Studies in 1963 by scientists from the University of California at Los Angeles showed that native plants—Russian thistle and various annuals—had become well established in the zone around the Sedan crater where the earth was thrown out. This area had remained barren for less than a year. Some of the shrubs most severely damaged by the blast, and exposed to cumulative gamma radiation doses of more than 4000 roentgens, had produced new growth. Populations of creosote bush, evergreen plants that in 1962 appeared to have been killed by heavy doses of radiation, were producing leafy branches in the summer of 1963. These developments permitted no conclusions, of course, for the possible radiation effects still needed to be identified. Studies were conducted, for example, of the effect of deliberately depositing nonradioactive dust on healthy creosote plants, and comparative studies of other phenomena were made. Since 1959, ecological studies have been carried forward at the Nevada site by investigators from Brigham Young University who are interested in the abundance, seasonal occurrence, and ecological influences affecting the vertebrate and invertebrate animals in plant communities of the region. Surveys have been made in areas where nuclear explosions had obliterated natural ecological relationships and in similar areas undisturbed by nuclear effects. The investigations are concerned primarily with desert ecology—with the identification of biotic communities and of predominant animal species. Among research programs in marine environments is that initiated in 1963 and 1964 by the University of California’s Institute of Marine Resources at La Jolla, where studies of marine food chains are conducted by a team of zoologists, chemists, botanists, and microbiologists. The program studies the interrelations among organisms at the lower levels of the food chains and the dynamics of marine phytoplankton cell division, photosynthesis, and excretion of organic matter as related to temperature, light intensity, and nutrient conditions. The work is conceived as a basic study of marine ecology. It is focused, however, on questions found to be significant in studies of radioactivity in the sea. The University of California’s Lawrence Radiation Laboratory has launched a long-term investigation of the effects of the release of radionuclides on the biosphere, which encompasses the origins, transport, and final localization of radionuclides in all types of organs, tissues, cells, and subcellular constituents. The objective is “to develop the most complete understanding possible of the potential hazards to man that arise from the release of nuclear radiation and radionuclides into the biosphere and to apply this knowledge to the prevention of damage to living forms...”. In programs such as these—multiplied by hundreds—the problems are being attacked. WHERE ARE WE NOW?