sedimentology – Geobites

November 29, 2022November 29, 2022

Unravelling the secrets of brine pools

Featured image: ROV Deep Discoverer approaching a brine pool in the Gulf of Mexico (2018). NOAA Office of Ocean Exploration and Research (Public domain)

Paper: Discovery of the deep-sea NEOM Brine Pools in the Gulf of Aqaba, Red Sea

Authors: Sam J. Purkis, Hannah Shernisky, Peter K. Swart, Arash Sharifi, Amanda Oehlert, Fabio Marchese, Francesca Benzoni, Giovanni Chimienti, Gaëlle Duchâtellier, James Klaus, Gregor P. Eberli, Larry Peterson, Andrew Craig, Mattie Rodrigue, Jürgen Titschack, Graham Kolodziej, Ameer Abdulla

Today, scientists are turning to extreme ecosystems on Earth to understand how life evolved on Earth and how life might be on other planets. One such alien place exists in the darkness of the ocean. It’s an extreme ecosystem where even fish think twice before entering. Brine pools are well known for being ‘death traps’ – extremely toxic, and any organism (with a few exceptions) that swims into them dies instantly. They are lakes of hypersaline water present on the ocean floor that are so dense that Remotely Operated Submersible Vehicles (ROVs) float on them!

October 19, 2021October 18, 2021

What can a delta’s history tell us about groundwater’s future?

Feature image: Mosiac of the the Ganges Delta in false color created with imagery from the Sentinal 2 satilite. CC-By Annamaria Luongo, via Wikimedia Commons

Article: Linking the Surface and Subsurface in River Deltas—Part 2: Relating Subsurface Geometry to Groundwater Flow Behavior
Authors: Xu, Z., Hariharan, J., Passalacqua, P., Steel, E., Paola, C., & Michael, H. A.

Deltas are striking features on Earth’s surface, where rivers meet large water bodies. Their flow spreads out into many channels, depositing the sediment they have been carrying, potentially since their headwaters. This sediment creates and sustains the delta, which can be hundreds of miles across. Beyond being mesmerizing, deltas are essential to human civilization, past and present. Nearly half a billion people live on deltas around the world, where the deposited sediment hosts some of the most fertile agricultural land available.

September 22, 2020September 28, 2020

What do deep-sea sediment cores tell us about past fish populations?

Black background with fish teeth of different heights and widths

Featured Image: Ichthyoliths (microfossil fish teeth) from deep-sea sediment cores displaying the variety of tooth morphology. Photo courtesy of Elizabeth Sibert, lead author of the paper.

Paper: No state change in pelagic fish production and biodiversity during the Eocene–Oligocene transition

Authors: Elizabeth C. Sibert, Michelle E. Zill, Ella T Frigyik, Richard D. Norris

The seafloor at the bottom of the ocean records what is happening in the water above. Sediments capture silica from diatoms and phytoplankton, carbon from zooplankton poop and detrital marine snow, and teeth after dead fish sink. This last piece of evidence is particularly important: fossilized fish teeth or icthyoliths can help estimate past fish abundance and can show shifts in fish species or biodiversity in the ocean over time.