Cells of many phytoplanktonic and multicellular algae are characteristically coated or embedded in material of an anionic mucopolysacharride nature. Similar substances are found also in the gastrointestinal tract and outer membranes of many zooplankton and other organisms. One characteristic of this mucilaginous surface layer resembles that of an ion exchange resin in that ionic and colloidal complexes bind to the surface where they may be freed by hydrogen ions. Studies indicate that levels of ionic material may exceed, by at least 100-fold, those ionic concentrations predicted on wet weight basis according to Donnan relationships. For ions in the rare earth and transuranium series, these levels are greatly exceeded. Photosynthesis has comparatively little effect on these properties except during a brief period, at its onset, during which proton and electron transport are not in dynamic equilibrium. These studies provide quantitation of the scavenging characteristic of certain organisms towards plutonium.
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