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For billions of years, Earth's continents have remained remarkably stable, forming the foundation for mountains, ecosystems and civilizations. But the secret to their stability has mystified scientists for more than a century. Now, a new study by researchers at Penn State and Columbia University provides the clearest evidence yet for how the landforms became and remained so stable—and the key ingredient is heat.

Drip by drip: Research provides first complete mathematical description of stalagmite shapes

Phys.org: Earth science - Mon, 10/13/2025 - 19:00

Deep inside caves, water dripping from the ceiling creates one of nature's most iconic formations: stalagmites. These pillars of calcite, ranging from centimeters to many meters in height, rise from the cave floor as drip after drip of mineral-rich water deposits a tiny layer of stone.

Studies improve modeling of ecosystem productivity and evapotranspiration

Phys.org: Earth science - Mon, 10/13/2025 - 17:25

Accurately modeling gross primary productivity (GPP) and evapotranspiration (ET) in terrestrial ecosystems is essential for understanding and predicting the global carbon and water cycles. However, current models face considerable uncertainties and limitations when estimating these two core components.

Researchers identify factors that influenced the expansion of the Patagonian ice sheet

Phys.org: Earth science - Mon, 10/13/2025 - 17:14

An international research team led by the University of Bremen has investigated what influenced the expansion of the Patagonian ice sheet during the last ice age. The scientists found evidence that the advances and retreats of glaciers in South America over the past 120,000 years were primarily influenced by changes in summer solar radiation and the duration of the summers.

Moderate warming may not doom humid subtropical forests' carbon storage

Phys.org: Earth science - Mon, 10/13/2025 - 15:52

A new study has challenged the long-standing assumption that global warming will inevitably turn humid subtropical forests into carbon sources, revealing these ecosystems may instead continue accumulating soil carbon under moderate temperature rises. The study was published in One Earth on Oct. 6.

New 3D model reveals geophysical structures beneath Britain

Phys.org: Earth science - Mon, 10/13/2025 - 14:12

Magnetotelluric (MT) data, which contain measurements of electric and magnetic field variations at Earth's surface, provide insights into the electrical resistivity of Earth's crust and upper mantle. Changes in resistivity, or the ability to conduct an electrical current, can indicate the presence of geologic features such as igneous intrusions or sedimentary basins, meaning MT surveys can complement other kinds of geophysical surveys to help reveal Earth's subsurface. In addition, such surveys can play an important role in improving understanding of the risks space weather poses to human infrastructure.

Understanding volcanoes better: Scientists find exact locations of magma movement

Phys.org: Earth science - Mon, 10/13/2025 - 14:01

How do volcanoes work? What happens beneath their surface? What causes the vibrations—known as tremor—that occur when magma or gases move upward through a volcano's conduits? Professor Dr. Miriam Christina Reiss, a volcano seismologist at Johannes Gutenberg University Mainz (JGU), and her team have located such tremor signals at the Oldoinyo Lengai volcano in Tanzania.

Centuries of mining turn saltwater lagoon into reservoir of toxic metals

Phys.org: Earth science - Mon, 10/13/2025 - 13:57

According to a study by the Department of Physics and the Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona (ICTA-UAB), the Mar Menor saltwater lagoon in Murcia, Spain, the largest in Europe, contains sediments with levels of lead, arsenic, zinc, mercury, copper, and silver that exceed toxicity thresholds and values reported for similar coastal ecosystems worldwide. The findings are published in the journal Marine Pollution Bulletin.

UK heat waves overwhelm natural ecological safeguards to increase wildfire risk

Phys.org: Earth science - Mon, 10/13/2025 - 13:50

Heat waves in the UK have led to unseasonable drying of vegetation bypassing natural ecological processes that limit the spread of wildfires, a new study has found.

Scientists probe Tajik glacier for clues to climate resistance

Phys.org: Earth science - Mon, 10/13/2025 - 09:40

Greenland is melting, the Alps are melting and the Himalayas are melting—yet in one vast mountain region, huge glaciers have remained stable, or even gained mass, in recent decades. Can it last?

New Australian fossil fuel site could have major impact on people and the planet

Phys.org: Earth science - Mon, 10/13/2025 - 09:00

A new fossil fuel site approved for development off Western Australia's coast is estimated to contribute 876 million tons of carbon dioxide (CO2) emissions over the course of its lifetime, according to new research led by The Australian National University (ANU) in collaboration with the ARC Center of Excellence for the Weather of the 21st century.

Earth enters 'new reality' as coral reefs reach first climate tipping point

Phys.org: Earth science - Sun, 10/12/2025 - 23:10

The world faces a "new reality" as we have reached the first of many Earth system tipping points that will cause catastrophic harm unless humanity takes urgent action, according to a report released by the University of Exeter and international partners.

Microbial Growth and Activity in Static Incubation: Spectral Induced Polarization (SIP) Measurements of Cell Suspensions in Non-Polarizing Media

Geophysical Journal International - Sat, 10/11/2025 - 00:00

SummaryA growing body of literature has contributed to linking the presence of bacteria with SIP signals. Yet, there are still unresolved questions concerning the contribution of cell density and microbial metabolic activity in porous media (soils and sediments) to SIP signals. Moreover, there is continued debate on whether cells themselves polarize or whether a cell-sediment interaction is a prerequisite for the measured responses. This study investigates the SIP response of Shewanella oneidensis MR-1 in isolation, that is, in the absence of a mineral porous medium using two setups (i) cells in aqueous suspension and (ii) alginate bead-packed reactors. Results from experiments conducted with static cell suspensions shed light on the strong control of cell settling that drives erratic, poorly reproducible and difficult to interpret SIP signals. However, incubating cells in bead packed reactors yielded reproducible trends in σ″, with strong (3 – 10 mrad) signals that followed the expected cell growth behaviour. Relating σ″ to measured cell density and metabolic activity (using ATP) highlighted the strongly linked contribution of both activity and cell density and SIP. Here, we report a lower frequency polarization peak between 0.01 and 0.1 Hz in the bead reactors, which we attribute to the polarization of cell colonies in the densely packed reactors. In summary, our findings shed light on the direct contribution of cells and their activity to polarization, in the absence of cell-sediment interactions and provide a novel approach for studying cell polarization in static incubation in a porous environment.