Sugar Kelp ( Saccharina latissima) dominates as a commercially produced seaweed species in Norway, and accumulation of potential toxic elements (PTE) is one of the obstacles for a wider use of the biomass. The aim of this study was to compare PTE accumulation from two geographically distant Sugar kelp populations in Bergen (west in Norway) and Tromsø (north in Norway) when grown in a standardized environment to reveal possible population effects on PTE accumulation.
F rom each population ~800 young sporophytes were produced and divided into 10 flow-through seawater tanks with overhead lighting, 5 tanks with 8 hour light per day and 5 with 12 hour light per day. After 7 weeks sporophytes from each population-tank combination were pooled and analysed for arsenic, cadmium, and iodine content.
While arsenic was unaffected by population and photoperiod, increased daylength tended to increase cadmium content while reduce iodine content (Figure 1). The Bergen population accumulated more cadmium and less iodine than the Tromsø population and was more sensitive to photoperiod . This implies that genotypes may vary in chemical composition when grown under the same conditions. Selecting the optimal genotype may reduce PTE content and increase the value of the sugar kelp biomass for food, feed, soil amendment or other purposes. The population differences may be local adaptation of the populations to different environments along the Norwegian coast.