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Picking up the pace to press   The atmosphere alight    Tracking groundwater in the Everglades



Picking up the pace to press

The American Geophysical Union (AGU) began the new year with a new system of journal publishing. As of Jan. 1, AGU publishes its peer-reviewed journal articles daily on the Web as they become press-ready. AGU will continue to publish its monthly and quarterly volumes in print; but the online article will be the version cited in the literature, with the print journal a byproduct of the electronic version. “The online article will now be the official ‘version of record,’” AGU said in a statement released Dec. 21.
 
Each journal article will now carry a Digital Object Identifier (DOI) — a unique number for use in citations to identify the article. The DOI system is an international standard developed by publishers for maintaining greater control of their publications over the Web. Several major scientific publishers are already using DOIs for citations.

 
Visit www.agu.org for more details.

Lisa M. Pinsker


The atmosphere alight

A Russian Space Agency Meteor-3M spacecraft aboard a Ukrainian Zenit-2 rocket successfully lifted off Dec. 10 from Kazakhstan, carrying a payload that will collect more data for atmospheric scientists.
 
SAGE III, the second launching of the Stratospheric Aerosol and Gas Experiment, is now in orbit and measuring how sunlight and moonlight travel and bend through Earth’s atmosphere. The measurements help atmospheric researchers understand the variation of aerosol concentrations in the middle atmosphere. These variations play a role in climate and in the depletion of ozone.
 
SAGE III follows on the heels of SAGE II, which has been orbiting Earth since 1984. SAGE III will orbit high latitudes, as does SAGE II, but will make more detailed measurements. It can also measure lunar occultation, which means watching aerosols that cannot exist in sunlight. One example is nitrogen trioxide, an important factor in ozone depletion, says Chip Trepte, the deputy project scientist for SAGE III, which is managed by the NASA Langley Research Center in Hampton, Va. The project uses the Russian spacecraft and Ukrainian rocket as part of an international collaboration, he says.

 “There are subtle changes in the atmosphere,” Trepte says. “The question you have at any given time is which process tends to dominate. That’s why it’s important to measure a variety of different species in the atmosphere to measure ozone.”
 
Volcanologists can also use the data to study the distribution of aerosols after volcanic eruptions.


Kristina Bartlett
This story first appeared as a Web Extra on Dec. 18, 2001.


Tracking groundwater in the Everglades

President George Bush and his brother, Florida Gov. Jeb Bush, signed an agreement Jan. 9 to split the price of rescuing freshwater in the Florida Everglades from a salty demise. But it might be too late for some parts of Florida Bay. The Comprehensive Everglades Restoration Plan is set to cost $7.8 billion and take 30 years to reroute and capture the freshwater that 50 years ago Congress ordered the U.S. Army Corps of Engineers to direct away from the Everglades. While the plan expects to make available 1.7 billion gallons a day to south Florida, some marine ecosystems may be here to stay.

 “What changed in Florida Bay defined the environment 50 years ago and what it is today. It is probably not going to go back the way it was,” says Charles Holmes of the U.S. Geological Survey in St. Petersburg, Fla. Holmes is the first to determine through isotopic analysis the rate at which groundwater in the northeastern part of Florida Bay is turning salty. “It is estimated that marine groundwater has encroached some 25 kilometers landward during the past hundred years,” writes Holmes in the abstract for his presentation at the American Geophysical Union meeting on Dec. 12, 2001.

 
Charles Holmes (right) with colleagues Bill Orem (left) and others collect sediment cores in northeastern Florida Bay. Photo by Deb Willard.

South Florida’s limestone and carbonate aquifers are riddled with pores that allow marine groundwater to infiltrate the system, especially when the less dense, overlying freshwater is removed. Holmes found that an isotope of lead (Pb-210) occurred in differing concentrations depending on whether it was in a marine or freshwater environment. Pb-210 is produced through the decay of radon — itself a decay product of the natural uranium found in the carbonate rocks.
 
With its cooler temperature, fresh groundwater has a higher capacity to absorb radon gas than warmer marine groundwater. When the radon mixes with the marine groundwater it diffuses out into the absorbent peat soil in the bay like “an open soda bottle,” Holmes says. After an initial outburst, the decay activity of Pb-210 drops as the amount of freshwater filled with radon gas decreases. Holmes compared the activity of Pb-210 to determine the last time marine areas in the bay had contact with fresh groundwater. His study also provided a unique view on the history of the bay. “Freshwater was bubbling up down there like an artesian well,” he says.

Christina Reed


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