Sea Water, the Natural Medium of Phytoplankton II. Trace Metals and Chelation, and General Discussion

Abstract

Assays and mixed culture experiments prove that the supply of chelating substances is frequently the most crucial aspect of phytoplankton nutrition in sea water. Experimental results, theoretical considerations and tentative calculations show that this supply is controlled by the stability of the trace metal chelates and in the sea may be mediated by certain unknown minor components of the dissolved organic matter.The results of Parts I and II are considered together and show how seawater quality is closely related to the chelation of trace metals, mainly iron, and various other factors previously listed in the summary to Part I.

Interactive influences of bioactive trace metals on biological production in oceanic waters

“…Johnston (1963Johnston ( , 1964 proposed that certain organic compounds present in seawater in trace quantities may exert an important influence on primary production in marine communities. Barber and Ryther (1969, p. 197) suggested that…”

“…Surface dissolved [Cu] in this area are 0.5-l nM (Bruland 19&O) (Sunda 1988(Sunda -1989. Either or both of these scenarios could result in [Mn2+] : [Cu2+] ratios favorable to growth and reproduction, and they could be among those factors involved in "conditioning" upwelled water (Johnston 1964;Barber and Ryther 1969) Stoecker et al (1986) observed that, for a given [Zn'+], growth rates decreased with increasing [Cu2+]; this trend was apparent for all free [Zn"] tested between lo-lo and lo-l2 M (Fig. IOA).…”

The relationship between cupric ion activity and the toxicity of copper to phytoplankton

“…of the cupric ion-selective electrode in solutions containing 1 0 ~M CuS04 at 250C support phytoplankton growth (Johnston, 1963(Johnston, , 1964. Johnston went so far as to say, lithe supply of chelating substances is frequently the most critical aspect of phytoplankton nutrition in seawater".…”

A study of certain trace metals in sea water using anodic stripping voltammetry

“…For example, Johnston (1964) has demonstrated that either no growth, or only poor growth, can be obtained with diatoms (also dinoflagellates that were part of the natural inocu lum) when chelated trace meta Is are n9t inCluded in the cu Ituring medium. As a result of a large number of cu Ituring experiments, with varying water types collected during different seasons, Johnston concludes that "the supply of chelating substances is frequently the most crucial aspect of phytoplankton nutrition in sea water.…”