April 2022 – Geobites

April 29, 2022April 29, 2022

Silver Doesn’t Grow on Trees: The Quest for the Ores that Formed Roman Coinage

Featured image: A silver Roman Denarius, featuring the likeness of emperor Marcus Aurelius. CC BY-SA 3.0 via Wikimedia Commons

Paper: Silver isotope and volatile trace element systematics in galena samples from the Iberian Peninsula and the quest for silver sources of Roman coinage

Authors: Jean Milot; Janne Blichert-Toft; Mariano Ayarzagüena Sanz; Chloé Malod-Dognin; Philippe Télouk; Francis Albarède

The Roman Empire was a superpower thousands of years ago, and with great power comes great (fiscal) responsibilities, including minting the money. To mint silver coins, the Romans needed vast amounts of silver, which historians and archeologists believe originated in the Iberian Peninsula, or present-day Spain and Portugal. However, the geologic origin of that silver is unknown as the depleted mines were abandoned long ago.

April 28, 2022April 28, 2022

Greenhouse gasses, ice cover, and the deep ocean shape Earth’s paleoclimate in unexpected ways

Featured Image: Line-scan image of sediment core from the Bay of Bengal. Image from the International Ocean Discovery Program. A. Volcanic ash associated with the Toba eruption. B. Pyrite-, foraminifer-, and shell fragment–rich sandy patch in foraminifer-rich clay with biosilica. C. Scaphopod in nannofossil-rich clay with foraminifers. D. Wood fragments in clay. E. Large dark gray burrow filled with the overlying sediment. F. Core disturbance (cracks) due to gas release when core liner was drilled on the catwalk. G. Minor core disturbance due to mud and water flow-in along the edges of the liner (~1 cm thickness).

Paper: Increased interglacial atmospheric CO₂ levels followed the mid-Pleistocene Transition

Authors: Masanobu Yamamoto, Steven C. Clemens, Osamu Seki, Yuko Tsuchiya, Yongsong Huang, Ryouta O’ishi, Ayako Abe-Ouchi

Mention of the ice age may conjure up images of giant mastodons, ferocious saber-tooth tigers, or of a prehistoric squirrel trying so desperately to secure his acorn—all taking place on the vast amount of ice that covered portions of the globe. We know that periods of ice cover followed by stretches of warm weather was a standard pattern in our Earth’s history*, but there was something special about the last ice age (during the Pleistocene) and how long it hung around.

April 27, 2022April 27, 2022

Methanotrophs: Nature’s catalytic converters

Featured image: A car exhaust pipe, by Matt Boitor on Unsplash.

Paper: Microbial methane oxidation efficiency and robustness during lake overturn

Authors: M. Zimmerman, M. Mayr, H. Bürgmann, W. Eugster, T. Steinsberger, B. Wehrli, A. Brand, D. Bouffard

If you own a car, you’re likely aware that your engine emits greenhouse gases to the atmosphere. Although we usually think of cars and other human activities as the primary source of such greenhouse gases, living ecosystems can also produce these gases through natural processes. For example, lakes are an important global source of methane, a potent greenhouse gas produced in lake sediments as organic matter decomposes. In their recent paper, Zimmerman and colleagues focus on a small but mighty team of microbes that work hard to limit the amount of methane emitted from lakes.

April 26, 2022April 26, 2022

How to connect methane in atmosphere to a planets geology and biology

Featuring image: Titan’s atmosphere is rich in organic molecules, but we still don’t know if there is life on Saturn’s icy moon. With JWST and the coming generation of telescopes, we will be able to observe the atmospheres of exoplanets. Is there a way to search for life on these distant worlds? NASA/JPL, public domain (CC0).

Paper: The case and context for atmospheric methane as an exoplanet biosignature

Authors: M. A. Thompson, J. Krissansen-Totton, N. Wogan, M. Telus and J. J. Fortney

Visiting and exploring exoplanets for extraterrestrial life still belong to the realm of science fiction. However, the coming generation of telescopes will enable us to look into the atmospheres of exoplanets and search for possible biosignatures, chemical compounds that could indicate the presence of life.

Searching for life on a planet is not a trivial task. Since the first Mars landing in 1976, scientists still search for recent or ancient traces of life. It becomes even more difficult on planets that we cannot directly visit. The next telescope generation will enable us to observe the atmosphere of distant planets remotely. Are there ways to find evidence of life in a planet’s atmosphere? A new study suggests that the freshly launched James Webb Space Telescope (JWST) could help us to search for life on other worlds.

April 26, 2022April 26, 2022

Earth’s darkest hour

Featured image: This is a Trilobite fossil from Volkhov river, Russia. Trilobites were marine arthropods which went extinct at the end of Permian period. CC BY-SA 3.0 via Wikimedia commons

Paper: Bioindicators of severe ocean acidification are absent from the end-Permian mass extinction.

Authors: William J. Foster, J.A. Hirtz, C. Farrell, M. Reistrofer, R. J.Twitchett, R. C. Martindale

What if I told you that an extinction event occurred In Earth’s history that dwarfs the demise of dinosaurs? This turbulent period dawned 252 million years ago, during the Late Permian period. The largest volcanic eruptions in the history of our planet began in now what is known as Siberia. The eruptions spewed out millions of cubic kilometers of lava, enough to bury an area the size of United States under a mile thick layer of rock!

April 12, 2022April 12, 2022

Breaking: all living things may produce methane, including you

Featured Image: Collage of Life. Image courtesy Bryan K. Lynn.

Paper: Methane formation driven by reactive oxygen species across all living organisms

Authors: Leonard Ernst, Benedikt Steinfeld, Uladzimir Barayeu, Thomas Klintzsch, Markus Kurth, Dirk Grimm, Tobias P. Dick, Johannes G. Rebelein, Ilka B. Bischofs, Frank Keppler

You may have heard how methane is a “potent greenhouse gas.” But what does that mean? Even though there are fewer molecules released in our atmosphere when compared to carbon dioxide, methane holds onto heat 25 times more effectively than carbon dioxide. In other words, if carbon dioxide acts as a linen sheet around Earth, then methane is akin to a downy comforter.