7. The Arctic carbon vault

2021 ◽  
pp. 125-136
Author(s):  
Klaus Dodds ◽  
Jamie Woodward
Keyword(s):  
Organic Carbon ◽  
Carbon Sink ◽  
Ice Age ◽  
The Arctic ◽  
Yamal Peninsula ◽  
Frozen Ground ◽  
Global Soil ◽  
Shelf Sea ◽  
Thawing Permafrost ◽  
Bodies Of Water

‘The Arctic carbon vault’ describes the large share of Earth's organic carbon sequestered in the frozen ground and within the shelf sea sediments of the Arctic Ocean. The organic carbon stock of the permafrost is roughly equivalent to half of total global soil carbon. A cold Arctic with extensive permafrost is an effective long-term carbon sink as carbon is safely locked away as long as permafrost is maintained. Giant craters appeared on the Yamal peninsula. The thawing permafrost leads to the formation of thermokarst lakes, which are frozen bodies of water held in subsidence depressions created by the thawing of ground ice. Well-preserved carcasses of extinct ice age beasts, including woolly mammoths and cave bears, have been recovered from the thawing permafrost.

scholarly journals Permafrost-Affected Soils of the Russian Arctic and their Carbon Pools

2014 ◽  
Vol 6 (1) ◽  
pp. 619-655
Author(s):  
S. Zubrzycki ◽  
L. Kutzbach ◽  
E.-M. Pfeiffer
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Sink ◽  
Global Climate ◽  
Fundamental Property ◽  
Climate System ◽  
The Arctic ◽  
Quaternary Period ◽  
Permafrost Regions

Abstract. Permafrost-affected soils have accumulated enormous pools of organic matter during the Quaternary Period. The area occupied by these soils amounts to more than 8.6 million km2, which is about 27% of all land areas north of 50° N. Therefore, permafrost-affected soils are considered to be one of the most important cryosphere elements within the climate system. Due to the cryopedogenic processes that form these particular soils and the overlying vegetation that is adapted to the arctic climate, organic matter has accumulated to the present extent of up to 1024 Pg (1 Pg = 1015 g = 1 Gt) of soil organic carbon stored within the uppermost three meters of ground. Considering the observed progressive climate change and the projected polar amplification, permafrost-affected soils will undergo fundamental property changes. Higher turnover and mineralization rates of the organic matter are consequences of these changes, which are expected to result in an increased release of climate-relevant trace gases into the atmosphere. As a result, permafrost regions with their distinctive soils are likely to trigger an important tipping point within the global climate system, with additional political and social implications. The controversy of whether permafrost regions continue accumulating carbon or already function as a carbon source remains open until today. An increased focus on this subject matter, especially in underrepresented Siberian regions, could contribute to a more robust estimation of the soil organic carbon pool of permafrost regions and at the same time improve the understanding of the carbon sink and source functions of permafrost-affected soils.

Organic carbon sorbed to reactive iron minerals released during permafrost collapse

2020 ◽  
Author(s):  
Monique S. Patzner ◽  
Merritt Logan ◽  
Carsten W. Mueller ◽  
Hanna Joss ◽  
Sara E. Anthony ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Greenhouse Gas ◽  
Carbon Sink ◽  
Gas Analysis ◽  
Mineral Dissolution ◽  
Dynamic Interactions ◽  
Iron Minerals ◽  
Reactive Iron ◽  
Permafrost Soils ◽  
Thawing Permafrost

