Sedimentation and Organic Carbon Burial in the Yangtze River and Hudson River Estuaries: Implications for the Global Carbon Budget

2013 ◽  
Vol 20 (2-3) ◽  
pp. 325-342 ◽  
Author(s):  
Jun Zhu ◽  
Curtis R. Olsen
Keyword(s):  
Organic Carbon ◽  
Yangtze River ◽  
Carbon Budget ◽  
Hudson River ◽  
The Yangtze River ◽  
Global Carbon Budget ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Global Carbon

scholarly journals Dynamics of riverine CO<sub>2</sub> in the Yangtze River fluvial network and their implications for carbon evasion

2017 ◽  
Vol 14 (8) ◽  
pp. 2183-2198 ◽  
Author(s):  
Lishan Ran ◽  
Xi Xi Lu ◽  
Shaoda Liu
Keyword(s):  
Organic Matter ◽  
Yangtze River ◽  
Carbon Budget ◽  
Temporal Dynamics ◽  
Water Discharge ◽  
High Pco2 ◽  
The Yangtze River ◽  
Global Carbon Budget ◽  
Fluvial Network ◽  
Global Carbon

Abstract. Understanding riverine carbon dynamics is critical for not only better estimates of various carbon fluxes but also evaluating their significance in the global carbon budget. As an important pathway of global land–ocean carbon exchange, the Yangtze River has received less attention regarding its vertical carbon evasion compared with lateral transport. Using long-term water chemistry data, we calculated CO2 partial pressure (pCO2) from pH and alkalinity and examined its spatial and temporal dynamics and the impacts of environmental settings. With alkalinity ranging from 415 to > 3400 µeq L−1, the river waters were supersaturated with dissolved CO2, generally 2–20-fold the atmospheric equilibrium (i.e., 390 µatm). Changes in pCO2 were collectively controlled by carbon inputs from terrestrial ecosystems, hydrological regime, and rock weathering. High pCO2 values were observed spatially in catchments with abundant carbonate presence and seasonally in the wet season when recently fixed organic matter was exported into the river network. In-stream processing of organic matter facilitated CO2 production and sustained the high pCO2, although the alkalinity presented an apparent dilution effect with water discharge. The decreasing pCO2 from the smallest headwater streams through tributaries to the mainstem channel illustrates the significance of direct terrestrial carbon inputs in controlling riverine CO2. With a basin-wide mean pCO2 of 2662 ± 1240 µatm, substantial CO2 evasion from the Yangtze River fluvial network is expected. Future research efforts are needed to quantify the amount of CO2 evasion and assess its biogeochemical implications for watershed-scale carbon cycle. In view of the Yangtze River's relative importance in global carbon export, its CO2 evasion would be significant for global carbon budget.

scholarly journals Dynamics of riverine CO<sub>2</sub> in the Yangtze River fluvial network and their implications for carbon evasion

2016 ◽  
Author(s):  
Lishan Ran ◽  
Xixi Lu ◽  
Shaoda Liu
Keyword(s):  
Organic Matter ◽  
Yangtze River ◽  
Carbon Budget ◽  
Temporal Dynamics ◽  
Co2 Production ◽  
High Pco2 ◽  
The Yangtze River ◽  
Global Carbon Budget ◽  
Fluvial Network ◽  
Global Carbon

