The Ecological Effects of the Chernobyl Disaster

Organized Oral Session 7: "Ecological effects of the Chernobyl disaster: Genes to ecosystems," will take place Monday 8 August 2005, 1:30 - 5:00 PM in Meeting Room 510 A, Level 5, Palais des congrès de Montréal.

Nearly 20 years ago Reactor number 4 at Chernobyl exploded, sending radiation across a large region of what is now the Ukraine, Belarus, and Russia. Some 40 radionucleotides were released into the environment, including Strontium 90 (90Sr) and Cesium 137 (137Cs). Yet despite radiation levels dangerous to humans, most natural areas in the region have rebounded, and by ecological standards, are functioning normally. The session, organized by James Morris and Timothy Mousseau (University of South Carolina, US) will reveal how the environment has responded -- from genetic mutation rates, to plant and animal communities, to nutrient cycling.

Sergey Gaschak (International Radioecology Laboratory, Ukraine) will open the session with his presentation, "Determinants of levels of 90Sr and 137Cs in birds in Chernobyl." Studying 228 birds of 23 different species captured in Chernobyl, Gaschak and colleagues from the University of South Carolina (US) and University Pierre et Marie Curie (France) measured the birds' levels of radioactive strontium and radioactive cesium, comparing migrating populations with those that remain in the area, as well as examining age, sex, and nesting preferences to determine the amounts and types of radiation accumulating in the birds. In the presentation, Gaschak will discuss how quantities of 90Sr and 137Cs vary with feeding, nesting and migration habits.

Timothy Mousseau will present "Consequences of radiation for reproduction and survival of barn swallows Hirundo rustica from Chernobyl." Barn swallows are long-distance migratory birds, which nest across Europe, providing researchers with numerous populations to sample. Examining swallows from the Chernobyl region and Kanev, southeast of Kiev, Mousseau and his colleague, Anders Moller (Laboratorie de Parasitologie Evolutive, France), found reproductive success was significantly reduced for the Chernobyl-nesting birds. Survival rates, number of eggs laid, and overall body condition was lower, despite similar nesting and laying dates.

The radio nucleotides in the area also filter into the soil, and from there into plants. Animals that consume these plants, including livestock, then take up the radionucleotides. Viktor Dolin (National Academy of Sciences, Kyiv, Ukraine) will discuss a newly described process of environmental self-cleaning in the talk, "Biogeochemical cycling of radionucleotide: Implications for the human food web." Dolin calculated the rate of 137Cs and 90Srs moving through the environment, then used the data to determine an ecosystem's ability to "clean" itself of excess radiation.

Oleksander Orlov's (Ukrainian Scientific Research Institute) presentation, "The distribution and cycling of 137Cs in forests of the Chernobyl exclusion zone," will focus on 137Cs levels in three 50-year old Scotch Pine forests. Forest litter, moss, lichens, understory, macromycetes, and canopy 137Cs activity measurements will be described. Also working in these pine forests, Vadim Skripkin and colleagues from the Institute for Environmental Geochemistry, Ukraine, and the University of South Carolina will report their findings on the distribution of 14C in, "The turnover of 14C carbon in forests of the Chernobyl exclusion zone."

The final presentation of the session, Ronald Chesser (Texas Tech University, US) will describe the distribution and effects of radiation doses that hit wildlife that were living in the area at the time of the accident, as well as how the populations recovered in the talk, "Temporal trends in radiation doses, survival, and recovery in wildlife populations at Chernobyl."

For more information about this session and other ESA-INTECOL Meeting activities, visit: http://www.esa.org/montreal. The theme of the meeting is "Ecology at multiple scales," and some 4,000 scientists are expected to attend.