Natural vs anthropogenic components in sediments from the Po River delta coastal lagoons (NE Italy)

The Sacca di Goro and Sacca di Scardovari are two coastal lagoons of the Po River delta facing the northern Adriatic Sea. They are sensitive ecosystems both from the naturalistic and socio-economic point of view, since they are included in a natural park and are high productivity shellfish sites. Bottom sediments from the two lagoons have been analysed for their textural and geochemical (major and trace elements by XRF) composition in order to identify natural backgrounds and anthropogenic inputs. OC, N and δ13COC data have been also carried out by EA-IRMS to highlight the association of heavy metals with inorganic or organic sedimentary components. Results show that abundances of siderophile (Cr, Ni, Co) heavy metals in samples from the two lagoons are generally in the range of those recorded in alluvial sediments from the neighbours and are associated with the finest (clayey) fraction. Among chalcophile heavy metals, Pb and Zn display significant enrichments relative to the local geochemical backgrounds suggesting anthropogenic sources. They appear to be preferentially associated with the sedimentary organic matter that, according to the isotopic composition, is mainly formed by the incorporation of different proportions of macroalgae and macrophytes that have a significant bioaccumulation capacity. Taking into consideration that the extent of the algal biomass is sensitive to anthropogenic pressure and climatic changes, the trace element budget of sediments from these lagoons has to be monitored in the future, also to assess the impact of heavy metals on shellfish production

Inter-population comparisons of copper resistance and accumulation in the red seaweed, Gracilariopsis longissima.

Copper (Cu) resistance and accumulation of five populations of the red seaweed Gracilariopsis longissima collected from sites in south west England (Fal Estuary, Helford Estuary and Chesil Fleet) that differ in their degree of Cu contamination was assessed under controlled laboratory conditions, on two separate occasions (April and October). The effects of a range of Cu concentrations (0-250 μg l(-1)) on relative growth rates was the same for all populations with reductions observable at concentrations as low as 12 μg l(-1) and cessation of growth at 250 μg l(-1). There was no significant difference in the calculated EC(50) values for the April and October samples, with means of 31.1 and 25.8 μg l(-1), respectively. Over the range of concentrations used in this study, copper content increased linearly and the pattern of accumulation was the same for all populations at both time periods. From the linear regressions of the pooled data a concentration factor of 2.25 × 10(3) was calculated. These results imply that G. longissima has an innate tolerance to Cu and that populations have not evolved copper-tolerant ecotypes. In laboratory studies, accumulated Cu was released when transferred to 'clean' seawater with approximately 80% being lost after 8 days, with no significant difference between populations in their response. The results from a 30 days in situ transplantation experiment using two populations from the Fal Estuary provided further evidence for dynamic changes in Cu content in response to changes in Cu bioavailability. The findings in this study are discussed in the context of implications for seaweed biomonitoring

Bioactive compounds in seaweed; functional food applications and legislation

Seaweed is more than the wrap that keeps rice together in sushi. Seaweed biomass is already used for a wide range of other products in food, including stabilising agents. Biorefineries with seaweed as feedstock are attracting worldwide interest and include low-volume, high value-added products and vice versa. Scientific research on bioactive compounds in seaweed usually takes place on just a few species and compounds. This paper reviews worldwide research on bioactive compounds, mainly of nine genera or species of seaweed, which are also available in European temperate Atlantic waters, i.e. Laminaria sp., Fucus sp., Ascophyllum nodosum, Chondrus crispus, Porphyra sp., Ulva sp., Sargassum sp., Gracilaria sp. and Palmaria palmata. In addition, Undaria pinnatifida is included in this review as this is globally one of the most commonly produced, investigated and available species. Fewer examples of other species abundant worldwide have also been included. This review will supply fundamental information for biorefineries in Atlantic Europe using seaweed as feedstock. Preliminary selection of one or several candidate seaweed species will be possible based on the summary tables and previous research described in this review. This applies either to the choice of high value-added bioactive products to be exploited in an available species or to the choice of seaweed species when a bioactive compound is desired. Data are presented in tables with species, effect and test organism (if present) with examples of uses to enhance comparisons. In addition, scientific experiments performed on seaweed used as animal feed are presented, and EU, US and Japanese legislation on functional foods is reviewed