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.

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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.

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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.

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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.

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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. 

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Life on Mars: a non-traditional source for warmer waters

Hydrothermal vent on the right spewing water into a river on the left. Background has trees and sky. From Yellowstone National Park.

Article: Amagmatic hydrothermal systems on Mars from radiogenic heat

Authors: L. Ojha, S. Karunatillake, S. Karimi, and J. Buffo

Many people are familiar with Yellowstone National Park’s famous geyser, Old Faithful – but did you know that the heat fueling Old Faithful’s eruptions are from magma chambers that warm up underground fluids until they shoot out of the ground? Hydrothermal systems like this are found in other places, too, and can be fueled by different kinds of heat sources. In fact, scientists at Rutgers University have recently identified one such heat source – the heat generated by radioactive decay from certain chemical elements – that could help answer questions about whether liquid water, a critical component for life as we know it, could exist on Mars.

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Wet Feet? No problem: sandy humid forests grow best with access to groundwater

Pine forest in Governor Thompson State Park, WI, USA

Feature Image: Pine forest in Governor Thompson State Park, WI, USA. Yinan Chen, Public Domain, via Wikimedia Commons

Article: Groundwater subsidizes tree growth and transpiration in sandy humid forests
Authors: D. M. Ciruzzi and S. P. Loheide

Drought is often in the news these days, especially in places with arid and semi-arid climates where water is already scarce. While ecosystems have adapted over millennia to cope with dry climates and seasonal droughts, the increasing intensity and frequency of drought due to climate change and human demand for water can pose significant threats to ecosystem health and survival.

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Strange water — the source of water in our solar system

Featured Image: The star-forming nebula W51 is one of the largest “star factories” in the Milky Way galaxy, NASA/JPL, Public Domain (CC0)

Paper: Origin of hydrogen isotopic variations in chondritic water and organics

Authors: L. Piani, Y. Marrocchi L.G.Vacher H. Yurimoto M. Bizzarro

Vast blue oceans, swirly rain or fluffy white snow – water is ubiquitous on Earth. But where does the water of our solar system come from?

A group of researchers were able to investigate the isotopic composition of water in different components of meteorites. Their findings hint that some of the water on Earth may have originated from a source beyond the solar system.

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Mysterious Eagle Deaths Linked to a Newly Discovered Cyanobacterial Toxin

Feature Image: Bald Eagle. Image from Wikimedia.

Article: Hunting the eagle killer: A cyanobacterial neurotoxin causes vacuolar myelinopathy

Authors: Steffen Breinlinger, Tabitha J. Phillips, Brigette N. Haram, Jan Mareš, José A Martínez, Pavel Hrouzek, Roman Sobotka, W. Matthew Henderson, Peter Schmieder, Susan M. Williams, James D. Lauderdale, H. Dayton Wilde, Wesley Gerrin, Andreja Kust, John W. Washington, Christoph Wagner, Benedikt Geier, Manuel Liebeke, Heike Enke, Timo H. J. Niedermeyer, Susan B. Wilde

Over the winter in 1994-1995, the largest undiagnosed mass mortality of bald eagles in the USA occurred at DeGray Lake in Arkansas. In total, 29 eagles were found dead and another 26 were found in the following winter. Other sick individuals were observed overflying perches or colliding with rock walls. Autopsies revealed open spaces called vacuolar lesions in the eagles’ brains and spinal cords. Since this incident, waterbirds with the same neurological disease have been discovered throughout the southeastern USA, which resulted in a severe loss of motor functions and ultimately death in American coots, ducks, geese, and various birds of prey. The new disease was coined Avian Vacuolar Myelinopathy (or AVM).

Since the first outbreaks in 1994-1995, the cause of AVM outbreaks has puzzled scientists. One commonality between all AVM outbreaks was that they were located on or near man-made water bodies; however, the analysis of the lakes and dead birds recovered from outbreak areas did not contain any chemicals or pathogens that were previously known to cause vacuolar lesions in mammals or birds. Moreover, coots and mallards released into AVM outbreak areas developed the disease, but housing healthy and sick birds together outside of AVM outbreak sites did not cause the disease in healthy birds. These results suggested that a novel environmental neurotoxin rather than a pathogen was the cause of the disease. Even then, the identity of the toxin eluded scientists for over 25 years. Now, through a feat of scientific detective work, AVM has been linked to a novel neurotoxin produced by a newly discovered species of cyanobacteria. How did researchers finally solve the mystery?

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The growing threat of hurricane-associated flooding in southeastern Texas

Feature Image: Flooding in Port Arthur, Texas on August 31, 2017 from Hurricane Harvey. Image from Wikimedia.

Article: Assessment of Future Flood Hazards for Southeastern Texas: Synthesizing Subsidence, Sea‐Level Rise, and Storm Surge Scenarios
Authors: M. M. Miller and M. Shirzaei

Residents of southeastern Texas are not strangers to hurricane landfalls, including Hurricane Harvey in 2017, which caused 80 fatalities and damaged over 80,000 houses without flood insurance. With the population of coastal areas in the United States expected to continue to grow, understanding how hurricane-associated flooding will change in the future is essential for informing policy decisions and flood resilience strategies. Unfortunately southeastern Texas is facing a triple threat of factors that increase the risk of flooding during hurricane landfalls: land subsidence, sea level rise, and more intense hurricanes.

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