Abstract. Understanding riverine carbon dynamics is critical for not only better estimates of various carbon fluxes but also evaluating their significance in the global carbon budget. As an important pathway of global land-ocean carbon exchange, the Yangtze River has received less attention regarding its vertical carbon evasion than lateral transport. Using long-term water chemistry data, we calculated CO2 partial pressure (pCO2) from pH and alkalinity and examined its spatial and temporal dynamics and the impacts of environmental settings. With alkalinity ranging from 415 to >3 400 μmol L−1, the river waters were supersaturated with dissolved CO2, generally 2–20 folds the atmospheric equilibrium (i.e., 390 μatm). Changes of pCO2 were collectively controlled by terrestrial ecosystems, hydrological regime, and rock weathering. High pCO2 values were observed spatially in catchments with abundant carbonate presence and seasonally in the wet season when recent-fixed organic matter was exported into the river network. In-stream processing of organic matter facilitated CO2 production and sustained the high pCO2, although the alkalinity presented an apparent dilution effect with lower alkalinity concentrations in higher flow periods. The decreasing pCO2 from the smallest headwater streams through tributaries to the mainstream illustrates the significance of direct terrestrial carbon input in controlling riverine carbon. With a basin-wide mean pCO2 of 2662 &amp;pm; 1240 μatm, substantial CO2 evasion from the Yangtze River fluvial network is expected. Future research efforts are thus needed to quantify the amount of CO2 evasion and assess its biogeochemical implications for watershed-scale carbon cycle. In view of the Yangtze River's relative importance in global carbon export, its CO2 evasion would be significant for global carbon budget.

Organic carbon burial in lake sediments in the middle and lower reaches of the Yangtze River Basin, China

Hydrobiologia ◽  
2012 ◽  
Vol 710 (1) ◽  
pp. 143-156 ◽  
Author(s):  
Zhi-fan Gui ◽  
Bin Xue ◽  
Shu-chun Yao ◽  
Wen-jia Wei ◽  
Sangheon Yi
Keyword(s):  
Organic Carbon ◽  
Lake Sediments ◽  
River Basin ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
The Yangtze River ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
The Yangtze River Basin

scholarly journals Reviews and syntheses: Hidden forests, the role of vegetated coastal habitats in the ocean carbon budget

2017 ◽  
Vol 14 (2) ◽  
pp. 301-310 ◽  
Author(s):  
Carlos M. Duarte
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
Primary Production ◽  
Deep Sea ◽  
Carbon Budget ◽  
Net Primary Production ◽  
Global Ocean ◽  
Coastal Habitats ◽  
Global Carbon Budget ◽  
Global Carbon

Abstract. Vegetated coastal habitats, including seagrass and macroalgal beds, mangrove forests and salt marshes, form highly productive ecosystems, but their contribution to the global carbon budget remains overlooked, and these forests remain hidden in representations of the global carbon budget. Despite being confined to a narrow belt around the shoreline of the world's oceans, where they cover less than 7 million km2, vegetated coastal habitats support about 1 to 10 % of the global marine net primary production and generate a large organic carbon surplus of about 40 % of their net primary production (NPP), which is either buried in sediments within these habitats or exported away. Large, 10-fold uncertainties in the area covered by vegetated coastal habitats, along with variability about carbon flux estimates, result in a 10-fold bracket around the estimates of their contribution to organic carbon sequestration in sediments and the deep sea from 73 to 866 Tg C yr−1, representing between 3 % and 1∕3 of oceanic CO2 uptake. Up to 1∕2 of this carbon sequestration occurs in sink reservoirs (sediments or the deep sea) beyond these habitats. The organic carbon exported that does not reach depositional sites subsidizes the metabolism of heterotrophic organisms. In addition to a significant contribution to organic carbon production and sequestration, vegetated coastal habitats contribute as much to carbonate accumulation as coral reefs do. While globally relevant, the magnitude of global carbon fluxes supported by salt-marsh, mangrove, seagrass and macroalgal habitats is declining due to rapid habitat loss, contributing to loss of CO2 sequestration, storage capacity and carbon subsidies. Incorporating the carbon fluxes' vegetated coastal habitats' support into depictions of the carbon budget of the global ocean and its perturbations will improve current representations of the carbon budget of the global ocean.

