Open AccessGeochemical and Dietary Drivers of Mercury Bioaccumulation in Estuarine Benthic Invertebrates
Author(s) -
Sofi Jonsson,
Van Liem-Nguyen,
Agneta Andersson,
Ulf Skyllberg,
Mats Nilsson,
Erik Lundberg,
Erik Björn
Publication year - 2022
Publication title -
environmental science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.851
H-Index - 397
eISSN - 1520-5851
pISSN - 0013-936X
DOI - 10.1021/acs.est.2c03265
Subject(s) - benthic zone , bioaccumulation , methylmercury , food web , pelagic zone , environmental chemistry , estuary , invertebrate , environmental science , mercury (programming language) , sediment , detritivore , ecology , plankton , oceanography , chemistry , biology , ecosystem , geology , paleontology , computer science , programming language
Sediments represent the main reservoir of mercury (Hg) in aquatic environments and may act as a source of Hg to aquatic food webs. Yet, accumulation routes of Hg from the sediment to benthic organisms are poorly constrained. We studied the bioaccumulation of inorganic and methylmercury (Hg II and MeHg, respectively) from different geochemical pools of Hg into four groups of benthic invertebrates (amphipods, polychaetes, chironomids, and bivalves). The study was conducted using mesocosm experiments entailing the use of multiple isotopically enriched Hg tracers and simulation of estuarine systems with brackish water and sediment. We applied different loading regimes of nutrients and terrestrial organic matter and showed that the vertical localization and the chemical speciation of Hg II and MeHg in the sediment, in combination with the diet composition of the invertebrates, consistently controlled the bioaccumulation of Hg II and MeHg into the benthic organisms. Our results suggest a direct link between the concentration of MeHg in the pelagic planktonic food web and the concentration of MeHg in benthic amphipods and, to some extent, in bivalves. In contrast, the quantity of MeHg in benthic chironomids and polychaetes seems to be driven by MeHg accumulation via the benthic food web. Accounting for these geochemical and dietary drivers of Hg bioaccumulation in benthic invertebrates will be important to understand and predict Hg transfer between the benthic and the pelagic food web, under current and future environmental scenarios.