Wildfires influence mercury transport, methylation, and bioaccumulation in headwater streams of the Pacific Northwest
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- More information: Publisher Index Page (via DOI)
- Data Release: USGS data release - Mercury in soil, water, sediment, and biota in headwater streams associated with wildfires in the northwestern U.S., 2021-2022
- Open Access Version: Publisher Index Page
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Abstract
The increasing frequency and severity of wildfires are among the most visible impacts of climate change. However, the effects of wildfires on mercury (Hg) transformations and bioaccumulation in stream ecosystems are poorly understood. We sampled soils, water, sediment, in-stream leaf litter, periphyton, and aquatic invertebrates in 36 burned (one-year post fire) and 21 reference headwater streams across the northwestern U.S. to evaluate the effects of wildfire occurrence and severity on total Hg (THg) and methylmercury (MeHg) transport and bioaccumulation. Suspended particulate THg and MeHg concentrations were 89 and 178% greater in burned watersheds compared to unburned watersheds and increased with burn severity, likely associated with increased soil erosion. Concentrations of filter-passing THg were similar in burned and unburned watersheds, but filter-passing MeHg was 51% greater in burned watersheds, and suspended particles in burned watersheds were enriched in MeHg but not THg, suggesting higher MeHg production in burned watersheds. Among invertebrates, MeHg in grazers, filter-feeders, and collectors was 33, 48, and 251% greater in burned watersheds, respectively, but did not differ in shredders or predators. Thus, increasing wildfire frequency and severity may yield increased MeHg production, mobilization, and bioaccumulation in headwaters and increased transport of particulate THg and MeHg to downstream environments.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Wildfires influence mercury transport, methylation, and bioaccumulation in headwater streams of the Pacific Northwest |
| Series title | Environmental Science & Technology |
| DOI | 10.1021/acs.est.4c00789 |
| Volume | 58 |
| Issue | 32 |
| Year Published | 2024 |
| Language | English |
| Publisher | ACS Publications |
| Contributing office(s) | Forest and Rangeland Ecosys Science Center, Idaho Water Science Center, Upper Midwest Water Science Center |
| Description | 14 p. |
| First page | 14396 |
| Last page | 14409 |
| Country | United States |
| State | Idaho, Oregon, Washington |
| Google Analytic Metrics | Metrics page |