<p>The release of vast amounts of organic carbon during thawing of high-latitude permafrost is an urgent issue of global concern, yet it is unclear what controls how much carbon will be released and how fast it will be subsequently metabolized and emitted as greenhouse gases. Binding of organic carbon by iron(III) oxyhydroxide minerals can prevent carbon mobilization and degradation. This “rusty carbon sink” has already been suggested to protect organic carbon in soils overlying intact permafrost. However, the extent to which iron-bound carbon will be mobilized during permafrost thaw is entirely unknown. We have followed the dynamic interactions between iron and carbon across a thaw gradient in Abisko (Sweden), where wetlands are expanding rapidly due to permafrost retreat. Using both bulk (selective extractions, EXAFS) and nanoscale analysis (correlative SEM and nanoSIMS), we found that up to 19.4±0.7% of total organic carbon is associated with reactive iron minerals in palsa underlain by intact permafrost. However, during permafrost collapse, the rusty carbon sink is lost due to more reduced conditions which favour microbial Fe(III) mineral dissolution. This leads to high dissolved Fe(II) (2.93±0.42 mM) and organic carbon concentrations (480.06±34.10 mg/L) in the porewater at the transition of desiccating palsa to waterlogged bog. Additionally, by combining FT-ICR-MS and greenhouse gas analysis both in the field and in laboratory microcosm experiments, we are currently determining the fate of the mobilized organic carbon directly after permafrost collapse. Our findings will improve our understanding of the processes controlling organic carbon turnover in thawing permafrost soils and help to better predict future greenhouse gas emissions.</p><p> </p>

scholarly journals Permafrost-affected soils and their carbon pools with a focus on the Russian Arctic

Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 595-609 ◽  
Author(s):  
S. Zubrzycki ◽  
L. Kutzbach ◽  
E.-M. Pfeiffer
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Sink ◽  
Fundamental Property ◽  
The Arctic ◽  
Quaternary Period ◽  
Organic Carbon Pool ◽  
Property Changes ◽  
Permafrost Regions

Abstract. Permafrost-affected soils have accumulated enormous pools of organic matter during the Quaternary period. The area occupied by these soils amounts to more than 8.6 million km2, which is about 27% of all land areas north of 50° N. Therefore, permafrost-affected soils are considered to be one of the important cryosphere elements within the climate system. Due to the cryopedogenic processes that form these particular soils and the overlying vegetation that is adapted to the arctic climate, organic matter has accumulated to the present extent of up to 1024 Pg (1 Pg = 1015 g = 1 Gt) of soil organic carbon stored within the uppermost 3 m of ground. Considering the observed progressive climate change and the projected polar amplification, permafrost-affected soils will undergo fundamental property changes. Higher turnover and mineralisation rates of the organic matter are consequences of these changes, which are expected to result in an increased release of climate-relevant trace gases into the atmosphere. The controversy of whether permafrost regions continue accumulating carbon or already function as a carbon source remains open until today. An increased focus on this subject matter, especially in underrepresented Siberian regions, could contribute to a more robust estimation of the soil organic carbon pool of permafrost regions and at the same time improve the understanding of the carbon sink and source functions of permafrost-affected soils.

scholarly journals Low soil organic carbon storage in a subarctic alpine permafrost environment

2014 ◽  
Vol 8 (4) ◽  
pp. 3493-3524 ◽  
Author(s):  
M. Fuchs ◽  
P. Kuhry ◽  
G. Hugelius
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Land Cover ◽  
Carbon Sink ◽  
Vegetation Zones ◽  
Permafrost Environment ◽  
Recent Origin ◽  
Thawing Permafrost ◽  
Organic Carbon Storage ◽  
Net Carbon Sink

Abstract. This study investigates the soil organic carbon (SOC) storage in Tarfala Valley, Northern Sweden. Field inventories upscaled based on land cover show that this alpine permafrost environment does not store large amounts of SOC, with an estimate mean of 0.9 ± 0.2 kg C m−2 for the upper meter of soil. This is one to two orders of magnitude lower than what has been reported for lowland permafrost terrain. The SOC storage varies for different land cover classes and ranges from 0.05 kg C m−2 for stone-dominated to 8.4 kg C m−2 for grass-dominated areas. No signs of organic matter burial through cryoturbation or slope processes were found and radiocarbon dated SOC is generally of recent origin (<2000 cal yr BP). An inventory of permafrost distribution in Tarfala Valley, based on bottom temperature of snow measurements and a ogistic regression model, showed that at an altitude where permafrost is probable, the SOC storage is very low. In the high altitude permafrost zones (above 1500 m), soils store only ca 0.1 kg C m−2. Under future climate warming an upward shift of vegetation zones may lead to a net ecosystem C uptake from increased biomass and soil development. As a consequence, alpine permafrost environments could act as a net carbon sink in the future, as there is no loss of older or deeper SOC from thawing permafrost.

