Scientists call for study of Earth’s critical zone
4:15 p.m., Aug. 1, 2006--Scientists who attended a National Science Foundation-sponsored workshop held last fall at the University of Delaware have called for an international initiative to study the Earth's critical zone, which encompasses the outermost surface of the planet from the vegetation canopy to groundwater and which sustains life.
As key parts of the initiative, the scientists call for the development of an international Critical Zone Exploration Network and a systematic approach to the investigation of processes in the critical zone across a broad array of sciences, including geology, soil science, biology, ecology, chemistry, geochemistry, geomorphology and hydrology.
The critical zone is the interface between the materials that comprise the planet and the biotic world, and it sustains life on the face of the Earth, according to Donald Sparks, S. Hallock du Pont Chair of Plant and Soil Sciences at UD and co-chairperson of the NSF workshop organizing committee.
“Because the critical zone includes air, water and soil and is the focal point of food production, it has a major effect on human life,” Sparks said. “It is imperative that we better understand the interactions that occur there.”
“We need to understand how living organisms interact with the solid earth at the scale of a billionth of a meter as well as the scale of landscapes, and how these effects have changed over geologic time and how they will change into the future as humans continue to drastically alter the earth's surface,” Sue Brantley, professor of geosciences at Penn State, who co-chaired the NSF workshop organizing committee, said.
Sparks and Brantley were joined on the committee by members Jon Chorover, University of Arizona; Mary Firestone, University of California, Berkeley; Dan Richter, Duke University; Tim White, Penn State; and Art White, U.S. Geological Survey.
Despite the critical zone's importance for life, scientific approach¬es and funding paradigms have neither promoted nor emphasized inte¬grated research agendas to investigate the coupling between the region's physical, biological, geological and chemical processes.
The scientists said a national initiative is needed to determine how the physical, chemical and biological components of Earth's weathering engine transform mineral and organic matter to nourish and sustain ecosystems, regulate the migration and fate of toxins, sculpt terrestrial landscapes, and control the exchange of greenhouse gases and dust with the global atmosphere.
Such an initiative would enable the prediction of complex feedbacks among processes in the critical zone, including changes in fluxes driven by climatic, tectonic and anthropogenic forces over a wide range of temporal and spatial scales. Of particularly pressing importance is the need to understand how the critical zone is being transformed by rapid anthropogenic, or man-made, change, the report said.
“We have to do more in collaborative and interdisciplinary research,” Sparks said. “We also must educate the public about this important issue, and reach out to policy makers to provide them the best science available to help them solve important problems that arise.”
Critical zone sites include an extraordinary diversity of soils and ecosystems ranging from the tropics to the poles, from deserts to wet¬lands, and from rock-bound uplands to delta sediments.
Understanding and predicting responses to global and regional change is necessary as scientists seek to mitigate anthropogenic impacts on the Earth, the report said.
Scientists believe there are four key questions, involving the atmosphere, landforms, ecosystems and water:
The report noted that a concerted research effort is needed and will require a network of observatories and people to quantify responses of the critical zone to environmental change. Scientists recommended creation of a Critical Zone Exploration Network to include short-term deployments of instrumentation at field sites along environmental gradients as well as long-term sites that will be equipped with the latest in equipment and provide intensive amounts of data. The network will provide for the integration of information across disciplines, with educational and outreach components.
“We need to learn how to stimulate scientists trained in different disciplines to communicate with one another effectively, Brantley said. “Once these scientists communicate and begin to tackle critical zone questions with the newest analytical and modeling techniques, we will see our ability to predict changes in this zone expand rapidly. Funding paradigms must also be found to facilitate this kind of research.”
The report concludes that Earth's terrestrial organisms, including humans, depend on the critical zone for survival and that the rates of change of air, water, solid Earth materials and biota must be understood as humans drive environmental change on the planet.
The best way to gain understanding is through creation of the network, the scientists said, noting “the proposed initiative will provide initial solutions to the driving questions while educating the next generation of scientists to expand this knowledge for stewardship of our environment.”
Funding for the critical zone workshop and associated activities was provided by grants from the National Science Foundation Division of Earth Sciences to both UD and Penn State and by the NSF Experimental Program to Stimulate Competitive Research (EPSCoR) program in Delaware.