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Journal ArticleDOI

More than just snowmelt: integrated watershed science for changing climate and permafrost at the Cape Bounty Arctic Watershed Observatory

01 Jan 2018-Wiley Interdisciplinary Reviews: Water (John Wiley & Sons, Ltd)-Vol. 5, Iss: 1
TL;DR: The Cape Bounty Arctic Watershed Observatory (CBAWO) was established in 2003 to investigate the hydrological processes and impacts associated with climate and permafrost change in the High Arctic.
Abstract: The Cape Bounty Arctic Watershed Observatory (CBAWO) was established in 2003 to investigate the hydrological processes and impacts associated with climate and permafrost change in the High Arctic. Comprehensive data collection at the paired watersheds has spanned a period containing both the coldest and warmest melt season conditions, including the recent decade that is the warmest on record. Through this period, the hydrological regime has transitioned from a nival (snowmelt) dominated to increased importance of rainfall runoff and baseflow. This hydrological shift and associated environmental changes have altered the seasonality and magnitude of fluxes. Permafrost degradation has resulted in both localized and catchment-wide soil and runoff perturbations, broadly increasing solute and nutrient flushing, with more intense sediment and solute impacts where physical disturbances have occurred. The recovery time to perturbations diverges with sedimentary systems responding in approximately 5 years, while dissolved fluxes remaining high due to repeated thermal perturbations. Permafrost carbon in this setting is relatively old and labile, both in particulate and dissolved phases. Permafrost degradation has altered microbial activity in soils, and increased nitrification in disturbed settings, which points to complex biogeochemical responses to climate and permafrost change. Sustained research activity at CBAWO has revealed new complexity in the hydrological and biogeochemical functioning of High Arctic watersheds. Long-term observatories like CBAWO provide critical context to place observations in, especially during periods of change, and are necessary to develop a comprehensive understanding of hydrological change and water security in the region. For further resources related to this article, please visit the WIREs website.
Citations
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Journal ArticleDOI
TL;DR: In this paper, passive polyethylene samplers (PEs) deployed on deep-water moorings in the Fram Strait and in surface waters of Canadian Arctic lakes and coastal sites were analyzed for a suite of common OPEs.
Abstract: Organophosphate esters (OPEs) have been found in remote environments at unexpectedly high concentrations, but very few measurements of OPE concentrations in seawater are available, and none are available in subsurface seawater. In this study, passive polyethylene samplers (PEs) deployed on deep-water moorings in the Fram Strait and in surface waters of Canadian Arctic lakes and coastal sites were analyzed for a suite of common OPEs. Total OPEs ( ∑11OPE) at deep-water sites were dominated by chlorinated OPEs, and ranged from 6.3 to 440 pg/L. Concentrations were similar in eastern and western Fram Strait. Chlorinated OPEs were also dominant in Canadian Arctic surface waters (mean concentration ranged from < DL to 4400 pg/L), while nonhalogenated alkyl/aryl-substituted OPEs remained low (1.3–55 pg/L), possibly due to the greater long-range transport potential of chlorinated OPEs. Polybrominated diphenyl ethers (PBDEs) were found at much lower concentrations than OPEs (

80 citations

Journal ArticleDOI
TL;DR: In this paper, the impacts of permafrost change on hydrological and related hydrochemical, particulate and organic fluxes in small Arctic catchments are reviewed and compared.

79 citations

Journal ArticleDOI
TL;DR: In this article, the authors provided a detailed analysis of streamflow data from 22 hydrological gauges in the Yana and Indigirka River Basin with a period of observation ranging from 35 to 79 years up to 2015.
Abstract: Large Arctic river basins experience substantial variability in climatic, landscape, and permafrost conditions However, the processes behind the observed changes at the scale of these basins are relatively poorly understood While most studies have been focused on the “Big 6” Arctic rivers – the Ob', Yenisey, Lena, Mackenzie, Yukon, and Kolyma – few or no assessments exist for small and medium-sized river basins, such as the Yana and Indigirka River basins Here, we provide a detailed analysis of streamflow data from 22 hydrological gauges in the Yana and Indigirka River basins with a period of observation ranging from 35 to 79 years up to 2015 These river basins are fully located in the zone of continuous permafrost Our analysis reveals statistically significant ( p ) positive trends in the monthly streamflow time series during the autumn–winter period for most of the gauges The streamflow increases in a stepwise pattern (post-1981) for 17 out of 22 gauges in September (average trend value for the period of record is 58 % or 98 mm) and 15 out of 22 gauges in October (61 % or 20 mm) The positive trends are seen in 9 out of 19 rivers that do not freeze in November (54 %, 04 mm) and 6 out of 17 rivers that do not freeze in December (95 %, 015 mm) Precipitation is shown to decrease in late winter by up to 15 mm over the observational period Additionally, about 10 mm of precipitation that used to fall as snow at the beginning of winter now falls as rain Despite the decrease in winter precipitation, no decrease in streamflow has been observed during the spring freshet in May and June in the last 50 years (from 1966); moreover, five gauges show an increase of 86 % or 122 mm in spring floods via an abrupt change in 1987–1993 The changes in spring freshet start date are identified for 10 gauges; the earlier onset in May varies from 4 to 10 d over the observational period We conclude that warmer temperatures due to climate change are impacting the hydrological regime of these rivers via changes in precipitation type (rain replacing snow) Other factors, such as the melting of permafrost, glaciers, and aufeis or changes in groundwater conditions, are likely to contribute as well; however, no direct observations of these changes are available The changes in streamflow can have a significant impact on the ecology of the zone of continuous permafrost, while the increasing freshwater fluxes to the Arctic Ocean can impact the Arctic thermohaline circulation

