Conference Contribution Details
Mandatory Fields
Murray, H., Stengel, D.B. ,Cave R.
21st Environ: Towards 2020: Environmental challenges and opportunities for the next decade
The effect of algal-exuded organic ligands on metal bioavailability in seawater (poster).The effect of algal-exuded organic ligands on metal bioavailability in seawater (poster).
University College Cork
Poster Presentation
Optional Fields
Aquatic organisms produce organic ligands via the active release of photosynthates, degradation of senescent cells, rupture of cells due to grazing, and cell lysis by pathogens. The release of organic ligands has important implications for metal toxicity in seawater, as such ligands are able to bind metals, altering their toxicity. While it is widely accepted that these ligands binds free metal ions, reducing their availability, some studies have concluded that they increase metal bioavailability. It is postulated that organic ligands bind the algal cell wall resulting in increased membrane permeability of metal complexes and hydrophilic substances. The same binding also increases the negative charge at the algal surface. This may result in the formation of a ternary complex between dissolved organic ligand, metal, and algae. Hence, it is at present unknown to what extent algal exudates may affect metal bioavailability. This work describes species-specific ligand profiles, which were observed for five macroalgae (Laminaria hyperborea, Fucus spiralis, Fucus vesiculosus, Ascophyllum nodosum, and Pelvetia canaliculata) as a function of exposure to multiple metals (Cd, Cu, Pb, Zn) and a range of environmental conditions. Phenolic and CDOM exudation were estimated by measurement of the absorbance of water at 274 nm and 440 nm, respectively. The determination of total dissolved metal, complexing ligands, glutathione and cysteine concentrations of the culture solutions by cathodic stripping voltammetry (CSV) are discussed. This
Publication Themes
Environment, Marine and Energy