184
Reef Zoo benthos
tentacles. When feeding, the worm peeps out from the hole and spreads the
fan of tentacles over the surface of the ground. Using the tentacles and the
threads of mucus which they excrete, the animal collects the settling detritus
and drives it to its mouth. With the aid of special "lips" this material is
sorted out and the food particles are swallowed. Among common reef
terebellids are: Terebella ehrenbergi, Liomia medusa, Streblosoma hesslei,
Hanchiella tribullata, Terebellides strommi, Eupolimnia nebulosa, and
Reteterebella queenslandia.
The capitellids build their tubes in soft bottom ground from sand particles
glued together with mucus. They collect from its surface the detritus and
microalgae. Among their common species are: Stychoproctus somalus,
Dasybranchues caducus, D. cadutus, and Pullicila armata.
The chaetopterids also live in tubes submerged in the sand or attached to
the walls of trenches in flat rocks or to boulders. They are filter-feeders.
Using their ciliated epithelium they pass water through the mucus nets
that are excreted by their parapodia (Barnes 1964). On reefs their usual
species are: Chaetopterus variopedutus, M esochaetopterus minutus, and
Phyllochaetopterus sp.
Other families of reef polychaetes are represented by the following
common genera: Cirri/ormia, Dodecaceria (fam. Cirratulidae), Phyllodoce,
Eulalia, Notophyllum, Pterocyrris (fam. Phyllodocidae), Armandia, and
Ophelia (family, Opheliidae).
Thus the polychaete worms occupy practically all the possible econiches
in reef biotopes. Among them we may find the sedentary filterers, the
wandering and settled detritovores and phytophages, the predators, the
commensals and parasites. They inhabit all possible kinds of bottom substrates: sand, rubble, caves and trenches in lime rocks sea grasses (Ansari
et al. 1991). They are also an important component of the cryptofauna,
inhabiting the dead colonies of corals. For example, in a large coral head on
one of the Great Barrier Reefs over 100 species of polychaetes have been
found (Grassle 1973). Their grazing impact on dead colonies of corals enhance the recruitment of boring organisms, thus accelerating the bioerosion
processes (Hutchings and Kiene 1989). Polychaetes are also an important
part of coral reef demersal and mezozooplankton (Sale et al. 1976a; see also
Sect. 3.3.2). Many small aldult polychaetes periodically rise at night up to
the water column. Some of their species swarm in water during their breeding
period. The dense swarms of polychaetes could be formed simultaneously
by several of their species (Hutchings and Howitt 1988). The trochophore
larvae of polychaetes are a usual element of reef plankton. Finally, there are
among them purely planktonic forms, like Tomopteriidae.
The quantification of polychaetes in solid reef rocks, where they are
among the main benthos components, is a difficult problem. To collect them
there it is necessary to cut out with the aid of chisel and hammer the rock
blocks. Then these blocks are soaked with formalin and crushed to wash out
the fauna (Kohn and Lloyd 1973; Hutchings 1974; Vittor and Johnson
Reef Zoo benthos
tentacles. When feeding, the worm peeps out from the hole and spreads the
fan of tentacles over the surface of the ground. Using the tentacles and the
threads of mucus which they excrete, the animal collects the settling detritus
and drives it to its mouth. With the aid of special "lips" this material is
sorted out and the food particles are swallowed. Among common reef
terebellids are: Terebella ehrenbergi, Liomia medusa, Streblosoma hesslei,
Hanchiella tribullata, Terebellides strommi, Eupolimnia nebulosa, and
Reteterebella queenslandia.
The capitellids build their tubes in soft bottom ground from sand particles
glued together with mucus. They collect from its surface the detritus and
microalgae. Among their common species are: Stychoproctus somalus,
Dasybranchues caducus, D. cadutus, and Pullicila armata.
The chaetopterids also live in tubes submerged in the sand or attached to
the walls of trenches in flat rocks or to boulders. They are filter-feeders.
Using their ciliated epithelium they pass water through the mucus nets
that are excreted by their parapodia (Barnes 1964). On reefs their usual
species are: Chaetopterus variopedutus, M esochaetopterus minutus, and
Phyllochaetopterus sp.
Other families of reef polychaetes are represented by the following
common genera: Cirri/ormia, Dodecaceria (fam. Cirratulidae), Phyllodoce,
Eulalia, Notophyllum, Pterocyrris (fam. Phyllodocidae), Armandia, and
Ophelia (family, Opheliidae).
Thus the polychaete worms occupy practically all the possible econiches
in reef biotopes. Among them we may find the sedentary filterers, the
wandering and settled detritovores and phytophages, the predators, the
commensals and parasites. They inhabit all possible kinds of bottom substrates: sand, rubble, caves and trenches in lime rocks sea grasses (Ansari
et al. 1991). They are also an important component of the cryptofauna,
inhabiting the dead colonies of corals. For example, in a large coral head on
one of the Great Barrier Reefs over 100 species of polychaetes have been
found (Grassle 1973). Their grazing impact on dead colonies of corals enhance the recruitment of boring organisms, thus accelerating the bioerosion
processes (Hutchings and Kiene 1989). Polychaetes are also an important
part of coral reef demersal and mezozooplankton (Sale et al. 1976a; see also
Sect. 3.3.2). Many small aldult polychaetes periodically rise at night up to
the water column. Some of their species swarm in water during their breeding
period. The dense swarms of polychaetes could be formed simultaneously
by several of their species (Hutchings and Howitt 1988). The trochophore
larvae of polychaetes are a usual element of reef plankton. Finally, there are
among them purely planktonic forms, like Tomopteriidae.
The quantification of polychaetes in solid reef rocks, where they are
among the main benthos components, is a difficult problem. To collect them
there it is necessary to cut out with the aid of chisel and hammer the rock
blocks. Then these blocks are soaked with formalin and crushed to wash out
the fauna (Kohn and Lloyd 1973; Hutchings 1974; Vittor and Johnson