Influence of Hydrodynamic Processes on the Fate of Sedimentary Organic Matter on Continental Margins

Bao, Rui; Voort, Tessa Sophia van der; Zhao, Meixun; Guo, Xinyu; Montluçon, Daniel B.; McIntyre, Cameron; Eglinton, T. I.

doi:10.1029/2018gb005921

Cited by 77 publications

(92 citation statements)

References 100 publications

(224 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…additional support for our interpretation: the ages of C org in 2009, 2011, 2013, and 2014 surface sediments (Δ 14 C org -ages of 1980-5040 years BP, average >2,000 years BP; Li et al, 2012;Bao et al, 2018) from the YRE and ECS were found to be approximately twice as old as the terrestrial C org (Δ 14 C org -ages of 305-1,570 years BP; in 2009 SPM derived from the Yangtze River. These results support the conclusion that reworked sedimentary C org from the riverbed and/or coastal areas appears to comprise pre-age C org and is important source of the modern YRE sediments.…”

Section: Journal Of Geophysical Research: Biogeosciencessupporting

confidence: 70%

“…Moreover, a linear relationship is observed between δ 15 N and CF in these sediments ( r = 0.671, p < 0.001, Figure b); this suggests that the enhanced coastal OM input relating to physical erosion (fine‐grained fraction) likely contributes amounts of C org to the estuarine sediments. Nevertheless, we have added additional support for our interpretation: the ages of C org in 2009, 2011, 2013, and 2014 surface sediments (Δ 14 C org ‐ages of 1980–5040 years BP, average >2,000 years BP; Li et al, ; Bao et al, ) from the YRE and ECS were found to be approximately twice as old as the terrestrial C org (Δ 14 C org ‐ages of 305–1,570 years BP; Wang et al, ) in 2009 SPM derived from the Yangtze River. These results support the conclusion that reworked sedimentary C org from the riverbed and/or coastal areas appears to comprise pre‐age C org and is important source of the modern YRE sediments.…”

Section: Discussionsupporting

confidence: 57%

See 1 more Smart Citation

Fate of Organic Carbon Burial in Modern Sediment Within Yangtze River Estuary

et al. 2020

View full text Add to dashboard Cite

Large river‐dominated margins play a potential key role in regulating global carbon cycle and budget due to high terrestrial organic carbon (Corg) inputs and sediment accumulation rates. Here bulk elements (Corg and TN), isotopic compositions (δ13Corg and δ15N), radioisotope 210Pb, sedimentary grain size, pH, Eh, and physicochemical properties were analyzed on samples from the Yangtze River Estuary to determine the mechanism involved in transporting sedimentary Corg offshore. In addition, nine box‐cores were analyzed to further reveal the potential effects of the declining sediment load on the modern depositional pattern of Corg. The statistical analyses indicate that the hydrodynamically driven sediment composition exerts a significant control on the transport, mobilization, and accumulation of sedimentary Corg from the river to the estuary, with respect to the redistribution of fine‐grained sediments. Furthermore, X‐radiographs and 210Pb indicate that reworked environment dominates carbon burial in the Yangtze proximal deposit, while a stable sedimentary environment of Corg (3.50–5.58 g cm−2 year−1) is observed in the Yangtze distal mud. Notably, the enhanced erosional inputs that contain terrestrial plant debris (mainly the coarse fractions) have tended to become important sources for Corg. Although reworked sediments in the Yangtze River Estuary are frequently exposed to oxygen during physical and biological processes, there appears to be a high potential for long‐term sedimentary Corg storage, due to its association with sediment particles (mainly the clay fractions) that provide physical protection against its degradation.

show abstract

Section: Journal Of Geophysical Research: Biogeosciencessupporting

confidence: 70%

Section: Discussionsupporting

confidence: 57%

Fate of Organic Carbon Burial in Modern Sediment Within Yangtze River Estuary

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Similarly, large amounts of HMW PAHs associated with fine-grained sediments were also transported southward to the ZMCMB, which led to a high concentration of HMW PAHs in the ZMCMB. Previous studies on widespread dispersal and aging of organic carbon in the ECS also suggested a longdistance transport process of Changjiang-derived sediments in the estuarine-inner shelf areas (Bao et al, 2016(Bao et al, , 2018. Therefore, variations in the distribution patterns of PAHs in the estuarine-inner shelf areas of the ECS after the impoundment of the TGD were mainly controlled by riverine input and sedimentary processes.…”

Section: 1029/2019jc015773mentioning

confidence: 84%

Shifts in the Distribution and Fate of Sedimentary Polycyclic Aromatic Hydrocarbons Within the Estuarine‐Inner Shelf Areas of the East China Sea: Response to Human‐Induced Catchment Change

