Sun’s Harmful Rays on Living Things Subject of Data Shared with National Science Community in Unique Program

Scientists might someday genetically alter plants that are sensitive to ultraviolet light to naturally produce sunscreen and antioxidants beneficial to human health – but that won’t happen without research produced by Colorado State University.

Since 1994, Colorado State scientists have established research stations all over the United States – and several around the world – to measure ultraviolet radiation and its effect on human health and agriculture. The U.S. Department of Agriculture funds the $1.85 million UVB Monitoring and Research Program in Colorado State’s Natural Resource Ecology Laboratory, part of the Warner College of Natural Resources.

Data collected at the 34 climate stations established by Colorado State is critical to projects conducted by many other universities and organizations around the country. Colorado State contracts with other scientists who use the data to study everything from spinach and soybeans to the spread of brucellosis in bison and cattle.

The U.S. Department of Agriculture is studying factors such as sunlight that may contribute to the staying power of brucellosis bacteria in Yellowstone National Park.

"Jim’s center has provided technical equipment and expertise in collaborating on this project to determine survivability of Brucella abortis in the greater Yellowstone area environment," said Jack Rhyan, senior staff veterinarian for the National Center for Animal Health Programs, USDA, APHIS, Veterinary Services.

UVB is a specific portion of the sun’s energy that is only partially absorbed by the ozone layer and can damage biological organisms. Ultraviolet light, a more energetic portion of the spectrum than light that is visible to the naked eye, is separated into three groups: UVA, which is not damaging to organisms; UVB; and UVC. Unlike UVB, harmful UVC rays are typically absorbed entirely by the ozone.

"We’re creating an enormous database that documents the distribution and variability of ultraviolet sunlight," said Jim Slusser, director of the UVB Monitoring and Research Program. "The record will become more and more valuable the longer we keep it up."

Researchers in Fort Collins collect the data every night from the research sites via computer and organize and distribute it the next day on the Web. It’s the only program of its kind in the country that provides a baseline for research on the effects of ultraviolet light on plants and animals.

"The USDA and Congress have been very generous in providing long-term funding of the study of the effects of ultraviolet radiation," Slusser said. "For the first time, we’re seeing the range of natural variations in ultraviolet light across the entire United States. Researchers are looking at day-to-day, week-to-week and year-to-year  variability. That’s never been done before."

Researchers know that increased UVB radiation in people causes skin cancer and increased incidence of cataracts. It is also known that moderate exposure to UVB helps the body stay healthy by producing vitamin D in the outer layers of exposed skin.  Colorado State is collaborating with the University of Brisbane in Australia to study how much sunlight people can handle based on their skin type.

Scientists also know that roughly two-thirds of the 300 plants that have been tested so far are susceptible to damage from UVB radiation. Now they’re taking that a step farther: Is it possible to someday engineer plants that can not only handle ultraviolet light, but also protect themselves from it?

Richard Grant, a professor in the Applied Meteorology Group at Purdue University, is in the early stages of finding out.

Grant contracts with Colorado State to monitor the effects of ultraviolet light on soybean plants. He artificially creates an environment that varies the amount of light and other environmental stressors on the plants and studies their responses.

He receives half of his funding from Colorado State and works closely with Wei Gao, one of his former graduate students who is also a Colorado State research scientist.

"The Colorado State contribution to the UV effort that I’ve got really keeps it going," Grant said. "I think what we’re doing is getting to the point where the kind of information that we’re learning can make significant inroads in understanding how crops will respond to climate change."

For example, studies have shown that sorghum and maize, which originated in equatorial regions with high UVB levels, have evolved to be very tolerant of ultraviolet radiation while soybeans, native to mid-latitudes, have not.

Differences also can occur within various plant species. For example, Grant knows some varieties of soybeans thrive under ultraviolet light while others don’t. Some plants actually change their physiology to protect themselves from ultraviolet rays just as they change their taste to be less palatable when a bug takes a bite from their leaves, he said.     

Still, scientists won’t know for many years how plants react to ultraviolet light and how to change their genetic makeup to minimize UV damage, Grant said.  Researchers are just now beginning to look at plants at the molecular level.

"We’re pretty far along in being able to define how much light’s getting to a certain place," he said. "In terms of getting the plant’s response understood, it’s many, many years away."

Back at Colorado State, Gao is taking plant response research from Grant and other scientists and building an integrated crop impact assessment system to eventually provide yield forecasts under various crop stresses such as UVB, drought and high temperatures for agriculture and livestock production.

The UVB Monitoring and Research Program employs two full-time programmers who work with the data, three scientists and three technicians who visit each of the 34 climatological sites – 31 in the United States, two in Canada and one in New Zealand – at least once per year. And the program is growing: Congress recently approved a 10 percent increase in the program’s budget for 2006.

Slusser has been at Colorado State for 10 years and director of the UVB Radiation Monitoring and Research Program since 1999. He obtained his doctoral degree in atmospheric science at the University of Alaska where he studied arctic ozone depletion, and he completed his post-doctorate work in atmospheric chemistry at Cambridge, England.