Geobites – Page 4 – Down-to-Earth Geoscience Writing

September 22, 2022September 23, 2022

Getting to Grips With the Sixth Mass Extinction

Featured Image: It is well-understood that the Earth’s biodiversity is in severe decline. However, it is less clear if this decline can now be called a mass extinction. Public domain image via. The Wilderness Society.

Paper: The Sixth Mass Extinction: fact, fiction, or speculation?

Authors: Robert H Cowie, Philippe Bouchet & Benoît Fontaine

Human-driven emissions and land use changes have impacted Earth’s biosphere greatly, causing global extinction rates to climb fast. However, does the current undeniable biodiversity crisis meet the requirements to be called a mass extinction?

September 14, 2022September 14, 2022

Chicxulub’s small sibling

Featuring image: 66 million years ago, a giant meteorite impact ended the age of the dinosaurs. Artist impression of the impact. Painting by Donald E. Davis, Public Domain (C0)

Paper: The Nadir Crater offshore West Africa: A candidate Cretaceous-Paleogene impact structure

Authors: U. Nicholson, V. J. Bray, S. P. S. Gulick, B. Aduomahor

The appearance of a flaming, 10 km wide meteorite over the Gulf of Mexico must have been striking, literally. But could the meteorite, which killed the dinosaurs, have had a small sibling or even a whole family of smaller space rocks hurtling towards Earth?

The massive meteorite impact at Chicxulub in the Gulf of Mexico ended the era of the dinosaurs 66 million years ago. Now, only a few thousand km apart from it, researchers might have found another, smaller crater of a similar age. And it might show that the Chicxulub meteorite was not alone but part of a cluster of meteorites, bombarding the Earth at the end of the Cretaceous period.

September 2, 2022September 2, 2022

We’re Here Because We’re Here Because… of Chance?

A painting of many stars as in a night sky, surrounded by planets, with their orbits drawn out.

Featured image: An artist’s depiction of many, many possible planets. This image was created by the European Southern Observatory (ESO).

Paper: Tyrrell, T. Chance played a role in determining whether Earth stayed habitable. Commun Earth Environ 1, 61 (2020). https://doi.org/10.1038/s43247-020-00057-8

Have you ever stayed up at night and wondered, why am I here? Or, more broadly, why are we here, including all living things on this Earth? Don’t worry, you’re not alone, and scientists like Professor Toby Tyrrell of the University of Southampton (UK) have been trying to answer these questions using the scientific method.

His conclusion? It may have just been the luck of the draw. After all, if we weren’t here in the first place, we couldn’t wonder why we were. (Scientists call this the weak anthropic principle.)

Climate scientists often describe their models as alternate (climate) histories. Tyrrell’s 2020 paper takes this idea to its ultimate conclusion, running 100 alternate climate histories on 100,000 randomly generated planets within the habitable zone of their randomly generated stars for 3 billion years. The question he’s trying to help answer is this: how likely was it that the Earth’s climate stayed habitable for the 4 billion years between the evolution of the first prokaryotic cells and us? Was it due to some intrinsic properties of planet Earth, or of life, or was it merely chance?

August 31, 2022August 31, 2022

The rise of Sponges

Featuring image: Venus flower basket glass sponges (Euplectella aspergillum) in the Gulf of Mexico. NOAA Okeanos Explorer Program – Gulf of Mexico 2012 Expedition, CC-BY-2.0

Paper: Palaeoecological Implications of Lower-Middle Triassic Stromatolites and Microbe-Metazoan Build-Ups in the Germanic Basin: Insights into the Aftermath of the Permian–Triassic Crisis

Authors: Y. Pei, H. Hagdorn, T. Voigt, J.-P. Duda, J. Reitner

The Permian-Triassic crisis was the greatest mass extinction in Earth’s history. But an unlikely animal might have benefited from this cataclysm: the sponge.

Microbial mats like stromatolites represent the lithified remains of different slimy accumulations of microorganisms. While there are many different types, Pei and co-workers investigated a special type of microbial mats with a very different internal structure, called microbial-metazoan build-up, mainly consisting of sponges. By comparing these fossil structures to common stromatolites from the Permian-Triassic boundary, the researcher team could show that sponges profited from the mass extinction with the aid of bacteria.

August 25, 2022August 31, 2022

One Sailors’ Legend Down, Many More To Go – Multiple Milky Sea Events Detected by Satellite

Processed satellite images showing a milky sea event in Java, 2019.

Featured image: Processed satellite images showing a milky sea event and its components in Java, 2019. From Miller et al, 2021 (figure 5).

Paper: Miller, S.D., Haddock, S.H.D., Straka, W.C. et al. Honing in on bioluminescent milky seas from space. Sci Rep 11, 15443 (2021). https://doi.org/10.1038/s41598-021-94823-z

Sailors see a lot of, well, stuff while they’re far from land. And they’re known for telling unbelievable tales, some of which later turn out to be more or less true. Milky seas are one of those: a horizon-to-horizon sea that glows white like the snow in the moonlight. In a 2021 paper, Dr. Steven Miller of Colorado State University and colleagues used satellites to look for these systems in hopes of understanding how and why these glowing patches form.

