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Saving our soil (part 2) | NPR
Monday, December 4, 2017
NPR talks with experts -- including UW Earth and space sciences professor David Montgomery -- about improving the nation's soil. [This is Part 2 of the program] Read More -
Saving our soil (part 1) | NPR
Monday, December 4, 2017
NPR talks with experts -- including UW Earth and space sciences professor David Montgomery -- about improving the nation's soil. [This is Part 1 of the program] Read More -
Groundwater on Mars? Salty Antarctic pond could reveal clues | Space.com
Monday, December 4, 2017
A shallow, briny pond located in the most Mars-like region on Earth is probably being fed by groundwater seeping up, rather than moisture seeping down from the atmosphere, providing clues as to what stores of liquid water, if they exist, might look like on Mars. Jonathan Toner, a geochemist at the UW, is quoted. Read More -
Shipping routes have more lightning | KOMO Radio
Thursday, November 30, 2017
A new University of Washington study shows ship exhaust along popular shipping routes actually increases lightning strikes. Robert Holzworth, UW professor of Earth and space sciences, and Joel Thornton, UW professor of atmospheric sciences, are interviewed. Read More -
Less life: Limited phosphorus recycling suppressed early Earth's biosphere
Tuesday, November 28, 2017
As Earth’s oxygen levels rose to near-modern levels over the last 800 million years, phosphorus levels also increased, according to modeling led by the UW’s Michael Kipp and others. Accordingly, Kipp said, large phosphate deposits show up in abundance in the rock record at about this time. This is a Wyoming portion of The Phosphoria Formation, a deposit that stretches across several states in the western United States and is the largest source of phosphorus fertilizer in the country. The photo shows layers of phosphorus that are 10s of meters thick, shales that contain high concentrations of organic carbon and phosphorus. Kipp said many such deposits are documented over time but are rare in the Precambrian era. “Thus, they might represent a conspicuous temporal record of limited phosphorus recycling.”Michael Kipp
The amount of biomass - life - in Earth’s ancient oceans may have been limited due to low recycling of the key nutrient phosphorus, according to new research by the University of Washington and the University of St. Andrews in Scotland.
The research, published online Nov. 22 in the journal Science Advances, also comments on the role of volcanism in supporting Earth’s early biosphere -- and may even apply to the search for life on other worlds.
The paper’s lead author is Michael Kipp, a UW doctoral student in Earth and space sciences; coauthor is Eva St?eken, a research fellow at the University of St. Andrews and former UW postdoctoral researcher. Roger Buick, UW professor of Earth and space sciences, advised the researchers.
Their aim, Kipp said, was to use theoretical modeling to study how ocean phosphorus levels have changed throughout Earth’s history.
“We were interested in phosphorus because it is thought to be the nutrient that limits the amount of life there is in the ocean, along with carbon and nitrogen,” said Kipp. “You change the relative amount of those and you change, basically, the amount of biological productivity.”
Kipp said their model shows the ability of phosphorus to be recycled in the ancient ocean “was much lower than today, maybe on the order of 10 times less.”
All life needs abundant food to thrive, and the chemical element phosphorus - which washes into the ocean from rivers as phosphate -- is a key nutrient. Once in the ocean, phosphorus gets recycled several times as organisms such as plankton or eukaryotic algae that “eat” it are in turn consumed by other organisms.
“As these organisms use the phosphorus, they in turn get grazed upon, or they die and other bacteria decompose their organic matter,” said Kipp, “and they release some of that phosphorus back into the ocean. It actually cycles through several times," allowing the liberated phosphorus to build up in the ocean. The amount of recycling is a key control on the amount of total phosphorus in the ocean, which in turn supports life.
Buick explained: "Every gardener knows that their plants grow only small and scraggly without phosphate fertilizer. The same applies for photosynthetic life in the oceans, where the phosphate 'fertilizer' comes largely from phosphorus liberated by the degradation of dead plankton."
But all of this requires oxygen. In today's oxygen-rich oceans, nearly all phosphorus gets recycled in this way and little falls to the ocean floor.
Several billion years ago, in the Precambrian era, however, there was little or no oxygen in the environment.
"There are some alternatives to oxygen that certain bacteria could use, said co-author St?eken. "Some bacteria can digest food using sulfate. Others use iron oxides." Sulfate, she said, was the most important control on phosphorus recycling in the Precambrian era.
"Our analysis shows that these alternative pathways were the dominant route of phosphorus recycling in the Precambrian, when oxygen was very low," St?eken said. "However, they are much less effective than digestion with oxygen, meaning that only a smaller amount of biomass could be digested. As a consequence, much less phosphorus would have been recycled, and therefore total biological productivity would have been suppressed relative to today."
Kipp likened early Earth's low-oxygen ocean to a kind of "canned" environment, with oxygen sealed out: "It's a closed system. If you go back to the early Precambrian oceans, there's not very much going on in terms of biological activity."