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

2020 ◽  
Vol 125 (2) ◽  
Author(s):  
Xueshi Sun ◽  
Dejiang Fan ◽  
Huijie Liao ◽  
Yuan Tian
Keyword(s):  
Organic Carbon ◽  
Yangtze River ◽  
River Estuary ◽  
Yangtze River Estuary ◽  
Modern Sediment ◽  
Carbon Burial ◽  
Organic Carbon Burial

scholarly journals Spatial Patterns of Organic and Inorganic Carbon in Lake Qinghai Surficial Sediments and Carbon Burial Estimation

2021 ◽  
Vol 9 ◽  
Author(s):  
Xi Chen ◽  
Xianqiang Meng ◽  
Yinxian Song ◽  
Bin Zhang ◽  
Zhiwei Wan ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Budget ◽  
Inorganic Carbon ◽  
Carbon Pool ◽  
Total Carbon ◽  
Tibet Plateau ◽  
Lake Area ◽  
Lake Qinghai ◽  
Carbon Burial ◽  
Global Carbon

Lake carbon burial is of vital significance in global carbon cycle and carbon budget, particularly in the large deepwater lakes. However, carbon burial in large deepwater lakes is hard to estimate due to the difficulty in obtaining high spatial-resolution samples. In this study, we investigated distributions of total organic carbon (TOC) and inorganic carbon (TIC), two main carbon components in lake sediments, based on dozens of surficial sedimentary samples (n = 26) covering whole Lake Qinghai, the largest saline lake in China. The results showed that the TOC content, with a range of 1.4–4.8%, was significantly higher in the lake area near the northern lakeshore where human activities are concentrated and lower in the lake areas near the Buha River mouth and the eastern lake area. In contrast, the TIC content, ranging from 1.5 to 3.8%, increased from the northwestern and southeastern lake areas toward the lake center, and mainly depended on hydro-chemical and hydraulic characteristics. The inorganic carbon burial (47.77 ± 19.73 Gg C yr−1) was approximately equal to organic carbon burial (47.50 ± 22.68 Gg C yr−1) and accounted for about 50% of the total carbon burial (95.27 ± 37.74 Gg C yr−1), suggesting that saline lakes constitute a large inorganic carbon pool in addition to an organic carbon pool. Because of saline water body type in arid and semiarid regions and alpine Qinghai–Tibet Plateau, lakes in these regions have huge inorganic carbon burial potential and important contributions to the global carbon budget.

scholarly journals Global carbon budget of reservoirs is overturned by the quantification of drawdown areas

2021 ◽  
Author(s):  
Philipp S. Keller ◽  
Rafael Marcé ◽  
Biel Obrador ◽  
Matthias Koschorreck
Keyword(s):  
Carbon Emissions ◽  
Carbon Budget ◽  
Water Level Fluctuations ◽  
Emission Rates ◽  
Global Carbon Budget ◽  
Carbon Burial ◽  
Reservoir Drawdown ◽  
The Tropics ◽  
Global Carbon

AbstractReservoir drawdown areas—where sediment is exposed to the atmosphere due to water-level fluctuations—are hotspots for carbon dioxide (CO2) emissions. However, the global extent of drawdown areas is unknown, precluding an accurate assessment of the carbon budget of reservoirs. Here we show, on the basis of satellite observations of 6,794 reservoirs between 1985 and 2015, that 15% of the global reservoir area was dry. Exposure of drawdown areas was most pronounced in reservoirs close to the tropics and shows a complex dependence on climatic (precipitation, temperature) and anthropogenic (water use) drivers. We re-assessed the global carbon emissions from reservoirs by apportioning CO2 and methane emissions to water surfaces and drawdown areas using published areal emission rates. The new estimate assigns 26.2 (15–40) (95% confidence interval) TgCO2-C yr−1 to drawdown areas, and increases current global CO2 emissions from reservoirs by 53% (60.3 (43.2–79.5) TgCO2-C yr−1). Taking into account drawdown areas, the ratio between carbon emissions and carbon burial in sediments is 2.02 (1.04–4.26). This suggests that reservoirs emit more carbon than they bury, challenging the current understanding that reservoirs are net carbon sinks. Thus, consideration of drawdown areas overturns our conception of the role of reservoirs in the carbon cycle.

