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- EPA Releases Final Health Assessment for Tetrachloroethylene (Perc) / Public health protections remain in placeWASHINGTON – Today the U.S. Environmental Protection Agency (EPA) posted the final health assessment for tetrachloroethylene – also known as perchloroethylene, or perc – to EPA’s Integrated Risk Information System (IRIS) database. Perc is a chemical solvent widely used in the dry cleaning industry. It is also used in the cleaning of metal machinery and to ma […]
- EPA Releases Final Health Assessment for Tetrachloroethylene (Perc) / Public health protections remain in place
Water
- EPA Awards City of Andrews, Texas, Over $380,000
to Improve Drinking Water Treatment System(DALLAS – February 10, 2012) A grant from the Environmental Protection Agency (EPA) will help improve the drinking water treatment system in Andrews, Texas. The grant for $388,000 will be used by the city to install a filtration and reverse osmosis system to reduce arsenic and fluoride levels in drinking water provided to municipal customers […]
- EPA Awards City of Andrews, Texas, Over $380,000
to Improve Drinking Water Treatment System
EPA
Ocean Temperatures
- The Battery NYRecent Water Temperature: 42.6°F (5.9°C) Observation Date and Time: Sun, 12 Feb 2012 08:54:00 GMT […]
- Galveston Bay Entrance, North Jetty, TXRecent Water Temperature: 53.1°F (11.7°C) Observation Date and Time: Sun, 12 Feb 2012 08:54:00 GMT […]
- Sandy Hook NJRecent Water Temperature: 45.0°F (7.2°C) Observation Date and Time: Sun, 12 Feb 2012 08:54:00 GMT […]
- The Battery NY
Invasive Species
- New Insights into Invasive Plant Management (Feb 3, 2012)New Insights into Invasive Plant Management (Feb 3, 2012) ARS... […]
- USDA Seeks Suggestions to Implement Section 10201 of the 2008 Farm Bill (Jan 30, 2012)USDA Seeks Suggestions to Implement Section 10201 of the 2008... […]
- New Insights into Invasive Plant Management (Feb 3, 2012)
Energy Research
- Ashok Gadgil's Physics in Service to the WorldAshok Gadgil, Director of the Environmental Energy Technologies Division at DOE's Lawrence Berkeley National Laboratory, already knew he wanted to be a scientist when he was nine years old. […]
- Ashok Gadgil's Physics in Service to the World
Energy Savers
- How Efficient is Your Fireplace?In the middle of winter, fireplaces are a popular topic. This week, Ernie talked about re-building his dual-sided fireplace and adding a damper and tempered-glass doors in the process. In the heating urban myth debate, Elizabeth shared her former roommate's assumption that using a gas fireplace to heat a single room would be more efficient than a centra […]
- How Efficient is Your Fireplace?
Food And Drugs
- FDA investigating illegal online sale of handheld dental X-ray unitsThe U.S Food and Drug Administration is warning dental and veterinary professionals to not purchase or use certain potentially unsafe hand-held dental X-ray units. The FDA is concerned that these devices may not be safe or effective and could expose the user and the patient to unnecessary and potentially harmful X-rays. The units, sold online by manufacturer […]
- FDA investigating illegal online sale of handheld dental X-ray units
Consumer Health
- Consumer Update AnalyticsThis page contains links to all past Consumer Update Analytics web pages. […]
- Consumer Update Analytics
Global Extinction: Gradual Doom as Bad as Abrupt
Global Extinction: Gradual Doom as Bad as Abrupt
In “The Great Dying” 250 million years ago, the end came slowly
Credit and Larger Version
February 2012
The deadliest mass extinction of all took a long time to kill 90 percent of Earth’s marine life–and it killed in stages–according to a newly published report.
It shows that mass extinctions need not be sudden events.
Thomas Algeo, a geologist at the University of Cincinnati, and 13 colleagues have produced a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic.
