The water quality of streams and rivers in the Arctic is sensitive to rapid climate change and altered disturbance regimes.
Return to Ecosystems or Water >> Fish and Aquatic Ecology
Widespread permafrost thaw, thaw-induced erosion, and wildfires have altered the concentration and flux of organic carbon, nutrients, and trace metals in Arctic rivers. Subsequently, changes in surface waters can impact the habitability for biota and growth rates for fish. Recent observations from Arctic Alaska indicate that waters draining permafrost landscapes may be susceptible to iron and carbon mobilization following thaw. One consequence of these altered iron-cycling processes is the abrupt change in color (orange) of stream and river reaches, reflecting a dramatic shift in water quality. Although the exact mechanisms are yet to be determined, evidence indicates that shifting hydrological and oxidation-reduction processes associated with permafrost thaw may function to transport high concentrations of iron in dissolved and colloidal forms from thawing soils to streams. Preliminary observations suggest that orange stream reaches have higher iron concentrations, less dissolved oxygen, and more acidic water than nearby clearwater streams. Further, the conversion of streams from clear to orange water appears to reflect a considerable deterioration of habitat for benthic macroinvertebrates and fish.
In 2022, USGS began working with the National Park Service, University of California-Davis, University of Alaska-Anchorage, and Alaska Pacific University to address several research objectives including:
- Map the spatial distribution of orange streams and the onset of stream color change across national parks in the Arctic Inventory & Monitoring Network.
- Quantify the effects of iron and other metal inputs on water quality in Arctic streams and determine landscape controls on metal mobilization.
- Assess consequences of shifts in stream water quality on stream biota, including biofilm, macroinvertebrates, and resident fish communities.
Funding: USGS Changing Arctic Ecosystem Initiative and USGS-NPS Water Quality Partnership


Below are other science projects associated with this project.
Fish and Aquatic Ecology
Q&A: Arctic Rivers Project
Hydro-Ecology of Arctic Thawing (HEAT): Ecology
Arctic – Boreal Catchment Studies
Hydro-Ecology of Arctic Thawing (HEAT): Hydrology
- Overview
The water quality of streams and rivers in the Arctic is sensitive to rapid climate change and altered disturbance regimes.
Return to Ecosystems or Water >> Fish and Aquatic Ecology
Widespread permafrost thaw, thaw-induced erosion, and wildfires have altered the concentration and flux of organic carbon, nutrients, and trace metals in Arctic rivers. Subsequently, changes in surface waters can impact the habitability for biota and growth rates for fish. Recent observations from Arctic Alaska indicate that waters draining permafrost landscapes may be susceptible to iron and carbon mobilization following thaw. One consequence of these altered iron-cycling processes is the abrupt change in color (orange) of stream and river reaches, reflecting a dramatic shift in water quality. Although the exact mechanisms are yet to be determined, evidence indicates that shifting hydrological and oxidation-reduction processes associated with permafrost thaw may function to transport high concentrations of iron in dissolved and colloidal forms from thawing soils to streams. Preliminary observations suggest that orange stream reaches have higher iron concentrations, less dissolved oxygen, and more acidic water than nearby clearwater streams. Further, the conversion of streams from clear to orange water appears to reflect a considerable deterioration of habitat for benthic macroinvertebrates and fish.
In 2022, USGS began working with the National Park Service, University of California-Davis, University of Alaska-Anchorage, and Alaska Pacific University to address several research objectives including:
- Map the spatial distribution of orange streams and the onset of stream color change across national parks in the Arctic Inventory & Monitoring Network.
- Quantify the effects of iron and other metal inputs on water quality in Arctic streams and determine landscape controls on metal mobilization.
- Assess consequences of shifts in stream water quality on stream biota, including biofilm, macroinvertebrates, and resident fish communities.
Funding: USGS Changing Arctic Ecosystem Initiative and USGS-NPS Water Quality Partnership
Sources/Usage: Public Domain. Visit Media to see details.Map of orange stream observations across Arctic Inventory and Monitoring Network (ARCN) parks in northern Alaska. Picture inserts show aerial images of select iron-impacted, orange streams. Sources/Usage: Public Domain. Visit Media to see details.Mainstem of Kugururok River located in Noatak National Park and Preserve, Alaska. - Science
Below are other science projects associated with this project.
Fish and Aquatic Ecology
Fish and aquatic habitats in Alaska support important commercial, sport, and subsistence fisheries and provide forage fish that support wildlife populations. The USGS Alaska Science Center conducts interdisciplinary research to inform local, state, federal, and international policy makers regarding conservation of fish, aquatic species, and their habitats. We work collaboratively with hydrologists...Q&A: Arctic Rivers Project
Alaska is home to numerous cultural and linguistic Indigenous groups and the largest number of Federally Recognized Tribes in the United States. Indigenous Alaskans, often living in rural remote communities, are facing multiple impacts due to climate change. As infrastructure, landscapes, and subsistence resources continue to be impacted by warming temperatures, the safety, well-being, and...Hydro-Ecology of Arctic Thawing (HEAT): Ecology
Permafrost thaw is leading to a myriad of changes in physical and chemical conditions throughout the Arctic.Arctic – Boreal Catchment Studies
Catchment hydrology focuses on the movement of water and solutes from landscapes to waterbodies. Our research addresses questions such as: Where is the stream water coming from? How long did it take to get here? What solutes, nutrients, and/or contaminants did the water pick up along the way? Because streams and lakes gather water and solutes, we can learn about the entire watershed by studying...Hydro-Ecology of Arctic Thawing (HEAT): Hydrology
The Arctic is warming at higher rates than much of the rest of the world. For Alaska, this results in changes in hydrology and ecosystems – permafrost is thawing, changing landscapes and releasing nutrients to soils and streams. - Multimedia
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