Geobites – Page 3 – Down-to-Earth Geoscience Writing

November 15, 2022November 15, 2022

Forests under (mega)fire in the Pacific Northwest

Accompaniment to the Third Pod from the Sun Episode

Featured Image: “Forests under fire” original artwork by Jace Steiner. Used with permission.

Paper: Cascadia Burning: The historic, but not historically unprecedented, 2020 wildfires in the Pacific Northwest, USA

Authors: Matthew Reilly, Aaron Zuspan, Joshua Halofsky, Crystal Raymond, Andy McEvoy, Alex Dye, Daniel Donato, John Kim, Brian Potter, Nathan Walker, Raymond Davis, Christopher Dunn, David Bell, Matthew Gregory, James Johnston, Brian Harvey, Jessica Halofsky, Becky Kerns

The natural legacy of fire in the Pacific Northwest (PNW) is complex. The variable geography of the wet, westside temperate rain forests, to the dry, high elevation forests beyond the Cascade crest make it difficult to find a “catch-all” description of PNW forest fires. For instance, drier forests of ponderosa pines in eastern Washington experience more frequent, low-severity fires while the temperate rain forests of western Oregon rarely see fires. However, scientists can reconstruct historical fire regimes and identify centuries-long patterns of burning related to precipitation, temperature, and ignition frequency to define what are historical patterns and what is modern climate change. In 2020, multiple megafires (a wildfire that burnt more than 100,000 acres of land) broke out in the typically wet parts of Oregon and Washington, burning more than 700,000 acres combined. This event is called the 2020 Labor Day Fires, and Matthew Reilly and colleagues have revealed these fires were likely part of historical regimes and not a product of accelerated climate change.

October 25, 2022October 25, 2022

The seeds of continental crust

Featuring image: Lava lake in Hawaii Volcanoes National Park, May 1954. Photo by J.P. Eaton, Public Domain (C0).

Paper: Did transit through the galactic spiral arms seed crust production on the early Earth?

Authors: C.L. Kirkland, P.J. Sutton, T. Erickson, T.E. Johnson, M.I.H. Hartnady, H. Smithies, M. Prause

Plate tectonics reshape the face of Earth over long periods of time, but how the first continental crust evolved is still unclear. Now, a new investigation of very old rocks showed that Earth structure might have been influenced by the galactic dance of our solar system through the Milky Way.

The dating of old continental crust from the Precambrian (2.8 – 3.6 billion year old rocks) indicates that the formation of continental crust happened in cycles. Scientists discovered these cycles, which indicate that the crust didn’t form continuously, decades ago by dating minerals contained in continental crust all over the globe. Now, new research suggests that these cycles correspond to the periods where Earth passed through the spiral arms of our galaxy, the Milky Way.

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.