41 citations


Cites background from "More than just snowmelt: integrated..."

  • ...Significant changes have been recently reported for small and middle-sized rivers of northwestern Canada (Spence et al., 2015), Finland (Ashraf et al., 2017), Alaska (Stuefer et al., 2017) and Canadian 75 High Arctic (Lamoureux and Lafrenière, 2017) and attributed to climate change and permafrost disturbances....

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  • ...…changes have been recently reported for small and middle-sized rivers of northwestern Canada (Spence et al., 2015), Finland (Ashraf et al., 2017), Alaska (Stuefer et al., 2017) and Canadian 75 High Arctic (Lamoureux and Lafrenière, 2017) and attributed to climate change and permafrost disturbances....

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Journal ArticleDOI
TL;DR: Overall, there was a general trend of higher fluvial PCB/OCP concentrations associated with the spring snow melt, while much lower concentrations were detected during the snow-free season, while the resulting air-water fugacity ratios and fluxes followed a remarkable shift during the sampling campaign.
Abstract: Concurrent sampling of freshwater (lakes and rivers), seawater, snow, air, and zooplankton for a range of legacy polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) was undertaken in the Canadian High Arctic during ice-covered, melting, and ice-free conditions. Overall, there was a general trend of higher fluvial PCB/OCP concentrations associated with the spring snow melt (early-mid June), while much lower concentrations were detected during the snow-free season (end of July). In contrast, PCB concentrations in two Arctic lakes (West and East Lakes, Melville Island) and in ocean waters, sharply increased in the ice-free period, likely because of inputs from the ice/snow layer melting and river runoff. The resulting air-water fugacity ratios and fluxes followed a remarkable shift during the sampling campaign. PCBs and OCPs shifted from equilibrium during ice/snow-covered conditions toward a clear net volatilization of PCBs and most of the OCPs during snow/ice-free conditions. Differences in the bioaccumulation factor for PCB/OCPs in zooplankton between West and East Lakes were observed, likely because of zooplankton being exposed to more contaminated food in West Lake due to higher turbidity related to in-lake disturbances.

28 citations

Journal ArticleDOI
TL;DR: Aufeis, also known as an icing or naled, is an accumulation of ice that forms primarily during winter when water is expelled onto frozen ground or ice surfaces and freezes in layers as discussed by the authors.
Abstract: Aufeis, also known as an icing or naled, is an accumulation of ice that forms primarily during winter when water is expelled onto frozen ground or ice surfaces and freezes in layers. Process‐oriented aufeis research initially expanded in the 20th century, but recent interest in changing hydrological conditions in permafrost regions has rejuvenated this field. Despite its societal relevance, the controls on aufeis distribution and dynamics are not well defined and this impedes projections of variation in aufeis size and distribution expected to accompany climate change. This paper reviews the physical controls on aufeis development, current broad‐scale aufeis distribution and anticipated change, and approaches to aufeis investigation. We propose an adjustment to terminology to better distinguish between the formation process and resulting ice bodies, a clarification of the aufeis classification approach based on source water, and a size threshold for broad‐scale aufeis inventory to facilitate collaborative research. We identify additional objectives for future research including advancing process knowledge at fine spatial scales, describing broad‐scale distribution using current remote sensing capabilities, and improving our understanding and predictive capacity over the interactions between aufeis and landscape‐scale permafrost, hydrogeological, geotectonic, and climate conditions.

22 citations


Cites background from "More than just snowmelt: integrated..."

