390 NATIONAL OCEANOGRAPHIC PROGRAM—1965 
c. Radioisotopes are used as tracers in studies of permanently 
stratified lakes. onic movement and biological transport of certain elements 
in these lakes are observed during various seasons of the year, utilizing 
radiological techniques. 
5. Pathologic effects in fishes exposed to radioactive iodine 
from fallout. 
eee Gorbman, Professor of Zoology, Columbia University. 
b. To study the effects on fish from fallout. 
c. Radioactive iodine is introduced into certain environments 
in the Great Lakes area to study the pathologic effects on members of the 
marine population. 
6. Radiation and other factors in influencing the distribution 
of animals. 
a. W. J. Breckenridge, Director, Museum of Natural History 
and others, University of Minnesota. 
b. To analyze the factors responsible for the peculiar 
distribution of toads in the Great Lakes (Minnesota) area. The differential 
tolerances of eggs and tadpoles in water have been studied under varying 
concentrations of sulfate, chlorides, carbonates, and hydrogen ions. The 
normal behavior and survival] of toads while underground is being studied in 
the Great Lakes in the field, and in the laboratory under simulated natural 
conditions of soil temperature and moisture, 
7. Studies on the productivity of vascular hydrophytes in 
acquatic ecosystems. 
a. KR. T. Hartman, Associate Professor of Botahy, and others, 
University of Pittsburgh. 
b. To study productivity rate of various organisms under 
varying conditions of the environment. 
c. Radioisotopes are used to study mineral uptake by the 
root and shoot system of the vascular hydrophytes. The loss of absorbed 
elements to surrounding water is studied as well as the rate of return of 
elements through organs. Compensation points, relative photosynthetic rates, 
and annual production values are determined for several species of these 
plants. Changes in the composition of their internal atmosphere are determined. 
