Posts Tagged ‘geology’
“Some say the world will end in fire, some say in ice.”*…
Ethan Siegel reminds us that the world– the living world– almost did end in ice…
… one event came closer than any other to bringing an end to life on Earth: a catastrophe known as either the Great Oxidation Event or the Great Oxygenation Event. Oxygen, one of the hallmark characteristics of our living Earth, was a tremendous destructive force when it first arrived in any sort of meaningful abundance some ~2 billion years after Earth first took shape. The slow alteration of our atmosphere by the gradual addition of oxygen proved to be fatal to the most common types of organism that were present on Earth at the time. For several hundred million years, the Earth entered a horrific ice age which froze the entire surface: known today as a Snowball Earth scenario. This disaster almost ended life on Earth entirely. Here’s the story of our planet’s near-death, culminating in life’s ultimate survival story…
For roughly 300 million years, the Earth was frozen: “What was it like when oxygen killed almost all life on Earth?” from @StartsWithABang in @bigthink. Eminently worth reading in full.
* Robert Frost, “Fire and Ice“
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As we contemplate change, we might send chilly birthday greetings to Raoul Pictet; he was born on this date in 1846. Remembered as a pioneer in cryogenics, Pictet was a Swiss chemist who spent much of his career trying to produce very low temperatures (in order to produce ice for refrigeration)– which led him to the creation of liquid oxygen in 1877 (for which he’s credited as co-discoverer, as French scientist Louis-Paul Cailletet, working completely separately, also produced liquid oxygen that year).
“The redwood is one of the few conifers that sprout from the stump and roots, and it declares itself willing to begin immediately to repair the damage of the lumberman and also that of the forest-burner”*…
Nature plans ahead: how redwoods survive fire…
When lightning ignited fires around California’s Big Basin Redwoods State Park north of Santa Cruz in August 2020, the blaze spread quickly. Redwoods naturally resist burning, but this time flames shot through the canopies of 100-meter-tall trees, incinerating the needles. “It was shocking,” says Drew Peltier, a tree ecophysiologist at Northern Arizona University. “It really seemed like most of the trees were going to die.”
Yet many of them lived. In a paper published [in late November] in Nature Plants, Peltier and his colleagues help explain why: The charred survivors, despite being defoliated, mobilized long-held energy reserves—sugars that had been made from sunlight decades earlier—and poured them into buds that had been lying dormant under the bark for centuries.
“This is one of those papers that challenges our previous knowledge on tree growth,” says Adrian Rocha, an ecosystem ecologist at the University of Notre Dame. “It is amazing to learn that carbon taken up decades ago can be used to sustain its growth into the future.” The findings suggest redwoods have the tools to cope with catastrophic fires driven by climate change, Rocha says. Still, it’s unclear whether the trees could withstand the regular infernos that might occur under a warmer climate regime.
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It’s not just the energy reserves that are old. The sprouts were emerging from buds that began forming centuries ago. Redwoods and other tree species create budlike tissue that remains under the bark. Scientists can trace the paths of these buds, like a worm burrowing outward. In samples taken from a large redwood that had fallen after the fire, Peltier and colleagues found that many of the buds, some of which had sprouted, extended back as much as 1000 years. “That was really surprising for me,” Peltier says. “As far as I know, these are the oldest ones that have been documented.”
Although the redwoods have sprouted new growth, Peltier and other forest experts wonder how the trees will cope with far less energy from photosynthesis, given that it will be years before they grow as many needles as they had before the fire. “They’re alive, but I would be a little concerned for them in the future.”
Another question is how the redwoods would cope if a second catastrophic fire strikes soon. Have they used up their emergency reserves? “The fact that the reserves used are so old indicates that they took a long time to build up,” says Susan Trumbore, a radiocarbon expert at the Max Planck Institute for Biogeochemistry. “Redwoods are majestic organisms. One cannot help rooting for those resprouts to keep them alive in decades to come.”…
After a devastating conflagration, trees regrow using energy stored long ago: “Ancient redwoods recover from fire by sprouting 1000-year-old buds,” from @ScienceMagazine.
* John Muir
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As we learn from nature, we might spare a thought for Louis Agassiz; he died on this date in 1873. A biologist and geologist, he was an important early scholar of Earth’s natural history. After studying with Georges Cuvier and Alexander von Humboldt in Paris, Agassiz was appointed professor of natural history at the University of Neuchâtel. He emigrated to the United States in 1847 after visiting Harvard University and went on to become professor of zoology and geology at Harvard, to head its Lawrence Scientific School, and to found its Museum of Comparative Zoology.
Agassiz is known for observational data gathering and analysis. He made institutional and scientific contributions to zoology, geology, and related areas, including multivolume research books running to thousands of pages. He founded the field of glaciology.
