Geobites – Page 9 – Down-to-Earth Geoscience Writing

August 4, 2021August 6, 2021

Glacial Lake Outburst Flood (GLOF) Drowns Villages Along Its Path In The Central Himalayas

Featured Image: Gori Ganga River near Munisiari, Pithoragarh district, Uttarakhand from Wikipedia under CC BY-SA 4.0.

Paper: Lake Evolution, Hydrodynamic Outburst Flood Modeling and Sensitivity Analysis in the Central Himalaya: A Case Study

Authors: Ashim Sattar, Ajanta Goswami, Anil. V. Kulkarni and Adam Emmer

What could be worse than waking up one morning to find yourself drowning in water? People living in the Himalayan terrain experience this fear every time flash floods occur in the valleys. Glacial retreat induced by climate change led to the formation and evolution of glacial lakes in the Himalayan region. The emerging threats possessed by these lakes result in the incidence of Glacial Lake Outburst Floods (GLOF) which wash away villages along its path. One such incident took place in June 2013 in Kedarnath Valley in Uttarakhand, India with a death toll of as many as five to six thousand people. This eventually led to the strong need for risk assessment and management related to the occurrences of such GLOF events.

July 29, 2021July 28, 2021

Throwing Earth Off Balance: Evidence Grows that Our Planet is Heating Up Faster than in the Past

Feature image: A satellite looks down at the surface of Earth. Image from Unsplash

Paper: Satellite and Ocean Data Reveal Marked Increase in Earth’s Heating Rate

Authors: N. G. Loeb, G. C. Johnson, T. J. Thorsen, J. M. Lyman, F. G. Rose, and S. Kato

At the most fundamental level, what causes climate change? Simply put, climate change is a symptom of an energy imbalance with more energy coming into Earth’s atmosphere than is able to go out. This imbalance drives changes in our climate system that scientists around the world study, including warming temperatures, rising sea levels, melting glaciers, and coral reef bleaching. Using two different kinds of observational data, a recent study has found evidence that the energy imbalance is increasing, which suggests climate change will only worsen.

July 22, 2021July 22, 2021

Breaking the ice — Climate systems during Snowball Earth

Featuring image: modern sea ice at Antarctica. Denis Luyten (Wikimedia Commons), public domain (CC0).

Paper: Orbital forcing of ice sheets during snowball Earth

Authors: R. N. Mitchell, T. M. Gernon, G. M. Cox, A. R. Nordsvan, U. Kirscher, C. Xuan, Y. Liu, X. Liu, X. He

When you think about the Earth, you might imagine a blue and green globe orbiting the Sun. But the face of Earth has changed significantly over its life time and in the past, there were times when the Earth resembled more to a frozen, white snowball. Geologists, studying the climate during these cold epochs, found a connection between climate conditions in frozen oceans and variations of Earth’s orbit.

Continue reading “Breaking the ice — Climate systems during Snowball Earth”

July 14, 2021July 14, 2021

A New Paradigm in Decision Making?

Paper: Quantifying Topological Uncertainty in Fractured Systems using Graph Theory and Machine Learning

Authors: Gowri Srinivasan, Jeffrey D. Hyman, David A. Osthus, Bryan A. Moore, Daniel O’Malley, Satish Karra, Esteban Rougier, Aric A. Hagberg, Abigail Hunter & Hari S. Viswanathan

Geophysics problems are as difficult as Nobel Prize-winning physics problems.
Dr. Jérõme A.R. Noir

This quote from Dr. Jérõme Noir has stayed with me throughout my career. The idea: while physicists face extreme math, but also have extremely precise data for unknown phenomena, geoscientists must find vital solutions for known phenomena using just a few data points on a planet. With very little data, how can complex problems in geoscience be solved? And, how do we assess the risk of being wrong? An uncertainty quantification framework recently developed by researchers at Los Alamos National Lab uses machine learning to help geoscientists arrive at quality decisions using limited data.

July 7, 2021July 7, 2021

One of the Moon’s most prominent features is older than we thought

Featured image: the Moon by Pedro Lastra on Unsplash

Paper: Černok, A., White, L.F., Anand, M. et al. Lunar samples record an impact 4.2 billion years ago that may have formed the Serenitatis Basin. Commun Earth Environ 2, 120 (2021). https://doi.org/10.1038/s43247-021-00181-z

About 4 billion years ago, the inner Solar System fell prey to an apocalyptic assault by asteroids. These asteroids slammed into the terrestrial planets—Mercury, Venus, Earth, Mars—and the Moon, leaving behind the scars and basins that make up the planets’ landscapes today. This attack, called the Large Heavy Bombardment, helps explain the genesis of a majority of the formations decorating the inner planets of the Solar System. Previous dating of Moon rocks helped pindown the occurrence of the Bombardment somewhere around 3.8 billion years ago. While this window of time is widely accepted in the planetary science community, one of the Moon’s most iconic features, the Serinatits Basin, might poke a hole in it.

July 1, 2021July 1, 2021

Buried treasure in the oceans: chemistry of small deep-sea crystals hints at past carbon cycling

Featured image: Crystals of the mineral barite from the deep ocean (Adapted from Kastner (1999)). These crystals precipitated in ocean sediments and are about 9 million years old, similar in age to some of the barite samples from the study discussed here.

