Nitrogen Uptake Dynamics in Marine Phytoplankton

Marine phytoplankton govern a major fraction of global primary production and modulate biogeochemical cycles by assimilating nitrogen in multiple chemical forms. Inorganic species such as nitrate, nitrite and ammonium are taken up via specific transporters and assimilated through reductive pathways, driving new production and carbon export. Equally important are organic substrates—urea, amino acids and cyanate—that can sustain growth under nutrient-poor (oligotrophic) conditions. Uptake rates vary among taxa and reflect adaptations in community composition, enzymatic machinery and gene regulation. Environmental drivers such as temperature, light, nutrient availability and competition shape spatial and temporal patterns of N acquisition. Recent advances in tracer techniques, ‘omics and in situ experiments have revealed how molecular regulation of transporters and enzymes interacts with ecosystem-scale processes to determine nitrogen fluxes and the efficiency of the biological carbon pump.

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Nitrogen Uptake Dynamics in Marine Phytoplankton publication trend

The graph below shows the total number of articles in nitrogen uptake dynamics in marine phytoplankton across all publications each year (not limited to Nature Index journals).

Technical terms

Dissolved inorganic nitrogen (DIN): mixture of bioavailable inorganic N species such as nitrate, nitrite and ammonium that phytoplankton assimilate.
Dissolved organic nitrogen (DON): organic molecular forms of N including urea, amino acids and cyanate that can be directly taken up by some phytoplankton.
Uptake rate: speed at which phytoplankton assimilate a given N substrate, typically expressed per unit biomass or volume per time.
Oligotrophic: nutrient-poor environments with low levels of inorganic N where specialised uptake strategies confer competitive advantage.
Transcriptome: full complement of RNA transcripts expressed by a cell or organism under specific conditions, revealing gene regulation patterns.
Cyanate lyase: enzyme catalysing the conversion of cyanate to ammonia and carbon dioxide, enabling utilisation of cyanate as a nitrogen source.

References

1. Nitrogen uptake rates and phytoplankton composition across contrasting North Atlantic Ocean coastal regimes north and south of Cape Hatteras. Frontiers in Microbiology (2024).
2. Transcriptomic response of the picoalga Pelagomonas calceolata to nitrogen availability: new insights into cyanate lyase function. Microbiology Spectrum (2025).