His second wife, Elizabeth Cabot Agassiz (née Cary) collaborated with him on much of his work and went on to found Radcliffe College.
“Dust to dust”*…
Back in 2016, we visited Jay Owens and his fascinating newsletter on dust… which went silent a couple of years later. Those of us who missed it, and were worried about its author were relieved to learn that he’d pulled back in order to turn his thinking into a book. That book is now here: Dust: The Modern World in a Trillion Particles, and The Guardian is here with an excerpt…
… Nobody normally thinks about dust, what it might be doing or where it should go: it is so tiny, so totally, absolutely, mundane, that it slips beneath the limits of vision. But if we pay attention, we can see the world within it.
Before we go any further, I should define my terms. What do I mean by dust? I want to say everything: almost everything can become dust, given time. The orange haze in the sky over Europe in the spring, the pale fur that accumulates on my writing desk and the black grime I wipe from my face in the evening after a day traversing the city. Dust gains its identity not from a singular material origin, but instead through its form (tiny solid particles), its mode of transport (airborne) and, perhaps, a certain loss of context, an inherent formlessness. If we knew precisely what it was made of, we might not call it dust, but instead dander or cement or pollen. “Tiny flying particles,” though, might suffice as a practical starting definition…
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Dust is simultaneously a symbol of time, decay and death – and also the residue of life. Its meaning is never black or white, but grey and somewhat fuzzy. Living with dust – as we must – is a slow lesson in embracing contradiction: to clean, but not identify with cleanliness; to respect the material need for hygiene while distrusting it profoundly as a social metaphor…
A fascinating sample of a fascinating book: “Empire of dust: what the tiniest specks reveal about the world,” from @hautepop in @guardian.
Pair with: “Nothing is built on stone; all is built on sand” and “In every grain of sand there is the story of the earth.”
* from the burial service in the Book of Common Prayer
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As we examine the elemental, we might send exploratory birthday greetings to Friedrich Wilhelm Heinrich Alexander von Humboldt; he was born on this date in 1769. The younger brother of the Prussian minister, philosopher, and linguist Wilhelm von Humboldt, Alexander was a geographer, geologist, archaeologist, naturalist, explorer, and champion of Romantic philosophy. Among many other contributions to human knowledge, his quantitative work on botanical geography laid the foundation for the field of biogeography; he surveyed and collected geological, zoological, botanical, and ethnographic specimens, including over 60,000 rare or new tropical plants.
As a geologist, Humboldt made pioneering observations of geological stratigraphy, structure (he named the Jurassic System), and geomorphology; and he understood the connections between volcanism and earthquakes. His advocacy of long-term systematic geophysical measurement laid the foundation for modern geomagnetic and meteorological monitoring.
For more, see: The Invention of Nature: Alexander Von Humboldt’s New World.
“Hurricane season brings a humbling reminder that, despite our technologies, most of nature remains unpredictable”*…
Still, as Katarina Zimmer explains, an emerging science can help us improve our forecasts…
… contemporary simulations suggest the Great Colonial Hurricane was a Category 3.5 storm, probably the strongest in recorded eastern New England history. (For reference, Sandy, which killed nearly 150 people and caused some $65 billion in damage in the United States, was technically no longer even a hurricane when it made landfall in the New York metro area in 2012.)
Scientists know about the Great Colonial Hurricane’s impact not only from written reports but curiously, also from hidden, physical impressions the long-ago storm left on the landscape.
At the bottom of a pond, Jeffrey Donnelly, a hurricane scientist at the Woods Hole Oceanographic Institution, and his colleagues found subtle, buried evidence of the storm that almost felled the Mather line. The researchers were collecting sediment cores from a lakebed on Cape Cod. The spot, known as Salt Pond, lies about a third of a mile from the ocean and has long been a place of mud. But in their core samples, they found a pinky finger-thick layer of pure ocean sand in layers that dated back to roughly 1635. The only thing that could have pulled that much beach material over the sand barrier and that far inland was a truly massive storm.
The cores revealed other clues, too. Although written accounts suggest the 1635 tempest was the strongest of its time, the exhumed samples showed it wasn’t the only intense storm in the area. Donnelly found evidence for 10 major storms in the area between 1400 and 1675—a surprising toll, given that major hurricanes are virtually unheard of this far north today. The fact that hurricanes were much more frequent in the past begs the question of why, and whether these levels of storm activity could someday return.
Which is why researchers like Donnelly are traipsing along coastlines and digging in the muck. They hope their relatively new branch of science, paleotempestology (the study of old storms), can use these buried traces of long-gone winds to augur ancient patterns. Patterns that might also help us predict the weather that lies ahead…
Paleotempestology promises to uncover patterns of historical hurricanes—to better predict destructive weather of the future. More at: “The Secret Messages in Ancient Storms,” (or here) from @katarinazimmer in @NautilusMag.
