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Magdalena Koziol, a former postdoc at Yale University, was the victim of scientific sabotage. Now, she is suing the...
Antiretroviral drugs can protect people from becoming infected by HIV. But so-called pre-exposure prophylaxis, or PrEP...
Two studies show that eating a diet low in protein and high in carbohydrates is linked to a longer, healthier life, and...
Considered an icon of conservation science, researchers at World Wildlife Fund (WWF) headquarters in Washington, D.C.,...
The new atlas, which shows the distribution of important trace metals and other substances, is the first product of...
Early in April, the first of a fleet of environmental monitoring satellites will lift off from Europe's spaceport in...
Since 2000, U.S. government health research agencies have spent almost $1 billion on an effort to churn out thousands...
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How Salmon See the World Anew
18 March 2004 (All day)
If you were used to finding food by day then suddenly switched to chasing your dinner in the dark, night-vision goggles might be a necessity. The concept applies to salmon too: New research suggests that the fish adjust the light-sensitive pigments in their eyes as they age and move to deeper waters.
When young pink salmon graduate from shallow streams to the open ocean, they also change their eating habits--from nibbling plankton on the surface to hunting fish in deep water. Scientists suspected that the salmon visual system adapted as the fish moved from shallow waters dominated by ultraviolet light to deeper waters filled with blue and green light, but they had only hunches about how this might happen.
The new study suggests that the salmon's secret is shuffling the light-sensitive pigments inside their cone cells--nerve cells in the retina that respond to light. Iñigo Novales Flamarique and Christiana Cheng of Simon Fraser University in Burnaby, British Columbia, came to that conclusion by examining the retinas of young Pacific pink salmon. They couldn't find any cone cells with blue-light sensitive pigments. But in the retinas of older salmon, such cones were common. And in fish of intermediate age, the pair spotted UV-light sensitive pigments at the cell's tip, but blue-light sensitive pigments at the base, suggesting the salmon were pumping those pigments into their UV-light sensitive cones. The scientists report their findings in the 18 March issue of Nature.
“The work is very interesting,” says Juliet Parry of University College London, adding that many researchers had assumed that salmon tweaked their vision by replacing entire cone cells, not merely replacing the pigment. Novales Flamarique suspects this potential for pigment change may be widespread in vertebrates and has been overlooked because it's difficult to detect in the tiny cone cells. Clearly there is more to color vision than meets the eye.