Epsilon Archive for Student Projects

Abstract

Bioaccumulation is a process that occurs when an organism’s assimilation of a substance, through diet or passive uptake, outweighs its elimination. As organisms consume each other in a food web, the concentrations of substrates may increase with increasing trophic levels, a process called biomagnification. The underlying mechanisms of bioaccumulation involve factors like diet, metabolism and energy allocation, and as organisms grow in size, bioaccumulation increases. In teleost fish, female biased sexual size dimorphism (SSD) is well documented, with females generally growing faster and larger than males due to differences in metabolism and energy allocation. By recognizing that the drivers of both SSD and bioaccumulation overlap, this study investigate potential influences of sex, size and growth on the bioaccumulation of the radionuclide 137Cesium(137Cs) in Eurasian perch (Perca fluviatilis). Using a small sample of perch from an artificially heated and enclosed coastal ecosystem in the Baltic Sea, 137Cs concentrations were measured in female and male perch of two size groups. Results revealed a significant increase in 137Cs concentration with body size, confirming biomagnification patterns reported in previous studies. Furthermore, sex differences in the bioaccumulation of 137Cs were found when controlling for growth, where males had a significantly higher increase of the radionuclide than females in relation to a proxy for the accumulated growth. These findings suggest that the underlying differences in processes, such as metabolism, energy allocation and growth patterns could influence radionuclide bioaccumulation in perch. Results from this study highlights the importance of considering both sex and growth in bioaccumulation models, as size alone may not fully capture the variation in contaminant concentrations in fish. Although the small sample size used in this study limits the generalizability of these results, they provide valuable preliminary insights for future research on sex-specific bioaccumulation patterns in fish.