. Bonner zoologische Monographien. Zoology. 103 appearance of a le\ elled heap of rubble. These areas are not recolonized by corals for at least eight \ ears. The steady grazing pressure of fish and sea-urchins may be the reason. In the experiment conducted near Aqaba. where grazing sea-urchins were excluded, steady grazing by acanthurids (doctor-fishes) and chaetodontids (butterfl\'-fishes). previously not suspected of bioerosion. not only resulted in bare surfaces but in a loss of 2 to 3 mm per year from the limestone substrate (Van Treeck et al 1996). Calcareous algae and other encrusting o
. Bonner zoologische Monographien. Zoology. 103 appearance of a le\ elled heap of rubble. These areas are not recolonized by corals for at least eight \ ears. The steady grazing pressure of fish and sea-urchins may be the reason. In the experiment conducted near Aqaba. where grazing sea-urchins were excluded, steady grazing by acanthurids (doctor-fishes) and chaetodontids (butterfl\'-fishes). previously not suspected of bioerosion. not only resulted in bare surfaces but in a loss of 2 to 3 mm per year from the limestone substrate (Van Treeck et al 1996). Calcareous algae and other encrusting organisms may con- solidate areas of rubble over the years, but only very rarely does this lead to the formation of three-dimensional limestone structure with the small-scale irradiance, current and sedimentation gradients required for colonization by corals. The damaged surfaces largely remain inhospitable and empty. In this situation the process of nucleation (see abo\ e) is initiated artificially. The installation of artificial reef modules represents a possibility of accelerating coral recruitment and facilitating the restoration of an extensive, irregular reef surface. Since 1998, Peter van Treeck, Markus Paster and Michael Eisinger, members of my department, have constructed mini-reefs in the Ras Mohammed National Park (Sinai peninsula. Egypt) on the basis of experience gained from experiments in the Mediterranean off the coast of Corsica (Meyer & Schuhmacher 1993, Schuhmacher & Schillak 1994, Schuhmacher 1996) and on the reef near Aqaba (Jordan) (Van Treeck & Schuhmacher 1997, Eisinger et al. 1998). On the basis of pioneering experiments made by Hilbertz ( Hilbertz et al. 1977), calcium carbonate can be deposited on a cathode of any shape by electrolysis. We use steel wire mesh which can be bent and folded to a shape offering comers and niches suitable for settlement by benthic organisms following encrustation \\ ith. Fig. 16. Natural (left) and artificial
Size: 2290px × 1091px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjectzoology
