Bioerosion in ancient and contemporary corals of the genus Porites: patterns and palaeoenvironmental implications

: Fossil and modern colonies of Pontes corals were collected from recent and ancient reefs in different localities along the Gulf of Eilat, Red Sea. Coral slabs were examined qualitatively and quantitatively for traces of bioeroding organisms. Burrows found in the fossil corals were remarkably preserved, enabling comparison with modern burrows. The most important borers were worms (sipunculids and polychaetes; 35 to 47%), while sponges showed relatively low bioerosion activity (10 to 32 %). Total bioeroded area in the slabs was similar for both recent and fossil Pontes (ca 3 %). However, the number of eroding individuals was significantly higher in fossil corals (p < 0.05). It is suggested that a higher number of eroding individuals in fossil corals may indicate elevated levels of primary productivity in the Red Sea during periods of the late QWuaternary.