A depositional history of particulate organic carbon in a floodplain lake from the lower Ob’ River, Siberia

Dickens, Angela F.; Baldock, J. A.; Kenna, T. C.; Eglinton, T. I.

doi:10.1016/j.gca.2011.05.032

Cited by 17 publications

(11 citation statements)

References 93 publications

(164 reference statements)

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“…These ratios from the Mackenzie freshet and lake sediments (Figures 7B, 8C) were similar to the values observed in many other polar, temperate and tropical rivers (Hedges et al, 1986;Lobbes et al, 2000;Farella et al, 2001;Gordon and Goñi, 2003;Aufdenkampe et al, 2007;Alin et al, 2008;Dickens et al, 2011) and are higher than those from fresh plant tissue (Goñi and Hedges, 1992). This indicates that the lignin in these sediments had been subject to some degree of oxidative degradation, most likely during storage in soils prior to entering the river system.…”

Section: Sources Of Oc To Suspended and Lower Delta (Lake Ld-1) Lake supporting

confidence: 81%

“…Lignin is a structural component of vascular land plant cell walls, and the concentration and composition of lignin-derived phenols is commonly used to trace higher plant-derived OC in the environment (e.g., Hedges and Mann, 1979a). The 2 values (OC-normalized) observed in the suspended and lake sediments ( Figure 8B) are similar to those observed in a number of Siberian rivers (Lobbes et al, 2000), with the exception of the Ob' and Yenisey, which drain large extents of peatlands and thus have higher 2 values (Lobbes et al, 2000;Dickens et al, 2011). The lignin content in the Mackenzie suspended sediments is also lower than most values observed from temperate (Mississippi; Bianchi et al, 2002) and tropical (Fly-Strickland and Amazon; Hedges et al, 2000;Alin et al, 2008;Feng et al, 2016) rivers.…”

Section: Sources Of Oc To Suspended and Lower Delta (Lake Ld-1) Lake supporting

confidence: 61%

“…However, because mosses yield very high amounts of p-hydroxy phenols (Williams et al, 1998;Williams and Yavitt, 2003), this ratio may provide insight into the presence of moss-or peat-derived OC in environments where this is a major source (Dickens et al, 2011;Feng et al, 2013b). The P/V values for both suspended and lake sediments ( Figure 8E) are similar to or lower than those observed in tropical (Alin et al, 2008;Feng et al, 2016) and temperate (Gordon and Goñi, 2003) rivers and (much) lower than the values of 1.0-1.4 observed in the Ob' River (Dickens et al, 2011) or 0.4-1.3 in the Lena River in Siberia (Winterfeld et al, 2015). This suggests that peat/mossderived OC is not a major source of carbon to the Mackenzie River, at least during our sampling period.…”

Section: Sources Of Oc To Suspended and Lower Delta (Lake Ld-1) Lake mentioning

confidence: 99%

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Arctic Deltaic Lake Sediments As Recorders of Fluvial Organic Matter Deposition

et al. 2016

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Arctic deltas are dynamic and vulnerable regions that play a key role in land-ocean interactions and the global carbon cycle. Delta lakes may provide valuable historical records of the quality and quantity of fluvial fluxes, parameters that are challenging to investigate in these remote regions. Here we study lakes from across the Mackenzie Delta, Arctic Canada, that receive fluvial sediments from the Mackenzie River when spring flood water levels rise above natural levees. We compare downcore lake sediments with suspended sediments collected during the spring flood, using bulk (% organic carbon, % total nitrogen, 13 δ C, 14 C) and molecular organic geochemistry (lignin, leaf waxes). High-resolution age models ( 137 Cs, 210 Pb) of downcore lake sediment records (n = 11) along with lamina counting on high-resolution radiographs show sediment deposition frequencies ranging between annually to every 15 years. Down-core geochemical variability in a representative delta lake sediment core is consistent with historical variability in spring flood hydrology (variability in peak discharge, ice jamming, peak water levels). Comparison with earlier published Mackenzie River depth profiles shows that (i) lake sediments reflect the riverine surface suspended load, and (ii) hydrodynamic sorting patterns related to spring flood characteristics are reflected in the lake sediments. Bulk and molecular geochemistry of suspended particulate matter from the spring flood peak and lake sediments are relatively similar showing a mixture of modern higher-plant derived material, older terrestrial permafrost material, and old rock-derived material. This suggests that deltaic lake sedimentary records hold great promise as recorders of past (century-scale) riverine fluxes and may prove instrumental in shedding light on past behavior of arctic rivers, as well as how they respond to a changing climate.

