Science news: mother-of-pearl’s perfect structure, news from the Yellowstone hotspot and its past supereruptions, drylands are not getting drier, why Australia’s Platypus is so bizarre

A cross-section through a shell showing the periodically layered nacre on top of a prismatic shell structure. Photo: Igor Zlotnikov

Recent discoveries about our planet, its rocks, and other “stone” topics

Scientists discovered how mother-of-pearl self-assembles into a perfect structure: The right-handed and left-handed defects move through the structure until they meet and cancel each other out. These events lead to a tissue-wide synchronization. Over time, it allows the structure to develop into a perfectly regular and defect-free.
https://tu-dresden.de/cmcb/die-einrichtung/news/opposites-attract-scientists-discover-how-mother-of-pearl-self-assembles-into-a-perfect-structure?set_language=en
 

The break in slope is coincident with a discontinuity representing a regional three- to five-million-year hiatus separating two distinct styles of volcanic activity in the Cascadia backarc region. Source: Victor Camp and Ray WellsInsights into the Yellowstone hotspot and its supereruptions in the geologic past: according to a new scenario, hotspot volcanism began offshore and migrated to the east-northeast across northeastern California, northern Nevada, southeastern Oregon, and southern Idaho to its current position at Yellowstone National Park.
https://www.geosociety.org/GSA/Publications/GSA_Today/GSA/GSAToday/archive/31/1/contents.aspx
 

A dryland ecosystem in Northern California shows decreasing soil moisture but little changes in surface water availability. Photo: Columbia EngineeringSurprising news: drylands are not getting drier. Researchers identified a long-term soil moisture regulation of atmospheric circulation and moisture transport that largely ameliorates the potential decline of future water availability in drylands, beyond that expected in the absence of soil moisture feedbacks.
https://www.engineering.columbia.edu/press-releases/gentine-drylands-not-getting-drier
 

Platypus (Ornithorhynchus anatinus) in its first description 1799. Frederick Polydore Nodder / Wikimedia commonsWhy Earth’s oddest mammal, Australia’s beaver-like, duck-billed Platypus, lays eggs instead of giving birth to live babies, sweats milk, has venomous spurs, and is even equipped with 10 sex chromosomes. The answer: it belongs to an ancient group of mammals – monotremes -, but is genetically a mixture of mammals, birds, and reptiles. It has preserved many of its ancestors’ original features.
https://www.science.ku.dk/english/press/news/2021/how-earths-oddest-mammal-got-to-be-so-bizarre

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(12.01.2021, USA: 01.12.2021)