Seep and ye shall find: hidden water flow.Subterranean rivers flowing slowly through the ground carry freshwater into the ocean in quantities far larger than scientists had suspected, according to recent research conducted off the coast of South Carolina South Carolina, state of the SE United States. It is bordered by North Carolina (N), the Atlantic Ocean (SE), and Georgia (SW). Facts and Figures
Area, 31,055 sq mi (80,432 sq km). Pop. (2000) 4,012,012, a 15. . These invisible seeps season the seas with salts, metals, and pollutants.
During July 1994, groundwater oozed out through sediments on the seafloor along the state's coastline at a rate of 30 billion liters per day. This is a little under half the water entering from the region's rivers, says Willard S. Moore of the University of South Carolina
• • in Columbia.
'What we've done is show that the groundwater input to the coastal ocean is extremely important,' says Moore, who described his results in the April 18 Nature.
'This has tremendous implications for understanding everything from pollution to geochemistry,' comments ecologist George M. Simmons of the Virginia Polytechnic Institute and State University Virginia Polytechnic Institute and State University, at Blacksburg; land-grant and state supported; coeducational; chartered and opened 1872 as an agricultural and mechanical college. in Blacksburg.
Although hidden from view, water stored in porous, underground rocks constitutes 97 percent of the world's supply of liquid freshwater. Like surface rivers, which flow downhill toward the sea, some of this groundwater migrates downward through subsurface formations that open beneath the ocean.
Scientists have made spot estimates of groundwater entering the sea, but Moore's study is the first to gauge this process on a regional scale.
The South Carolina geochemist happened on a technique for measuring groundwater flow while he was studying naturally occurring radium radium (rā`dēəm) [Lat. radius=ray], radioactive metallic chemical element; symbol Ra; at. no. 88; at. wt. 226.0254; m.p. 700°C;; b.p. 1,140°C;; sp. gr. about 6.0; valence +2. Radium is a lustrous white radioactive metal. in a salt marsh. Moore found that the amount of an isotope, 226Ra, in the marsh water exceeded that in ocean water. Because no rivers emptied into the inlet, the radium must have come from groundwater seeping into the marsh, he reasoned.
He then used 226Ra to trace groundwater entering coastal waters and again found excess radium that could not have come from the ocean or rivers. 'By process of elimination The process of elimination is a basic logical tool to solve real world problems. By subsequently removing options that may be deemed impossible, illogical, or can be easily ruled out due to some sort of explicit understanding relative to the entire set of options, the pool of , the primary source of the 226Ra enrichment must be the discharge of groundwater containing dissolved 226Ra,' he concludes.
Moore suspects that when brackish brack·ish
1. Having a somewhat salty taste, especially from containing a mixture of seawater and fresh water: "You could cut the brackish winds with a knife/Here in Nantucket" groundwater penetrates fresh aquifers, it causes sediments to release 226Ra, which can then flow into the ocean. People enhance radium movement by pumping drinking water drinking water
supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. from coastal aquifers; this reduces pressure in the aquifer and allows saltwater to intrude farther inland than it otherwise would.
He expects that other elements and ions behave similarly, making groundwater an important source for many of the ocean's trace constituents, including nutrients that support aquatic life.
In unpublished studies, geochemist William C. Burnett of Florida State University Florida State University, at Tallahassee; coeducational; chartered 1851, opened 1857. Present name was adopted in 1947. Special research facilities include those in nuclear science and oceanography. in Tallahassee also has found significant groundwater movement into the northeast Gulf of Mexico Noun 1. Gulf of Mexico - an arm of the Atlantic to the south of the United States and to the east of Mexico
Golfo de Mexico
Atlantic, Atlantic Ocean - the 2nd largest ocean; separates North and South America on the west from Europe and Africa on the east . Burnett's group used dissolved radon as a tracer of groundwater flow.
'When you look at the process, it's a lot larger than people might have thought. We were surprised. It's been one of those things in earth science where people know it goes on, but no one to date had really developed a good way of measuring it, so it's generally not talked about,' says Burnett.
Before these new measurements, some scientists had suggested that groundwater flow into the ocean might equal only one-thousandth of the river flow. But Burnett estimates that groundwater contributions to the ocean total about one-tenth of the amount supplied by rivers globally. In some locations, the groundwater component may dominate, he says.
Measurements off many coasts indicate that subterranean flow can carry pollutants, as well as naturally occurring elements, into the ocean. In particular, nitrates from septic tanks have seeped into seawater seawater
Water that makes up the oceans and seas. Seawater is a complex mixture of 96.5% water, 2.5% salts, and small amounts of other substances. Much of the world's magnesium is recovered from seawater, as are large quantities of bromine. , says Burnett.