St?eken noted that volcanoes were the biggest source of sulfate in the Precambrian, unlike now, and so they were necessary for sustaining a significant biosphere by enabling phosphorus recycling.
In fact, minus such volcanic sulfate, St?eken said, Earth’s biosphere would have been very small, and may not have survived over billions of years. The findings, then, illustrate “how strongly life is tied to fundamental geological processes such as volcanism on the early Earth,” she said.
Kipp and St?eken’s modeling may have implications as well for the search for life beyond Earth.
Astronomers will use upcoming ground- and space-based telescopes such as the James Webb Space Telescope, set for launch in 2019, to look for the impact of a marine biosphere, as Earth has, on a planet’s atmosphere. But low phosphorus, the researchers say, could cause an inhabited world to appear uninhabited -- making a sort of “false negative.”
Kipp said, “If there is less life -- basically, less photosynthetic output -- it’s harder to accumulate atmospheric oxygen than if you had modern phosphorus levels and production rates. This could mean that some planets might appear to be uninhabited due to their lack of oxygen, but in reality they have biospheres that are limited in extent due to low phosphorus availability.
"These ‘false negatives’ are one of the biggest challenges facing us in the search for life elsewhere," said Victoria Meadows, UW astronomy professor and principal investigator for the NASA Astrobiology Institute’s Virtual Planetary Laboratory, based at the UW.
“But research on early Earth’s environments increases our chance of success by revealing processes and planetary properties that guide our search for life on nearby exoplanets."
The work was funded by grants from NASA and the National Science Foundation.
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For more information, contact Kipp at kipp@uw.edu, Buick at 206-543-1913 or buick@ess.washington.edu or St?eken at
ees4@st-andrews.ac.uk.NASA Exobiology grant NNX16AI37G to Prof. Buick.
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UW researchers use unmanned subs | KOMO 4
Monday, November 27, 2017
The UW is going to send robots into ice caves to collect data. Knut Christianson, assistant professor of Earth and space sciences at the UW, is interviewed. Read More -
A Bolt from the Brown: Why Pollution May Increase Lightning Strikes
Thursday, November 16, 2017
Scientific American reports on a University of Washington paper using World Wide Lightning Location Network data to show that pollution from ship exhaust in the Indian Ocean and South China Sea enhances the probability of lightning by a factor of two. This pollution problem and consequent increase in lightning was shown to occur every year over the last decade or more. Read More -
Salt pond in Antarctica, among the saltiest waters on Earth, is fed from beneath
Wednesday, November 15, 2017
At the base of the Transantarctic Mountains lies a geological oddity. Don Juan Pond is one of the saltiest bodies of water on the planet, filled with a dense, syrupy brine rich in calcium chloride that can remain liquid to minus 50 degrees Celsius, far below the freezing point of water. But the source of water and salt to this unusual pond remains a mystery -- even as hints emerge that water in a similar form could exist on Mars.
The liquid in Don Juan Pond is almost 45 percent salts by weight. It is in Wright Valley, one of the Antarctic valleys where the air is very cold and dry.Pierre Roudier/Flickr
A new University of Washington study uses the pond’s bizarre chemistry to pinpoint the water’s source. The recent paper, published Sept. 15 in Earth and Planetary Science Letters, reports that it is fed by a regional deep groundwater system and not, as previously suggested, from moisture seeping down from local valley slopes.
“Don Juan Pond is probably one of the most interesting ponds on Earth,” said lead author Jonathan Toner, a UW research assistant professor in Earth and space sciences. “After 60 years of extensive study, we still don't really know exactly where it’s coming from, what drives the fact that it’s visible on the surface, and how it’s changing.”
The perennial pond measures about 100 by 300 meters, the size of a few football fields, and is about 10 centimeters (4 inches) deep on average. It was first visited in 1961 and named after the expedition’s helicopter pilots, Donald Roe and John Hickey, earning it the name Don Juan Pond. The unique salts in the pond lower the freezing point, which is why this saline pond can exist in a place where the temperature ranges from minus 50 to plus 10 degrees Celsius (-58 to +50 F).
The pond was long believed to be fed by deep groundwater. But then a high-profile 2013 paper suggested that near-surface moisture seeps, similar to recurring slope lineae features recently observed on Mars, were transporting salts downhill to create the salt pond.
A satellite picture shows Don Juan Pond and surrounding slopes. Understanding the hydrology of this cold, dry environment could help explain conditions on Mars.NASA
Toner is a geochemist specializing in the formation and properties of water in extreme environments on Earth, Mars and beyond. For the new study, Toner created a model to compute how salty water changes during evaporation, freezing, and with different water and salt inputs and outputs. In Antarctica’s appropriately named McMurdo Dry Valleys, water evaporation concentrates salts in the pond, which forces some salts to crystallize. These processes, along with inputs and outputs, cause the pond’s water to change over time.
