Food web controls on mercury fluxes and fate in the Colorado River, Grand Canyon

Science Advances
By: , and 



Mercury (Hg) biomagnification in aquatic food webs is a global concern; yet, the ways species traits and interactions mediate these fluxes remain poorly understood. Few pathways dominated Hg flux in the Colorado River despite large spatial differences in food web complexity, and fluxes were mediated by one functional trait, predation resistance. New Zealand mudsnails are predator resistant and a trophic dead end for Hg in food webs we studied. Fishes preferred blackflies, which accounted for 56 to 80% of Hg flux to fishes, even where blackflies were rare. Food web properties, i.e., match/mismatch between insect production and fish consumption, governed amounts of Hg retained in the river versus exported to land. An experimental flood redistributed Hg fluxes in the simplified tailwater food web, but not in complex downstream food webs. Recognizing that species traits, species interactions, and disturbance mediate contaminant exposure can improve risk management of linked aquatic-terrestrial ecosystems.

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Publication type Article
Publication Subtype Journal Article
Title Food web controls on mercury fluxes and fate in the Colorado River, Grand Canyon
Series title Science Advances
DOI 10.1126/sciadv.aaz4880
Volume 6
Issue 20
Year Published 2020
Language English
Publisher AAAS
Contributing office(s) Columbia Environmental Research Center
Description eaaz4880, 10 p.
Country United States
State Arizona, Nevada
Other Geospatial Colorado River, Grand Canyon
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