Recent foraminifera from inter-reef channels, nearshore North Rarotonga, Cook Islands, South Pacific

Abstract

Abstract. The Avatiu and Avarua sand-covered channels within the fringing reef of north Rarotonga, Cook Islands, contain foraminiferal assemblages considered to be predominantly derived from the adjacent reef platform. Benthonic species which display a depth restriction include Melonis affinis, Cassidulina delicata, Clavulina pacifica and Bolivina alata. Small (less than 200 μm), rare planktonic species, including Globigerina bulloides, are recovered from sediments as shallow as 8 m, but an increase in species diversity and abundance is noted at 30 m in Avarua channel and 48 m in Avatiu channel.No clear depth, substrate nor symbiont-associated restriction of species is evident, and this may result from mixing of primary microfaunal assemblages by sediment transport in this exposed part of the island.