|Foraminiferal bio- and thanatogoenoses of reef flats, Lizard Island, Great Barrier Reef, Australia: nature of substrate|
Baccaert, J. (1986). Foraminiferal bio- and thanatogoenoses of reef flats, Lizard Island, Great Barrier Reef, Australia: nature of substrate
. Ann. Soc. R. Zool. Bel. 116(1): 3-14
In: Annales de la Société Royale Zoologique de Belgique = Annalen van de Koninklijke Belgische Vereniging voor Dierkunde. Société Royale Zoologique de Belgique: Bruxelles. ISSN 0771-5528
ISEW, Great Barrier Reef, Lizard I. [Marine Regions]
Reef flats; Algal substrates
The foraminiferal communities on three reef flats of the reef complex of Lizard Island are studied by the author. The Lizard archipelago is situated in the Northern Province of the Australian Great Barrier Reef and consists of granitic islands (Lizard, Palfrey and South) linked by a reef complex. The reef flats of the « Windward » and « Southern » barriers belong to a reef « barrier » system linking respectively Lizard and South, and South and Palfrey islands. Both reef flats show comparable physiographic zonation though upon the southern flat only impoverished coral growth occurs. The third reef flat belongs to the fringing reef system along the East coast of Lizard Island and again shows the same zonation except for the backreef area where the microatoll zone rises up towards a sandy-gravelly beach. The thanatocoenoses of Foraminifera found in the sand pockets, drain channels and beach accurately reflect the biocoenoses of Foraminifera living mainly upon and in a well-developed algal cover which covers large areas of the three reef flats except the algal pavement (forereef) where algal growth is reduced to the crustose coralline lithothamnioid Rhodophyta. Only smaller empty tests and finer sediment particles are transported in a leeward direction. Highest foraminiferal abundances are reached (bio- as well as thanatocoenoses) by the Soritidae, Amphisteginidae, Calcarinidae and Elphidiidae. The distribution of the foraminiferal communities is closely related to the distribution of the algal cover which is shown to form an ideal protecting habitat for larger as well as smaller Foraminifera. The algal composition of this cover is slightly variable but Chlorophyta, and, in particular, smaller non-encrusting Rhodophyta dominate. The foraminiferal distribution is only secondarily influenced by the biological composition and species diversity of the algal cover; the physical properties (size, shape, flexibility and surface texture of the thalli) play the primary role in this respect. Palaeoecological applications of this algal-foraminiferal interdependence are possible but should be treated with caution.