Distributions of bacterial and archaeal membrane lipids in surface sediments reflect differences in input and loss of terrestrial organic carbon along a cross-shelf Arctic transect

Selver, Ayça Doğrul; Sparkes, R.; Bischoff, Juliane; Talbot, Helen M.; Gustafsson, Örjan; Semiletov, I. P.; Dudarev, Oleg; Boult, Stephen; Dongen, Bart E. van

doi:10.1016/j.orggeochem.2015.01.005

Cited by 39 publications

(24 citation statements)

References 84 publications

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“…The lowest lignin concentrations were found at stations YS39 and YS4 (Figure a), which both are samples farthest offshore (Figure ). This is in agreement with a recent report on another class of terrestrial biomarkers, the branched Glycerol Dialkyl Glycerol Tetraethers, in the underlying sediment, decreasing away from the shore, indicating a reduced influence of riverine organic matter [ Doğrul Selver et al , ]. These patterns probably mirror the larger share of woody plants and different vegetation pattern in the Lena catchment compared to farther east.…”

Section: Resultssupporting

confidence: 92%

Different sources and degradation state of dissolved, particulate, and sedimentary organic matter along the Eurasian Arctic coastal margin

Karlsson

Gelting

Tesi

et al. 2016

Global Biogeochemical Cycles

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Thawing Arctic permafrost causes massive fluvial and erosional releases of dissolved and particulate organic carbon (DOC and POC) to coastal waters. Here we investigate how different sources and degradation of remobilized terrestrial carbon may affect large‐scale carbon cycling, by comparing molecular and dual‐isotope composition of waterborne high molecular weight DOC (>1 kD, aka colloidal OC), POC, and sedimentary OC (SOC) across the East Siberian Arctic Shelves. Lignin phenol fingerprints demonstrate a longitudinal trend in relative contribution of terrestrial sources to coastal OC. Wax lipids and cutins were not detected in colloidal organic carbon (COC), in contrast to POC and SOC, suggesting that different terrestrial carbon pools partition into different aquatic carrier phases. The Δ14C signal suggests overwhelmingly contemporary sources for COC, while POC and SOC are dominated by old C from Ice Complex Deposit (ICD) permafrost. Monte Carlo source apportionment (δ13C, Δ14C) constrained that COC was dominated by terrestrial OC from topsoil permafrost (65%) and marine plankton (25%) with smaller contribution ICD and other older permafrost stocks (9%). This distribution is likely a result of inherent compositional matrix differences, possibly driven by organomineral associations. Modern OC found suspended in the surface water may be more exposed to degradation, in contrast to older OC that preferentially settles to the seafloor where it may be degraded on a longer timescale. The different sources which partition into DOC, POC, and SOC appear to have vastly different fates along the Eurasian Arctic coastal margin and may possibly respond on different timescales to climate change.

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Section: Resultssupporting

confidence: 92%

Different sources and degradation state of dissolved, particulate, and sedimentary organic matter along the Eurasian Arctic coastal margin

Karlsson

Gelting

Tesi

et al. 2016

Global Biogeochemical Cycles

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“…They were highest close to the Lena River delta and northward (roughly along 130°E). This also agrees with the patterns reported for terrestrial biomarkers such as lignin phenols (e.g., Bröder, Tesi, Andersson, et al, 2016;Karlsson et al, 2014;Tesi et al, 2014) and solvent-extractable lipids (e.g., Bischoff et al, 2016;Bröder, Tesi, Andersson, et al, 2016;Doğrul Selver et al, 2015;Karlsson et al, 2011Karlsson et al, , 2014Sparkes et al, 2015). The comparison of the distribution of bulk OC with terrOC revealed that the high OC concentrations on the outer eastern East Siberian Sea shelf are probably to a large part caused by marine primary production, since terrOC concentrations in that area are rather low.…”

Section: 1029/2018gb005967supporting

confidence: 88%

“…Earlier investigations of terrOC in Arctic margin surface sediments reported a strong decrease of terrigenous biomarker concentrations with increasing water depth/distance from the shore for the East Siberian Arctic Shelf (Bischoff et al, 2016;Bröder, Tesi, Salvadó, et al, 2016;Doğrul Selver et al, 2015;Sparkes et al, 2015Sparkes et al, , 2016Tesi et al, 2014;Vonk et al, 2010) and parts of the North American Arctic margin (Goni et al, 2013). The extent of terrOC degradation appears to be depending on its exposure to oxygen, which in turn is a function of the sediment transport time (e.g., Keil et al, 2004;Mollenhauer et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Quantifying Degradative Loss of Terrigenous Organic Carbon in Surface Sediments Across the Laptev and East Siberian Sea

