The mesophotic, coral reef-associated, marine algal flora of Puerto Rico, Caribbean Sea

Deep-water open-circuit SCUBA, dredging, submersible and technical mixed gas (closed-circuit) rebreather diving collections of marine benthic algae made over the last approximately 30 years in Puerto Rico are summarized in this account. In total 181 taxa (160 identified to species) (comprising 61% Rhodophyta. 12% Phaeophyceae and 27% Chlorophyta) are reported from depths greater than 35 m. Ninety-four of these, (59% of taxa identified to species) from the Puerto Rican mesophotic are thought to be the deepest known distributional records for the species recognized. Forty-three species (or 8% of the entire benthic flora of Puerto Rico) are mostly or entirely restricted to depths greater than 35 m.