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Mysteries of the deep (and bumpy) seafloor

Featured image: Elevation map of a seamount in the central Pacific, shown in a persepctive view. Image courtesy of the NOAA Office of Ocean Exploration and Research (public domain).

Paper: Fluid-rich subducting topography generates anomalous forearc porosity
Authors: Christine Chesley, Samer Naif, Kerry Key, Dan Bassett

Open any geology textbook, and you’re guaranteed to find a cartoon of a subduction zone showing how an incoming oceanic plate dives down beneath another tectonic plate (either continent or ocean) on its way back into Earth’s deep interior. These simple sketches typically show the top of the incoming plate as a smooth, gently curved line meeting and joining another smooth line at the base of the overriding plate – and that’s not exactly wrong, given the enormous scale of a subduction zone compared to the smallness of the drawing. But if you zoom in far enough on oceanic tectonic plates, the seafloor is often rough and bumpy. What happens, then, when rough seafloor heads into a subduction zone?

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Antarctic seafloor oxygen is diminishing–and glaciers may be to blame

Featured Image: Iceberg floating through thin sea ice. Image courtesy NASA ICE, used with permission.

Paper: Glacial melt disturbance shifts community metabolism of an Antarctic seafloor ecosystem from net autotrophy to heterotrophy

Authors: Ulrike Braeckman, Francesca Pasotti, Ralf Hoffmann, Susana Vázquez, Angela Wulff, Irene R. Schloss, Ulrike Falk, Dolores Deregibus, Nene Lefaible, Anders Torstensson, Adil Al-Handal, Frank Wenzhöfer, Ann Vanreusel

Nothing compares to the ethereal beauty of a clear lake. Looking down, you can see a whole world flourishing below: plants, fish, and critters. Compare that to a cloudy, or turbid, lake and suddenly you may feel very small, worried about what’s lurking beneath you. New research shows that the Antarctic ocean is transitioning from clear to turbid water, with big implications for ocean ecosystems.

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Climate records written on the seafloor

Featured image: A perspective view of the seafloor at the East Pacific Rise, 9N. Made with GeoMapApp (www.geomapapp.org, CC-BY), and GMRT topography data (Ryan et al. 2009, CC-BY).

Paper: Do sea level variations influence mid-ocean ridge magma supply? A test using crustal thickness and bathymetry data from the East Pacific Rise
Authors: B. Boulahanis, S. M. Carbotte, P. J. Huybers, M. R. Nedimovic, O. Aghaei, J. P. Canales, and C. H. Langmuir

Many of our records of past sea level come from local measurements from coastal towns logged over decades or centuries, or are estimated from ice or sediment cores spanning the last few thousand years, but new research suggests that much longer records can be found in an unlikely place: imprinted deep underground in the oceanic crust.

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How to locate oceanic earthquakes without getting your feet wet

Photo of a fence offset by fault slip on the San Andreas during the 1906 San Francisco earthquake

Featured image: A fence broken by the 1906 San Francisco earthquake, by G. K. Gilbert. Public domain.

Paper: Absolute Centroid Location of Submarine Earthquakes from 3D Waveform Modeling of Water Reverberations
Authors: Jorge C. Castellanos, Zhongwen Zhan, Wenbo Qu

For the millions of people living near the San Andreas fault zone in California, the billion-dollar question is when the next “big one” is going to happen.

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How Algae Emissions Could Affect the Weather

Featured image by Jesse Allen and Robert Simmon, Public Domain

Paper: Unprecedented DMSP Concentrations in a Massive Dinoflagellate Bloom in Monterey Bay, CA
Authors: Ronald P. Kiene, Brent Nowinski, Kaitlin Esson, Christina Preston, Roman Marin III, James Birch, Christopher Scholin, John Ryan, and Mary Ann Moran

Tiny marine organisms have been showing up in higher and higher numbers in bodies of water. These organisms also emit sulfur-containing compounds – and if they emit enough sulfur, their emissions could affect the climate. Continue reading “How Algae Emissions Could Affect the Weather”