et al. 2020

View full text Add to dashboard Cite

Human-induced changes in river catchments, such as damming, can affect estuarine depositional settings and further affect the transport of sediments and associated pollutants. Polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the East China Sea (ECS) at two time nodes (2006 and 2018) were compared to understand the response of PAHs to human-induced catchment changes. PAH concentrations in the ECS ranged from 8-414 ng g −1 (dry weight), with a mean value of 112 ± 77 ng g −1 , relatively low than that in 2006 (38-308 ng g −1 , with a mean of 122 ± 60 ng g −1 ). Sharp decreases in sediment loads have triggered erosion in subaqueous delta and changed the distribution of sediment components, which may eventually influence the distribution pattern of PAHs. The obvious spatial differentiation of PAHs between 2006 and 2018 suggested that the depositional center of PAHs shifted from the estuary to the inner shelf area. PAH deposition patterns in the ECS were primarily influenced by riverine input before 2006 but are now dominated by winnowing processes related to long-distance transport due to sharply decreased sediment loads. Dam construction in the river catchment intercepted large amounts of sediments and PAHs, shifting the Changjiang-derived PAH depositional center from the ocean to reservoirs. Overall, depositional patterns of PAHs in the ECS were largely altered by human-induced catchment changes, which may cause significant impacts on the region's biogeochemical cycles and ecosystem health. Plain Language SummaryCoastal oceans are usually considered important sinks of terrestrial materials, especially river-dominated coastal margins. However, river-derived terrestrial materials have decreased drastically in the last several decades worldwide, due to intensified human activities that have changed the local sedimentary environment. In this study, changes in the surface sediment grain size within the East China Sea from 2006 to 2018 indicated that the sedimentary environment in this region was clearly altered. Similarly, the distributions and compositions of PAHs in surface sediments changed from 2006 and 2018. Based on combined analysis of grain size and PAHs, we found that PAH dynamics in this region were primarily influenced by riverine inputs before dam construction in the Changjiang (Yangtze) River basin but are now dominated by winnowing processes related to long-distance transport due to sharply decreased sediment loads. Therefore, intensified human-induced catchment changes have significant influenced the fate of PAHs in the East China Sea.

show abstract

“…Recent studies have revealed significant aging of sedimentary OC due to its prolonged lateral transport (~4–6 year per kilometer for finer [< 63 μm] sediments; Bröder et al, ; Bao, Uchida, Zhao, et al, ; Bao, Zhao, et al, ). Hydrodynamic processes have been attributed for widespread OC aging observed in marginal sea systems globally, regardless of carbon source (Bao, van der Voort, Zhao, et al, , reference therein). The XLJ SPM sampling location is ~150 km away from P01 location.…”

Section: Resultsmentioning

confidence: 99%

“…Lateral dispersal of sedimentary OM and associated hydrodynamic processes on continental shelves add another temporal dimension (Bian et al, ; Li et al, ), further influencing 14 C ages of sedimentary OC (Bao, van der Voort, Zhao, et al, ; Bao, Uchida, Zhao, et al, ; Bröder et al, ; Keil et al, ; Mollenhauer et al, ; Tesi et al, ). These processes in marginal seas can increase 14 C ages of OM by several millennia; the magnitude of aging depends on many factors such as dispersal distance, current velocity, and sediment grain size (Bao, Zhao, et al, ; Bao, Uchida, Zhao, et al, ; Bröder et al, ).…”

Section: Introductionmentioning

confidence: 99%

On the Origin of Aged Sedimentary Organic Matter Along a River‐Shelf‐Deep Ocean Transect

et al. 2019

Self Cite

View full text Add to dashboard Cite

To assess the influences of carbon sources and transport processes on the 14 C age of organic matter (OM) in continental margin sediments, we examined a suite of samples collected along a river-shelf-deep ocean transect in the East China Sea (ECS). Ramped pyrolysis-oxidiation was conducted on suspended particulate matter in the Yangtze River and on surface sediments from the ECS shelf and northern Okinawa Trough. 14 C ages were determined on OM decomposition products within different temperature windows. These measurements suggest that extensive amounts of pre-old (i.e., millennial age) organic carbon (OC) are subject to degradation within and beyond the Yangtze River Delta, and this process is accompanied by an exchange of terrestrial and marine OM. These results, combined with fatty acid concentration data, suggest that both the nature and extent of OM preservation/degradation as well as the modes of transport influence the 14 C ages of sedimentary OM. Additionally, we find that the age of (thermally) refractory OC increases during across-shelf transport and that the age offset between the lowest and highest temperature OC decomposition fractions also increases along the shelf-to-trough transect. Amplified interfraction spread or 14 C heterogeneity is the greatest in the Okinawa Trough. Aged sedimentary OM across the transect may be a consequence of several reasons including fossil OC input, selective degradation of younger OC, hydrodynamic sorting processes, and aging during lateral transport. Consequently, each of them should be considered in assessing the 14 C results of sedimentary OM and its implications for the carbon cycle and interpretation of sedimentary records.

show abstract

Influence of Hydrodynamic Processes on the Fate of Sedimentary Organic Matter on Continental Margins

Cited by 77 publications

References 100 publications

Fate of Organic Carbon Burial in Modern Sediment Within Yangtze River Estuary

Fate of Organic Carbon Burial in Modern Sediment Within Yangtze River Estuary

Shifts in the Distribution and Fate of Sedimentary Polycyclic Aromatic Hydrocarbons Within the Estuarine‐Inner Shelf Areas of the East China Sea: Response to Human‐Induced Catchment Change

On the Origin of Aged Sedimentary Organic Matter Along a River‐Shelf‐Deep Ocean Transect

Contact Info

Product

Resources

About