Algal growth limitation

The effects of N supply on uptake and growth rates in phytoplankton and periphyton are the subject of volumes of literature, a summary of which is beyond the scope of this chapter. However, certain aspects of the limitation of algal growth by the supply of N and other nutrients will be discussed later in the section on eutrophication by N deposition. Other details on algal nutrition can be found in reviews by Goldman and Glibert (31), Button (32), Kilham and Hecky (33), and Hecky and Kilham (34). 

Hund, K. 1997. Algal growth inhibition test—feasibility and limitations for soil assessment. Chemosphere 35 1069-1082. 

The experiments described here are principally diagnostic in nature where cellular biomass was significantly enhanced in bottles after resource (iron or light) amendment, relative to control (or other) treatments, we infer that algal growth rates in the control (or other) treatments were limited by a deficiency in that resource. The statistical significance of differences between mean values of parameters measured in different treatments were assessed using a two-tailed r-test for comparisons between two treatments, or a one-way analysis of variance (ANOVA) for comparisons between three or more treatments, at a confidence level of 95% (P = 0.05). 

Iron is a nutritive trace element whose role as a limiting agent for algal growth has been demonstrated in areas where certain Phaeocystis species (e.g., P. antarctica) are also commonly found. Viral lysis will affect the absolute concentration of iron that is potentially available for biological requirement, but may also directly affect the spe-ciation and bioavailability as iron is mostly com-plexed with organic ligands and colloids. 

Limiting Nutrients For most inland waters phosphorus is the limiting nutrient in determining productivity. In some estuaries and in many marine coastal waters, nitrogen appears to be more limiting to algal growth than phosphoms. Deficiency in trace elements occurs usually only as a temporal or spatial transient. 

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