Marine algae of Pohnpei and Ant Atoll with comparisons to other Pacific Atolls and island groups

A study of benthic marine algae collected from Pohnpei Island and Ant Atoll, Federated States of Micronesia, documented the occurrence of 113 species of red algae (Rhodophyta), 60 species of green algae (Chlorophyta) and 17 species of brown algae (Phaeophyta), many of which are new records for Pohnpei, Ant Atoll and Micronesia. Added to reports from the literature, a total known marine benthic flora of Ant and Pohnpei (exclusive of Cyanobacteria and crustose coralline algae) now stands at 241. The high island, volcanic nature, and larger size of Pohnpei which is very different from the low, calcareous geomorphology of smaller Ant Atoll, led us to expect higher species numbers from Pohnpei relative to Ant, and greater differences in their algal floras than we found. Comparisons of the Ant-Pohnpei algal flora were also made using Jaccard and Sorensen's indices to Ifaluk Atoll (Caroline Islands), Enewetak Atoll (Marshall Islands), the Northern Mariana Islands, and the distant south Pacific island groups of Fiji and French Polynesia. Biogeographical investigation of the marine algae flora revealed that Ant Atoll and Pohnpei have a large number of widespread and Indo-Pacific species, but very few probable regional endemics.