Determinants of differential metal accumulation across thallus parts in Lessonia trabeculata

Determine the physico-chemical and biological factors responsible for the different, metal-specific patterns of accumulation of Fe, Cr, Cu, Zn, Mn, Pb, Cd, Ni, and Al across the blades, stipes, and holdfasts of the kelp Lessonia trabeculata, to inform accurate use of this species in biomonitoring protocols.

Background

The study measured concentrations of nine essential and non-essential metals (Fe, Cr, Cu, Zn, Mn, Pb, Cd, Ni, Al) in blades, stipes, and holdfasts of Lessonia trabeculata along a pollution gradient from an illegal sewage outfall compared with a pristine control site. Results showed that accumulation patterns varied by metal and thallus part, with blades, stipes, and holdfasts each exhibiting distinct metal burdens.

The authors highlight that these intra-individual differences are inconsistent and metal-specific, complicating the interpretation of seaweed-based biomonitoring data. They note that while factors such as alginate composition, phenolic exudates, and tissue physiology may play roles, the underlying reasons remain unresolved, necessitating targeted investigation to support robust biomonitoring applications.