The sequestration of terrestrial organic carbon in Arctic Ocean sediments: A comparison of methods and implications for regional carbon budgets

Belicka, Laura L.; Harvey, H. Rodger

doi:10.1016/j.gca.2009.07.020

Cited by 86 publications

(69 citation statements)

References 73 publications

(127 reference statements)

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“…Mass balance calculations-Quantification of the relative input of terrestrial OM to Arctic marine sediments is usually based on bulk and molecular parameters by means of simplified two end-member mixing models (Schubert and Calvert 2001;Winkelmann and Knies 2005;Belicka and Harvey 2009). However, in general terms this approach is an oversimplification because terrestrial OM brought to the ocean is in nature heterogeneous, containing soil and ancient OM, in addition to contemporary vascular plants (Hedges et al 1997).…”

Section: Discussionmentioning

confidence: 99%

Large ancient organic matter contributions to Arctic marine sediments (Svalbard)

Kim

Peterse

Willmott

et al. 2011

Limnology & Oceanography

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Soils, fine-grained ice-rafted detritus (IRD), coals, and marine surface sediments in the Arctic realm (Svalbard) were collected in 2007 and 2008 to characterize organic matter (OM) sources in Arctic marine sediments. Bulk geochemical (C : N ratio and stable carbon isotopic composition) parameters suggest a predominant marine contribution to sedimentary OM. The branched and isoprenoid tetraether index (a proxy of soil OM input) indicates that soil OM contribution to the marine sediments is minor. However, the presence of retene (used as an indicator for coal-derived OM), the low carbon preference index and the average chain length of n-alkanes, and the depleted bulk radiocarbon content (D 14 C value) suggest that ancient OM of both coal-derived and mature IRD-derived OM is being buried in the Kongsfjord-Krossfjord system of Svalbard in the high Arctic. The relatively low retene concentrations in the marine surface sediments other than those in close vicinity of Ny Å lesund, previously a coal-mining town, indicated that input of IRD-derived OM was predominantly responsible for the generally low D 14 C value. We applied three-end-member models based on D 14 C and retene and n-alkane concentration data to disentangle relative coal-derived, IRD-derived, and marine OM proportions to sedimentary OM. Sediments were comprised on average 2% 6 4% of coal-derived OM, 37% 6 17% of IRD-derived OM, and 61% 6 18% of marine OM with higher IRD-derived OM deposit in the Kongsvegen glacier front. Our results highlight the important role of ancient OM on carbon dynamics in Arctic environments, in particular for benthic food webs.

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Section: Discussionmentioning

confidence: 99%

Large ancient organic matter contributions to Arctic marine sediments (Svalbard)

Kim

Peterse

Willmott

et al. 2011

Limnology & Oceanography

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“…Scientists in other fields use many more than 2 tracers to completely solve mixing problems with 4−8 sources (Schauer et al 1996, Belicka & Harvey 2009, Collins et al 2010. Employing more tracers to deal with multiple sources (Weiss et al 2008, Griffith et al 2009) is probably the long-term solution for currently underconstrained isotope mixing problems.…”

Section: More Tracersmentioning

confidence: 99%

Alternative approaches for solving underdetermined isotope mixing problems

Fry¹

2013

Mar. Ecol. Prog. Ser.

139

147

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Statistical mixing models have been developed to help ecologists deal with isotope tracer data and to estimate source contributions in complex systems such as food webs and sediments. However, there are often too few tracer measurements and too many sources, so that unique solutions are not possible in underdetermined mixing models. This review highlights 3 approaches for solving otherwise underdetermined mixing models. The approaches include frequency-based statistics, calculations based on sectors measured in mixing polygons, and linear mixing between central and sidewall points in the mixing polygons. All approaches have some assumptions that allow extrapolation of mean solutions from measured data, with the simplest assumption being that any uncertainty in source contributions is divided in an even-handed manner among sources. A new graphical approach is proposed that allows scientists to critically recognize and separate datasupported aspects of solutions from any assumed aspects of solutions. The data-supported aspects of solutions can be tracked conservatively as the sum of the minimum source contributions, ΣMIN , and for the many cases where ΣMIN is low, additional ways to approach mixing problems are summarized from the published literature. Many underdetermined mixing problems do not have robust mean solutions with tracers employed thus far, so that there is a longerterm need for additional tracers and methodologies to really solve these complex ecological problems. This review concludes with several practical steps one can take to interpret isotope tracer information from underdetermined systems.

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“…The GDGTs are found in diverse environments worldwide but the brGDGTs are mainly produced in the soil (by the bacteria domaine.g., Weijers et al, 2006), and the crenarchaeol is predominant in the aquatic environments and produced by Thaumarchaeota (Sinninghe Damsté et al, 2002). Accordingly, the relative amount of brGDGTs to the crenarchaeol, the so-called Branched and Isoprenoid Tetraether (BIT) index, have been proposed to quantify the OC proportion originating from soils and aquatic environments (e.g., Hopmans et al, 2004;Herfort et al, 2006;Belicka and Harvey, 2009;Smith et al, 2010). Previously, this method was successfully applied in rivers and floodplain lakes of the Amazon basin (e.g., Kim et al, 2012;Zell et al, 2013a;Moreira et al, 2014).…”

Section: R L Sobrinho Et Al: Spatial and Seasonal Contrasts Of Sedmentioning

confidence: 99%

Spatial and seasonal contrasts of sedimentary organic matter in floodplain lakes of the central Amazon basin

et al. 2016

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Abstract. In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter (SOM) in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Canaçari, Mirituba and Curuai) which have different morphologies, hydrodynamics and vegetation coverages. Surface sediments were collected in four hydrological seasons: low water (LW), rising water (RW), high water (HW) and falling water (FW) in 2009 and 2010. We investigated commonly used bulk geochemical tracers such as the C : N ratio and the stable isotopic composition of organic carbon (δ 13 C org ). These results were compared with lignin phenol parameters as an indicator of vascular plant detritus and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the input of soil organic matter (OM) from land to the aquatic settings. We also applied the crenarchaeol as an indicator of aquatic (rivers and lakes) OM. Our data showed that during the RW and FW seasons, the surface sediments were enriched in lignin and brGDGTs in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of allochthonous, C 3 plant-derived OM. However, a downstream increase in C 4 macrophyte-derived OM contribution was observed along the gradient of increasing open waters -i.e., from upstream to downstream. Accordingly, we attribute the temporal and spatial difference in SOM composition to the hydrological dynamics between the floodplain lakes and the surrounding flooded forests.

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The sequestration of terrestrial organic carbon in Arctic Ocean sediments: A comparison of methods and implications for regional carbon budgets

Cited by 86 publications

References 73 publications

Large ancient organic matter contributions to Arctic marine sediments (Svalbard)

Large ancient organic matter contributions to Arctic marine sediments (Svalbard)

Alternative approaches for solving underdetermined isotope mixing problems

Spatial and seasonal contrasts of sedimentary organic matter in floodplain lakes of the central Amazon basin

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