scholarly journals Siberian Arctic inland waters emit mostly contemporary carbon

2020 ◽  
Author(s):  
Joshua Dean ◽  
Ove Meisel ◽  
Melanie Martyn Roscoe ◽  
Luca Belelli Marchesini ◽  
Mark Garnett ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Carbon Emissions ◽  
Carbon Sink ◽  
Inland Waters ◽  
Terrestrial Carbon ◽  
Study Region ◽  
Inland Water ◽  
Radiocarbon Age ◽  
Thawing Permafrost

&lt;p&gt;Inland waters (rivers, lakes and ponds) are important conduits for the emission of terrestrial carbon in Arctic permafrost landscapes. These emissions are driven by turnover of contemporary terrestrial carbon and additional &amp;#8220;pre-aged&amp;#8221; (Holocene and late-Pleistocene) carbon released from thawing permafrost soils, but the magnitude of these source contributions to total inland water carbon fluxes remains unknown. Here we present unique simultaneous radiocarbon age measurements of inland water CO&lt;sub&gt;2&lt;/sub&gt;, CH&lt;sub&gt;4&lt;/sub&gt; and dissolved and particulate organic carbon in northeast Siberia during summer. We show that &gt;80% of total inland water carbon emissions were contemporary in age, but that pre-aged carbon contributed &gt;50% at sites strongly affected by permafrost thaw. CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; were younger than dissolved and particulate organic carbon, suggesting emissions were primarily fuelled by contemporary carbon decomposition. The study region was a net carbon sink (-876.9 &amp;#177; 136.4 Mg C for 25 July to 17 August), but inland waters were a source of contemporary (16.8 Mg C) and pre-aged (3.7 Mg C) emissions that respectively offset 1.9 &amp;#177; 1.2% and 0.4 &amp;#177; 0.3% of CO&lt;sub&gt;2&lt;/sub&gt; uptake by tundra (&amp;#8209;897 &amp;#177; 115 Mg C). Our findings reveal that inland water carbon emissions from permafrost landscapes may be more sensitive to changes in contemporary carbon turnover than the release of pre-aged carbon from thawing permafrost.&lt;/p&gt;

scholarly journals Characterising organic carbon sources in Anthropocene affected Arctic upland lake catchments, Disko Island, West Greenland

2020 ◽  
Author(s):  
Mark A. Stevenson ◽  
Suzanne McGowan ◽  
Emma J. Pearson ◽  
George E. A. Swann ◽  
Melanie J. Leng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Isotope Composition ◽  
Carbon Sources ◽  
Fold Increase ◽  
Arctic Lakes ◽  
Ice Age ◽  
The Arctic ◽  
Terrestrial Vegetation ◽  
Range Limit

