Multiple environmental controls on phytoplankton growth strategies determine adaptive responses of the N : P ratio

• Published in: Ecology Letters
• Main Authors: Daines, SJ, Clark, JR, Lenton, TM
• Other Authors: Grover, J
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2014
• Subjects: Ecology and Environment; Marine Sciences; Southern Ocean
• Online Access: https://plymsea.ac.uk/id/eprint/6207/; https://doi.org/10.1111/ele.12239

The controls on the 'Redfield' N:P stoichiometry of marine phytoplankton and hence the N:P ratio of the deep ocean remain incompletely understood. Here, we use a model for phytoplankton ecophysiology and growth, based on functional traits and resource-allocation trade-offs, to show how environmental filtering, biotic interactions, and element cycling in a global ecosystem model determine phytoplankton biogeography, growth strategies and macromolecular composition. Emergent growth strategies capture major observed patterns in marine biomes. Using a new synthesis of experimental RNA and protein measurements to constrain per-ribosome translation rates, we determine a spatially variable lower limit on adaptive rRNA:protein allocation and hence on the relationship between the largest cellular P and N pools. Comparison with the lowest observed phytoplankton N:P ratios and N:P export fluxes in the Southern Ocean suggests that additional contributions from phospholipid and phosphorus storage compounds play a fundamental role in determining the marine biogeochemical cycling of these elements.