Biyoloji koray

Corals are living organisms in the phylum Cnidaria. There are two main types of corals: soft corals and stony corals (also called ‘hard’ corals). Stony corals of the order Scleractinia are the corals primarily responsible for reef formation through the production and secretion of calcium carbonate (CaCO₃). Most reef-building corals have a symbiotic relationship with photosynthetic dinoflagellate algae called zooxanthellae (or Symbiodiniaceae, previously referred to as Symbiodinium). The relationship is considered mutualistic, where the coral provides a protected environment, carbon dioxide (CO₂) ak eleman nitritif (nitwojèn ak fosfò) nan alg la, epi alg la an vire bay oksijèn (O₂) ak kabòn nan koray la atravè fotosentèz. Pandan ke polip koray ka manje sou plankton, yo jwenn apeprè 95% nan kondisyon nitrisyonèl yo nan senbyotik ak zooxanthellae yo.

Coral colonies are considered modular organisms because they consist of repeated morphological units, or polyps. The way these polyps are arranged dictates the different coral colony growth forms, or morphologies. Common descriptive terms include branching, columnar, massive, foliose, laminar, encrusting, and free-living (Veron 2000). ref

Anpil polip klonal sou yon branch Porites koloni nan Ostrali. Foto © Margaux Hein

Corals can reproduce through asexual and sexual reproduction. Asexual reproduction occurs through budding, where a coral polyp divides into clones forming two polyps, and fragmentation, where pieces of coral colonies break or detach and then resettle in a new location on the reef under suitable conditions. New and genetically unique coral colonies are formed through sexual reproduction. There are two modes of sexual reproduction: broadcast spawning (in which coral colonies release sperm and eggs in the water) and brooding (in which fertilization occurs internally).