  • ...suggested on the basis of 24 years of data that whereas aufeis dynamics are likely to be most affected by changing air temperature and precipitation regimes, the outcome is not clear.(22,56) Although...

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References
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Journal ArticleDOI
09 Mar 2006-Nature
TL;DR: This work has suggested that several environmental constraints obscure the intrinsic temperature sensitivity of substrate decomposition, causing lower observed ‘apparent’ temperature sensitivity, and these constraints may, themselves, be sensitive to climate.
Abstract: Significantly more carbon is stored in the world's soils--including peatlands, wetlands and permafrost--than is present in the atmosphere. Disagreement exists, however, regarding the effects of climate change on global soil carbon stocks. If carbon stored belowground is transferred to the atmosphere by a warming-induced acceleration of its decomposition, a positive feedback to climate change would occur. Conversely, if increases of plant-derived carbon inputs to soils exceed increases in decomposition, the feedback would be negative. Despite much research, a consensus has not yet emerged on the temperature sensitivity of soil carbon decomposition. Unravelling the feedback effect is particularly difficult, because the diverse soil organic compounds exhibit a wide range of kinetic properties, which determine the intrinsic temperature sensitivity of their decomposition. Moreover, several environmental constraints obscure the intrinsic temperature sensitivity of substrate decomposition, causing lower observed 'apparent' temperature sensitivity, and these constraints may, themselves, be sensitive to climate.

5,367 citations


"More than just snowmelt: integrated..." refers background in this paper

  • ...In addition to there being an abundance of carbon that is vulnerable to being released with warming, there are questions surrounding the relative biodegradability of this organic matter, which is likely to have been subject to limited decomposition.(36) Our research at CBAWO suggests that although spring thaw and flushing of the surface soil horizons typically releases the highest contributions of POC, and dissolved organic carbon (DOC) over the season, permafrost disturbance combined with changes to rainfall stand to significantly affect both the mass and the composition of the organic carbon transferred between the terrestrial and aquatic systems....

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Journal ArticleDOI
09 Apr 2015-Nature
TL;DR: In this paper, the authors find that current evidence suggests a gradual and prolonged release of greenhouse gas emissions in a warming climate and present a research strategy with which to target poorly understood aspects of permafrost carbon dynamics.
Abstract: Large quantities of organic carbon are stored in frozen soils (permafrost) within Arctic and sub-Arctic regions. A warming climate can induce environmental changes that accelerate the microbial breakdown of organic carbon and the release of the greenhouse gases carbon dioxide and methane. This feedback can accelerate climate change, but the magnitude and timing of greenhouse gas emission from these regions and their impact on climate change remain uncertain. Here we find that current evidence suggests a gradual and prolonged release of greenhouse gas emissions in a warming climate and present a research strategy with which to target poorly understood aspects of permafrost carbon dynamics.

2,282 citations

Journal ArticleDOI
TL;DR: The magnitude of species-driven differences is much larger than previously thought and greater than climate-driven variation, and the decomposability of a species' litter is consistently correlated with that species' ecological strategy within different ecosystems globally, representing a new connection between whole plant carbon strategy and biogeochemical cycling.
Abstract: Worldwide decomposition rates depend both on climate and the legacy of plant functional traits as litter quality. To quantify the degree to which functional differentiation among species affects their litter decomposition rates, we brought together leaf trait and litter mass loss data for 818 species from 66 decomposition experiments on six continents. We show that: (i) the magnitude of species-driven differences is much larger than previously thought and greater than climate-driven variation; (ii) the decomposability of a species' litter is consistently correlated with that species' ecological strategy within different ecosystems globally, representing a new connection between whole plant carbon strategy and biogeochemical cycling. This connection between plant strategies and decomposability is crucial for both understanding vegetation-soil feedbacks, and for improving forecasts of the global carbon cycle.

