The margins of carbonate platforms can be steep, and even form vertical walls. This contribution from Ginsburg et al. uses submersible observations of geomorphology, biota, and sediment (illustrated by striking hand-drawn figures) of one of the steepest margins, in Tongue of The Ocean (TOTO), a deep-water embayment in the Bahamas, to explore the growth potential of such margins. The results revealed a “luxurious reef-building community” including corals, sponges, and Halimeda present even on near-vertical walls; these organisms were interpreted to “produce slow but significant outward accretion of the wall.” And so it turns out that beyond just being another brick in the wall, organisms are important in building these features.
The growth potential of a bypass margin, Great Bahama Bank by R.N. Ginsburg, P.M. Harris, G. Eberli, and Peter K. Swart