Nitrogen fixation is driven by cellular nitrogen stores in a diazotrophic cyanobacterium: Evidence from culture experiments and model validation

Diazotrophic cyanobacteria, including those responsible for harmful algal blooms, fix atmospheric dinitrogen (N2) to sustain growth when they are limited by dissolved inorganic nitrogen (DIN) supply. Conventional models fail to accurately predict the timing and magnitude of N2 fixation, partly because of oversimplified assumptions about diazotrophic species responses to N. We hypothesized that cellular carbon (C) and N would co‐vary with DIN availability, and cellular N quota reduced below a critical threshold would trigger heterocyst differentiation and N2 fixation. Conversely, we hypothesized that heterocysts would be discarded, and N2 fixation would cease at another higher cellular N quota threshold. To test this hypothesis, we undertook experiments to provide data to calibrate a model of cellular C and N of N2 fixation in the cyanobacterium Raphidiopsis raciborskii. The model incorporated internal N quotas, external DIN supply and a time lag for N2 fixation as key regulators of heterocyst production and N2 fixation, explaining > 70% of the variation in measured cellular N and C : N molar ratios. Heterocysts were predicted to form at a cellular N quota of 0.085 mg N mg−1 C and were discarded from filaments at 0.275 mg N mg−1 C. There was a 5‐d time lag between DIN deprivation and initiation of N2 fixation. Continuous DIN supply was predicted to enhance N2 fixation more than an equivalent one‐off pulse. Our study highlighted the need to consider cellular N and N supply regimes in driving N2 fixation to provide more accurate predictions of the response of cyanobacteria to DIN availability.

• Publication year

  2026

• Venue

  Limnology and Oceanography

• Publication date

  2026-02-01

• Fields of study

  Not labeled

• Identifiers
  DOI 10.1002/lno.70326
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar

• No claims are published for this paper.

• No concepts are published for this paper.

• A global dataset of nitrogen fixation rates across inland and coastal waters

  2025influential reference
• Nitrogen fixation may not alleviate stoichiometric imbalances that limit primary production in eutrophic lake ecosystems

  2025cited by this paper
• Global importance of nitrogen fixation across inland and coastal waters.

  2025influential reference
• Current and Historical Resource Nitrogen Supply Affects the Eco‐Physiological Traits and the Ionome of a Diazotrophic Cyanobacterium

  2024cited by this paper
• Heterocyte production, gene expression and phylogeography in Raphidiopsis ( = Cylindrospermopsis) Raciborskii.

  2022cited by this paper
• Evidence, causes, and consequences of declining nitrogen availability in terrestrial ecosystems

  2022cited by this paper
• Diazotrophy modulates cyanobacteria stoichiometry through functional traits that determine bloom magnitude and toxin production

  2022cited by this paper
• Pelagic cyanobacterial nitrogen fixation in lakes and ponds of different latitudinal zones

  2022cited by this paper
• Competitive superiority of N-fixing cyanobacteria when fixed N is scarce: Reconsiderations based on a model with heterocyst differentiation

  2022cited by this paper
• Terminal heterocyst differentiation in the Anabaena patA mutant as a result of post-transcriptional modifications and molecular leakage

  2021cited by this paper
• Environmental factors and thresholds for nitrogen fixation by phytoplankton in tropical reservoirs

  2021cited by this paper
• Biological stoichiometry and growth dynamics of a diazotrophic cyanobacteria in nitrogen sufficient and deficient conditions.

  2021influential reference
• Dynamics of nitrogen-fixing cyanobacteria with heterocysts: a stoichiometric model

  2020cited by this paper
• Life in fluctuating environments

  2020cited by this paper
• Are laboratory growth rate experiments relevant to explaining bloom-forming cyanobacteria distributions at global scale?

  2020cited by this paper
• Why Lake Taihu continues to be plagued with cyanobacterial blooms through 10 years (2007-2017) efforts.

  2019cited by this paper
• A short review of contemporary developments in aquatic ecosystem modelling of lakes and reservoirs

  2019cited by this paper
• Towards evidence-based parameter values and priors for aquatic ecosystem modelling

  2018cited by this paper
• Competition between a toxic and a non-toxic Microcystis strain under constant and pulsed nitrogen and phosphorus supply

  2017cited by this paper
• Variation within and between cyanobacterial species and strains affects competition: Implications for phytoplankton modelling.

  2017cited by this paper
• The role of heterocytes in the physiology and ecology of bloom-forming harmful cyanobacteria.

  2016influential reference
• Formation and maintenance of nitrogen-fixing cell patterns in filamentous cyanobacteria

  2016cited by this paper
• Nitrogen fixation by the diazotroph Cylindrospermopsis raciborskii (Cyanophyceae)

  2016influential reference
• N2-fixation, ammonium release and N-transfer to the microbial and classical food web within a plankton community

  2015cited by this paper
• Intercellular transfer along the trichomes of the invasive terminal heterocyst forming cyanobacterium Cylindrospermopsis raciborskii CS-505.