Bröder

Andersson

Tesi

et al. 2019

Global Biogeochemical Cycles

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Ongoing permafrost thaw in the Arctic may remobilize large amounts of old organic matter. Upon transport to the Siberian shelf seas, this material may be degraded and released to the atmosphere, exported off‐shelf, or buried in the sediments. While our understanding of the fate of permafrost‐derived organic matter in shelf waters is improving, poor constraints remain regarding degradation in sediments. Here we use an extensive data set of organic carbon concentrations and isotopes ( n = 109) to inventory terrigenous organic carbon (terrOC) in surficial sediments of the Laptev and East Siberian Seas (LS + ESS). Of these ~2.7 Tg terrOC about 55% appear resistant to degradation on a millennial timescale. A first‐order degradation rate constant of 1.5 kyr −1 is derived by combining a previously established relationship between water depth and cross‐shelf sediment‐terrOC transport time with mineral‐associated terrOC loadings. This yields a terrOC degradation flux of ~1.7 Gg/year from surficial sediments during cross‐shelf transport, which is orders of magnitude lower than earlier estimates for degradation fluxes of dissolved and particulate terrOC in the water column of the LS + ESS. The difference is mainly due to the low degradation rate constant of sedimentary terrOC, likely caused by a combination of factors: (i) the lower availability of oxygen in the sediments compared to fully oxygenated waters, (ii) the stabilizing role of terrOC‐mineral associations, and (iii) the higher proportion of material that is intrinsically recalcitrant due to its chemical/molecular structure in sediments. Sequestration of permafrost‐released terrOC in shelf sediments may thereby attenuate the otherwise expected permafrost carbon‐climate feedback.

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“…[] observed increasing contributions of shoreline‐derived TOC (total organic carbon) with distance from the Colville Delta (ranging from 15% at SL2 to 85% at SL6); however, temperature reconstructions within Simpson Lagoon do not exhibit significant changes with distance from the river mouth. Furthermore, recent investigations of East Siberian Arctic Shelf sediments and the adjacent terrestrial environments have demonstrated that brGDGT concentrations in the Arctic shoreline bluffs are significantly lower than concentrations present in catchment soils, rivers, and marine sediments [ Peterse et al ., ; Dogrul Selver et al ., ; Sparkes et al ., ]. Sparkes et al .…”

Section: Discussionmentioning

confidence: 99%

“…In such systems aquatic brGDGT production is likely to be minimized, leading to a signal that is dominated by terrigenous brGDGT contributions. However, the use of the MBT/CBT paleothermometer in fluvial and marine sediments may also be complicated by the influx of sediment eroded from aged sediment deposits containing brGDGT distributions characteristic of the temperature/pH conditions at the time of soil formation [ De Jonge et al ., ; Dogrul Selver et al ., ; Sparkes et al ., ]. The contribution of these aged‐brGDGTs to nearshore marine sediments may be particularly significant in the Arctic, as the rates of shoreline retreat/coastal erosion are among the highest in the world [ Rachold et al ., ; Jones et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Distribution of branched GDGTs in surface sediments from the Colville River, Alaska: Implications for the MBT′/CBT paleothermometer in Arctic marine sediments

Hanna

Shanahan

2016

JGR Biogeosciences

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Significant climate fluctuations in the Arctic over the recent past, and additional predicted future temperature changes, highlight the need for high‐resolution Arctic paleoclimate records. Arctic coastal environments supplied with terrigenous sediment from Arctic rivers have the potential to provide annual to subdecadal resolution records of climate variability over the last few millennia. A potential tool for paleotemperature reconstructions in these marine sediments is the revised methylation index of branched tetraethers (MBT′)/cyclization ratio of branched tetraethers (CBT) proxy based on branched glycerol dialkyl glycerol tetraethers (brGDGTs). In this study, we examine the source of brGDGTs in the Colville River, Alaska, and the adjacent Simpson Lagoon and reconstruct temperatures from Simpson Lagoon sediments to evaluate the applicability of this proxy in Arctic estuarine environments. The Colville catchment soils, fluvial sediments, and estuarine sediments contain statistically similar brGDGT distributions, indicating that the brGDGTs throughout the system are soil derived with little alteration from in situ brGDGT production in the river or coastal waters. Temperatures reconstructed from the MBT′/CBT indices for surface samples show good agreement with regional summer (June through September) temperatures, suggesting a seasonal bias in Arctic temperature reconstructions from the Colville system. In addition, we reconstruct paleotemperatures from an estuarine sediment core that spans the last 75 years, revealing an overall warming trend in the twentieth century that is consistent with trends observed in regional instrumental records. These results support the application of this brGDGT‐based paleotemperature proxy for subdecadal‐scale summer temperature reconstructions in Arctic estuaries containing organic material derived from sediment‐laden, episodic rivers.

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Distributions of bacterial and archaeal membrane lipids in surface sediments reflect differences in input and loss of terrestrial organic carbon along a cross-shelf Arctic transect

Cited by 39 publications

References 84 publications

Different sources and degradation state of dissolved, particulate, and sedimentary organic matter along the Eurasian Arctic coastal margin

Different sources and degradation state of dissolved, particulate, and sedimentary organic matter along the Eurasian Arctic coastal margin

Quantifying Degradative Loss of Terrigenous Organic Carbon in Surface Sediments Across the Laptev and East Siberian Sea

Distribution of branched GDGTs in surface sediments from the Colville River, Alaska: Implications for the MBT′/CBT paleothermometer in Arctic marine sediments

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