Abstract

Marine phytoplankton are responsible for removing much of the CO2 that we pump into the atmosphere and for producing much of the oxygen that we breath. Particular groups such as the calcifying coccolithophores and silicifying diatoms represent the major biomineralizing organisms on Earth. Our work addresses some of the fundamental membrane properties of phytoplankton with implications for understanding cell-environment interactions, cellular regulation, biomineralization and evolution of ion channels.

While the phytoplankton are photosynthetic, exploration of their membrane properties has revealed a number of features that are more similar to animals, including animal-like electrical excitability in the form of sodium- and calcium-based action potentials. Parallel molecular studies are revealing a number of new and surprising ion channel types, some of which are novel for eukaryotes and which are likely to underlie electrical excitability and cellular signalling. The talk will address some of the wider physiological, ecological and evolutionary implications of these findings and will speculate on why land plants lost some of these “ancient” ion channel types that remain widespread amongst the eukaryotes.