Skeletal development in Acropora cervicornis: II Diel patterns of calcium carbonate accretion

Gladfelter, Elizabeth

Monthly linear extension and calcium carbonate accretion were measured over a year in a population of the Caribbean staghorn coral, Acropora cervicornis, growing at a depth of 8 m on the bank adjacent to the south eastern forereef of Buck Island. Monthly skeletal growth parameters were made on tips stained with Alizarin-red S and allowed to grow for 30 days. X-radiographs of cross sections of branches were used to measure radial growth. Correlations were made between parameters of skeletal growth and four environmental parameters : temperature, daylight hours, sun hours and plankton abundance. The results indicate that rates of linear extension did not change during the year (with the possible exception of April). It is suggested that temperatures outside an optimal range (ca. 260-290 C) may cause a decline in linear extension, however. Specific accretion (mg.mm-1) does show significant variation through the year. Calcium carbonate accretion (mean specific accretion times linear extension, mg.tip-1) is most strongly correlated with sun hours. A comparison is made between diel patterns of extension and accretion and longer term measurements. It is suggested that the accretion process is most strongly influenced by some activity influenced by light. there are no annual growth bands in X-radiographs of cross-sections of branches of A. cervicornis. This may be a result of secondary infiling of the skeleton.

Skeletal development in Acropora cervicornis: II Diel patterns of calcium carbonate accretion

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