Meeting Abstract

P3.8  Jan. 6  Localization and metabolism of calcium in developing scleractinian coral ROGERS-LOWERY, CL*; SZMANT, AM; Catawba College, Salisbury, NC; University of North Carolina Wilmington clowery@catawba.edu

The calicoblastic epithelium of scleractinian coral secretes the calcium carbonate skeleton that forms massive reefs. This process involves the use of channels and pumps to translocate calcium, bicarbonate, and other components from the seawater to the calcification space between the calicoblast and skeleton. While calcification in adult corals has received much attention, development of the early skeleton requires additional attention. In the current study, we utilize larvae and newly-settled polyps from several Caribbean coral (Acropora palmata and Montastraea faveolata) loaded with Calcium Orange to examine calcium localization as the organisms transitions from a motile, non-calcifying planula larva to a sessile, calcifying adult polyp. In the planulae, calcium is primarily localized in the apical portions of ectodermal cells, the amount of which is influenced by concentrations of calcium in the seawater and modulators of calcium-transport proteins. This pattern of calcium localization persists after settlement. As polyp structures begin to form, the distribution of calcium becomes more localized in spirocysts and early calicoblast cells. Additionally, calcium is more basally distributed. In Acropora, sclerasepta and skeleton begin to form rapidly after settlement and calicoblast cells in the region of these structures are evident by their calcium fluorescence. In contrast, spat of Montastraea do not calcify as quickly and require attachment to substrate to begin secreting skeleton. A greater understanding of the mechanisms of calcification during the development of these threatened organisms may provide valuable insight for rearing larval coral to restore reefs.