as an ecological factor,
it is difficult to do more than specu-
late concerning the cause of the specific anomalies observed.
Fosberg
(1959) has accurately described the poor condition of
the plants at the northern islets of Rongelap and has suggested
that the primary cause of this condition is radiation.
opinion, however,
other factors,
In our
particularly edaphic factors,
have probably been more important than radiation.
The fact
that the nitrogen content of the soils of the northern islets
is lower than that of the rest of the atoll is at least circumstantial evidence that for some time there have been differences
between these areas with respect to plant growth.
Stone et al.
(1957) has concluded from studies of Drosophila populations at
Bikini,
Eniwetok,
Rongelap and uncontaminated atolls that while
there is evidence of genetic changes caused by radiation other
factors mask the radiation effects.
In short,
it is not likely
that such questions will be resolved without controlled experimentation with the species involved,
under varying conditions,
and with an eye toward the possibility of synergistic effects.
Approximately five years after fallout the long-lived fission products csl37 and sr?° are the principal radionuclides
found in the land organisms,while the neutron induced radionuclides 2n©> ,
organisms.
co®® and mn°4 are found primarily in the
marine