Along the northwestern margin of Safaga Island (Northern Bay of Safaga
, Red Sea, Egypt) a small fringing reef (several hundred meters long,
up to 2m high) and small patch reefs are developed due to the local cu
rrent regime which is favorable for coral growth. Corals and reef rock
are encrusted by coralline algae, predominantly by branched Lithophyl
lum kotschyanum. Owing to destructional processes dominated by sea urc
hin activities, fragmentation of (1) corals, (2) reef rock, and (3) co
ralline algae takes place resulting in the formation of almost monospe
cific, branched Lithophyllum kotschyanum rhodoliths. Rhodolith formati
on takes place in various reef environments: (1) in depressions on the
reef flat where ellipsoidal rhodoliths develop, with interlocking and
fusing branches leading to a coralline algal framework; (2) in discha
rge channels where smaller elongated rhodoliths occur; (3) in leeward
positions between reef flat and seagrass meadows, where a dense belt o
f spheroidal to ellipsoidal rhodoliths is formed; scattered rhodoliths
occur in adjacent seagrass beds. The formation and preservation of rh
odoliths requires a complex interplay of destruction, growth, transpor
tation, movement, and stabilization.