Influences of glacier melt and permafrost thaw on the age of dissolved organic carbon in the Yukon River basin

Aiken, George R.; Spencer, Robert G. M.; Striegl, Robert G.; Schuster, Paul F.; Raymond, Peter A.

doi:10.1002/2013gb004764

Cited by 79 publications

(106 citation statements)

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“…The nonlinear relationship between Δ 14 C‐HPOA and α 254 is described by the equation y = −74 + 128 (1 − e −0.06 x ) ( R 2 = 0.50, P = 0.0003), and closely resembles the relationship between Δ 14 C‐DOC and α 254 observed by Aiken et al . []. (b) Long‐term trend in mean α 254 during maximum thaw depth (August through October) for Hess Creek.…”

Section: Resultsmentioning

confidence: 99%

“…Recent work by Aiken et al . [] documented a highly significant, nonlinear relationship between Δ 14 C‐DOC and α 254 in the Yukon River basin, highlighting the potential use of absorbance measurements to track DOM age in high‐latitude rivers. Our results further support these findings, as we observed a strong correlation between Δ 14 C‐HPOA and α 254 (Figure a).…”

Section: Discussionmentioning

confidence: 99%

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Using dissolved organic matter age and composition to detect permafrost thaw in boreal watersheds of interior Alaska

et al. 2014

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Recent warming at high latitudes has accelerated permafrost thaw, which can modify soil carbon dynamics and watershed hydrology. The flux and composition of dissolved organic matter (DOM) from soils to rivers are sensitive to permafrost configuration and its impact on subsurface hydrology and groundwater discharge. Here, we evaluate the utility of DOM composition and age as a tool for detecting permafrost thaw in three rivers (Beaver, Birch, and Hess Creeks) within the discontinuous permafrost zone of interior Alaska. We observed strong temporal controls on Δ14C content of hydrophobic acid isolates (Δ14C‐HPOA) across all rivers, with the most enriched values occurring during spring snowmelt (75 ± 8‰) and most depleted during winter flow (−21 ± 8‰). Radiocarbon ages of winter flow samples ranged from 35 to 445 yr BP, closely tracking estimated median base flow travel times for this region (335 years). During spring snowmelt, young DOM was composed of highly aromatic, high molecular‐weight compounds, whereas older DOM of winter flow had lower aromaticity and molecular weight. We observed a significant correlation between Δ14C‐HPOA and UV absorbance coefficient at 254 nm (α254) across all study rivers. Using α254 as an optical indicator for Δ14C‐HPOA, we also observed a long‐term decline in α254 during maximum annual thaw depth over the last decade at the Hess Creek study site. These findings suggest a shift in watershed hydrology associated with increasing active layer thickness. Further development of DOM optical indicators may serve as a novel and inexpensive tool for detecting permafrost degradation in northern watersheds.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Using dissolved organic matter age and composition to detect permafrost thaw in boreal watersheds of interior Alaska

et al. 2014

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“…In large Arctic rivers, Amon et al (2012) and Guo et al (2007) measured 14 C-DOC values ranging from 83 to 113 % modern (1440 to modern yr BP). Within large Arctic river basins there is significant spatial variability in riverine 14 C-DOC values, reflecting dominant water and carbon source materials (Alaska, Aiken et al, 2014;O'Donnell et al, 2014). Export of contemporary DOC in rivers dominates the spring freshet, a time of year when the majority of water and DOC export occurs.…”

Section: Release Of Old Permafrost Oc Into Aquatic Systemsmentioning

confidence: 99%

“…3.1), indicating that it may be degraded to CO 2 well before reaching the mouth of larger river systems (Kolyma River, Mann et al, 2015). Deep groundwater can also be a source of ancient DOC in large river systems (Yukon River, Aiken et al, 2014).…”

