Macroalgae e large, multicellular algae e can sequester
dissolved metals through a two-phase process, with the metals first
being passively bound to the cellular surface followed by active
transport of metals across the cell membrane to be stored in
intracellular storage vacuoles (Chojnacka, 2010). Once internalized,
excess metals are sequestered by metal-binding pycho-chelatins
that are produced by algal cells in response to high concentrations
of metals (Pawlik-Skowronska, 2001). These metal-protein complexes
can then be stored in vacuoles to isolate metals from
essential cellular processes and allow algae to store relatively high
concentrations of some metals in an inert, detoxified form
(Nishikawa et al., 2003; Volland et al., 2011).