Geobites – Page 16 – Down-to-Earth Geoscience Writing

September 8, 2020September 8, 2020

Did a change in phosphorus cycling lead to the diversification of macroscopic life?

Featured image: The earliest examples of life on Earth are microbial buildups known as stromatolites, like these 1.8 Ga old examples from Great Slave Lake, Canada. What changed on our planet for organisms to evolve from microbes to macroscopic lifeforms?

Paper: Ediacaran reorganization of the marine phosphorus cycle
Authors: Laakso, T.A., Sperling, E.A., Johnston, D.T., and Knoll, A.H.

This is a guest post by Akshay Mehra and Danielle Santiago Ramos. Contact us to submit a guest post of your own!

The history of life on Earth—as recorded in the rock record—stretches back to more than 3.5 billion years ago (Ga). The earliest fossilized remains of living organisms appear in the form of stromatolites, which are laminated constructions built in part (or completely) by microbes. While there have been some tantalizing hints that living organisms were mobile by 2.1 Ga (Albani et al., 2019) and multicellular by 1.6 Ga (Bengston et al. 2017), what is definitively known is that by ~750 million years ago (Ma), complex microscopic lifeforms were widespread on our planet. As time progressed, life became macroscopic. Then, during the Cambrian Era (beginning 539 Ma), most modern phyla (i.e. a grouping of organisms based on body plans) appeared in a flurry of diversification so drastic that it has been nicknamed “the Cambrian explosion.” Scientists are still trying to understand what combination of physical and biological processes may have driven the Cambrian explosion.

September 2, 2020September 4, 2020

Warmer climate could mean corals thrive in the southern Great Barrier Reef

Featured image: Jeremy Bishop on Pexels

Paper: Re-evaluating mid-Holocene reef “turn-off” on the inshore Southern Great Barrier Reef
Authors: Leonard, N.D., Lepore, M.L., Zhao, J.X., Rodriguez-Ramirez, A., Butler, I.R., Clark, T.R., Roff, G., McCook, L., Nguyen, A.D., Feng, Y. and Pandolfi, J.M.

A new study has reconstructed the complex growth history of coral communities in the Keppel Islands, southern Great Barrier Reef, revealing that the area might provide a safe-haven for coral under climate change.

September 1, 2020September 2, 2020

Marsquakes give scientists an InSight to Mars

Featured image: An artist’s concept of NASA’s InSight lander on Mars with a cutaway of the surface below. Credit: IPGP/Nicolas Sarter.

Paper: Constraints on the shallow elastic and anelastic structure of Mars from InSight seismic data

Authors: Philippe Lognonné et al.,

Scientists are able to ‘see’ the internal structure of the Earth based on seismic waves recorded during Earthquakes. Earthquakes send seismic waves out in all directions with two main types: (1) surface waves are the major culprits of Earthquake damage as they remain on the surface; (2) faster body waves can travel down within Earth’s interior. The body waves are the fastest seismic waves, consisting of the first (primary; P-wave) and second (secondary, S-wave) waves to arrive at a location away from the epicentre of an Earthquake.

August 28, 2020August 30, 2020

Do Microbes Release Fluorine from Rocks?

Featured Image used with permission of photographer (Cassi Wattenburger)

Paper: Indigenous microbes induced fluoride release from aquifer sediments

Authors: Xubo Gao, Wenting Luo, Xuesong Luo, Chengcheng Li, Xin Zhang, Yanxin Wang

My science textbook taught me that fluorine (F) was really important for dental health, and I’ve since learned that both excessive and insufficient amounts of fluoride in groundwater can cause health issues. While the chemistry behind the release of fluoride ions from rocks or sediments into groundwater is well understood, the microbiology of this process is not. Specifically, scientists have been wondering whether microbes could speed up the release of F from sediments into groundwater.

August 26, 2020August 16, 2020

The Extraction of Hidden Waters: 11th century Persian scientist laid the foundations for hydrology and water engineering

Featured Image: Areal view of the vertical shafts of a qanat in Jupar, Iran. S.H. Rashedi / CC BY-ND via UNESCO.

Paper: The millennium-old hydrogeology textbook The Extraction of Hidden Waters by the Persian mathematician and engineer Abubakr Mohammad Karaji (953 CE–1029 CE)

Authors: Ataie-Ashtiani, B., & Simmons, C. T.

Reliable sources of water are essential for every civilization. However, the Western science of hydrology is relatively young. It started perhaps at the turn of the 19^th century when John Dalton completed the first water balance for England and Wales by estimating the amount of water that fell as precipitation and left as evaporation and flow from rivers to oceans. Since ancient times, civilizations have built water infrastructure like aqueducts and wells, and writings by Aristotle and Plato suggest that the ancient Greeks had a basic understanding of the water cycle. Though in many respects, the study of hydrology in Europe and the Mediterranean stagnated between the time of these early philosophers and the 19^th century.

