Like restaurateurs watching food-laden plates move from the kitchen to customers, scientists with the US Geological Survey have been watching - and measuring - nitrogen and phosphates pouring down the Mississippi and Atchafalaya rivers into the Gulf of Mexico.
While algae in the Gulf have been munching on these nutrients, a team of scientists has fed their measurements into computers and announced last Friday the first annual forecast for the Gulf's "dead zone" - a vast region of ocean deprived of dissolved oxygen as the area's algae population explodes, dies, and then decays.
For top federal officials here, the effort is a small-scale example of what they hope will grow into a coordinated, long-term international effort to monitor the environment planet-wide.
Thursday, ministers from 34 nations and several nongovernmental organizations are meeting at the State Department to lay the political foundation for pulling together disparate systems of sensors - from "floats" gathering data deep below the sea surface to satellites in Earth's orbit. The idea is to create a more tightly linked set of tools for tracking and forecasting environmental changes that can affect fisheries, agriculture, water resources, and climate.
If successful, the effort would be historic. Not since scientists around the world marshaled their efforts for a coordinated study of the planet during the International Geophysical Year, which began in July 1957 and involved 67 countries, has the global community put such a plan on the table.
But while a 21st-century global network will pay scientific dividends, "this is not a scientific hobbyhorse," says Vice Adm. Conrad Lautenbacher Jr. (ret.), who heads the US National Oceanic and Atmospheric Administration and is the lead US representative to today's Earth Observation Summit. Any network, he says, must be able to support efforts to provide useful forecasts - from the effects of solar storms on communications and climate to the emergence of harmful algae blooms along coasts to crucial shifts in the salinity of water in seaports, which effects the buoyancy of cargo ships.
The summit comes a week after the Bush administration unveiled its blueprint for reorganizing and setting priorities for federal climate-change research. It listed efforts to establish an international Earth-observation network as one of those initiatives.
Yet Admiral Lautenbacher points out that the concept of a global environmental observation network has a long pedigree, and it covers far more than elevation alone. For the past 20 to 30 years, he says, various scientific organizations have been interested in establishing what he terms "a Hubble Space Telescope for the Earth." Meanwhile, population growth, economic development, and the degradation they can bring to ecosystems have prompted increased interest in using an Earth-observation system to help manage the planet's resources.
Finally, watershed events like last year's summit on sustainable development in Johannesburg and the growing recognition that environmental problems are no respecters of international boundaries have helped pave the way politically.
"The confluence of these things makes this an interesting period, and a time when we're ready" for a truly international environmental monitoring effort, Lautenbacher says.
From the standpoint of sensors, US officials say, a broad range of useful measuring systems already are in place. For example, through NASA's Mission to Planet Earth program, the US has spent $7 billion on 18 satellites currently in orbit. These measure changes in sea levels, monitor ocean biological activity, track changes in glaciers, and gather data on other key features of the planet.
Yet other systems of sensors, ranging from tide gauges for measuring sea level in developing countries to weather stations in some of the former Soviet republics, are falling into disrepair.
Elsewhere, technological advances such as GPS- capable sensors on weather balloons, increasingly used in developed countries, are beyond the financial reach of some developing nations who contribute data twice a day for use by weather forecasters worldwide.
One of the challenges, analysts say, will be devising a way to help participants gather and interpret information using the latest available technology and at a level of precision that will be useful to science as well as commerce.
"The basic thrust of the meeting seems to be that observations are good, yet bad observations are not good and can mislead" researchers and other people interested in using the information, notes Kevin Trenberth, who heads the climate-modeling section at the National Center for Atmospheric Research in Boulder, Colo. "With climate, for example, you're looking for very small changes over long periods of time."
He also warns that data gathered from a global network "should be freely and openly available to everyone." To do otherwise, he says, would leave the impression that the industrial countries, and particularly the US, are enlisting the aid of nations worldwide to develop information that would be usable only in nations that have the money, talent, and equipment to capture, archive, and analyze the vast volumes of information that a global network would generate.
For example, the data management system for NASA's Mission to Planet Earth alone carried a $1 billion price tag, says Ghassem Asrar, associate administrator for NASA's office of earth science.
And even the raw data have economic value, adds Brig. Gen. Jack Kelly (ret.), director of the National Weather Service. Satellite photos of croplands can have a direct bearing on the futures markets worldwide. "So as you build a network, how do you integrate the needs of the private sector" with those of noncommercial users? he asks.
Yet, General Kelly continues, the challenges are hardly insurmountable. "At the height of the cold war, when we were kids learning to duck underneath a desk, the US, Russia, and communist China agreed on very little. But we were able agree that we would routinely and reliably exchange weather information. It took political will, but we created the standards and telecommunications networks to rapidly and reliably share" the data, he says.
The proposal for a global Earth-observation network "is on a bigger scale and covers more elements of the ocean, land, and atmosphere. But it's doable now," he adds. "The only thing that has been lacking is political will."
He and other proponents say they hope Thursday's meeting will bridge that gap.