Wednesday, May 26, 2010

Could the oil spill reach Virginia?

As officials make another attempt to cap the well spilling oil into the Gulf of Mexico, Virginians might be asking, “Could oil show up here?” As of now, it appears a large oil slick on Virginia waterways is unlikely, but oil residue in the form of tar balls could wash up on local beaches. How could oil that’s currently in the Gulf of Mexico end up in Virginia?
The Earth’s oceans are always on the move, their motion influenced by atmospheric circulation patterns, water temperature and salinity, ocean floor topography, and the Earth’s rotation. These ocean currents can occur both at the surface and deep in the ocean; they often travel great distances and have an enormous effect on regional climates.
As far as the oil spill goes, the Loop Current is the first culprit that could carry oil toward the East Coast. This current flows north between the Yucatan Peninsula and Cuba into the Gulf of Mexico, loops east and then south along the west coast of Florida. The Florida Current would take up where the Loop Current left off, carrying the oil around Florida. Then the Gulf Stream would take over and carry it up the southeast coast.
The Gulf Stream is an enormous river of warm water averaging 60 miles in width and 3000 feet in depth. At Cape Hatteras, the current’s flow rate is an incredible 85 million cubic meters per second, equivalent to over 1 billion fire hoses! (By comparison, the Mississippi River moves water at roughly 0.6 million cubic meters per second.) A major influence on East Coast weather, the Gulf Stream sometimes breeds Nor’easters in the winter and intensifies hurricanes in the summer, as happened with Hurricane Hugo off the coast of South Carolina in 1989.
At present, disruptions in the Loop Current appear to be keeping oil away from Florida and the Gulf Stream. Eddies often form and then break off from the main body of the current; the majority of the oil that had drifted into the Loop Current in recent weeks appears to be caught in an eddy and cut off from the main body of the current. Satellite pictures even suggest that the current itself may soon sever entirely, lessening the imminent threat of oil coming ashore in Florida and beyond.
This afternoon BP began an attempt to plug the leak with a method called top kill, an ambitious procedure intended to clog the well with thousands of pounds of heavy fluids pumped through extremely long pipes. This procedure has never been attempted so far beneath the surface; it could take several days to determine if it was successful. For everyone’s sake, let’s hope they succeed.
Satellite image courtesy of NASA. Colors indicate water temperature: darker colors = cooler temperatures, lighter colors = warmer temperatures.

Wednesday, May 5, 2010

Why Hot Sauce is Hot…..

By Fernando Luna Vera
Ph.D. Candidate, Chemistry Department, VCU
Science Museum of Virginia Volunteer
Can you please pass me the hot sauce?” a friend of mine asked. “This one?” I replied, holding up and showing him a warm spinach dip cup. “No! The spicy one,” he said. As I passed it to him, I mentally wondered an almost childish question, “Why do we call it hot sauce if it is not really hot…nor is it even served warm!” Appreciating and feeling the taste of food involves a complex mechanism that uses the sense of taste, smell and touch. This rise of sensations and perceptions sparked by food requires hundreds of chemical signals and our brain acting as traffic officer to control them.
After you bite a spicy taco your body can recognize that familiar, pungency sensation thanks to a well equipped network of sensors called neurons. Neurons, as do all animal cells, contain a boundary layer called a membrane, where specific receptors are allocated. These receptors are like the geometric figures on the surface of a shape sorter toy which recognizes specific shapes. Certain neurons, called nociceptors, have the specialized job of sensing pain. These kinds of neurons contain a specific receptor for capsaicin, the molecule found in high concentration within chili peppers. One can image then, capsaicin molecules traveling to the tongue and getting caught later by the nociceptors, which immediately after recognizing them, trigger an electrical signal that travels to the brain and makes us aware of the irritating sensation of the hot sauce. That specific capsaicin receptor is called TRPV-1.
But why does our brain read the signal produced by capsaicin as an increment in temperature? An experiment performed in 2000 by scientist of UCLA helped us to better understand this outcome. By using genetic techniques, they “knocked out” the gene that produces the capsaicin receptor (TRPV-1) from a group of mice and compared it with other group that still had the TRPV-1. After exposing the two groups to capsaicin, the one lacking TRPV-1 showed to be insensitive to the irritant substance, as expected. However, surprisingly the same group showed a high insensibility to temperatures above 43ºC, which is when pain is normally sensed. This result implied that the same receptor for the chili peppers irritant molecule is the same receptor for sensing high temperature. So when neurons bind capsaicin, the brain interprets the signal produced as an increase in temperature, like something “hot” is touching your tongue.
Additionally, neurons possess certain receptors called TRM8, which are activated by low temperatures (> 12 ºC). These receptors also happen to be sensitive to menthol, the compound found in high concentration within peppermint and used in products like mouthwashes and toothpaste. By then using the same mechanism for associating capsaicin and hot temperatures, the menthol bond to a TRM8 receptor sends a signal that tricks the brain; therefore, by just the taste of mint, makes you feel cool!
Sven-Eric Jordt, David D McKemy and David Julius, Current Opinion in Neurobiology, 2003, 13:487–492.
M. J. Caterina, A. Lefßer, A. B. Malmberg, W. J. Martin, J. Trafton, K. R. Petersen-Zeitz, M. Koltzenburg, A. I. Basbaum, D. Julius, Science, 2000, 288, 306-313