Their analysis, published today in the Geological Society of America Bulletin, provides strong evidence that Earth’s biggest mass extinction phased in over hundreds of thousands of years.
About 252 million years ago, at the end of the Permian period, Earth almost became a lifeless planet.
Around 90 percent of all living species disappeared then, in what scientists have called “The Great Dying.”
Algeo and colleagues have spent much of the past decade investigating the chemical evidence buried in rocks formed during this major extinction.
The world revealed by their research is a devastated landscape, barren of vegetation and scarred by erosion from showers of acid rain, huge “dead zones” in the oceans, and runaway greenhouse warming leading to sizzling temperatures.
The evidence that Algeo and his colleagues are looking at points to massive volcanism in Siberia as a factor.
“The scientists relate this extinction to Siberian Traps volcanic eruptions, which likely first affected boreal life through toxic gas and ashes,” said H. Richard Lane, program director in the National Science Foundation’s (NSF) Division of Earth Sciences, which funded the research.
The Siberian Traps form a large region of volcanic rock in Siberia. The massive eruptive event which formed the traps, one of the largest known volcanic events of the last 500 million years of Earth’s geologic history, continued for a million years and spanned the Permian-Triassic boundary.
The term “traps” is derived from the Swedish word for stairs–trappa, or trapp–referring to the step-like hills that form the landscape of the region.
A large portion of western Siberia reveals volcanic deposits up to five kilometers (three miles) thick, covering an area equivalent to the continental United States. The lava flowed where life was most endangered, through a large coal deposit.
“The eruption released lots of methane when it burned through the coal,” Algeo said. “Methane is 30 times more effective as a greenhouse gas than carbon dioxide.
“We’re not sure how long the greenhouse effect lasted, but it seems to have been tens or hundreds of thousands of years.”
Much of the evidence was washed into the ocean, and Algeo and his colleagues look for it among fossilized marine deposits.
Previous investigations have focused on deposits created by a now vanished ocean known as Tethys, a precursor to the Indian Ocean. Those deposits, in South China particularly, record a sudden extinction at the end of the Permian.
“In shallow marine deposits, the latest Permian mass extinction was generally abrupt,” Algeo said. “Based on such observations, it has been widely inferred that the extinction was a globally synchronous event.”
Recent studies are starting to challenge that view.
Algeo and co-authors focused on rock layers at West Blind Fiord on Ellesmere Island in the Canadian Arctic.
That location, at the end of the Permian, would have been much closer to the Siberian volcanoes than sites in South China.
The Canadian sedimentary rock layers are 24 meters (almost 80 feet) thick and cross the Permian-Triassic boundary, including the latest Permian mass extinction horizon.
The investigators looked at how the type of rock changed from the bottom to the top. They looked at the chemistry of the rocks and at the fossils contained in the rocks.
They discovered a total die-off of siliceous sponges about 100,000 years earlier than the marine mass extinction event recorded at Tethyan sites.
What appears to have happened, according to Algeo and his colleagues, is that the effects of early Siberian volcanic activity, such as toxic gases and ash, were confined to the northern latitudes.
Only after the eruptions were in full swing did the effects reach the tropical latitudes of the Tethys Ocean.
The research was also supported by the Canadian Natural Sciences and Engineering Research Council and the National Aeronautics and Space Administration Exobiology Program.
In addition to Algeo, co-authors of the paper are: Charles Henderson, University of Calgary; Brooks Ellwood, Louisiana State University; Harry Rowe, University of Texas at Arlington; Erika Elswick, Indiana University, Bloomington; Steven Bates and Timothy Lyons, University of California, Riverside; James Hower, University of Kentucky; Christina Smith and Barry Maynard, University of Cincinnati; Lindsay Hays and Roger Summons, Massachusetts Institute of Technology; James Fulton, Woods Hole Oceanographic Institution; and Katherine Freeman, Pennsylvania State University.
-NSF-