Paper: A 35-million-year record of seawater stable Sr isotopes reveals a fluctuating global carbon cycle

Authors: Adina Paytan, Elizabeth M. Griffith, Anton Eisenhauer, Mathis P. Hain, Klaus Wallmann, Andrew Ridgwell

What do ancient ocean sediments and the walls around x-ray machines have in common? One possible answer? Sometimes the mineral barite is an important part of both! Barite (or barium sulfate) is able to block gamma and x-ray emissions, and therefore is sometimes used in high-density concrete in hospitals and laboratories. In the deep ocean, tiny crystals of barite naturally accumulate on the seafloor over time, particularly in regions ideal for this mineral formation where many decaying remains of organisms sink to the seafloor. The chemistry of this barite can give scientists clues into Earth’s past, which is what Adina Paytan and her colleagues did in this study.

June 27, 2021June 27, 2021

The only way is… down? Groundwater on Mars could support microbial life in the present day

Featured image: A person exploring the rocks of a cave on Earth, Pixabay.

Paper: Earth-like Habitable Environments in the Subsurface of Mars

Authors: J.D. Tarnas, J.F. Mustard, B. Sherwood Lollar, V. Stamenković, K.M. Cannon, J.-P. Lorand, T.C. Onstott, J.R. Michalski, O. Warr.

Mars exploration has been looking “up” recently: the Ingenuity helicopter performed the first powered flight on another planet, and veteran rover Curiosity gave us stunning images from the top of Mount Mercou. But if we want to look for life on Mars, it might be time for us to look down instead. New research suggests that life on present day Mars could be sustained by chemical energy produced through the interaction between water and rocks deep underground, like it is here on Earth.

June 24, 2021June 24, 2021

Microbes, tectonics, and the global carbon cycle

Featured image: Steam rising from a pool in the Aguas Termales area near the base of Rincón de la Vieja volcano in Costa Rica. Courtesy of the Global Volcanism Program, Smithsonian Institution; photo by Paul Kimberly.

Paper: Effect of tectonic processes on biosphere-geosphere feedbacks across a convergent margin
Authors: K. M. Fullerton, M. O. Schrenk, M. Yucel, E. Manini, M. Basili, T. J. Rogers, D. Fattorini, M. Di Carlo, G. d’Errico, F. Regoli, M. Nakagawa, C. Vetriani, F. Smedile, C. Ramirez, H. Miller, S. M. Morrison, J. Buongiorno, G. L. Jessen, A. D. Steen, M. Martinez, J. M. de Moor, P. H. Barry, D. Giovannelli, and K. G. Lloyd

Plate tectonics describes the workings of our planet on the gigantic scale of continents and oceans, moving graduallly over hundreds of millions of years. But the tectonic processes that slowly shape and reshape the whole surface of the Earth also directly influence the lives of some of our planet’s tiniest residents: microbes. And those microbes, in turn, may have a larger effect on Earth’s carbon cycle than previously estimated.

June 17, 2021June 17, 2021

Mercury on the Move

Featured image: Gravel and rocks crushed by the Greenland Ice Sheet. Image courtesy PennStateNews, used with permission.

Paper: Large subglacial source of mercury from the southwestern margin of the Greenland Ice Sheet

Authors: Jon R. Hawkings, Benjamin S. Linhoff, Jemma L. Wadham, Marek Stibal, Carl H. Lamborg, Gregory T. Carling, Guillaume Lamarche-Gagnon, Tyler J. Kohler, Rachael Ward, Katharine R. Hendry, Lukáš Falteisek, Anne M. Kellerman, Karen A. Cameron, Jade E. Hatton, Sarah Tingey, Amy D. Holt, Petra Vinšová, Stefan Hofer, Marie Bulínová, Tomáš Větrovský, Lorenz Meire, Robert G. M. Spencer

The Greenland Ice Sheet is melting at an astounding rate as our planet continues to warm. Mercury levels in the glacial meltwater traveling into the ocean are the highest levels ever measured in natural systems and rival heavily polluted rivers in Asia. By measuring and tracing mercury in the meltwater, Hawkings and coworkers estimated that the Greenland Ice Sheet contributes up to 10% of all mercury found in Earth’s Oceans today. Where is this mercury coming from within the Greenland Ice Sheet? It is not actually coming from the ice itself, but rather the rocks that have been crushed under the immense weight of the Ice Sheet over thousands of years.

June 10, 2021June 14, 2021

The future cost of mercury exposure

Featured image: Rice paddy fields in Indonesia by Steve Douglas on Unsplash

Paper: Zhang, Y., Song, Z., Huang, S. et al. Global health effects of future atmospheric mercury emissions. Nat Commun 12, 3035 (2021). https://doi.org/10.1038/s41467-021-23391-7

Methylmercury, the organic form of the element mercury, is everywhere. A common global pollutant, this form of mercury is most commonly consumed by humans in food, and subsequent impacts include heart failure and loss of IQ. Environmental mercury is nothing short of a public health crisis, and while global interventions are rolling out to protect humans from this toxic pollutant, new research published in Nature Communications is showing us that the damage isn’t just in human lives, it’s also in dollars and cents.