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Section: Sources Of Oc To Suspended and Lower Delta (Lake Ld-1) Lake supporting

confidence: 81%

Section: Sources Of Oc To Suspended and Lower Delta (Lake Ld-1) Lake supporting

confidence: 61%

Section: Sources Of Oc To Suspended and Lower Delta (Lake Ld-1) Lake mentioning

confidence: 99%

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Arctic Deltaic Lake Sediments As Recorders of Fluvial Organic Matter Deposition

et al. 2016

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“…The shift from mainly inorganic, fine grained sediments to more organic-rich material suggests contemporaneous changes in the watershed, linked to stream hydrology and possible active layer detachments (Lamoureux and Lafrenière 2009;Dickens et al 2011). The changes in sediment characteristics in this uppermost zone are further evidence for effects of warming in the region.…”

Section: Discussionmentioning

confidence: 89%

A high resolution multi-proxy record of pronounced recent environmental change at Baker Lake, Nunavut

et al. 2012

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Arctic aquatic systems are considered to be especially sensitive to anthropogenic disturbance, which can have cascading effects on biological communities as aquatic food-web structure is altered. Bio-indicators that respond to major limnological changes can be used to detect and infer major environmental change, such as climate warming, with the use of paleolimnological techniques. A multiproxy approach was used to quantify recent environmental changes at Baker Lake, Nunavut, Arctic Canada. Analyses of fossilized remains of chironomids and diatoms were conducted on a sediment core of 20 cm in length sampled at 0.5-cm intervals. A new surface sediment training set of subfossil chironomid assemblages from 65 lakes across the eastern Canadian Arctic generated a robust (r jack 2 = 0.79) surface water paleotemperature transfer function. The transfer function was applied to stratigraphic intervals from the Baker Lake sediment core to generate a paleotemperature reconstruction of sub-decadal resolution. The surface water temperature reconstruction inferred a 2°C increase in mid-summer surface water temperature for Baker Lake over the last 60 years, which was corroborated by the local instrumental record spanning the period of 1950-2007 AD. The chironomid record shows a recent decline of several cold-water taxa and appearance of warm-water indicators. This shift in community structure began circa 1906 AD, and intensified after 1940 AD. The corresponding fossil diatom record showed an increase in small planktonic Cyclotella taxa over the past 60 years, intensifying in the last 5 years, which also suggests a warmer climate and longer ice-free periods. The shifts in the diatom assemblages began later than the shifts in the chironomid assemblages, and were of lower magnitude, reflecting differences in the mechanisms in which these two indicators respond to environmental change.

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“…Source-tracing organic molecules offer a unique perspective into the fate of specific carbon pools during fluvial and coastal transport (6,(16)(17)(18)(19). As the second most abundant biopolymer and rigidifying tissue in terrestrial vascular plants, lignin represents both an excellent tracer and a quantitatively significant fraction of terrestrial OC (20).…”

mentioning

confidence: 99%

Differential mobilization of terrestrial carbon pools in Eurasian Arctic river basins

Feng

Vonk

Dongen

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Mobilization of Arctic permafrost carbon is expected to increase with warming-induced thawing. However, this effect is challenging to assess due to the diverse processes controlling the release of various organic carbon (OC) pools from heterogeneous Arctic landscapes. Here, by radiocarbon dating various terrestrial OC components in fluvially and coastally integrated estuarine sediments, we present a unique framework for deconvoluting the contrasting mobilization mechanisms of surface vs. deep (permafrost) carbon pools across the climosequence of the Eurasian Arctic. Vascular plant-derived lignin phenol 14 C contents reveal significant inputs of young carbon from surface sources whose delivery is dominantly controlled by river runoff. In contrast, plant wax lipids predominantly trace ancient (permafrost) OC that is preferentially mobilized from discontinuous permafrost regions, where hydrological conduits penetrate deeper into soils and thermokarst erosion occurs more frequently. Because river runoff has significantly increased across the Eurasian Arctic in recent decades, we estimate from an isotopic mixing model that, in tandem with an increased transfer of young surface carbon, the proportion of mobilized terrestrial OC accounted for by ancient carbon has increased by 3–6% between 1985 and 2004. These findings suggest that although partly masked by surface carbon export, climate change-induced mobilization of old permafrost carbon is well underway in the Arctic.

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A depositional history of particulate organic carbon in a floodplain lake from the lower Ob’ River, Siberia

Cited by 17 publications

References 93 publications

Arctic Deltaic Lake Sediments As Recorders of Fluvial Organic Matter Deposition

Arctic Deltaic Lake Sediments As Recorders of Fluvial Organic Matter Deposition

A high resolution multi-proxy record of pronounced recent environmental change at Baker Lake, Nunavut

Differential mobilization of terrestrial carbon pools in Eurasian Arctic river basins

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