Low organic carbon burial efficiency in arctic lake sediments

Sobek, Sebastian; Anderson, Nicholas; Bernasconi, Stefano M.; Sontro, T. Del

doi:10.1002/2014jg002612

Cited by 62 publications

(62 citation statements)

References 59 publications

(75 reference statements)

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“…This can be substantial with, for example, averages up to 75 % of the OC mineralized over the first few decades following sediment deposition in boreal lakes in Québec (Ferland et al, 2014). Long-term (century-scale to full Holocene) accumulation rates in sediments of Arctic and boreal nonthermokarst lakes ranged between 0.2 and 13 g C m −2 yr −1 across sites in Greenland, boreal Québec, and boreal Finland (Anderson et al, 2009b;Ferland et al, 2014;Kortelainen et al, 2004;Sobek et al, 2014). Thermokarst lakes in yedoma regions, however, show much larger long-term sediment accumulation rates (47 ± 10 g C m −2 yr −1 ; Walter see Sect.…”

Section: Carbon Burial In Arctic Aquatic Ecosystemsmentioning

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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Section: Carbon Burial In Arctic Aquatic Ecosystemsmentioning

confidence: 99%

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

et al. 2015

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“…Allochthonous lakes mineralize and release large quantities of their OM input as CO 2 via photochemical and microbial degradation (Vähätalo and Wetzel ; Guillemette et al ), but also may contribute to C burial in lakes via flocculation (Wachenfeldt and Tranvik ). In contrast to hydrologically connected systems in the boreal zone, sediment records from some arctic lakes suggest an increase in autochthonous C burial (Sobek et al ; Anderson et al ). The allochthony paradigm is essentially derived from studies of lake‐watersheds that are hydrologically well connected, that is, boreal and wet, tundra environments (Kling et al ).…”

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confidence: 99%

Stable isotopes reveal independent carbon pools across an Arctic hydro‐climatic gradient: Implications for the fate of carbon in warmer and drier conditions

Osburn

Anderson

Leng

et al. 2019

Limnol Oceanogr Letters

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Arctic lakes are poised for substantial changes to their carbon (C) cycles in the near future. Autochthonous processes in lakes which consume inorganic C and create biomass that can be sequestered in sediments are accompanied by allochthonous inputs of organic matter from the surrounding watershed. Both C sources can be mineralized and degassed as CO2, but also become recalcitrant and accumulate in pelagic waters. Using stable carbon isotope (δ13C) values and elemental ratios as geochemical proxies, we investigated diverse organic matter sources to lakes located across a hydro‐climatic gradient in Southwest Greenland. Particulate organic matter (POM) and sediments were clearly of autochthonous algal origin, while dissolved organic matter (DOM) was a mix between autochthonous macrophytes and allochthonous watershed sources. Our results imply that a warmer and drier Arctic will lead to decoupled C pools: a water column dominated by increasingly autochthonous, macrophytic DOM, and sediments dominated by autochthonous algal POM.

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“… Organic carbon burial rates from lakes of the floodplain of three main river water types, i.e., whitewater 78 ± 14 ( n = 3), blackwater 203 ± 57 ( n = 13 cores), and clearwater 498 ± 124 ( n = 6) using original and previously published data (dark grey bars) compared to other freshwater lake types; arctic n = 7: 5.9 ± 1.3 SE (Sobek et al ), boreal n = 12: 19.6 ± 4.8 SE (Ferland et al ), temperate n = 116: 33 ± 2.1 SE (Dietz et al ), and tropical n = 2: 23.5 ± 5.5 SE (Sobek et al ; Alcocer et al ) (white bars). Different capital letters indicate significant difference ( p < 0.05) in carbon burial between lake types.…”

Section: Resultsmentioning

confidence: 99%

Carbon accumulation in Amazonian floodplain lakes: A significant component of Amazon budgets?

Sanders

Taffs

Stokes

et al. 2017

Limnol Oceanogr Letters

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The Amazon floodplains cover approximately 10% of the Amazon Basin and are composed of predominantly anoxic sediments that may store large amounts of carbon. Our study combines 210 Pb derived sedimentation rates from four recently analyzed sediment cores (n 5 4) with previously published organic carbon (OC) burial estimates (n 5 18) to provide a broad, first order estimate of carbon accumulation in Amazon floodplain lakes. The OC burial rates were 266 6 57 g C m 22 yr 21. This rate is several folds greater than those reported for lakes in arctic, boreal, temperate, and tropical regions. The large amount and spatial variation of OC burial rates in these floodplain lakes highlights the need for increased sampling efforts to better measure these potentially important components of the Amazon Basin carbon budget. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. Scientific Significance StatementIn the Amazon Basin, floodplains and the lakes within them are major sources of greenhouse gases. However, it is not known whether carbon burial in the floodplain lakes is large enough to offset their greenhouse gas emissions. Here, we show that Amazonian floodplain lakes can partly offset greenhouse gas emissions through significant carbon burial rates (266 6 57 g C m 22 yr 21) that are greater than any other measured lake type. By extrapolating our observations, we show that burial in Amazon floodplain lakes may play an important role in the carbon budget of the Amazon Basin.

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Low organic carbon burial efficiency in arctic lake sediments

Cited by 62 publications

References 59 publications

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

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

Stable isotopes reveal independent carbon pools across an Arctic hydro‐climatic gradient: Implications for the fate of carbon in warmer and drier conditions

Carbon accumulation in Amazonian floodplain lakes: A significant component of Amazon budgets?

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