 |
|
It
appears that zoning is most noticable where the living conditions change
greatly over a short vertical distance and where the cliffs are smooth and
even and not broken by many small environments like cracks, cavities and
overhangs. Coincidence also plays an important roll. Certain summers with
for example, long periods of low water, certain otherwise prominent organisms,
die.
Here are a few examples of how
organisms can be distributed on cliffs and rocky beaches:
Those terrestials organisms that reach the furthest down are certain lichens
(e.g. wall
lichen and orange
lichen ), then there is a bare belt above Marine organisms, salt
lichen , green algae(e.g. sea-lettuce),
northern
rock barnacle, knotted,
bladder
and toothed
wrack . These three specie of seaweed house
a large variety of organisms. This is especially true of bladder and
toothed wrack from the late summer until the beginning of winter. There
are several thread-like algae that use seaweed as a substrate upon which
to live. Two examples are Ceramium
rubrum and Sphacelaria cirrosa,
as shown in the picture below. Many creatures gladly attach themselves to
seaweed, which is true of e.g. several specie of hydroids
and sea mats.
| Oakweed
with a growth of red and brown tufts. Ceramium
rubrum grows on several different algae, but even directly on
rocks and cliffs. To the contrary, it is almost only on oakweed
that the brown algae Sphacelaria cirrosa is found. The largest
tufts are about 5 cm across. |
 |
Page
4 of 52 |
 |
|
