The dispersion of zoospores in a horizontal direction is considered to
be the sum of their own swimming power and the effect of eddy current
s, while in the vertical direction it is regarded as a uniform movemen
t sedimentation. If the total number of liberated zoospores is regarde
d as 100%, the relative number of zoospores showed 0.047%/cm right bel
ow the zoospore liberation point and 0.020%/cm at a point 10 m away fr
om there. Furthermore, the dispersion range of zoospores became wider
in the seawater as turbidity increased, while the number of zoospores
settling on the bottom decreased; when the sea water turbidity was mor
e than 2 mg/l, the density of settled zoospores was 0.023%/cm right be
low the zoospore liberation point. Meanwhile, the formational range of
kelp beds is also largely reduced in accordance with increasing turbi
dity. When the turbidity is 10 mg/l, the area of kelp beds is estimate
d to reduce to less than 1/10 of its ordinary area under normal turbid
ity.