A selection of islands was chosen for the study, representative of the two main island forms: (i) atolls and limestone islands dependent on rainwater and groundwater – nauru, Majuro Atoll (in Republic of the Marshall islands) and Fongafale islet (Tuvalu); and (ii) volcanic islands with river systems – including Rarotonga (cook islands), Viti levu (Fiji), new Guinea (Papua new Guinea) and Upolu (Samoa).