Abstract. The Arctic is rapidly changing, disrupting biogeochemical cycles and the processing, delivery and sedimentation of carbon (C), in linked terrestrial-aquatic systems. In this investigation, we coupled a hydrogeomorphic assessment of catchment soils, sediments and plants with a recent lake sediment sequence to understand the source and quality of organic carbon present in three Arctic upland lake catchments on Disko Island, located just south of the Low-High Arctic transition zone. This varied permafrost landscape has exposed soils with less vegetation cover at higher altitudes, and all lakes received varying extent of glacial meltwater inputs. We provide improved isotope and biomarker source identifications for palaeolimnological studies in high latitude regions, where terrestrial vegetation is at or close to its northerly and altitudinal range limit. The poorly developed catchment soils lead to lake waters with low dissolved organic carbon (DOC) concentrations (≤ 1.5 mg L−1). Sedimentary Carbon / Nitrogen (C / N) ratios, the C isotope composition of organic matter (δ13Corg) and biomarker ratios (n-alkanes, n-alkanols, n-alkanoic acids and sterols) showed that sedimentary organic matter (OM) in these lakes is mostly derived from aquatic sources (algae and macrophytes). We used a 210 Pb dated sediment core to determine how carbon cycling in a lake-catchment system (Disko 2) had changed over recent centuries. Recent warming since the end of the Little Ice Age (LIA ~1860 AD), which accelerated after ca. 1950, led to melt of glacier ice and permafrost releasing nutrients and DOC to the lake, stimulating pronounced aquatic algal production, as shown by a > 10 fold increase in β-carotene, indicative of a major regime shift. Our findings highlight that in Arctic lakes with sparsely developed catchment vegetation and soils, recent Anthropocene warming results in pronounced changes to in-lake C processing and the deposition of more reactive, predominately autochthonous C, compared with extensively vegetated low Arctic systems.

scholarly journals Projected increase of Arctic coastal erosion and its sensitivity to warming in the 21st Century

2021 ◽  
Author(s):  
David Nielsen ◽  
Patrick Pieper ◽  
Armineh Barkhordarian ◽  
Paul Overduin ◽  
Tatiana Ilyina ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Coastal Erosion ◽  
Erosion Rate ◽  
Carbon Sink ◽  
The Arctic ◽  
Coastal Conservation ◽  
Organic Carbon Flux ◽  
High Emission ◽  
Future Work ◽  
The Impact

Abstract Arctic coastal erosion damages infrastructure, threatens coastal communities, and releases organic carbon from permafrost. However, the magnitude, timing and sensitivity of coastal erosion increase to global warming remain unknown. Here, we project the Arctic-mean erosion rate to roughly double by 2100 and very likely exceed its historical range of variability by mid-21st century. The sensitivity of erosion to warming also doubles, reaching 0.4-0.5 m year-1 oC-1 and 2.3-2.8 TgC year-1 oC-1 by the end of the century under moderate and high-emission scenarios. Our first 21st-century pan-Arctic coastal erosion rate projections should inform policy makers on coastal conservation and socioeconomic planning. Our organic carbon flux projections also lay out the path for future work to investigate the impact of Arctic coastal erosion on the changing Arctic Ocean, on its role as a global carbon sink, and on the permafrost-carbon feedback.

Characterization of an optical signature of the DOM of the coastal permafrost in the Mackenzie delta, by PARAFAC analysis

2021 ◽  
Author(s):  
Aude Flamand ◽  
Gwénaëlle Chaillou ◽  
Lauren Kipp ◽  
Dustin Whalen
Keyword(s):  
Organic Carbon ◽  
Coastal Area ◽  
The Arctic ◽  
Mackenzie Delta ◽  
Excitation Spectra ◽  
Northern Latitudes ◽  
Optical Signature ◽  
Arctic Soil ◽  
Global Soil ◽  
Thawing Rate

&lt;p&gt;&lt;span&gt;&lt;span&gt;Global warming increases the thawing rate of the permafrost in high northern latitudes. The Arctic soil organic carbon accounts for over 50% of global soil carbon which is roughly twice the amount present in the atmosphere. An increasing amount of the newly mobilized old organic carbon, and its associated compounds, originating from permafrost thaw, is expected to be delivered to the Arctic Ocean by rivers and groundwater discharges all along the Arctic coastline. Absorbance and fluorescence spectroscopy can be used to identify a specific optical signature of permafrost-derived solutes with the objective of studying their transport and transformation to coastal waters. &lt;/span&gt;&lt;/span&gt;&lt;span&gt;Emission-excitation spectra (EEMs) from three sampling sites along the coastal area of the delta were assessed and parallel factor analysis (PARAFAC) was used to identify three different components characterizing the origin and the nature of the organic carbon present in various types of samples (massive ice, groundwater, seawater and water samples on top/bottom of slumps). This study suggests that the carbon originating from the thawing of the permafrost could indeed be traced along the coastal area of the Delta. &lt;/span&gt;&lt;/p&gt;

scholarly journals Low below-ground organic carbon storage in a subarctic Alpine permafrost environment

