The offshore Foraminifera of the Togean Islands, Tomini Gulf; distribution and ecological significance

Abstract

The hydrological complexity, the gulf shape, and the undeveloped geological setting of the Togean Islands in the middle of the waters assembled the area to be such an interesting place to discover its ecological uniqueness. Foraminifera was widely used as proxies for various ecological aspects. Real time and retrospective studies of the vertical and horizontal distribution of foraminiferal communities on such waters are the reflection of many ecological factors in the area. The purpose of the Foraminiferal research on the offshore Togean Islands is to discover the ecological roles that directly and indirectly affect the characteristics of the vertical and horizontal distribution. The study was also referring various ecological aspects from previous studies at the research site. Sampling was carried out in September 2015 using the Baruna Jaya VIII RV in the Togean Islands waters, Tomini Gulf, through a gravity core. Foraminifera analysis was carried out at four core samples from the adjacent waters of four reef islands; Una-una, Pengempang, Togean, and Kalla at 5 m to 455 m water depths. Core samples of various lengths, from 8 cm to 34 cm were dominated by planktonic foraminifera. The dominance of planktonic taxa in reef waters indicates a robust oceanic influence to the reef islands. Upwelling events in several locations in the region as well as volcanic processes that are ongoing also play a role in the distribution of the bulk of planktonic taxa in the reef waters of Togean Islands.