Line Island Foraminifera – the ultimate stepping stone for the dispersal of species across the Pacific Ocean

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The Line Islands form a chain of 11 atolls in the central Pacific Ocean and are among the most isolated islands in the world. They occupy a key position for the biogeographical distribution of tropical reef organisms, and function as the ultimate stepping stones for the dispersal of species throughout the tropical Pacific. However, their key role as dispersal sites for reef organisms is countered by the limited dispersal capabilities of individual species, which are limited by temperature gradients, nutrient conditions, and current patterns. Based on previous studies of large and small benthic foraminifera in the Pacific, this follow-up proposal will determine the entire inventory of the benthic foraminiferal fauna and document it in a fully illustrated monograph. The documented species diversity can thus be compared with existing foraminifera databases of the Pacific. Through this comparison, it will be possible to determine i.) the degree of endemism, ii.) the dispersal ability of individual species, iii.) the key role of the Line Island for biogeography, and iv.) the factors regulating the distribution of taxa across the Pacific. Based on our previous studies of the benthic foraminifera of Kiritimati, Kingman, and Palmyra, three additional Line Islands will be studied for complete data collection. They include: Tabuaeran/Fanning, Teraina, and Jarvis Island. All species collected will be documented by SEM and identified to species level. Apart from a single publication on foraminifera from Kirimati, where only 29 species were recorded, nothing is known about foraminifera from the Line Island. To date, we have documented and illustrated over 100 species from the islands of Kiritimati, Kingman, and Palmyra, thus quadrupling the number of all species described from there. With additional analysis of foraminifera from Tabuaeran/Fanning Islands, Teraina Island and Jarvis Island, this number is likely to increase substantially. All species recorded will be documented with scanning electron microscopy and their distribution will be quantified over depth gradients. To continue our investigation on the effects of anthropogenic activities on faunal diversity, habitat distribution, and composition, comparative studies of benthic foraminifera from uninhabited (Kingman, Jarvis, and Palmyra) and inhabited islands (Tabuaeran, Teraina, Kiritimati) will be conducted.