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How “Crustivoltaics” Could Restore Arid Lands

April 23, 2023

Replacing Lead Pipes with PVC Is “Leaping from the Frying Pan into the Fire”

As many communities across the country remove lead water lines following the Flint, Michigan, crisis, there’s concern they may be “leaping from the frying pan into the fire” if they replace those pipes with ones made from polyvinyl chloride or PVC. A report by the nonprofit organization Beyond Plastics says using plastic pipes made from polyvinyl chloride can threaten human health. They identify dozens of dangerous chemicals leaching from pipes including benzene, styrene, and other volatile organic compounds.

Credit: Freepik

PVC can also release hormone disruptors that can cause health problems particularly in children and developing fetuses. According to the authors, it’s difficult to be certain about the exact number of chemicals released by the pipes because manufacturers use different formulas. The government has not researched PVC pipe safety and doesn’t require manufacturers to provide information to the public about chemical releases.

The potential harm to humans from exposure to these chemicals is not well understood. However, Bruce Blumberg, a professor of development and cell biology of the University of California, Irvine, told Beyond Plastics that PVC is a “horror show.” Beyond Plastics recommends that more data are urgently needed to show the potential toxic consequences of using the PVC pipes, and in the meantime, copper or stainless steel should be considered.

Hitchhiking Invaders Ride Garbage Patch Across Pacific

You’ve probably heard of the Great Pacific Garbage Patch, which is made up of plastics and other debris collecting between California and Hawai’i. That patch is not like a solid island, and you can’t even see it on satellite images. Rather, it’s more like a cloudy soup of plastic and debris that circulates in a gyre or vortex about twice the size of Texas. It’s dotted with things like shoes and fishing gear and extends from the surface to the ocean floor. Those pieces of plastic are teeming with life—not what one would expect to see in the open ocean.

Floating plastics collected in the North Pacific Subtropical Gyre during The Ocean Cleanup’s 2018 expedition. | Credit: The Ocean Cleanup

Scientists at the University of Hawai’i, Mānoa, and the Smithsonian Environmental Research Center have shown that creatures which previously survived only in coastal communities are now unexpectedly colonizing and reproducing in the garbage patch. Dozens of species of invertebrates survive and thrive on the trash circulating in the open ocean, including worms, anemones, mollusks, and crabs. They were found on 70 percent of the garbage surveyed.

The majority of the trash that washes up on the Hawai’ian Islands is from the plastic vortex, which could lead to an invasion of non-native species. The authors say their observations are a game changer, showing the risk to the fragile ecosystems in the islands, which had been protected from invasive organisms by the long distances from Asia and North America. Before the plastic conveyor, the way species could reach new locales was by hitchhiking on vegetation like seaweed; however, unlike plastics, that organic matter breaks down quickly.

The study was published in the journal Nature Ecology & Evolution.

“SeaChange” Uses the Ocean to Capture More Carbon

As we marked Earth Day on April 22, millions of people around the world rolled up their sleeves to clean up beaches, plant gardens, or commit to living more sustainably on the planet to avoid the catastrophic effects of climate change. While the most crucial thing humans can do is to stop burning fossil fuels, a growing number of methods—from planting trees to carbon capture—are attempting to remove the tons of greenhouse gases already pumped into the atmosphere.

Credit: Institute for Carbon Management (ICM), UCLA

Given our oceans play a huge role in absorbing carbon, researchers at the University of California, Los Angeles, were inspired to create a technology called SeaChange that can rinse out CO2 from seawater and return the less acidic water to the ocean where it can absorb more greenhouse gases.

At a barge docked at AltaSea, an ocean-based campus at the Port of Los Angeles, seawater is zapped with an electrical charge that kicks off a series of chemical reactions that convert the CO2 into solids like limestone and magnesite—the stuff of seashells. Cleaned water is then returned to the ocean ready to take up more CO2, and the shell minerals are sent to the seafloor—or possibly to be used to replenish beach sand or made into building materials like cement, according to the Los Angeles Daily News. A by-product of the process is hydrogen, a clean fuel being used in transportation. The researchers also say a filtration system prevents marine life from being sucked into the system.

Sounds good, but this project won’t capture anywhere near the amount of carbon needed, as 37 billion tons are dumped into the atmosphere each year. The team says, however, roughly 1,800 industrial-scale plants could sequester about ten billion tons annually and make a dent. Another demonstration project is starting this month in Singapore, and data collected between the two sites will help in scaling up larger test plants.

Biocrust Has Bright Future Under Crustivoltaics

Hiking through a desert might give the impression of a mostly barren space with just patches of shrubs, but the craggy surface beneath your shoes is actually a living skin called “biocrust,” and it’s teeming with life that’s performing remarkable feats.

In a proof-of-concept study, ASU researchers adapted a suburban solar farm in the lower Sonoran Desert as an experimental breeding ground for biocrust. During the three-year study, photovoltaic panels promoted biocrust formation, doubling biocrust biomass and tripling biocrust cover compared with open areas with similar soil characteristics. | Graphic Credit: Shireen Dooling

Biocrusts contain cyanobacteria, algae, fungi, lichens, and mosses that sequester carbon, stabilize soils, retain water, and fix nitrogen for plants—unless it’s trampled, driven across, and built upon, which is increasingly the case around the globe because drylands occur on over 40 percent of the world’s continents. Biocrusts are also threatened by climate change, so what to do to restore these vital ecosystems?

Enter “crustivoltaics”—a newly coined term by researchers at Arizona State University, who rejuvenated biocrusts by covering them with solar panels. During a three-year study in the lower Sonoran Desert, the team found that photovoltaic panels created a greenhouse-like microclimate that promoted biocrust formation, doubling its biomass and tripling biocrust cover when compared with uncovered areas with similar soil characteristics.

In short, crustivoltaics are a biocrust nursery, which can be used to replenish arid lands that have been damaged or destroyed. The team says the technique requires fewer resources and minimal management than other methods—and has the added benefit of producing renewable energy as it stores carbon and builds biodiversity.

Next steps will involve implementing crustivoltaics at regional scales, which could include offering carbon credits to solar farm operators.

The group’s findings appear in the journal Nature Sustainability.