Metal mobilization from thawing permafrost to aquatic ecosystems is driving rusting of Arctic streams – Communications Earth & Environment

Abstract

Climate change in the Arctic is altering watershed hydrologic processes and biogeochemistry. A recent observation from Alaska’s Brooks Range shows 75 streams turning orange, indicating increased iron and toxic metal loading, likely due to permafrost thaw. This has significant implications for drinking water and subsistence fisheries in rural Alaska.

Introduction

The Arctic is experiencing rapid warming, affecting the linkages between terrestrial and aquatic ecosystems. Permafrost thaw alters hydrologic flow paths and mobilizes chemical constituents from soils to streams and rivers. An emergent phenomenon in Alaska’s Brooks Range threatens pristine streams, with surface waters changing from clear to orange color, suggesting an impaired state.

Results and Discussion

Observations of Orange Streams in Alaska’s Brooks Range

Orange streams have been observed across northern Alaska, with 75 altered headwater tributaries documented. These streams have lower pH, higher turbidity, and higher concentrations of sulfate, iron, and trace metals compared to clear reference streams.

Geochemical Consequences of Trace Metal Mobilization

The chemical composition of recently degraded streams indicates mobilization of at least iron from catchment soils. This has led to lower pH and higher concentrations of metals in orange streams.

Constraining the Onset of Stream Discoloration

Landsat images suggest elevated redness in these streams since 2018, indicating discoloration due to Fe mobilization.

Biological Consequences of Trace Metal Mobilization

Mobilization of Fe and toxic metals to Arctic streams may degrade water quality and reduce habitat, affecting fish species critical for subsistence fisheries.

Possible Causes of Trace Metal Mobilization to Streams

Permafrost thaw alters stream chemistry through changes in watershed hydrology and biogeochemical cycling. Climate change-induced permafrost thaw is hypothesized to be responsible for the abrupt shifts in stream color and chemistry.

Implications for Rural Communities and Subsistence Users

The emergence of orange streams represents a threat to subsistence fisheries and rural drinking water supplies. Communities dependent on subsistence foods may face challenges due to increased vulnerability of fish species and potential drinking water impairment.

Methods

Geochemical Assessment of Impaired and Reference Streams

Water samples were collected from discolored reaches and compared to nearby unimpaired reference streams.

Time Series of Stream Discoloration Using Landsat

Landsat images were analyzed to produce time series of historical water conditions.

Stream Food Web Characterization

Benthic biofilm, macroinvertebrates, and resident fish were collected from a tributary of the Akillik River before and after stream discoloration.

Data Availability

Data supporting this study are publicly available through the U.S. Geological Survey.

Acknowledgements

The work was supported by the U.S. Geological Survey-National Park Service Water Quality Partnership Program, the USGS Changing Arctic Ecosystem Initiative, and the NPS Arctic Inventory & Monitoring Program.

Author Information

The study was conducted by a team of researchers from various institutions including the National Park Service, U.S. Geological Survey, University of Alaska Anchorage, Alaska Pacific University, and University of California-Riverside.

Ethics Declarations

The authors declare no competing interests.

Peer Review

The article was peer-reviewed by experts in the field.

Additional Information

Publisher’s note: Springer Nature remains neutral regarding jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Supplementary information is available for this paper.

Rights and Permissions

This article is licensed under a Creative Commons Attribution 4.0 International License.

About this Article

This article discusses the impact of climate change on Arctic watersheds, specifically the discoloration of streams in Alaska’s Brooks Range due to permafrost thaw.

Which SDGs are addressed or connected to the issues highlighted in the article?

The Sustainable Development Goals (SDGs) addressed or connected to the issues highlighted in the article include:

• SDG 6: Clean Water and Sanitation
• SDG 13: Climate Action
• SDG 14: Life Below Water
• SDG 15: Life on Land

What specific targets under those SDGs can be identified based on the article’s content?

Specific targets under the SDGs based on the article’s content include:

• Target 6.3: Improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials
• Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters
• Target 14.1: Prevent and significantly reduce marine pollution of all kinds, particularly from land-based activities
• Target 15.1: Ensure the conservation, restoration, and sustainable use of terrestrial and inland freshwater ecosystems

Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

The indicators mentioned or implied in the article that can be used to measure progress towards the identified targets include:

• Indicator for Target 6.3: Concentrations of hazardous chemicals in water bodies (e.g., iron, toxic metals)
• Indicator for Target 13.1: Occurrence and severity of climate-related hazards (e.g., permafrost thaw)
• Indicator for Target 14.1: Levels of pollutants in rivers and streams leading to the ocean
• Indicator for Target 15.1: Status of water bodies within terrestrial and freshwater ecosystems (e.g., stream discoloration)

Create a table with three columns titled ‘SDGs, Targets and Indicators” to present the findings from analyzing the article.

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Fuente: nature.com

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