Elemental and isotopic signatures of particulate organic carbon in the Zengjiang River, southern China

Gao, Qiuming; Zuyi, Tao; Yao, Guanrong; Ding, Jing; Liu, Zufa; Liu, Kexin

doi:10.1002/hyp.6358

Cited by 34 publications

(31 citation statements)

References 46 publications

(53 reference statements)

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“…Given the relationship between density and survivor functions, Eqs. (14) and (15) Gao et al (2007) values that overlaps with our best-fit estimate of α d from fitting Eq. (14) to the deposit age distribution derived from fifty replicate model simulations (α d = 0.1; Fig.…”

Section: Meandering Model Predictions Of Storage Durationsmentioning

confidence: 54%

Model predictions of long-lived storage of organic carbon in river deposits

et al. 2017

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Abstract. The mass of carbon stored as organic matter in terrestrial systems is sufficiently large to play an important role in the global biogeochemical cycling of CO 2 and O 2 . Field measurements of radiocarbon-depleted particulate organic carbon (POC) in rivers suggest that terrestrial organic matter persists in surface environments over millennial (or greater) timescales, but the exact mechanisms behind these long storage times remain poorly understood. To address this knowledge gap, we developed a numerical model for the radiocarbon content of riverine POC that accounts for both the duration of sediment storage in river deposits and the effects of POC cycling. We specifically target rivers because sediment transport influences the maximum amount of time organic matter can persist in the terrestrial realm and river catchment areas are large relative to the spatial scale of variability in biogeochemical processes.Our results show that rivers preferentially erode young deposits, which, at steady state, requires that the oldest river deposits are stored for longer than expected for a well-mixed sedimentary reservoir. This geometric relationship can be described by an exponentially tempered power-law distribution of sediment storage durations, which allows for significant aging of biospheric POC. While OC cycling partially limits the effects of sediment storage, the consistency between our model predictions and a compilation of field data highlights the important role of storage in setting the radiocarbon content of riverine POC. The results of this study imply that the controls on the terrestrial OC cycle are not limited to the factors that affect rates of primary productivity and respiration but also include the dynamics of terrestrial sedimentary systems.

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Section: Meandering Model Predictions Of Storage Durationsmentioning

confidence: 54%

Model predictions of long-lived storage of organic carbon in river deposits

et al. 2017

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“…The Nanliu River is characterized by intermediate concentrations of suspended particulate matter compared to other rivers (Bouillon et al, 2007a;Burns et al, 2008;Davies, 2004;Gao et al, 2007;Jennerjahn et al, 2008Jennerjahn et al, , 2004Unger et al, 2013), including some major Chinese streams (Ni et al, 2008;Zhang et al, 1998), but concentrations are lower than in the Changjiang (Ittekkot and Zhang, 1989;Mao et al, 2010;Wang et al, 2012) and Huanghe (Ittekkot and Zhang, 1989;Mayer et al, 1998;Wang et al, 2012). The Red River, also debouching into the Beibu Gulf, carries considerably higher SPM concentrations of 4200 mg L À 1 (Dang et al, 2010).…”

Section: Concentrations and Fluxes Of Suspended Particulate Mattermentioning

confidence: 99%

Particulate organic matter dynamics in coastal systems of the northern Beibu Gulf

Kaiser

Unger

Qiu

2014

Continental Shelf Research

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“…2b and 3b). A decrease of particulate organic carbon with increasing SS is reported in studies worldwide (Onstad et al, 2000;Meybeck, 1982;Gao et al, 2007;Zhang et al, 2009). The pattern can be explained by a dilution of C org during high sediment loads with mineral matter derived from terrigenous soil erosion or remobilizing of mineral matter of the riverbed (Zhang et al, 2009).…”

Section: Spatial and Temporal Dynamics Of C Org In Sedimentsmentioning

confidence: 84%

“…Sediment tracer-based methods have been used to distinguish possible sources in watersheds. Stable carbon (C) and nitrogen (N) isotopes and as well as the carbon to nitrogen atomic ratio (C/Na) have been found to be reliable tracers in recent studies (Onstad et al, 2000;McConnachie and Petticrew, 2006;Fox and Papanicolaou, 2007;Gao et al, 2007;Fox et al, 2010). Stable isotope compositions as well as C/Na are affected by many factors including soil depth, vegetation, climate and cultural history (Kendall, 1998).…”

mentioning

confidence: 99%

Organic matter dynamics and stable isotope signature as tracers of the sources of suspended sediment

Wildhaber¹,

Liechti²,

Alewell³

2012

Biogeosciences

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Abstract. Suspended sediment (SS) and organic matter in rivers can harm brown trout Salmo trutta by affecting the health and fitness of free swimming fish and by causing siltation of the riverbed. The temporal and spatial dynamics of sediment, carbon (C), and nitrogen (N) during the brown trout spawning season in a small river of the Swiss Plateau were assessed and C isotopes as well as the C/N atomic ratio were used to distinguish autochthonous and allochthonous sources of organic matter in SS loads. The visual basic program IsoSource with 13 C tot and 15 N as input isotopes was used to quantify the temporal and spatial sources of SS. Organic matter concentrations in the infiltrated and suspended sediment were highest during low flow periods with small sediment loads and lowest during high flow periods with high sediment loads. Peak values in nitrate and dissolved organic C were measured during high flow and high rainfall, probably due to leaching from pasture and arable land. The organic matter was of allochthonous sources as indicated by the C/N atomic ratio and δ 13 C org . Organic matter in SS increased from up-to downstream due to an increase of pasture and arable land downstream of the river. The mean fraction of SS originating from upper watershed riverbed sediment decreased from up to downstream and increased during high flow at all measuring sites along the course of the river. During base flow conditions, the major sources of SS are pasture, forest and arable land. The latter increased during rainy and warmer winter periods, most likely because both triggered snow melt and thus erosion. The measured increase in DOC and nitrate concentrations during high flow support these modeling results. Enhanced soil erosion processes on pasture and arable land are expected with increasing heavy rain events and less snow during winter seasons due to climate change. Consequently, SS and organic matter in the river will increase, which will possibly affect brown trout negatively.

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Elemental and isotopic signatures of particulate organic carbon in the Zengjiang River, southern China

Cited by 34 publications

References 46 publications

Model predictions of long-lived storage of organic carbon in river deposits

Model predictions of long-lived storage of organic carbon in river deposits

Particulate organic matter dynamics in coastal systems of the northern Beibu Gulf

Organic matter dynamics and stable isotope signature as tracers of the sources of suspended sediment

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