Hydrology and Riparian Areas, EAR’s newest STC, the University of
Arizona and its partners 7 seek to move scientific knowledge about these issues
from research groups to the agencies responsible for managing water resources.
The storage and flux of water in the Critical Zone are multidisciplinary problems
that connect hydrology to the study of the oceans and atmosphere and to the solid
Earth. On the geological side, the investigation of aquifers and groundwater
systems now relies extensively on the use of geochemical and geobiological
techniques, as well as geophysical methods. Such techniques have been used to
investigate the cause and distribution of elevated levels of arsenic in
groundwater, for example, which pose a serious health hazard in many parts of
the world. The problem is particularly acute in Bangladesh, where groundwater
provides 97% of the drinking water supply. Because contamination is localized,
data from hydrogeological (groundwater flow velocities and directions),
geophysical (resistivity, seismic), and geochemical (isotopic, trace element
chemistry) techniques will help guide the placement of new wells that draw water
with acceptable concentrations of arsenic. 8
Soil
Soils are an immense and valuable natural resource. In their most obvious
capacity, they serve as the foundation and primary reservoir of nutrients for
agriculture and the ecosystems that produce renewable natural resources, but soils
are also fundamental for waste disposal and water filtration, and as raw materials
for construction and manufacturing activities. More generally, these biologically
active, intricately structured, porous media—collectively called the pedosphere
—mediate most of the life-sustaining interactions among the land, its surface
waters, and the atmosphere. Organic carbon is recycled to the atmosphere through
soils; about 25% of atmospheric carbon dioxide comes from soil biological
oxidation reactions in the pedosphere, which contains twice as much carbon as
the atmosphere and up to three times the carbon in all vegetation. Soils have a
major influence on the hydrologic cycle.
7 STC participants include the University of Arizona; Arizona State University; Scripps
Institution of Oceanography; U.S. Geological Survey; University of New Mexico;
Pennsylvania State University; Los Alamos National Laboratory; U.S. Department of
Agriculture; Institute del Medio Ambiente y el Desarrollo Sustentable del estado de
Sonora; Desert Research Institute; Columbia University’s Biosphere 2 Center; University
of California, Riverside; Northern Arizona University; U.S. Army Corps of Engineers; and
the University of California, Los Angeles.
8 See West Bengal and Bangladesh Arsenic Information Centre ( http://bicn.com/acic )
and World Health Organization Fact Sheet 210 ( http://www.who.int/inf-fs/en/
fact210.html ).
BASIC EARTH SCIENCE AND SOCIETY
19
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