scholarly journals Sediment Organic Carbon Sequestration of Balkhash Lake in Central Asia

2021 ◽  
Vol 13 (17) ◽  
pp. 9958
Author(s):  
Wen Liu ◽  
Long Ma ◽  
Jilili Abuduwaili ◽  
Gulnura Issanova ◽  
Galymzhan Saparov
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
The Past ◽  
Burial Rate ◽  
Carbon Burial ◽  
Sediment Organic Carbon ◽  
Organic Carbon Burial ◽  
Organic Carbon Burial Rate ◽  
Organic Carbon Sequestration ◽  
Global Carbon

As an important part of the global carbon pool, lake carbon is of great significance in the global carbon cycle. Based on a study of the sedimentary proxies of Balkhash Lake, Central Asia’s largest lake, changes in the organic carbon sequestration in the lake sediments and their possible influence over the past 150 years were studied. The results suggested that the organic carbon in the sediments of Lake Balkhash comes mainly from aquatic plants. The organic carbon burial rate fluctuated from 8.16 to 30.04 g·m−2·a−1 and the minimum appeared at the top of the core. The organic carbon burial rate continues to decline as it has over the past 150 years. Global warming, higher hydrodynamic force, and low terrestrial input have not been conducive to the improvement of organic carbon sequestration in Balkhash Lake; the construction of a large reservoir had a greater impact on the sedimentary proxy of total organic carbon content, which could lead to a large deviation for environmental reconstruction. This is the first study to assess the sediment organic carbon sequestration using the modern sediments of Central Asia’s largest lake, which is of great scientific significance. The results contribute to an understanding of organic carbon sequestration in Central Asia and may provide a scientific basis for carbon balance assessment in regional and global scales.

Rates of Organic Carbon Burial in a Floodplain Lake of the Lower Yellow River Area During the Late Holocene

Radiocarbon ◽  
2014 ◽  
Vol 56 (3) ◽  
pp. 1129-1138 ◽  
Author(s):  
Shi-Yong Yu ◽  
Chunhai Li ◽  
Xuexiang Chen ◽  
Guiyun Jin ◽  
Hui Fang
Keyword(s):  
Organic Carbon ◽  
Late Holocene ◽  
Carbon Budget ◽  
Bohai Sea ◽  
Yellow River ◽  
The Yellow River ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Carbon Burial ◽  
Organic Carbon Burial

The rapid outward and upward growth of the world's large fluvial sedimentary systems during the second half of the Holocene is a remarkable geologic process that may have buried considerable areas of pre-existing riparian wetlands, which in turn would sequester massive carbon. However, the role of floodplain lakes in the global carbon budget has long been neglected. This article demonstrates the potential of organic carbon burial due to floodplain aggradation during the late Holocene by analyzing a sediment core from a buried floodplain lake in the lower Yellow River area. Based on detailed radiocarbon dating, this study inferred that landscape development in the study area has experienced three disparate stages closely related to the displacement of the lower Yellow River channel. The first stage (∼2250–1700 cal yr BP) represents a widespread pedogenic process while the Yellow River discharged to the northern Bohai Sea through a course much farther north from the present-day position. The subsequent stage (∼1700–1000 cal yr BP) broadly corresponds to the calm period of the Yellow River while it discharged to the southern Bohai Sea through a course slightly north from the present-day position. A lacustrine environment prevailed during this period, sequestering organic carbon at a rate of ∼0.58 kg m 2 yr 1. The final stage (∼1000 cal yr BP to present) is marked by the rapid growth of the floodplain due to the frequent rerouting of the lower Yellow River. This analysis suggests that fluvial sedimentary systems should be integrated into the terrestrial carbon budget when accounting for the aberrant rise of the atmospheric CO2 in the face of global cooling during the second half of the Holocene.

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