Willenz, P.; Hartman, W.D. (1985). Calcification rate of Ceratoporella nicholsoni (Porifera: Sclerospongiae): an in situ study with calcein. Pp. 113-118. In: Delesalle, B., Galzin, R. & Salvat, B.(Eds), Proceedings of the Fifth Coral Reef Congress, Tahiti. 5. (Antenne Museum-EPHE: Moorea, French Polynesia).

8590

Willenz, P.; Hartman, W.D.

1985

Publication

Available for editors   [request]

The calcareous skeletons of sclerosponges play a secondary but not insignificant role as framework builders on modern coral reefs. They contribute to and strengthen the walls of caves, tunnels and crevices in reefs, are important as framework constructors on the Jamaican deep fore-reef and fill the interstices of the reef even at relatively shallow depths. These facts have led us to investigate the growth rate of the skeleton of sclerosponges. In the work reported here, calcein, a fluorochrome stain taken up by calcif ying tissues, has been employed to mark newly deposited aragonite in the skeleton of Ceratoporella nicholsoni (Hickson). Experiments were performed in situ in a reef tunnel at a depth of 28 m off Pear Tree Bottom, Jamaica. A plastic bag containing a solution of the dye in sea wate r was tied around e ach specimen and removed 24 hours later. Identical treatments were repeated on the same specimens after times ranging from one week to six months. Ground sections perpendicular to the surface of harvested samples of the dried skeleton were examined and photographed by fluorescence microscopy. The distance measured between successive fluorescent lines revealed a growth rate of less th an 0.2 mm per year. Growth lines apparent to the naked eye in sections of C. nicholsoni do not represent annual accretions of aragonite. It is suggested that caution is needed in the interpretation of growth lines in ancient sponges with massive calcareous skeletons.

Caribbean region

Porifera

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