[B-PT03] Biomineralization, Geochemistry, and Environmental Studies

[BPT03-10] Chemical sensing in living benthic foraminifera during the feeding process

*Laurie M. Charrieau¹, Christina C. Roggatz², Jan Tebben³, Michal Kucera², Yukiko Nagai⁴, Takashi Toyofuku⁴ (1.MARUM, Bremen, 2.Bremen University, 3.Alfred Wegener Institute (AWI), 4.Japan Agency for Marine-Earth Science and Technology (JAMSTEC))

Keywords:Benthic foraminifera, Chemical sensing, Culture experiments

Benthic foraminifera, which are among the most diverse and abundant micro-organisms inhabiting past and modern seafloors, can build a shell that has great preservation potential in the sediment. As environmental conditions are reflected in their faunal composition, foraminifera have been widely used for past and present climate reconstructions. To improve the reliability of these reconstructions, it is necessary to understand all the mechanisms behind their population dynamics. Particularly, the feeding process has implications for the reproductive success and therefore population densities of foraminifera.
The aim of this work is to elucidate the mechanism of a chemical sensing during the foraging (food searching) and feeding in benthic foraminifera.
During behaviour experiments, living microalgae were presented as food in the vicinity of inactive foraminifera individuals. They repeatedly and rapidly responded by extending pseudopodia and/or by initiating active movement towards the food, compared to control test adding only seawater. Because of the observed temporal correlation in the absence of physical contact, we assume that the activity of the foraminifera is triggered by a chemical stimulus. The existence of such chemical sensing would have significant consequences for our understanding of the ecology of foraminifera and their role as carriers of proxies of past environmental conditions.