Geology Reference
In-Depth Information
Table 5.
Summary of the standing stock values of epiphytes along the South Australian
coastline. Values are averaged site values.
N
= number of sites where species found,
sg = seagrass.
Carbonate
Mean
Std error
N
Minimum
Maximum
CaCO
3
g m
2
Total
94.7
21.8
23
10.3
364.6
A. antarctica
Whole
106.5
32.7
10
2.6
324.7
Blade
39.8
8.4
5
18.9
61.1
Stem
88.5
22.5
5
46.5
174.5
A. griffi thii
Whole
184.8
88.0
3
95
360.8
Blade
19.15
2.1
2
17.1
21.2
Stem
100.1
7
2
93.1
107.1
Amphibolis
sp.
218.0
100.4
10
3.1
1061.9
P. angustifolia
19.6
5.5
8
9
56.3
P. australis
30.4
5.2
9
10.3
63
P. sinuosa
42.8
9.9
12
3.1
128.7
Posidonia
sp.
32.1
5.8
23
3.1
128.7
Other
37.7
10.2
10
4.2
113.1
CaCO
3
g kg
1
sg
1
Total
165.2
18.4
23
27.82
373.5
A. antarctica
Whole
224.5
32.8
10
65.8
378.1
Blade
135
15.9
5
97.8
185.2
Stem
315.1
48.9
5
189.9
442.5
A. griffi thii
Whole
344.9
14.6
3
315.8
362.1
Blade
92.8
3.9
2
88.9
96.6
Stem
459.6
19.5
2
440.1
479
Amphibolis
sp.
458.9
132.6
10
132.9
1148.5
P. angustifolia
126.2
27.3
8
69.2
311.1
P. australis
115.3
27.1
9
27.8
314
P. sinuosa
138.4
19.4
12
42.8
255.1
Posidonia
sp.
129.5
15.8
23
27.8
314
The high relative proportion of corallines
agrees with other studies worldwide (Land,
1970 - Discovery Bay; Patriquin, 1972 -
Barbados, Jamaica; Boscence, 1989 - Florida Bay;
Frankovitch & Zieman, 1994 - Florida Bay; Lord,
1998 - Success Bank Western Australia; Perry &
Beavington-Penney, 2005 - Mozambique). Non-
geniculate (encrusting) types are more abundant
than geniculate (articulated) types (e.g. Patriquin
(1972) found that
Melanesia
formed the bulk of
the calcareous material on
Thalassia
blades). In
this study of
Amphibolis
there is a preference
of encrusting types on blades and erect types
on stems.
Carruthers (1994) and Hillman
et al
. (1994)
found coralline values of 80% and 88% respect-
ively, and that
Amphibolis
blades have signifi c-
antly greater abundance of calcareous epiphytes
than do
Posidonia
blades (Lavery
et al
., 2000)
(although other studies have found more on
Posidonia
blades - Walker & Woelkerling, 1988;
Sim, 1991). This is because of the morphological
structure of
Amphibolis
blades and their proximity
to conspecifi c adults. The greater abundance on
stems is because of greater longevity.
In spite of their importance, the corallines are
not species rich, with only eight genera compared
with 44 bryozoan genera and 18 foraminifera
genera. Sim (1991) identifi ed articulated coral-
lines as the dominant type of epiphyte in Western
Australia, similar to the fi ndings of this study,
especially for
Amphibolis
plants. Bryozoans are
similar to other studies (Hayward, 1974). Overall
corallines do not show a preference for grass, i.e.
they will attach to other substrates.
Dominance of corallines has implications for
sediment production; non-geniculate forms are
subject to abrasion while living. Even before the
plant dies it sheds blades and pieces may be bro-
ken off. Geniculate corallines are made up of cal-
careous rods linked by non-calcareous segments,
and so the alga produces numerous stick-like
sand-size grains. Thus, non-geniculates produce
mud; geniculates produce sand. The mineralogy
of such sediment is Mg calcite. Whereas coral-
lines compete successfully for space, bryozoans