2015 ◽  
Vol 9 (2) ◽  
pp. 427-438 ◽  
Author(s):  
M. Fuchs ◽  
P. Kuhry ◽  
G. Hugelius
Keyword(s):  
Organic Carbon ◽  
Land Cover ◽  
Carbon Sink ◽  
Vegetation Zones ◽  
Permafrost Environment ◽  
Below Ground ◽  
Recent Origin ◽  
Thawing Permafrost ◽  
Organic Carbon Storage ◽  
Net Carbon Sink

Abstract. This study investigates the soil organic carbon (SOC) storage in Tarfala Valley, northern Sweden. Field inventories, upscaled based on land cover, show that this alpine permafrost environment does not store large amounts of SOC, with an estimate mean of 0.9 ± 0.2 kg C m−2 for the upper meter of soil. This is 1 to 2 orders of magnitude lower than what has been reported for lowland permafrost terrain. The SOC storage varies for different land cover classes and ranges from 0.05 kg C m−2 for stone-dominated to 8.4 kg C m−2 for grass-dominated areas. No signs of organic matter burial through cryoturbation or slope processes were found, and radiocarbon-dated SOC is generally of recent origin (<2000 cal yr BP). An inventory of permafrost distribution in Tarfala Valley, based on the bottom temperature of snow measurements and a logistic regression model, showed that at an altitude where permafrost is probable the SOC storage is very low. In the high-altitude permafrost zones (above 1500 m), soils store only ca. 0.1 kg C m−2. Under future climate warming, an upward shift of vegetation zones may lead to a net ecosystem C uptake from increased biomass and soil development. As a consequence, alpine permafrost environments could act as a net carbon sink in the future, as there is no loss of older or deeper SOC from thawing permafrost.

scholarly journals Laminarin is a major molecule in the marine carbon cycle

2020 ◽  
Vol 117 (12) ◽  
pp. 6599-6607 ◽  
Author(s):  
Stefan Becker ◽  
Jan Tebben ◽  
Sarah Coffinet ◽  
Karen Wiltshire ◽  
Morten Hvitfeldt Iversen ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Atmospheric Carbon Dioxide ◽  
Carbon Sink ◽  
Light Availability ◽  
Structural Type ◽  
Trophic Levels ◽  
The Arctic ◽  
Terrestrial Plants ◽  
Carbon Export ◽  
The North

Marine microalgae sequester as much CO2into carbohydrates as terrestrial plants. Polymeric carbohydrates (i.e., glycans) provide carbon for heterotrophic organisms and constitute a carbon sink in the global oceans. The quantitative contributions of different algal glycans to cycling and sequestration of carbon remain unknown, partly because of the analytical challenge to quantify glycans in complex biological matrices. Here, we quantified a glycan structural type using a recently developed biocatalytic strategy, which involves laminarinase enzymes that specifically cleave the algal glycan laminarin into readily analyzable fragments. We measured laminarin along transects in the Arctic, Atlantic, and Pacific oceans and during three time series in the North Sea. These data revealed a median of 26 ± 17% laminarin within the particulate organic carbon pool. The observed correlation between chlorophyll and laminarin suggests an annual production of algal laminarin of 12 ± 8 gigatons: that is, approximately three times the annual atmospheric carbon dioxide increase by fossil fuel burning. Moreover, our data revealed that laminarin accounted for up to 50% of organic carbon in sinking diatom-containing particles, thus substantially contributing to carbon export from surface waters. Spatially and temporally variable laminarin concentrations in the sunlit ocean are driven by light availability. Collectively, these observations highlight the prominent ecological role and biogeochemical function of laminarin in oceanic carbon export and energy flow to higher trophic levels.

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