Tolstoy and Lamont-Doherty colleague Felix Waldhauser set an array of ocean bottom seismometers along a section of the East Pacific Rise off the coast of Mexico in 2003 to study the little-understood process of seafloor spreading--a process that is responsible for the formation of nearly three-quarters of the Earth's crust. When a team went back in April 2006 to retrieve the instruments, however, only four out of 12 responded to the coded release signal and bobbed to the surface; three more responded to the signal, but did not come up. The rest remained silent.
Tests of the water temperature and light-scattering near the sea floor revealed signs of a recent volcanic eruption. A second expedition led by James Cowen of the University of Hawaii on the research vessel R/V New Horizon in early May lowered a camera that confirmed what the scientists suspected: Their instruments had been directly on top of a section of the East Pacific Rise that erupted and were trapped in fresh lava flows.
Instead of bemoaning their fate, the group celebrated their fortune--no one has ever closely recorded the series of micro-earthquakes associated with the formation of new seafloor. Preliminary analysis of their data appears in an upcoming issue of the journal Science and will be released on the Science Express Web site November 23.
"It's amazing that we know so little about something so fundamental to the planet," said Tolstoy. "Even if we don't get the rest of the instruments back we'll have learned quite a bit."
The East Pacific Rise is one of three active seafloor spreading centers targeted by the National Science Foundation's Ridge 2000 program to document the process of crustal formation as it is happening. Ridge 2000 was formed in 2001 as an interdisciplinary effort to study the geology, chemistry and biology of the poorly understood process by which the Earth's crust is formed.
"Discovering new lava so soon after a seafloor eruption is a unique opportunity," said Donna Blackman, current chair of the Ridge 2000 program. "It allows Ridge researchers a rare chance to see how geologic processes affect the deep-sea ecosystems that thrive near hydrothermal vents."
The first underwater eruption was not documented until 1990, even though many probably occur each year, and seismometers on land still cannot detect the many small, distant earthquakes that scientists believe precede a submarine eruption for many months. By comparison, earthquakes often occur only a few days or hours before a land-based volcanic eruption.
Tolstoy found that seismic activity at the site gradually built up for at least two years leading up to the brief, January 2006 eruption that entombed her instruments, raising the possibility that future eruptions may be forecast a year or more in advance.
"Our success emphasizes the importance of real-time monitoring on the seafloor so that next time we'll be collecting many different types of data the moment an eruption starts," said Tolstoy. "That way we can really begin to understand this fundamental building block of our planet, from the mantle to the microbe.
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21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
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Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.
Graphene is up to the job
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
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