  2015cited by this paper
• Regulation of heterocyst frequency in Baltic Sea Aphanizomenon sp.

  2014cited by this paper
• An Integrative Approach for Modeling and Simulation of Heterocyst Pattern Formation in Cyanobacteria Filaments

  2014cited by this paper
• Nitrogen fixation and respiratory electron transport in the cyanobacterium Cyanothece under different light/dark cycles.

  2014cited by this paper
• Modelling the dynamics of carbon–nitrogen metabolism in the unicellular diazotrophic cyanobacterium Crocosphaera watsonii WH8501, under variable light regimes

  2014cited by this paper
• Nutrient-related changes in the toxicity of field blooms of the cyanobacterium, Cylindrospermopsis raciborskii.

  2014cited by this paper
• Phytoplankton growth formulation in marine ecosystem models: should we take into account photo-acclimation and variable stoichiometry in oligotrophic areas?

  2013cited by this paper
• Dinitrogen Fixation Is Restricted to the Terminal Heterocysts in the Invasive Cyanobacterium Cylindrospermopsis raciborskii CS-505

  2013cited by this paper
• Optimality-based model of phytoplankton growth and diazotrophy

  2013cited by this paper
• Light-dark (12:12) cycle of carbon and nitrogen metabolism in Crocosphaera watsonii WH8501: relation to the cell cycle.

  2012cited by this paper
• Heterocyst placement strategies to maximize the growth of cyanobacterial filaments

  2012cited by this paper
• The dilemma of controlling cultural eutrophication of lakes

  2012cited by this paper
• Compartmentalized function through cell differentiation in filamentous cyanobacteria

  2010cited by this paper
• Low dissolved inorganic nitrogen and increased heterocyte frequency: precursors to Anabaena planktonica blooms in a temperate, eutrophic reservoir

  2010cited by this paper
• Variability in the response of the cyanobacterium Nodularia spumigena to nitrogen supplementation.

  2010cited by this paper
• Nitrogen fixation may not balance the nitrogen pool in lakes over timescales relevant to eutrophication management

  2010cited by this paper
• PULSES OF PHOSPHATE PROMOTE DOMINANCE OF THE TOXIC CYANOPHYTE CYLINDROSPERMOPSIS RACIBORSKII IN A SUBTROPICAL WATER RESERVOIR 1

  2009cited by this paper
• Eutrophication of lakes cannot be controlled by reducing nitrogen input: Results of a 37-year whole-ecosystem experiment

  2008cited by this paper
• Carbon and nitrogen fixation and metabolite exchange in and between individual cells of Anabaena oscillarioides

  2007influential reference
• Analysis and modelling of the interactive effects of temperature and light on phytoplankton growth and relevance for the spring bloom

  2007cited by this paper
• Evaluation of the current state of mechanistic aquatic biogeochemical modeling: citation analysis and future perspectives.

  2006cited by this paper
• The Ecology of Phytoplankton

  2006influential reference
• Modeling Culture Profiles of the Heterocystous N2‐Fixing Cyanobacterium Anabaenaflos‐aquae

  2006cited by this paper
• The effect of growth rate, phosphorus concentration, and temperature on N2 fixation, carbon fixation, and nitrogen release in continuous cultures of Trichodesmium IMS101

  2005cited by this paper
• Comparison of Models Describing Light Dependence of N2 Fixation in Heterocystous Cyanobacteria

  2002cited by this paper
• Effect on Heterocyst Differentiation of Nitrogen Fixation in Vegetative Cells of the Cyanobacterium Anabaena variabilisATCC 29413

  2001cited by this paper
• Ammonium release by nitrogen sufficient diatoms in response to rapid increases in irradiance

  2000cited by this paper
• TWO MORPHOLOGICAL FORMS OF CYLINDROSPERMOPSIS RACIBORSKII (CYANOBACTERIA) ISOLATED FROM SOLOMON DAM, PALM ISLAND, QUEENSLAND

  1999influential reference
• The Darling River : Algal growth and the cycling and sources of nutrients.

  1999cited by this paper
• N2 Fixation by non-heterocystous cyanobacteria

  1997cited by this paper
• Release of Dissolved Organic Nitrogen by Marine Diazotrophic Cyanobacteria, Trichodesmium spp

  1994cited by this paper
• Ammonium excretion by a mutant of the nitrogen-fixing cyanobacterium Anabaena siamensis

  1991cited by this paper
• Nitrogen fixation in freshwater, estuarine, and marine ecosystems. 1. Rates and importance1

  1988cited by this paper
• Photoinhibition of photosynthesis in natural assemblages of marine phytoplankton

  1980cited by this paper

• No citing papers are available for this paper.