90Sr in Zostera marina from the Gulf of Gdańsk (southern Baltic Sea)

Abstract

Abstract 90Sr activity was determined in Zostera marina collected in the Gulf of Gdańsk in 2008-2013. 90Sr activity in Z. marina from Jama Kuźnicka and Klif Orłowski range from 0.83 Bq kg−1 d.w. to 3.78 Bq kg−1 d.w. and from 0.68 Bq kg−1 d.w. to 4.95 Bq kg−1 d.w., respectively. The plants collected in spring-summer showed significant differences between 90Sr content in blades - 1.55 Bq kg−1 d.w. in 2011 and 2.18 Bq kg−1 d.w. in 2013, and in roots - 7.75 Bq kg−1 d.w. and 11.44 Bq kg−1 d.w., respectively. The reduction in 90Sr concentrations in Z. marina roots to 1-2 Bq kg−1 d.w. in summer resulted from the transport of this element to the young parts of the plant. In autumn and winter, the 90Sr content in the blades of Z. marina was increasing and reached the maximum of 3.77 Bq kg−1 d.w. This could be explained by the process opposite to dilution, related to the biomass reduction and strontium concentration in the plant tissues. Changes in 90Sr concentration in Z. marina tissues are affected by isotope concentration in seawater as well as by salinity, which affects the concentration of Ca2+ - for which Sr2+ is a chemical analogue.