Elemental composition of seaweed (Fucus vesiculosus) from the Swedish west coast

Sammanfattning

Seaweed has the ability to accumulate elements from the surrounding water, such as radionuclides and heavy metals. This makes them into useful bioindicators; suitable for assessing the pollution in the marine environment as well as the effect of potential future additions of heavy metals and radionuclides. Seaweed content has been examined in many studies, and over long time periods. However, these studies have largely disregarded how the elements are distributed within the seaweed organism. In this project, the localization of elements has been investigated, focusing on around twenty elements and their distribution in cross sections of four different thallus parts of the seaweed species Fucus vesiculosus. The goal was to examine whether elements localize in different tissues and to attempt to quantify this. Elemental concentration maps obtained through micro-PIXE measurements were analyzed. The concentrations in different regions of the samples were extracted and compared. The results showed that the elements accumulated in different regions. Some, like K and S, showed high concentrations throughout the samples. Others, like Fe and I, were almost only localized in the outermost layer (the meristoderm). For some elements, the highest concentrations were instead found in the inner parts of the cross sections, such as Sr and Ca. The elemental distribution also varied between thallus parts, indicating different structure and morphology. This knowledge can be used to improve how sampling and measurements are conducted and be a foundation for future studies.