over a period of several years with a fundamentally 
denser station network. 
However, in general, one can state from the measure- 
ments already carried out, that certain deviations of 
the 15708 and D0s activity concentration values in the 
upper water layers down to about 200 m depth can occur 
on both sides, which give an indication of the layering 
of the water in this region. Below these depths - from 
1972 onwards, only from about 500 m depth —- a stronger 
decrease in concentration occurs down to about 1,000 m 
depth. In the depths below 1,000 m to 1,500 m, the values 
then stay fairly constant. The advance of the fallout 
products, transported here from the surface, into greater 
depths takes place only very slowly in the sea area 
investigated. 
During the year 1972 only, extraordinarily high 
13708 concentration values were measured in the depth 
range between about 500 m and 1,500 m. In individual 
cases, these were several times higher than those surface 
concentrations which were available at the same time, 
In fact, in one case, the value was about double so high 
as the highest 1966 surface water measurement. We can 
provide no explanation for this phenomenon, As, however, 
the 90m did not show the same behaviour, it appears to 
lie within the possibility that biological mechanisms 
are responsible for these accumulations. 90sp practically 
will not — on the other hand, 15708 can —- accumulate in 
plankton or other marine organisms to about a factor of 
100. It is astounding that, in the 1974 measurement 
values, absolutely no indication of this distribution 
anomaly —- which occurred in 1972 —- was to be recognized. 
In total, the 15705 concentration activity values 
in the surface water during the period from 1966 to 1974 
sank to about half the initial values.