Nutrients, landbased or
atmospheric sources
¥
~
"nutrient opportunists"
(finely branched
annual
seaweeds) favoured
change of hydrodynamic conditions
j
(bottom currents)
turbidity increases
euphotic layer
becomes shallower
~
? ----~~-~~
\
~
I mechanical stress
by Increased epiI phyte load
shading effects,
more substrate
;;;l
lower distribution
food for Juvenile" 'u
I
limits of benthic
Idothea
I
plants rise
/
sublittoral algae adapted
to lower light levels move
upward and outcompete
Fucus
~
.-Fucus adapted to
high light levels,
lower distribution
level rises
~.~
/
1
increased number ofl
Idothea and grazing
I
on FU~------1
/
I
I
[Stone fishing
I
~nges in climatic
I ~~~ditions, rising
water
level
.-r
Gncreasing
cl iff erosion
sand deposition
~
~
---:J
recolonization
disturbed, reduce.]
Minor factors
- - - - - - - - 1
ice scouring I
diseases
:
pollution
I
________ J
Fig. 5.11. Hypothetical model showing the major causes for the decline of
Fucus spp. in Kiel Bight, western Baltic. (After Vogt
and Schramm 1991)
'"" <.n
N
~
u;
8...
:>l
~