August 2022 – Geobites

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?”