13
Islands, which ranged from 0-16 d/n/g.
however,
Activity in the water,
immediately south of Guam was about three times high-
er at the time of the Marsh survey than during Operation Troll.
The distritution of plankton activity is shown in Figure 3
and Table 1.
from Table 1.
Figure 4 is a graphic presentation of the data
There is a sharp decrease in activity east of
Bikini and 4a gradual but irregular decrease west of Eniwetok.
Activity levels in plankton samples from immediately east of
Bikini are about the same as those in the vioinity of Guam.
The plankton tows were made to a derth of about 200 metera,
which assured complete sampling of the stirred layer.
It is gen-
erally accepted that the stirred layer exists only above the”
thermocline.
a region in which temperature decreases rapidly
with increase in depth.
Bath, thermograph casts were made at
each station to determine temperature changes with depth.
Un-
fortunately the only bathythermograph which was operable et stations 1 - 30 wae only able to meésure temperatures to a depth of
200 feet.
This situation wes remedied at Guam and from that
point on temperature meésurements were avélilable to 400 feet.
From the later dete and the results of the Walton and Troll surveya
it is evident that in general the upper level of the
mocline was just below 100 meters.
ther-
DOE ARCHIVES
The average of the ratios of plankton activity to water
activity was 2500;
possible reasons for variations
in this
value are discussed on pages 27-33.
Water
The activity of the water from all depths is presented in
‘9