1,935 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented revised estimates of permafrost organic carbon stocks, including quantitative uncertainty estimates, in the 0-3 m depth range in soils as well as for sediments deeper than 3 m in deltaic deposits of major rivers and in the Yedoma region of Siberia and Alaska.
Abstract: Soils and other unconsolidated deposits in the northern circumpolar permafrost region store large amounts of soil organic carbon (SOC). This SOC is potentially vulnerable to remobilization following soil warming and permafrost thaw, but SOC stock estimates were poorly constrained and quantitative error estimates were lacking. This study presents revised estimates of permafrost SOC stocks, including quantitative uncertainty estimates, in the 0–3 m depth range in soils as well as for sediments deeper than 3 m in deltaic deposits of major rivers and in the Yedoma region of Siberia and Alaska. Revised estimates are based on significantly larger databases compared to previous studies. Despite this there is evidence of significant remaining regional data gaps. Estimates remain particularly poorly constrained for soils in the High Arctic region and physiographic regions with thin sedimentary overburden (mountains, highlands and plateaus) as well as for deposits below 3 m depth in deltas and the Yedoma region. While some components of the revised SOC stocks are similar in magnitude to those previously reported for this region, there are substantial differences in other components, including the fraction of perennially frozen SOC. Upscaled based on regional soil maps, estimated permafrost region SOC stocks are 217 ± 12 and 472 ± 27 Pg for the 0–0.3 and 0–1 m soil depths, respectively (±95% confidence intervals). Storage of SOC in 0–3 m of soils is estimated to 1035 ± 150 Pg. Of this, 34 ± 16 Pg C is stored in poorly developed soils of the High Arctic. Based on generalized calculations, storage of SOC below 3 m of surface soils in deltaic alluvium of major Arctic rivers is estimated as 91 ± 52 Pg. In the Yedoma region, estimated SOC stocks below 3 m depth are 181 ± 54 Pg, of which 74 ± 20 Pg is stored in intact Yedoma (late Pleistocene ice- and organic-rich silty sediments) with the remainder in refrozen thermokarst deposits. Total estimated SOC storage for the permafrost region is ∼1300 Pg with an uncertainty range of ∼1100 to 1500 Pg. Of this, ∼500 Pg is in non-permafrost soils, seasonally thawed in the active layer or in deeper taliks, while ∼800 Pg is perennially frozen. This represents a substantial ∼300 Pg lowering of the estimated perennially frozen SOC stock compared to previous estimates.

1,168 citations


"More than just snowmelt: integrated..." refers background in this paper

  • ...The total carbon stored in the circumpolar permafrost is estimated to be approximately 1300 Pg of C, of this 800 Pg is in permafrost, while the remaining 500 Pg is in the active layer.(35) There is, therefore, approximately an equal mass of carbon in Arctic permafrost, that is, potentially vulnerable to decomposition and mobilization following permafrost thaw and/or disturbance, as there is carbon in the atmosphere....

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Journal ArticleDOI
TL;DR: A review of recent studies investigating linkages between permafrost dynamics and river biogeochemistry in the Arctic is presented in this article, including consideration of likely impacts that warming-induced changes in permfrost may be having (or will have in the future) on the delivery of organic matter, inorganic nutrients, and major ions to the Arctic Ocean.
Abstract: Over the next century, near-surface permafrost across the circumpolar Arctic is expected to degrade significantly, particularly for land areas south of 70°N. This is likely to cause widespread impacts on arctic hydrology, ecology, and trace gas emissions. Here, we present a review of recent studies investigating linkages between permafrost dynamics and river biogeochemistry in the Arctic, including consideration of likely impacts that warming-induced changes in permafrost may be having (or will have in the future) on the delivery of organic matter, inorganic nutrients, and major ions to the Arctic Ocean. These interacting processes can be highly complex and undoubtedly exhibit spatial and temporal variabilities associated with current permafrost conditions, sensitivity to permafrost thaw, mode of permafrost degradation (overall permafrost thaw, active layer deepening, and/or thermokarst processes), and environmental characteristics of watersheds (e.g. land cover, soil type, and topography). One of the most profound consequences of permafrost thaw projected for the future is that the arctic terrestrial freshwater system is likely to experience a transition from a surface water-dominated system to a groundwater-dominated system. Along with many other cascading impacts from this transition, mineral-rich groundwater may become an important contributor to streamflow, in addition to the currently dominant contribution from mineral-poor surface water. Most studies observe or predict an increase in major ion, phosphate, and silicate export with this shift towards greater groundwater contributions. However, we see conflicting accounts of whether the delivery of inorganic nitrogen and organic matter will increase or decrease with warming and permafrost thaw. It is important to note that uncertainties in the predictions of the total flux of biogeochemical constituents are tightly linked to future uncertainties in discharge of rivers. Nonetheless, it is clear that over the next century there will be important shifts in the river transport of organic matter, inorganic nutrients, and major ions, which may in turn have critical implications for primary production and carbon cycling on arctic shelves and in the Arctic Ocean basin interior. Copyright © 2008 John Wiley & Sons, Ltd.

605 citations


"More than just snowmelt: integrated..." refers background in this paper

  • ...Rapidly changing climate and permafrost in the Arctic has resulted in an unprecedented scientific effort to advance knowledge in the processes and impacts of this change on hydrological systems and increasingly on related biogeochemical processes.(1,2) Key research themes include: hydrological responses to *Correspondence to: scott....

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