* Diane Ackerman
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As we muse on the meteorological, we might send exploratory birthday greetings to Bernard Brunhes; he was born on this date in 1867. A geophysicist, he is known for his pioneering work in paleomagnetism, in particular, his 1906 discovery of geomagnetic reversal [see here]. The current period of normal polarity, Brunhes Chron, and the Brunhes–Matuyama reversal are named for him.
Brunes made his discovery in a way that presaged the work of paleotempestologists: he found volcanic lava and clay samples that recorded the Earth’s inversion of its magnetic field.
“Over the long term, symbiosis is more useful than parasitism. More fun, too.”*…
There are many more varieties of minerals on earth than previously believed– and about half of them formed as parts or byproducts of living things…
The impact of Earth’s geology on life is easy to see, with organisms adapting to environments as different as deserts, mountains, forests, and oceans. The full impact of life on geology, however, can be easy to miss.
A comprehensive new survey of our planet’s minerals now corrects that omission. Among its findings is evidence that about half of all mineral diversity is the direct or indirect result of living things and their byproducts. It’s a discovery that could provide valuable insights to scientists piecing together Earth’s complex geological history—and also to those searching for evidence of life beyond this world.
In a pair of papers published on July 1, 2022 in American Mineralogist, researchers Robert Hazen, Shaunna Morrison and their collaborators outline a new taxonomic system for classifying minerals, one that places importance on precisely how minerals form, not just how they look. In so doing, their system acknowledges how Earth’s geological development and the evolution of life influence each other.
Their new taxonomy, based on an algorithmic analysis of thousands of scientific papers, recognizes more than 10,500 different types of minerals. That’s almost twice as many as the roughly 5,800 mineral “species” in the classic taxonomy of the International Mineralogical Association, which focuses strictly on a mineral’s crystalline structure and chemical makeup.
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Morrison and Hazen also identified 57 processes that individually or in combination created all known minerals. These processes included various types of weathering, chemical precipitations, metamorphic transformation inside the mantle, lightning strikes, radiation, oxidation, massive impacts during Earth’s formation, and even condensations in interstellar space before the planet formed. They confirmed that the biggest single factor in mineral diversity on Earth is water, which through a variety of chemical and physical processes helps to generate more than 80 percent of minerals.
But they also found that life is a key player: One-third of all mineral kinds form exclusively as parts or byproducts of living things—such as bits of bones, teeth, coral, and kidney stones (which are all rich in mineral content) or feces, wood, microbial mats, and other organic materials that over geologic time can absorb elements from their surroundings and transform into something more like rock. Thousands of minerals are shaped by life’s activity in other ways, such as germanium compounds that form in industrial coal fires. Including substances created through interactions with byproducts of life, such as the oxygen produced in photosynthesis, life’s fingerprints are on about half of all minerals.
But they also found that life is a key player: One-third of all mineral kinds form exclusively as parts or byproducts of living things—such as bits of bones, teeth, coral, and kidney stones (which are all rich in mineral content) or feces, wood, microbial mats, and other organic materials that over geologic time can absorb elements from their surroundings and transform into something more like rock. Thousands of minerals are shaped by life’s activity in other ways, such as germanium compounds that form in industrial coal fires. Including substances created through interactions with byproducts of life, such as the oxygen produced in photosynthesis, life’s fingerprints are on about half of all minerals.
Historically, scientists “have artificially drawn a line between what is geochemistry and what is biochemistry,” said Nita Sahai, a biomineralization specialist at the University of Akron in Ohio who was not involved in the new research. In reality, the boundary between animal, vegetable, and mineral is much more fluid.
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A new origins-based system for classifying minerals reveals the huge geochemical imprint that life has left on Earth. It could help us identify other worlds with life too: “Life Helps Make Almost Half of All Minerals on Earth,” from @jojofoshosho0 in @QuantaMagazine.
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As we muse on minerals, we might send systemic birthday greetings to Thomas Samuel Kuhn; he was born on this date in 1922. A physicist, historian, and philosopher of science, Kuhn believed that scientific knowledge didn’t advance in a linear, continuous way, but via periodic “paradigm shifts.” Karl Popper had approached the same territory in his development of the principle of “falsification” (to paraphrase, a theory isn’t false until it’s proven true; it’s true until it’s proven false). But while Popper worked as a logician, Kuhn worked as a historian. His 1962 book The Structure of Scientific Revolutions made his case; and while he had– and has— his detractors, Kuhn’s work has been deeply influential in both academic and popular circles (indeed, the phrase “paradigm shift” has become an English-language staple).
“What man sees depends both upon what he looks at and also upon what his previous visual-conception experience has taught him to see.”
Thomas S. Kuhn, The Structure of Scientific Revolutions
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