Combining ‘OMIC tools and other targeted molecular methods to evaluate iron limitation of diatoms in the Northeast Pacific Ocean.

Diatoms are an abundant and widespread group of phytoplankton capable of exerting a profound influence on global carbon cycling. It is widely accepted that iron (Fe) controls diatom production in many ocean systems and the Fe stress response has been a focus of research for some time. Assessing the Fe status of natural diatom populations has proven challenging, as diatom species in the same genus may be difficult to distinguish using microscopy and the physiological and molecular responses to Fe stress can vary widely within a genus. A targeted high-throughput sequencing method to characterize the diatom community in field samples has been developed. Additionally, comparative transcriptomics of laboratory experiments with ecologically relevant species have been used to elucidate genes whose expression is tightly coupled to specific limitation scenarios. These two methods have been combined with data mining of the growing database of diatom transcriptomes to develop species-specific markers of physiological status in field populations. Data will be presented on the development and use of these methods to analyze samples collected on field expeditions to the Northeast Pacific Ocean sampling across gradients of Fe.