Iceland’s constantly changing landscape: A Book Review

Featured Image: Lake in a volcano’s crater at Mývatn, Iceland. Photo by Philipp Wüthrich on Unsplash.

Book: Iceland: Tectonics, Volcanics, and Glacial Features, Geophysical Monograph 247 (First Edition, 2020)
Author: Dr. Tamie J. Jovanelly
Figure Illustrations: Nathan Mennen
Additional Text:
Emily Larrimore
Publisher:
American Geophysical Union, John Wiley & Sons, Inc.

I have always wanted to go to Iceland and travel the countryside marveling at the island’s unique geology and icy wonder. Reading through Iceland: Tectonics, Volcanics, and Glacial Features by Dr. Tamie J. Jovanelly, I felt like I got my chance to tour Iceland; this time with a very experienced guide. Dr. Jovanelly has been to Iceland more than ten times since 2006 to explore and study and her familiarity with the place and the people who live there is engrained in this text.

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New instrument maps and preserves frozen habitats on Earth- and potentially icy worlds

Featured Image: Iceberg in North Star Bay, Greenland by Jeremy Harbeck – NASA, Public Domain

Paper: Subsurface In Situ Detection of Microbes and Diverse
Organic Matter Hotspots in the Greenland Ice Sheet

Authors: Michael J. Malaska, Rohit Bhartia, Kenneth S. Manatt, John C. Priscu, William J. Abbey, Boleslaw Mellerowicz, Joseph Palmowski, Gale L. Paulsen, Kris Zacny, Evan J. Eshelman, and Juliana D’Andrilli

Like the rings of a tree, core samples extracted from glacial ice preserve a unique record of past events. But instead of recording seasonal growth, the ancient ice sheets of Antarctica and Greenland have preserved the conditions of long gone climates and ecosystems. Some sheets have continuously accumulated so much snowfall over the past series of millennia that in some places the ice can reach depths that are miles deep. Analyzing this immense glacial record can inform us about not just the global patterns of climate change, but also the evolution of microbial life on Earth, and maybe even the icy worlds of our Solar System. 

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Where’s the plastic gone?

Featured image: Plastic pollution in Ghana. Photo courtesy Wikimedia Commons/ Muntaka Chasant, CC BY-SA 4.0 license.

Paper: The global biological microplastic particle sink

Authors: K. Kvale, A. E. F. Prowe, C.-T. Chien, A. Landolvi & A. Oschlies

Scientists estimate that about 4% of the plastic waste generated globally ends up in the ocean, much of it in the form of microplastics. These tiny plastics, smaller than the width of a pencil, are a major pollution problem: because of their small size, they are extremely difficult to remove and can be transferred up the food chain to species that humans eat. Furthermore, harmful chemicals have been shown to adsorb onto microplastics, so consumption of microplastics may have indirect health impacts.  While scientists have put together a “plastic budget” for the ocean by estimating inputs of plastic to the ocean and fragmentation rates of larger plastics into microplastics, models based on observations of the amount of plastic waste in the ocean suggest that there is less plastic in the surface ocean than expected based on these budgets. The authors of this study used a model to test two possible explanations for this ‘missing’ plastic, zooplankton ingestion and sinking to the sea floor with marine particles, and find that these biological pathways can account for 100% of the observed “missing” surface microplastic, even in simulations where these processes are modeled as being inefficient.

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Ancient ocean temperatures outline a puzzling period in Earth’s climate history

Paper: The enigma of Oligocene climate and global surface temperature evolution

Featured image: Figure 1 from O’Brien et al. (2020). Paleogeographic reconstruction of the late Oligocene world, with continents and oceans in slightly different positions than today. Symbols indicate paleo-locations of ocean sediments that these scientists discuss in their paper, with stars indicating sites where they estimated Oligocene temperatures.

Authors: Charlotte L. O’Brien, Matthew Huber, Ellen Thomas, Mark Pagani, James R. Super, Leanne E. Elder, Pincelli M. Hull

We know that the amount of carbon dioxide in the atmosphere strongly affects climate –and temperature – on Earth. As carbon dioxide concentrations increase, so does average global temperature; this pattern is clear from direct historical measurements and ice core records going back hundreds of thousands of years. Nevertheless, it’s important to understand how this relationship operated in the past (for example, during times when there was less ice in the cold polar regions of the globe). A new study suggests that, millions of years in the past, the simple relationship between carbon dioxide and temperatures may not have been so clearcut.

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The early evolution of the bird-hipped dinosaurs

Featured image: Landscape mountain sky by Enrique Lopez Garre, Pixabay License.

Paper: A paraphyletic ‘Silesauridae’ as an alternative hypothesis for the initial radiation of ornithischian dinosaurs

Authors: Rodrigo Muller and Maurício Garcia

Dinosaurs dominated terrestrial ecosystems for nearly 170 million years in the Mesozoic. There were three major groups of dinosaurs. The long-necked sauropodomorphs, which included the largest animals ever to live on land, could grow as long as a Boeing 737 aircraft. The meat-eating theropods, which included the famous Tyrannosaurus rex, have evolved into the modern dinosaurs: birds. And the bird-hipped ornithischians, an assorted group of herbivorous dinosaurs, evolved some of the most bizarre anatomy known in evolutionary history. This ranged from the plate-backed Stegosaurus, to the thumb-spiked Iguanodon, and from the exaggerated crests of Triceratops to the walking coffee table that is Ankylosaurus.

