A Molecular-Informed Species Inventory of the Order Ceramiales (Rhodophyta) in the Narragansett Bay Area (Rhode Island and Massachusetts), USA

Narragansett Bay is an estuarine system in the western North Atlantic Ocean that harbors a diverse marine flora, providing structure, habitat, and food for native biodiversity. This area has been the center of numerous environmental, biological, ecological, and oceanographic studies; however, marine macroalgae have not been extensively examined using modern molecular methods. Here, we document the biodiversity of the red algal order Ceramiales based on DNA sequence comparisons of the 3′ end of the RuBisCo large subunit (rbcL-3P) and the universal plastid amplicon (UPA). Thirty-seven distinct species of this order were identified and validated with molecular data, including five new species reports and at least one new report of an introduced species, Antithamnionella spirographidis, in the vicinity of Narraganset Bay. Novel sequence data were generated for numerous species, and it was discovered that the UPA marker, which has been less frequently used in red algal floristics, revealed an identical inventory of ceramialean algae as the rbcL-3P marker. Thus, the shorter length of the UPA marker holds promise for DNA metabarcoding studies that seek to elucidate biodiversity across algal phyla.