The first satellite detection of a milky sea event was also the work of Dr. Miller, in a 2005 paper that detected just a single event by combing ships’ logs and satellite archives from the preceding decade. Now, Miller’s research team has refined the algorithm that he’d previously developed for modern satellite records. Today’s satellite technology is better able to ‘see’ these events due to higher resolution of their images and can pick out the bioluminescent glow of microbes in the ocean better than the last generation of satellites.

August 10, 2022August 10, 2022

Understanding highly explosive basaltic eruptions using simulations

Featured image: A fissure cone of Kīlauea (Hawaii) erupting during the 2018 eruptive episode. via Wikimedia commons (Public domain)

Paper: Role of volatiles in highly explosive basaltic eruptions.

Authors: Giuseppe La Spina, Fabio Arzilli, Mike R. Burton, Margherita Polacci, Amanda B. Clarke

When we think of Hawaii or Iceland, the first thing that comes to mind is volcanoes. Lava fountains spew out basaltic lava, which silently meanders its way to the ocean. The notion that basaltic eruptions are always less explosive compared to other types like rhyolitic and andesitic eruptions is not entirely true. For example, Mount Etna in Italy has produced highly explosive basaltic eruptions such as the 122 BCE Plinian Eruption and another in 1669. Because highly explosive basaltic eruptions are not very common, they’re not fully understood leaving scientists wondering “What could be the reason behind this erratic behaviour?”

July 26, 2022July 26, 2022

Dreaming of a green Moon – farming lunar fields

Featuring image: Cress can grow nearly everywhere, but can it also survive on the Moon? Bastet78, Wikimedia Commons, Creative Commons (CC BY-SA 4.0).

Paper: Plants grown in Apollo lunar regolith present stress-associated transcriptomes that inform prospects for lunar exploration

Authors: A.-L. Paul, S. M. Elardo and R. Ferl

Plants surround us everywhere and dominate our planet. We feed from them, we build our homes from them and we need them as a source for oxygen. We couldn’t imagine a world without them. But can we take them with us, when we visit other worlds?

In space science, plants have already played an important role. They are often used as model organisms for experiments and in future space missions they might even be used as important additions to the astronauts’ food and life supply. Thus, they already made their way up to the International Space Station. Now for the first time, Paul and colleagues have tried to grow plants in original lunar soil, finding that we may be able to take our green companions with us to the Moon.

July 25, 2022July 25, 2022

A Historical Link Between Thiamine Deficiency in Salmon and the Presence of Thiaminase in their Prey

Featured Image: A salmon in a stream on the Oregon coast. Photo credit: Conrad Gowell

Paper: Thiaminase activity of gastrointestinal contents of salmon and herring from the Baltic Sea

Authors: S. Wistbacka, A. Heinonen, and G. Bylund

Flintstones vitamins are generally marketed for children, but should fish be taking them too? Thiamine (vitamin B1) deficiency in fish, especially species of salmon, is a widespread issue with serious implications, as this vitamin is an integral compound required by virtually all living organisms. Vitamin B1 deficiency can lead to an array of negative health outcomes for salmon, which collectively manifest as the condition known as thiamine deficiency complex. This condition inhibits many salmon and other anadromous fish (those that migrate from the oceans to rivers to spawn) from spawning, posing a major problem for their long-term survival.

July 22, 2022July 22, 2022

What Makes a Supervolcano “Super”?

Featured Image: Yellowstone National Park attracts millions of people a year and has been a major focal point for discussions about supervolcanoes in recent decades. Public domain image via pixabay.

Paper: Capturing the Extreme in Volcanology: The Case for the Term “Supervolcano”

Authors: S. De Silva & S. Self

The earth sciences can be challenging to communicate. Definitions change over time and, in some cases, become widely reported in the media and often without a formal definition. A recent paper by Shanaka de Silva and Stephen Self addresses these issues surrounding the popular word “supervolcano.” The authors discuss the variables used to distinguish between these extreme events and regular eruptions. They then suggest a new working definition for researchers to use moving forward, clearing up much confusion that surrounds the word. The concept of supereruptions exploded in popularity after the 2005 Discovery TV/BBC documentary Supervolcano, promoted with the by-line “Is Yellowstone Overdue?“

June 30, 2022June 30, 2022

Is geothermal energy fit for megacities?

Featured image: Steam rising from Nesjavellir Geothermal Power Station in Iceland via Wikimedia commons. Public Domain.

Article: Geothermal energy as a means to decarbonize the energy mix of megacities

Authors: Carlos A. Vargas, Luca Caracciolo, Philip Ball

As the world grapples with climate change, the transition to renewable energy has become a necessity. Governments are investing heavily in solar and wind power to reduce the dependence on fossil fuels. Another non-conventional source of energy that’s still understudied is geothermal energy. But what is geothermal energy? Geo means earth, thermal means heat. The internal heat of Earth is harnessed to heat water and produce power. An advantage of using geothermal energy over solar and wind is that, it doesn’t rely on weather to produce electricity. It provides clean, constant, stable and predictable supply of power. The question is, can geothermal energy cater to the demand of megacities where a large chunk of the world’s population resides?