Diatoms are among the most important primary producers in the ocean. Coastal species can respond to dynamic inputs of nutrients into the surface ocean and form large biomass blooms. Phytoplankton growth in much of the ocean is limited by one nutrient or another, and species that persist in these environments must be able to function under these low nutrient conditions. Oceanic diatom species have lower Fe requirements for growth and may have evolved to subsist in low Fe environments by changing the composition of Fe-demanding metabolic pathways. Iron and light responsive pathways are intimately linked because of the large Fe requirement of photosynthesis and the potential for both to limit growth and the efficiency of the biological carbon pump. Physiological and field studies have shown that many diatoms are susceptible to Fe/light co-limitation, but we lack information on the biochemical basis for co-limitation and how this differs between diatom species. This project holds the sequence data for Thalassiosira weissflogii, an oceanic diatom, grown under low light and low light/low iron co-limitation.