Related Experiment Video
Updated: May 3, 2026

Comparison of Scale in a Photosynthetic Reactor System for Algal Remediation of Wastewater
Published on: March 6, 2017
Acclimation and toxicity of high ammonium concentrations to unicellular algae
Yves Collos1, Paul J Harrison2
1Ecologie des Systèmes Marins Côtiers (UMR5119), Université Montpellier 2, CNRS, IRD, case 093, 34095 Montpellier Cedex 5, France.
Abstract:
A literature review on the effects of high ammonium concentrations on the growth of 6 classes of microalgae suggests the following rankings. Mean optimal ammonium concentrations were 7600, 2500, 1400, 340, 260, 100 μM for Chlorophyceae, Cyanophyceae, Prymnesiophyceae, Diatomophyceae, Raphidophyceae, and Dinophyceae respectively and their tolerance to high toxic ammonium levels was 39,000, 13,000, 2300, 3600, 2500, 1200 μM respectively. Field ammonium concentrations <100 μM would not likely reduce the growth rate of most microalgae. Chlorophytes were significantly more tolerant to high ammonium than diatoms, prymnesiophytes, dinoflagellates, and raphidophytes. Cyanophytes were significantly more tolerant than dinoflagellates which were the least tolerant. A smaller but more complete data set was used to estimate ammonium EC₅₀ values, and the ranking was: Chlorophyceae>Cyanophyceae, Dinophyceae, Diatomophyceae, and Raphidophyceae. Ammonia toxicity is mainly attributed to NH₃ at pHs >9 and at pHs <8, toxicity is likely associated with the ammonium ion rather than ammonia.
Related Concept Videos
Other Algae
Overview of Algae
Common Ion Effect
Responses to Salt Stress
Red Algae
Metabolism of Chemolithotrophs

