Abstract
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.
| Original language | English |
|---|---|
| Article number | eaaz4880 |
| Journal | Science advances |
| Volume | 6 |
| Issue number | 20 |
| DOIs | |
| State | Published - May 2020 |
Funding
We thank the students, volunteers, and USGS employees who collected and processed the samples, and C. Eagles-Smith, W. Schlesinger, and K. Kidd for reviewing the manuscript. This research was subjected to USGS review and approved for publication. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Handling of vertebrates conformed with Arizona Game and Fish Permit #SP565911 and National Park Service Permit #2006-SCI-0003, with protocols approved by the Idaho State University Animal Care and Use Committee (project 626R1008). This study is supported by USGS Cooperative Agreement 05WRAG0055 and the USGS Environmental Health Contaminant Biology Program.
| Funder number |
|---|
| 565911 |
| 1757351 |
| 2006-SCI-0003, 626R1008, 05WRAG0055 |
