-22-
of plankton as determined in methane-flow counters has been reported
on the wet basis so that the
specific
pared with that of other substances.
water uniformly from
the plates.
activity of plankton may be com-
This involves attempting to drain
the plankton samples at the time of preparing
The varying water content of the planktonic organisms
causes uncertainty in
radioassayed.
evaluating the
amount of wet plankton being
It was shown (UWFL-53:19) that if results were based
on the amount of planktonic ash rather than on the amount of wet plank-
ton, the variability in radioactivity of replicated tows
was reduced to
only one half the value obtained on the wet basis.
Similarly, the present data for Rongelap Atoll were more consistent on an ash than on a wet basis.
The greatest disparities between
the two values for paired tows occurred in the 1956 collections, as seen
in Table 3.
At Kabelle Island, the ratio between the two values was only
3.6 on the ash basis, but 8.9 on the
wet basis,
and at Rongelap Island,
only 4.3 ash basis, but 8.6 wet basis, so that here,
as
at Eniwetok
Atoll, the variability is only half as great on the ash as on the wet basis.
Further, the average level of activity in plankton from Ailinginae
lagoon in October 1955 was noted (UWFL-43:46) to be higher than in
Rongelap lagoon on the wet weight basis.
But
if
unit of ash weight instead of wet weight is used,
the
radioactivity per
the Ailinginae levels
are no higher than in Rongelap lagoon near Kabelle Island (Table 3).