Section: Release Of Old Permafrost Oc Into Aquatic Systemsmentioning

confidence: 99%

Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

et al. 2015

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Abstract. The Arctic is a water-rich region, with freshwater systems covering about 16 % of the northern permafrost landscape. Permafrost thaw creates new freshwater ecosystems, while at the same time modifying the existing lakes, streams, and rivers that are impacted by thaw. Here, we describe the current state of knowledge regarding how permafrost thaw affects lentic (still) and lotic (moving) systems, exploring the effects of both thermokarst (thawing and collapse of ice-rich permafrost) and deepening of the active layer (the surface soil layer that thaws and refreezes each year). Within thermokarst, we further differentiate between the effects of thermokarst in lowland areas vs. that on hillslopes. For almost all of the processes that we explore, the effects of thaw vary regionally, and between lake and stream systems. Much of this regional variation is caused by differences in ground ice content, topography, soil type, and permafrost coverage. Together, these modifying factors determine (i) the degree to which permafrost thaw manifests as thermokarst, (ii) whether thermokarst leads to slumping or the formation of thermokarst lakes, and (iii) the manner in which constituent delivery to freshwater systems is altered by thaw. Differences in thaw-enabled constituent delivery can Published by Copernicus Publications on behalf of the European Geosciences Union. J. E. Vonk et al.: Effects of permafrost thaw on Arctic aquatic ecosystemsbe considerable, with these modifying factors determining, for example, the balance between delivery of particulate vs. dissolved constituents, and inorganic vs. organic materials. Changes in the composition of thaw-impacted waters, coupled with changes in lake morphology, can strongly affect the physical and optical properties of thermokarst lakes. The ecology of thaw-impacted lakes and streams is also likely to change; these systems have unique microbiological communities, and show differences in respiration, primary production, and food web structure that are largely driven by differences in sediment, dissolved organic matter, and nutrient delivery. The degree to which thaw enables the delivery of dissolved vs. particulate organic matter, coupled with the composition of that organic matter and the morphology and stratification characteristics of recipient systems will play an important role in determining the balance between the release of organic matter as greenhouse gases (CO 2 and CH 4 ), its burial in sediments, and its loss downstream. The magnitude of thaw impacts on northern aquatic ecosystems is increasing, as is the prevalence of thaw-impacted lakes and streams. There is therefore an urgent need to quantify how permafrost thaw is affecting aquatic ecosystems across diverse Arctic landscapes, and the implications of this change for further climate warming.

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“…Overland flow is generally limited to extreme rain events, and represents a relatively minor carbon flux relative to rainfall and throughfall. In the Arctic, certain regions have experienced a decrease in the role of DOM from overland flow to rivers, with greater importance on lateral flow inputs of deep soil sources due to greater thaw and increased infiltration of snowmelt waters through the active soil layer (Striegl et al, 2005;Aiken et al, 2014).…”

Section: Above-ground Carbon Flow Pathsmentioning

confidence: 99%

Where Carbon Goes When Water Flows: Carbon Cycling across the Aquatic Continuum

et al. 2017

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The purpose of this review is to highlight progress in unraveling carbon cycling dynamics across the continuum of landscapes, inland waters, coastal oceans, and the atmosphere. Earth systems are intimately interconnected, yet most biogeochemical studies focus on specific components in isolation. The movement of water drives the carbon cycle, and, as such, inland waters provide a critical intersection between terrestrial and marine biospheres. Inland, estuarine, and coastal waters are well studied in regions near centers of human population in the Northern hemisphere. However, many of the world's large river systems and their marine receiving waters remain poorly characterized, particularly in the tropics, which contribute to a disproportionately large fraction of the transformation of terrestrial organic matter to carbon dioxide, and the Arctic, where positive feedback mechanisms are likely to amplify global climate change. There are large gaps in current coverage of environmental observations along the aquatic continuum. For example, tidally-influenced reaches of major rivers and near-shore coastal regions around river plumes are often left out of carbon budgets due to a combination of methodological constraints and poor data coverage. We suggest that closing these gaps could potentially alter global estimates of CO 2 outgassing from surface waters to the atmosphere by several-fold. Finally, in order to identify and constrain/embrace uncertainties in global carbon budget estimations it is important that we further adopt statistical and modeling approaches that have become well-established in the fields of oceanography and paleoclimatology, for example.

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Influences of glacier melt and permafrost thaw on the age of dissolved organic carbon in the Yukon River basin

Cited by 79 publications

References 80 publications

Using dissolved organic matter age and composition to detect permafrost thaw in boreal watersheds of interior Alaska

Using dissolved organic matter age and composition to detect permafrost thaw in boreal watersheds of interior Alaska

Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

Where Carbon Goes When Water Flows: Carbon Cycling across the Aquatic Continuum

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