Eddlemon will present his research on the possible harmful effects of downed weather balloons on whales in the Antarctic at the annual meeting of the Ecological Society of America (ESA) in Albuquerque, N.M., Aug. 10-14. The meeting is being held jointly with The Nature Conservancy.
The federally funded U.S. Antarctic Programs (USAP) launches approximately 1,300 of the more than 9,000 weather and research balloons released each year by several nations. The balloons range in diameter from two to hundreds of meters. The balloons are made of polyethylene or neoprene - estimated by some to persist in the environment up to 400 years - and are known to harm animals by ingestion or entrapment. The balloons are used to provide weather information for safe aircraft operations, measure atmospheric contaminants and make astrophysical observations.
Eddlemon chose to study the ecological impact of downed weather balloons on whales because all the great whales that visit the Antarctic ocean are endangered, they swim great distances while there, and whale deaths in other oceans have been attributed to the ingestion of plastic bags. The blue whale, which migrates to the Antarctic every summer for feeding, once had a population of approximately 230,000 and is now estimated at between 1,000 and 10,000. Other endangered whale species that visit the Antarctic include the fin whale, sei whale, humpback whale, right whale and the sperm whale.
"The situation is very, very complicated," says Eddlemon. "There is still a lot to learn about the natural habits and life span of whales, and there isn't enough known about the ocean's currents and the movement of downed balloons across the ice to predict what they will do when they land in the water."
Using estimated balloon densities over time, balloon length, the whale's gape and swimming velocities, and population estimates, Eddlemon predicted the frequency of physical encounters with balloons for an individual whale and a population. Although he made conservative assumptions (due to the inadequacy of the data), the resulting whale/balloon encounter frequencies were remarkably high. In some scenarios they were in the thousands of encounters per year. In one estimate, the cumulative length of plastic floating in the Antarctic ocean from one launch site (representing a fraction of the total launches) would be as much as 24 miles long after only 10 years.
"Even if we use a low ratio of fatalities resulting from encounters with balloons, the model still predicts substantial losses of these endangered animals," says Eddlemon. "The 64 million dollar question is how whales really act on encountering floating balloon material."
At the ESA meeting, Eddlemon also will discuss his suggestions for remedying the possible impact of balloons. These include changing the balloon materials to a substance that degrades quickly, reducing the number of balloons launched, and using alternative ways of gathering atmospheric data, such as remote sensing.
USAP has responsibilities for environmental impact assessment under the 1969 National Environmental Policy Act, the Antarctic Treaty (signed by 39 nations), and the Madrid Protocol. USAP chose researchers from ORNL, including Eddlemon, to help meet some of those requirements because of their extensive experience and reputation in the assessment of environmental impacts of a wide range of large-scale federal projects from weapon ranges to nuclear power plants.
Some of the policies of the international laws include avoiding activities that cause further jeopardy to endangered or threatened species of plant and animal populations, avoiding degradation of areas of biological, scientific, aesthetic and wilderness significance, and obligations to remove most solid and hazardous wastes from Antarctica.
ORNL, one of DOE's multiprogram national research and development facilities, is managed by Lockheed Martin Energy Research Corporation.