Marine benthic macroalgae of a small uninhabited South Pacific atoll (Rose Atoll, America Samoa)

Study Extent

Swains Island, American Samoa

Sampling

Rose Atoll was visited as part of the U.S. National Oceanic and Atmospheric Administration’s (NOAA) Pacific Islands Fisheries Science Center’s (PIFSC) Coral Reef Ecosystem Division’s (CRED) Pacific Reef Assessment and Monitoring Program (Pacific RAMP). Stations at Rose Atoll were identified using the first three letters of the island’s name, e.g., ROS-05P-04 signifies Rose Atoll (ROS), permanent station number (05P), and the year 2004 (04) when the specimens were collected. The designation “b” after a station number refers to a site visited only by the benthic team.

Method steps

1. Algal samples were hand collected by scuba divers following the protocol of Preskitt et al. (2004) where transects were mainly at depths of 12.2 to 18.3 m; and immediately frozen. Algae were collected at one shallow station (ROS-24-04) at 1.2 m deep and one deeper station (ROS-16-02) at 27.4 m. Prior to taxonomic examination, plastic bags of frozen algae from each station were thawed in tap water. Thawed seawater was poured carefully from the bag and replaced with 4% formalin in seawater to prevent the fragile turf algae and epiphytes from decomposing. The collections were examined using a dissecting microscope, and representative epiphytes and turf were separated. The small specimens were mounted on glass slides by decalcifying with 10% hydrochloric acid, staining with aniline blue, and mounting with 30% corn syrup (Karo) with phenol. Larger specimens were mounted on segments of herbarium paper. A maximum of five specimens served as vouchers for each species recorded here.

Rose Atoll, American Samoa