solved radioactive material, may accumulate on the surface of
plenkton organisms,
ticles
and that in addition there are larger par-
(the cheesy material)
Algae.
suspended in the water.
In order to evaluate the "speck" contamination of
algae, autoradiographs of washed and unwashed specimens were
made.
Washing was done by scrubbing with a brush and detergent
and was followed by rinsing with running tap water.
Autoradiographs of an alga, Udotea, before and after washing, are shown in Figure 2la
and».
spots were removed by washing,
Some of the radioactive
but most of them were not,
showing
that a major portion of the radioactivity is actually present
within the alga. The even distribution of radioactivity in the
filaments of Lyngbia and in the ramuli of Bryopsis,
shown in
c and d of this figure, indicate that "speck" contamination is
of minor importance
in these specimens.
In one alga of the pre-
shot collection (Fig. 2le) adhering soil particles were responsible for numerous hot spots
in the autoradiograph.
The
autoradiographic method has indicated the presence of both surface and absorbed contamination in the algae collected before
and after Mike shot.
The relative amount of speck contamina-
tion was high in some cases and low in others;
however, a quan-
titative estimation cannot be made.
Invertebrates.
Among the invertebrates, an outstanding
example of spotty distribution of activity was
on @ piece of coral of the genus Acropora,
November 8,
1952,
the occurrence
taken at Bogallua
of 3 highly radioactive nodules firmly at-
o2
-
oonyt AY’
yet
CO Te