As a limiting nutrient

Paasche, E. (1973a). Silicon and the ecology of marine plankton diatoms. I. Thalassiosira pseudonana Cyclotella nana) growth in a chemostat with silicate as a limiting nutrient. Mar. Biol. 19, 117—126. 

The role of Fe as a limiting nutrient has been well established in the last decade in the so-called high-nutrient low chlorophyll regions of the oceans. A series of massive iron seeding experiments carried out to test the iron hypothesis advanced by Martin and Fitzwater (1988) have unequivocally shown that iron supply limits plankton production in one third of the world s oceans, despite the perennially high surface concentration of macronutrients (Fig. 7.1). The dynamics of phytoplankton blooms are limited by iron supply, which... 

Consistent with the role of iron as a limiting nutrient in EINLC systems is the notion that organisms may have evolved competitive mechanisms to increase iron solubility and uptake. In terrestrial systems this is accomplished using extracellularly excreted or membrane-bound siderophores. Similar compounds have been shown to exist in sea water where the competition for iron may be as fierce as it is on land. In open ocean systems where it has been measured, iron-binding ligand production increases with the... 

Reevaluating the Role of Phosphorus as a Limiting Nutrient in the Ocean... 

Sulfur fulfills many diverse roles in lakes. As the sixth most abundant element in biomass, it is required as a major nutrient by all organisms. For most algae, S is abundant in the form of sulfate in the water column however, in dilute glacial lakes in Alaska (I) and in some central African lakes (2) low concentrations of sulfate may limit primary production. Sulfur also serves the dual role of electron acceptor for respiration and, in reduced forms, source of energy for chemolithotrophic secondary production. Net sulfate reduction can account for 10-80% of anaerobic carbon oxidation in lakes (3-5), and hence this process is important in carbon and energy flow. Sulfate reduction, whether associated with uptake of sulfate and incorpo-... 

Finely ground phosphate rock (Ca3(P04)2) is occasionally added to fertilizer formulations as a diluent or filler. However, because phosphate rock has only a very limited water solubility its action as a phosphate nutrient is small and very slow. Hence, this ingredient is not allowed to be included in the % P2O5 analysis appearing on fertilizer packaging. Before use as a filler, phosphate rock is normally defluorinated by heating with silica and steam to decrease the risk of soil contamination by fluoride (Chap. 10). 

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