are responsible for 71 percent of global greenhouse gas emissions, climate action by individuals can feel daunting or ineffective. My end-of-life decisions—in collaboration with my daughters—won’t transform the climate crisis, but I believe in the momentum created by individuals in community, especially when our last best act could create connections between life, death, and earth. Planning for our deaths can engage our family, friends, and communities while nourishing the land, rather than fueling our climate emergency.