Sponges
179
to 120 m depth) enlists about 400 species, and reefs off Madagascar 150
species (Vacelet and Vasseur 1977). The shallow biotopes are dominated by
demosponges, and to a lesser degree by calcareous ones, while the deeper
shadowed zones of the outer reef slopes, caves and tunnels mainly by
sclerosponge species (Hartman and Goreau 1970). Among the common
sponges which occupy the shallow and middle-depth biotopes of the IndoPacific reefs there could be named Tethya, Plectronia, Mycale, Timea,
Spirastrella, Ulosa, Higginsia, Pericharax, laspis, Mycale, Neofibularis,
A sterop us , Haliclonia, lantella, Phyllospongia, Dysidea, Ircinia, Carterospongia, Pseudoaxinissa, Scleroderma, Carmina, Reineria, Callyspongia,
Cacospongia, Dictyonella, Prianos, Cliona, Psamaplysilla. In deeper zones
of the outer reef slopes and in the shadowed biotopes the sponge genera
Spirorhabda, A canthotriaena , Scleritoderma, Astrosclera, Leucetta, Murrayona are most common. At the Western Atlantic reefs in shallow and
middle-depth zones the species in mass are Tethya, Chondrilla, Haliclona,
Gelloides, Iotrochota, Grantella, Cliona, Verongia. Deeper, the sponges
Amphimedon, Ulosa, Ectypoplasia, Calyspongia, Niphates, Xestospongia,
Chondrilla, Anthosigmella become more common. In the fore-reef zone at
the base of the outer reef slope the sclerosponges Ceratoporella, Stromatospongia, Hispidoptera and the calcareous sponge Leucetta are usual (Lang
et al. 1975). Within the colonies of the living and dead corals as well as in
the trenches and holes of calcareous reef-flat rocks, under the boulders the
incrusting species of sponges Erylis, Paratetilla, Tethya, Timea, Spirastrella,
Ulosa, Higginsia are most numerous. The sponges fauna of the Atlantic
reefs include much less symbiotic species compared with the Pacific reefs
(Wilkinson 1989).
On the reef-flat and on upper zones of the reef slope the spongal fauna
consists mostly of phototrophic and boring species, which have small flat
colonies, or of those incrusting trenched undersides of boulders and stones
or covering the coral rubble. In deeper parts of the lagoons many sponges
dig part of their body into the sediment or attach it to pieces of solid
substratum. But the most abundant and various sponge communities inhabit
the middle depths of the outer slope and especially the buttress zone and the
upper part of the fore-reef, which are the areas of intensive water drive so
important for the filtration activity of sponges (Wilkinson and Cheshire
1989; Wilkinson 1989). The biomass of sponges in shallow areas ranges
usually within 10 to 150 g m -2, and at depths of 20-40 m of outer slopes
within 100 to 500gm- 2 . But on the reef-flat areas covered with rubble it
could be also as high as 1.2kgm- 2 (de Laubenfels 1950; Hartman and
Goreau 1970; Reiswig 1973; Hartman 1977; Vacelet and Vasseur 1977; Bak
and Luckhurst 1980; Suchanek 1983; Wilkinson and Trott 1985).
Having relatively high growth rates, sponges often overgrow corals and
other colonial sessile fauna and thus successfully compete with these,
especially because some sponges excrete toxins, which inhibit neighboring
corals and even kill them. Many sponge species contain antibiotical
179
to 120 m depth) enlists about 400 species, and reefs off Madagascar 150
species (Vacelet and Vasseur 1977). The shallow biotopes are dominated by
demosponges, and to a lesser degree by calcareous ones, while the deeper
shadowed zones of the outer reef slopes, caves and tunnels mainly by
sclerosponge species (Hartman and Goreau 1970). Among the common
sponges which occupy the shallow and middle-depth biotopes of the IndoPacific reefs there could be named Tethya, Plectronia, Mycale, Timea,
Spirastrella, Ulosa, Higginsia, Pericharax, laspis, Mycale, Neofibularis,
A sterop us , Haliclonia, lantella, Phyllospongia, Dysidea, Ircinia, Carterospongia, Pseudoaxinissa, Scleroderma, Carmina, Reineria, Callyspongia,
Cacospongia, Dictyonella, Prianos, Cliona, Psamaplysilla. In deeper zones
of the outer reef slopes and in the shadowed biotopes the sponge genera
Spirorhabda, A canthotriaena , Scleritoderma, Astrosclera, Leucetta, Murrayona are most common. At the Western Atlantic reefs in shallow and
middle-depth zones the species in mass are Tethya, Chondrilla, Haliclona,
Gelloides, Iotrochota, Grantella, Cliona, Verongia. Deeper, the sponges
Amphimedon, Ulosa, Ectypoplasia, Calyspongia, Niphates, Xestospongia,
Chondrilla, Anthosigmella become more common. In the fore-reef zone at
the base of the outer reef slope the sclerosponges Ceratoporella, Stromatospongia, Hispidoptera and the calcareous sponge Leucetta are usual (Lang
et al. 1975). Within the colonies of the living and dead corals as well as in
the trenches and holes of calcareous reef-flat rocks, under the boulders the
incrusting species of sponges Erylis, Paratetilla, Tethya, Timea, Spirastrella,
Ulosa, Higginsia are most numerous. The sponges fauna of the Atlantic
reefs include much less symbiotic species compared with the Pacific reefs
(Wilkinson 1989).
On the reef-flat and on upper zones of the reef slope the spongal fauna
consists mostly of phototrophic and boring species, which have small flat
colonies, or of those incrusting trenched undersides of boulders and stones
or covering the coral rubble. In deeper parts of the lagoons many sponges
dig part of their body into the sediment or attach it to pieces of solid
substratum. But the most abundant and various sponge communities inhabit
the middle depths of the outer slope and especially the buttress zone and the
upper part of the fore-reef, which are the areas of intensive water drive so
important for the filtration activity of sponges (Wilkinson and Cheshire
1989; Wilkinson 1989). The biomass of sponges in shallow areas ranges
usually within 10 to 150 g m -2, and at depths of 20-40 m of outer slopes
within 100 to 500gm- 2 . But on the reef-flat areas covered with rubble it
could be also as high as 1.2kgm- 2 (de Laubenfels 1950; Hartman and
Goreau 1970; Reiswig 1973; Hartman 1977; Vacelet and Vasseur 1977; Bak
and Luckhurst 1980; Suchanek 1983; Wilkinson and Trott 1985).
Having relatively high growth rates, sponges often overgrow corals and
other colonial sessile fauna and thus successfully compete with these,
especially because some sponges excrete toxins, which inhibit neighboring
corals and even kill them. Many sponge species contain antibiotical