August 21, 2020September 22, 2020

Hillsides collapsing into Arctic streams can trigger CO₂ release to the atmosphere

Featured Image: Permafrost thaw slumps draining into a river on the Peel Plateau in western Canada. Photo courtesy Scott Zolkos, lead author of the paper.

Paper: Experimental Evidence That Permafrost Thaw History and Mineral Composition Shape Abiotic Carbon Cycling in Thermokarst-Affected Stream Networks

Authors: Zolkos, Scott & Suzanne E. Tank.

The rivers and streams of the Arctic transfer atmospheric heat into the surrounding permafrost (perennially frozen) soil. At the same time, surface soils up to 1 meter deep undergo annual freeze-thaw cycles. When warmer air arrives in the summer months, the combination of warming air and river water can thaw large chunks of ice-rich permafrost soil along the stream’s edge. Thawed permafrost breaks away from the surrounding hillsides and causes catastrophic slope failures, transporting huge amounts of sediment into the nearby waterways. As the stream water becomes murky it takes on the appearance of chocolate milk, and simultaneously, the geochemistry of the water changes.

August 20, 2020August 21, 2020

Lava tubes on the Moon and Mars might be big and stable enough for humans to live in

Featured image: A hole with approximately 150 metres diameter, indicating a potential lava tube on Mars. Public Domain (NASA/JPL/University of Arizona).

Paper: Lava tubes on Earth, Moon and Mars: A review on their size and morphology revealed by comparative planetology

Authors: Francesco Sauro, Riccardo Pozzobon, Matteo Massironi, Pierluigi De Berardinis, Tommaso Santagata, Jo De Waele.

Editor’s note: due to an editorial mixup, two Geobites authors—unbeknownst to each other—wrote about the same paper. We encourage readers to take advantage of this opportunity to learn how two different geoscientists would describe the same exciting development in their field. The other post is here.

When you picture living on another planet, you probably don’t imagine living underground. But lava tubes – underground cave systems formed by flowing lava – are more sheltered from radiation and micrometeorites than the surface of the Moon or Mars. They are also more stable in temperature and could contain water ice. For these reasons both popular culture, such as the National Geographic Mars series, and scientists alike, have hypothesised that humans might live in them one day. Now, a new review and analysis study led by Francesco Sauro at the University of Bologna has sought to investigate potential lava tubes on both the Moon and Mars.

August 18, 2020August 18, 2020

North Atlantic Ice Melt May Increase the Storminess of the Northern Hemisphere

Featured image of sea ice from Free-Photos on Pixabay

Paper: Rapid Cooling and Increased Storminess Triggered by Freshwater in the North Atlantic
Authors: M. Oltmanns, J. Karstensen, G. W. K. Moore, and S. A. Josey

Way up north in the Arctic Circle, sea ice and glaciers are rapidly melting and sending a massive amount of cold, fresh water into the North Atlantic Ocean. At first this influx of cold water may seem beneficial to offset the warming from climate change, but new research suggests that this meltwater from Greenland and the Arctic increases the number of winter storms that occur in the Northern Hemisphere.

August 17, 2020August 20, 2020

Out of this world! Evaluating the presence of lava tubes on other planets and the potential for future human habitats

Paper: Lava tubes on Earth, Moon and Mars: A review on their size and morphology revealed by comparative planetology

Authors: F. Sauro, R. Pozzobon, M. Massironi, P. De Berardinis, T. Santagata, J. De Waele

Ever since humankind set foot on the surface of the Moon in 1969, the question of whether one day the human race would inhabit other planets has been pondered over. As a result of the return of samples collected by the Apollo astronauts, and the delivery of meteorites to the Earth, scientists are continuously learning about the geological evolution of other planets.

August 16, 2020August 16, 2020

Citizen science project identifies extensive mining pollution in central Peru

Featured image: Anti mining protesters in Downtown Lima, Peru. Photo credit: Geraint Rowland on Flickr (CC BY-NC 2.0).

Paper: Citizen science campaign reveals widespread fallout of contaminated dust from mining activities in the central Peruvian Andes
Authors: James B. Molloy, Donald T. Rodbell, David P. Gillikin, and Kurt T. Hollocher

At the heart of Cerro de Pasco, Peru, one of the highest cities on Earth, is an enormous open pit mine. People have been mining at the Cerro de Pasco site since pre-Incan times, but after silver was discovered there in the 1630s, it became one of the world’s richest and most heavily worked mines.