Studies from a submersible on a seamount off San Salvador (Bahamas) revealed a diverse multilayered macrophyte community, with net productivity levels comparable to shallow water seaweeds although receiving only 1–2% of the light energy available at the surface. Four zonal assemblages occur over the depth range from 81 to 268 m and consist of a Labophora-dominated group (81–90 m), a Halimeda assemblage (90–130 m), a Peyssonnelia group (130–189 m), and a crustose coralline zone (189–268 m). This deep flora is composed of unique deep-water taxa combined with shallow water forms characteristics of shaded, low-light conditions.