5 Reef Zoo benthos
The bottom fauna of coral reefs is extremely rich and varied. It finds there
good trophic conditions, plenty of hiding places to escape grasing for vagi Ie
animals and a great abundance of solid substratum for sessile benthic
invertebrates (Paine 1974; Kohn and Levitien 1976; Reichelt 1982). A
sample of 2-3 kg of the rock material may contain over 100 species of
animals from several tens of families (Hutchings 1974). Main groups of reef
zoo benthos could be represented on a separate reef by hundreds of species:
50-150 species of forams, 150-500 species of molluscs, 100-250 species of
crustaceans, 50-100 species of echinoderms, 100-200 species of
polychaetes, and 50 and more species of sponges. This high species diversity
of benthic animals has its origin in their fine trophic and ecological
partitioning and specializations, and in a wide distribution among them of
commensalism, symbiosis, different morphological adaptations, chemical
and color information, and chemical defence. The macrobenthos is probably
one of the best-studied components of reef fauna from the chorological
aspect. The meio- and the microbenthos have been much less studied, which
is explained by the methodological obstacles of sampling in rocky substrata
of the reef (Hutchings 1974). The same is the cause of deficiency in the
quantifications of the biomass of reef benthos, and especially of its meyoand microcomponents. Much easier is apparently to sample quantitatively
benthos found in separate dead coral heads. They are covered by plankton
mesh and then separated from the base and crushed. This way of sampling
gave extremely high biomass values (Grassle 1973). The sampling is much
easier and quantitative in the soft-bottom biotopes. But even for these sites
the biomass of benthos had been mostly underestimated because of meyoand microbenthos missing in many of the benthos quantification studies.
Inexactness in biomass estimations was aggravated by the variation in units
of data presentation. Either the wet, the dry, the total or only the tissue
weight unit were used. Thus the available information on the reef benthic
biomass is still insufficient for its real evaluation.
5.1 Molluscs
Molluscs form one of the main groups of reef benthos as regards species
number and also the biomass. They represent all the sizes in the trophic
The bottom fauna of coral reefs is extremely rich and varied. It finds there
good trophic conditions, plenty of hiding places to escape grasing for vagi Ie
animals and a great abundance of solid substratum for sessile benthic
invertebrates (Paine 1974; Kohn and Levitien 1976; Reichelt 1982). A
sample of 2-3 kg of the rock material may contain over 100 species of
animals from several tens of families (Hutchings 1974). Main groups of reef
zoo benthos could be represented on a separate reef by hundreds of species:
50-150 species of forams, 150-500 species of molluscs, 100-250 species of
crustaceans, 50-100 species of echinoderms, 100-200 species of
polychaetes, and 50 and more species of sponges. This high species diversity
of benthic animals has its origin in their fine trophic and ecological
partitioning and specializations, and in a wide distribution among them of
commensalism, symbiosis, different morphological adaptations, chemical
and color information, and chemical defence. The macrobenthos is probably
one of the best-studied components of reef fauna from the chorological
aspect. The meio- and the microbenthos have been much less studied, which
is explained by the methodological obstacles of sampling in rocky substrata
of the reef (Hutchings 1974). The same is the cause of deficiency in the
quantifications of the biomass of reef benthos, and especially of its meyoand microcomponents. Much easier is apparently to sample quantitatively
benthos found in separate dead coral heads. They are covered by plankton
mesh and then separated from the base and crushed. This way of sampling
gave extremely high biomass values (Grassle 1973). The sampling is much
easier and quantitative in the soft-bottom biotopes. But even for these sites
the biomass of benthos had been mostly underestimated because of meyoand microbenthos missing in many of the benthos quantification studies.
Inexactness in biomass estimations was aggravated by the variation in units
of data presentation. Either the wet, the dry, the total or only the tissue
weight unit were used. Thus the available information on the reef benthic
biomass is still insufficient for its real evaluation.
5.1 Molluscs
Molluscs form one of the main groups of reef benthos as regards species
number and also the biomass. They represent all the sizes in the trophic