Variation in Patterns of Metal Accumulation in Thallus Parts of Lessonia trabeculata (Laminariales; Phaeophyceae): Implications for Biomonitoring

Abstract

Seaweeds are well known to concentrate metals from seawater and have been employed as monitors of metal pollution in coastal waters and estuaries. However, research showing that various intrinsic and extrinsic factors can influence metal accumulation, raises doubts about the basis for using seaweeds in biomonitoring programmes. The thallus of brown seaweeds of the order Laminariales (kelps) is morphologically complex but there is limited information about the variation in metal accumulation between the different parts, which might result in erroneous conclusions being drawn if not accounted for in the biomonitoring protocol. To assess patterns of individual metals in the differentiated parts of the thallus (blade, stipe, holdfast), concentrations of a wide range of essential and non-essential metals (Fe, Cr, Cu, Zn, Mn, Pb, Cd, Ni and Al) were measured in the kelp Lessonia trabeculata. Seaweeds were collected from three sampling stations located at 5, 30 and 60 m from an illegal sewage outfall close to Ventanas, Chile and from a pristine location at Faro Curaumilla. For the majority of metals the highest concentrations in bottom sediment and seaweed samples were found at the site closest to the outfall, with concentrations decreasing with distance from the outfall and at control stations; the exception was Cd, concentrations of which were higher at control stations. The patterns of metal concentrations in different thallus parts were metal specific and independent of sampling station. These results and the available literature suggest that biomonitoring of metals using seaweeds must take account of differences in the accumulation of metals in thallus parts of complex seaweeds.

Metal content of kelp ( Laminaria digitata ) co-cultivated with Atlantic salmon in an Integrated Multi-Trophic Aquaculture system

“…Macroalgae, including kelps, have a tendency to accumulate certain metals in approximate proportion to their ambient bio-availabilities and with concentration factors typically of 10 3 -10 5 (Leal et al, 1997;Ryan et al, 2012). Analysis of kelp tissue therefore provides a time-integrated picture of the contamination of a site, avoiding difficulties of accounting for temporal and spatial fluctuations in concentration, and simultaneously indicating those metals that are of biological significance (Burger et al, 2007;Fink and Manley, 2011;Sáez et al, 2012;Shimshock et al, 1992).…”

A novel field transplantation technique reveals intra-specific metal-induced oxidative responses in strains of Ectocarpus siliculosus with different pollution histories

“…Due to the documented information of metal contamination in the location (Gonz alez et al, 2008;S aez et al, 2012a, 2012b, the Bay of Ventanas (32 44 0 36.55 00 S and 71 29 0 35.70 00 W) was chosen as the contaminated site (Fig. 1A); metal concentrations of up to 68 mg g À1 have been recorded in subtidal sediments at this site (S aez et al, 2012a).…”

“…In estuaries and coastal waters, seaweeds are the main primary producers at the base of trophic networks and provide habitat for a large diversity of other marine organisms (S aez et al, 2012b). Because of their ecological importance and metal accumulation capacities brown seaweeds of the orders Fucales and Laminariales are the most widely used macroalgae for metal bioaccumulation studies (Brown and Depledge, 1998;S aez et al, 2012a). Typically, assessment of metal pollution using seaweeds has involved a 'passive' bio-monitoring approach, whereby resident species are sampled and analysed for their metal content (e.g.…”

“…Typically, assessment of metal pollution using seaweeds has involved a 'passive' bio-monitoring approach, whereby resident species are sampled and analysed for their metal content (e.g. Pawlik-Skowronska et al, 2007;Ratkevicius et al, 2003;S aez et al, 2012a). However, intrinsic and extrinsic factors can influence the accumulation of some metals and population responses to metal exposure; the latter may result in differential tolerance and potentially create uncertainties in the interpretation of data leading to false environmental diagnoses (Brown et al, 2012).…”

“…However, intrinsic and extrinsic factors can influence the accumulation of some metals and population responses to metal exposure; the latter may result in differential tolerance and potentially create uncertainties in the interpretation of data leading to false environmental diagnoses (Brown et al, 2012). As an alternative procedure, several authors have suggested 'active' bio-monitoring as a better option, whereby individuals of species whose responses to metal-pollution are well researched are cultured in the laboratory and then transplanted to locations to be investigated (Brown et al, 2012;Chaphekar, 1991;S aez et al, 2012a). Advantages of this approach include individuals from the same population, or ramets of the same individual, can be transplanted into different locations, similar age individuals can be used, the time period of exposure is known and monitoring can be carried out even if the species is absent from a site.…”