Toner ran his model for two situations: one where the water was gurgling up from beneath, and another where it was trickling down from near-surface seeps. Results show that the observed chemical makeup could only be produced from underneath.
“You couldn't get Don Juan Pond from these shallow groundwaters,” Toner said. “It's definitely coming from the deep groundwater.”
His calculations also show that upwelling groundwater cycles through the pond every six months, meaning the water must exit the pond via some unseen underground outflow.
The pond’s hydrology is important to geologists because nowhere on Earth is more similar to Mars. The Red Planet is extremely cold and dry, and the McMurdo Dry Valleys are one of the coldest and driest locations on Earth.
“If there is water on Mars, it’s probably going to look a lot like this pond,” Toner said. “Understanding how it formed has large implications for where would you expect to find similar environments on Mars.”
Recent studies hint that liquid water might exist on the surface of Mars, potentially harboring life or even eventually supporting long-term human settlements. The darker lines on steep slopes, which look like moisture streaks observed above Don Juan Pond, could be caused by a similar groundwater system.
Jonathan Toner in Antarctica doing field work toward his UW doctorate.Ronald Sletten/University of Washington
Toner will be part of a team exploring Don Juan Pond and surrounding areas this December, sponsored by NASA and the National Science Foundation. Researchers will spend six weeks camping near the pond and taking repeated chemical measurements of its liquid. They will also explore the nearby slopes to measure the chemistry of the moisture seeps, and try to find further evidence for the source of salts to Don Juan Pond.
“If we accept that the deep groundwater theory is true, then what we’re seeing could be part of a bigger process that involves quite an extensive aquifer,” Toner said. “When thinking about the implications for a similar environment on Mars, that’s much more exciting than just a localized surface phenomenon.”
The research was funded by NASA. Other co-authors are Ronald Sletten and David Catling in the UW Department of Earth & Space Sciences.
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For more information, contact Toner at toner2@uw.edu.
NASA grant: NNX15AP19G
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Ships Cause their own Stormy Seas
Thursday, November 9, 2017
Physics Today (Search and Discovery) of the November 2017 edition reports on research using WWLLN lightning network data: 'Increased lightning frequency over maritime trade routes links pollution to the development of thunderclouds.' Underlying paper by Thornton (Atmos. Sci), Virts (NASA Huntsville), Holzworth (ESS) and Mitchell (JISAO) recently published in Geophysical Research Letters). Read More -
Paul Bodin named interim director of Pacific Northwest Seismic Network
Tuesday, October 10, 2017
Paul Bodin, a research professor in the UW’s Department of Earth and Space Sciences, has been named the interim director of the UW-based Pacific Northwest Seismic Network. PNSN is a collaboration between the University of Washington, the University of Oregon and the U.S. Geological Survey that tracks earthquake and volcano activity throughout the two states, with the support of federal, state and private funding.
Paul Bodin
Former PNSN director John Vidale stepped down to accept a faculty position at the University of Southern California and direct the Southern California Earthquake Center in Los Angeles. The search for his permanent replacement is expected to take about one year.
In the interim, Bodin will also serve as the Washington’s state seismologist, serving on the Washington state Seismic Safety Committee that makes seismic policy recommendations to the state’s Emergency Management Division and Gov. Jay Inslee, as well as answering questions from reporters and the public about earthquake and volcanoes.
Bodin will join other regional earthquake experts for a Reddit “Ask Us Anything” Q&A Thursday, Oct. 19 from noon to 2 p.m. PDTBodin is an observational seismologist whose research expertise includes studies of earthquake source physics, seismic wave propagation, and the impacts of strong ground shaking on soils. Bodin spent the first part of his career at the University of Memphis. In Tennessee he studied earthquake processes and hazards associated with earthquakes that occur far from tectonic plate boundaries. Such earthquakes are infrequent and poorly understood, but have very large impacts when they do occur. He also performed field studies in the aftermath of large earthquakes in Mexico, California, India and Taiwan, and was part of a U.S. team monitoring underground nuclear testing in the former Soviet Union.
Bodin joined the UW faculty in 2006 to become manager of the PNSN. During more than a decade since he has overseen upgrades of the network’s technology to enable faster and more accurate detection, analysis and communication of ground shaking from a major earthquake. These network improvements have led to the inclusion of Washington and Oregon into ShakeAlert, a West Coast-wide earthquake early warning system that will provide advance warnings for imminent large earthquakes. Bodin has also published academic papers on triggered earthquakes and tremors; seismic wave propagation and aftershocks; exploring swarm seismicity in Richland and Spokane, Washington; and on the potential for developing earthquake early warning systems in Hawaii and Chile.
Bodin earned his bachelor’s degree at the University of California, San Diego, his master’s at California’s Humboldt State University and his doctorate at the University of Colorado, Boulder.
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For more information, contact Bodin at bodin@uw.edu or 206-616-7315 or PNSN communications manager Bill Steele at 206-685-5880 or wsteele@uw.edu.
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