Rhodolith occurrences in the Azores (central north Atlantic) between 1998 and 2018

Rhodoliths is a general term used to designate non-geniculate coralline red algae (Rhodophyta) that live unattached (Riosmena-Rodríguez, 2017). The term is used here to encompass (i) branched free-living coralline algae devoid of an evident nucleus, but also (ii) nucleated nodules where the biogenic calcium carbonate deposit around the core represents >50%, as well as (iii) “coated grains” where the core is larger than the algal carbonate component.