Phytoplankton growth is limited in vast oceanic regions by the low bioavailability
of iron. Iron fertilization often results in diatom blooms, yet the physiological
underpinnings for how diatomssurvive in chronically iron-limited waters and
outcompete other phytoplankton when iron becomes available are unresolved. I will
present work that demonstrates how some diatoms can use siderophore-bound iron, and exhibit a species-specific recognition for siderophore types. We are in the process
of uncovering the molecular mechanisms for siderophore uptake into the cells, and
tracking its delivery to the chloroplasts (which we know to be their ultimate
destination). Since no diatoms are known to synthesise siderophores, we are
investigating the role of these molecules in forging community interactions between
diatoms and siderophore-producing bacteria”.
