April 21, 2023 | David F. Coppedge

How Earth Cleans Itself

Scientists are surprised at new findings
showing automatic cleanup of air and water



Clean air, clean water: those are frequent goals in political campaigns. While humans need to exercise better stewardship of the Earth, they are getting some help from microbes and geochemistry. Undoubtedly celebrations for Earth Day tomorrow will include blaming humans for everything bad in the environment, especially climate change. It’s true that ecological disasters caused by mankind are many and serious. But maybe this Earth Day people should learn something about natural processes that help with the cleanup automatically, if allowed to operate on their own.

We have seen oil spills cleaned up by bacteria, animals reviving the ecology after the Chernobyl nuclear disaster, and plants covering up ancient cities in Amazonia and Cambodia. Given time, what can these natural processes do to clean up human messes? These are no excuses for making messes, but it’s beginning to look like no job short of global nuclear war is too big for the self-cleaning Earth.

Sea turtle hatchling in open ocean (Illustra Media)

Ocean Chemistry

Scientists discover a way Earth’s atmosphere cleans itself (UC Irvine, 7 April 2023). Hydroxyl ions (OH) can be damaging inside the body, but out in the atmosphere they are beneficial. A new process measured in the ocean shows that these ions form spontaneously at the ocean’s surface at night and accelerate cleanup of the air. Scientists have known about hydroxyl ions, but thought the production was caused by sunlight and was limited. Now, UCI scientists have found it to be far more widespread and effective than thought, working 24 by 7.

How OH itself forms in the atmosphere was viewed as a complete story, but in new research published in Proceedings of the National Academy of Sciences, a research team that includes Sergey Nizkorodov, a University of California, Irvine professor of chemistry, report that a strong electric field that exists at the surface between airborne water droplets and the surrounding air can create OH by a previously unknown mechanism.

It’s a finding that stands to reshape how scientists understand how the air clears itself of things like human-emitted pollutants and greenhouse gases, which OH can react with and eliminate. “You need OH to oxidize hydrocarbons, otherwise they would build up in the atmosphere indefinitely,” said Nizkorodov.

The open-access paper in PNAS says that the extent of this natural process was not realized before because it works at night in the dark.

Amazing FactsIn summary, we have provided strong experimental evidence for the spontaneous production of OH radicals at the air–water interface of aerosolized droplets in the dark. This production does not depend on any precursors and correlates with the air–water interfacial area. Some of the interfacial OH can initiate oxidation chemistry of gas-phase compounds and thus may generate gas-phase products. Extrapolation of our observed OH formation rates to atmospheric conditions indicates that this source could be a major but previously unrecognized contributor to the atmospheric aqueous OH formation, particularly in the dark.


Fungi makes meal of hard to recycle plastic (University of Sydney, 14 April 2023). Polypropylene is one of the toughest plastics to degrade. Found in toys, furnishings and fashion, this plastic accounts for 28% of plastic waste that ends up in landfills. What to do? These scientists looked for natural processes that might be able to degrade polypropylene,

“One big question our result has raised is – what are the naturally occurring conditions which can fast track the degradation of plastics? We seek to further explore the role of biological processes offered by fungi and other microorganisms.

They isolated two species of fungi with superpowers, able to break down the hard plastic. These two species commonly live in the soil and on plants.

Professor Dee Carter, an expert in mycology (the study of fungi) in the School of Life and Environmental Sciences and co-author of the study said: “Fungi are incredibly versatile and are known to be able to break down pretty much all substrates. This superpower is due to their production of powerful enzymes, which are excreted and used to break down substrates into simpler molecules that the fungal cells can then absorb.”

Much work remains to be done, but the team is working to isolate the conditions under which plastic degradation by ‘Superfungi’ can be optimized.

Ecosystem in harmony


Lake Tahoe’s clarity is the best it’s been in 40 years: Researchers say this animal is helping (Phys.org, 11 April 2023). A war goes on between predator and prey in California’s beautiful, large Lake Tahoe: Daphnia and Bosmina, which are tiny crustaceans known as “water fleas,” and the mysis shrimp that preys on them. In their proper ratios, the crustaceans clean the water and give the lake its famous clarity and blue color.

Scientists with UC Davis’ Tahoe Environmental Research Center said the improved clarity is “due in part to a resurgence of the lake’s native zooplankton,” researchers said in the report. “They’ve provided a natural clean-up crew to help restore the lake’s famous blue waters.”

Scientists had been worried that particles from wildfires would further cloud the lake. But the article says that the zooplankton “eat the particles that cloud the lake.”

Garbage Community

Great Pacific Garbage Patch hosts stable community of coastal animals (New Scientist, 17 April 2023). The garbage humans have sent into the ocean, 1.6 million square kilometers of it between California and Hawaii, is a monument to human waste and environmental carelessness. Scientists were surprised, though, to find stable communities living on the trash, including coastal creatures not previously known to live in such conditions—arthropods, sea anemones and molluscs among them. James Carlton of Williams College was surprised to find coastal species outnumbering pelagic species by 3 to 1.

The discovery upends the assumption that coastal species couldn’t survive out in the open ocean and helps to solidify evidence that new types of ecological “neopelagic communities” are establishing themselves on plastic debris in the open ocean. “This has reset my thinking about how coastal species can survive in an environment in which they’ve not evolved,” says Carlton.

Carlton doesn’t know what the creatures eat or how they interact with other ocean fish. Undoubtedly life out there requires eating something, excreting waste, and interacting with microbes that may be at work decomposing at least some of the garbage.


Another recent news item showed that fish and reef creatures seem to adapt to sunken ships as easily as they do to natural reefs. Our 13 Oct 2022 story “Volcanoes Feed the Planet with Nutrients” gave hope that devastated lands could be brought back to life with nutrients brought from deep in the Earth. Our 12 May 2018 entry described how beavers clean the soil with their ponds. Our 6 July 2019 story pointed out that trees help save the planet because the greenhouse gas carbon dioxide is like food to them. They take in CO2 and release oxygen.

One might almost think the Earth was designed for the sustenance of life. These are not excuses for polluting, but they give hope that our messes can be cleaned up. Instead of taking draconian measures, maybe scientists should consider ways to optimize existing planet-cleansing processes.

Recommended Reading: Michael Denton’s book The Miracle of Man is a treasure chest of amazing facts about the Earth, showing how many “coincidences” have conspired to make our planet tailor-made for complex life, especially for large beings like us. Denton is not a creationist, and accepts deep time, but the geological, chemical and biological facts he has assembled are mind-boggling to consider. For a quick introduction to his thinking, look at the videos on his Privileged Species website and the Discovery Science YouTube Playlist. The episode on The Wonder of Water is a good sample.

Share these and Illustra’s masterpiece The Privileged Planet with friends for Earth Day. On YouTube it is separated into 12 episodes.


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