Mercury and selenium biomagnification in a coastal food web from the Gulf of California influenced by agriculture and shrimp aquaculture

The biomagnification of Hg and Se was studied using nitrogen stable isotope analysis during four seasons in a coastal lagoon of the eastern central Gulf of California. This lagoon receives agricultural, municipal, and shrimp aquaculture effluents. The species were categorized into organism groups and presented a significant accumulation of Hg and Se with respect to the sources, while the concentration of both elements in sediment and suspended particulate matter (SPM) was low. Our data confirms the positive transfers (biomagnification factors >1) of Hg and Se in the entire studied food web, and it was structured in five trophic levels across all seasons. Additionally, there were no linear correlations between the molar Se:Hg ratios and the trophic levels of the organism groups. However, the Se:Hg ratios among organism groups were >1, which indicates that there is an excess of Se and that it is not a limiting factor for the detoxification of Hg.

Automated summary

The study examined the biomagnification of Hg and Se in a coastal lagoon in the eastern central Gulf of California using nitrogen stable isotope analysis. The results showed a significant accumulation of both elements in the food web, with no linear correlations between the Se:Hg ratios and trophic levels. The excess of Se among organism groups indicates that it is not a limiting factor for the detoxification of Hg.