Symbiotic algae in milioline foraminifera: CO2 uptake and shell adaptations

Abstract

Experiments with living Amphisorus hemprichii demonstrated algal symbiont uptake of 14CO2 directly through the thin lateral test walls of this imperforate, porcellaneous species. An identical uptake mechanism is suggested for Sorites and Marginopora because of their similar thin lateral walls. Peneroplis, Spirolina, Cyclorbiculina, and Triloculina rupertiana show structural adaptations towards thin test walls by development of furrows and pits. These features may also enhance CO2 diffusion through the test walls for use by their symbiotic algae.