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What lies beneath: tracing human migrations through stone tools, India

A map demonstrating possible migration routes of modern humans

Featured image: Katerina Douka, Michelle O’Reilly, Michael D. Petraglia – On the origin of modern humans: Asian perspectives; Science 08 Dec 2017: Vol. 358, Issue 6368, DOI: 10.1126/science.aai9067 [1], CC BY-SA 4.0 (Wikimedia Commons) with minor edits

Paper: Human occupation of northern India spans the Toba super-eruption ~74,000 years ago

Authors: Chris Clarkson, Clair Harris, Bo Li, Christina M. Neudorf, Richard G. Roberts, Christine Lane, Kasih Norman, Jagannath Pal, Sacha Jones, Ceri Shipton, Jinu Koshy, M.C. Gupta, D.P. Mishra, A.K. Dubey, Nicole Boivin & Michael Petraglia

Modern humans evolved around 200,000 years ago in Africa, and dispersed from there to other parts of the globe. The Out of Africa theory is a well-established model that explains the early dispersal of Homo sapiens or modern humans from Africa, into Asia and Oceania. Among the routes proposed is the Southern Route migration from East Africa to the Near East, across the Red Sea, and around Arabia and the Persian Plateau to India, and then finally with modern humans settling in Asia and Australasia. 

India’s geographic location is a key piece of this puzzle. Mitochondrial DNA of contemporary populations in India indicate that the country was an important stepping stone in the colonisation of Australasia. However, the timeline for the proposed Southern Route migration is still a matter of debate – could dating the arrival and settlement of modern humans in India provide some clues?

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When space is time: evolving soil hydrology on glacial moraines

Featured image: The Stein Glacier in the central Swiss Alps, where the study was conducted. Left panel © Google, right panels CC BY Florian Lustenberger in Hartmann et al. 2020.

Paper: Field observations of soil hydrological flow path evolution over 10 millennia

Authors: Hartmann , A., Semenova, E., Weiler, M., & Blume, T.

The way water flows through soil and sediments can be incredibly diverse. In the simplest case, water flows uniformly through all of the pore space between grains. Most soils act very differently though. Water moves quickly through certain pathways and not at all through other areas. This preferential flow of water has important consequences for the ability of the soil to hold water, and for the movement of nutrients and contaminants. Understanding what factors affect the evolution of preferential flow pathways can help scientists better understand how soils work now, and how they will respond to human induced changes into the future.

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Isotopes Begin to Unlock the Mystery of Methane Source in the Scheldt Estuary

Scheldt Estuary with tidal flats and water shown

Featured Image: Eastern Scheldt Estuary near Zeeland, Netherlands. Photo courtesy Wikimedia Commons/ Luka Peternel, CC BY-SA 4.0 license.

Paper: Carbon and Hydrogen Isotope Signatures of Dissolved Methane in the Scheldt Estuary

Authors: Caroline Jacques, Thanos Gkritzalis, Jean-Louis Tison, Thomas Hartley, Carina van der Veen, Thomas Röckmann, Jack J. Middelburg, André Cattrijsse, Matthias Egger, Frank Dehairs & Célia J. Sapart

Estuaries are dynamic coastal environments where freshwater and saltwater collide and mix. Across the world, estuaries regularly have higher methane concentrations in the water than would be expected from equilibrium with the atmosphere. If the water was in equilibrium, or at a happy balance, with the atmosphere, then there would be no net transfer of methane to the atmosphere. Because there is more methane than expected in the water, estuaries are a source of this potent greenhouse gas, methane (CH4), to the atmosphere. The problem is that the processes leading to the excess methane in the estuary’s surface water are not well known in many European estuaries.

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Tracing the origin of Earth’s water with meteorites

Paper: Earth’s water may have been inherited from material similar to enstatite chondrite meteorites

Authors: Laurette Piani, Yves Marrocchi, Thomas Rigaudier, Linel G. Vacher, Dorian Thomassin, Bernard Marty

To date, Earth is the only planetary object known to have extensive bodies of liquid water (H2O) at its surface. Water is fundamental to supporting life as we know it with every single organism on our planet requiring water to survive. Even our own human bodies are made up of 60-70% water. However, the origin of Earth’s water has long been debated.


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What’s in the Water?

Paper: Contemporary limnology of the rapidly changing glacierized
watershed of the world’s largest
High Arctic lake

Authors: K. A. St. Pierre, V. L. St. Louis, I. Lehnherr, S. L. Schiff, D. C. G. Muir , A. J. Poulain, J. P. Smol, C. Talbot, M. Ma, D. L. Findlay, W. J. Findlay, S. E . Arnott, Alex S . Gardner

As glaciers recede in the arctic, the increase in meltwater may significantly impact downstream ecosystems. Glacial ice can hold thousands of years’ worth of dust, nutrients, and other materials that are released during melting. As the rate of melt increases with a warming climate, the release has the potential to increase nutrient flows and sediment loads, alter pH, and impact other physical, chemical, and biological aspects of downstream watersheds. These changes could negatively impact water clarity and ecosystem function in lakes, rivers, and the ocean.

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