I am interested in the factors that limit marine primary production, particularly the nutrient demands of phytoplankton taxa competing in different ecological settings. My previous work has shown that seasonally blooming diatoms have nitrogen-to-phosphorous requirements lower than the canonical “Redfield Ratio”, and has clarified the roles of phosphorous and iron in limiting the growth of diazotrophic (nitrogen-fixing) plankton. Future work will focus on the ecological strategies that control elemental demands at the cellular scale, and environmental selection between those strategies at the biome scale.
Figure adapted from Weber & Deutsch, 2010, Nature.
Top: Nitrogen-to-phosphorous ratio in exported organic matter (N:P), diagnosed in an ocean circulation. Bottom: Zonal mean N:P covaries with diatom abundance.