scholarly journals Increase of organic carbon burial response to mangrove expansion in the Nanliu River estuary, South China Sea

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Tao Liu ◽  
Shengfa Liu ◽  
Bin Wu ◽  
Huipeng Xu ◽  
Hui Zhang
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Carbon Storage ◽  
South China ◽  
Accumulation Rate ◽  
River Estuary ◽  
Series Data ◽  
Coastal Zones ◽  
Mangrove Area ◽  
Mangrove Expansion

AbstractDue to high productivity, periodic submersion, and rapid sedimentation rate, mangroves are important carbon sinks in tropical-subtropical coastal zones. Mangrove expansion can significantly enhance burial carbon storage in coastal zones and has been reported in many subtropical regions due to climate change in recent years. To better understand the response of carbon storage to climate change in subtropical-tropical coastal zones, it is necessary to estimate the change in burial organic carbon (OC) storage in mangroves undergoing expansion. In the Nanliu River estuary of South China, the total mangrove area has increased from 72 to 622 ha in recent decades. Based on a sedimentology study combined with historical satellite images analysis, the accumulation rate of burial OC in these mangroves is estimated to be 400–500 g‧m−2‧y−1, of which the part imported to the stratigraphy beneath the mangrove deposit layer is approximately 130 g‧m−2‧y−1. Globally, the reported OC accumulation rate is linearly correlated to the accretion rate in mangroves. The accumulation rate of mangrove burial OC estimated in this study is significantly higher than the corresponding value on this fitted curve, indicating that the OC accumulation rates may be underestimated in such mangroves because the OC imported to the lower root layer has been not been taken into account. Based on the estimated OC accumulation rate and the time-series data of the mangrove area, the increase in burial OC storage in the mangroves of the Nanliu River estuary from 1988 to 2018 is estimated at more than 35 Gg. This study provides an example of estimating soil OC storage increase in expanding mangroves, which can help us better understand the response of coastal carbon pool to climate change.

Soil organic carbon storage by shaded and unshaded coffee systems and its implications for climate change mitigation in China

2021 ◽  
pp. 1-8
Author(s):  
Ziwei Xiao ◽  
Xuehui Bai ◽  
Mingzhu Zhao ◽  
Kai Luo ◽  
Hua Zhou ◽  
...  
Keyword(s):  
Climate Change ◽  
Linear Regression ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Multiple Linear Regression ◽  
Carbon Storage ◽  
Soil Ph ◽  
Soil Bulk Density ◽  
Soil N ◽  
And Storage

Abstract Shaded coffee systems can mitigate climate change by fixation of atmospheric carbon dioxide (CO2) in soil. Understanding soil organic carbon (SOC) storage and the factors influencing SOC in coffee plantations are necessary for the development of sound land management practices to prevent land degradation and minimize SOC losses. This study was conducted in the main coffee-growing regions of Yunnan; SOC concentrations and storage of shaded and unshaded coffee systems were assessed in the top 40 cm of soil. Relationships between SOC concentration and factors affecting SOC were analysed using multiple linear regression based on the forward and backward stepwise regression method. Factors analysed were soil bulk density (ρb), soil pH, total nitrogen of soil (N), mean annual temperature (MAT), mean annual moisture (MAM), mean annual precipitation (MAP) and elevations (E). Akaike's information criterion (AIC), coefficient of determination (R2), root mean square error (RMSE) and residual sum of squares (RSS) were used to describe the accuracy of multiple linear regression models. Results showed that mean SOC concentration and storage decreased significantly with depth under unshaded coffee systems. Mean SOC concentration and storage were higher in shaded than unshaded coffee systems at 20–40 cm depth. The correlations between SOC concentration and ρb, pH and N were significant. Evidence from the multiple linear regression model showed that soil bulk density (ρb), soil pH, total nitrogen of soil (N) and climatic variables had the greatest impact on soil carbon storage in the coffee system.

scholarly journals Carbon storage along altitudes in agrisilviculture system- Case study of Devprayag Block, Tehri District, Uttarakhand, India

2020 ◽  
Vol 7 (9) ◽  
pp. 29-38
Author(s):  
K.K. Vikrant ◽  
D.S. Chauhan ◽  
R.H. Rizvi
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Storage ◽  
Carbon Stock ◽  
Total Carbon ◽  
Total Biomass ◽  
Biomass Carbon ◽  
Total Carbon Stock ◽  
Crop Biomass

Climate change is one of the impending problems that have affected the productivity of agroecosystems which calls for urgent action. Carbon sequestration through agroforestry along altitude in mountainous regions is one of the options to contribute to global climate change mitigation. Three altitudes viz. lower (286-1200m), middle (1200-2000m), and upper (2000-2800m) have been selected in Tehri district. Ten Quadrates (10m × 10 m) were randomly selected from each altitude in agrisilviculture system. At every sampling point, one composite soil sample was taken at 30 cm soil depth for soil organic carbon analysis. For the purpose of woody biomass, Non destructive method and for crop biomass assessment destructive method was employed. Finally, aboveground biomass (AGB), belowground biomass carbon (BGB), Total tree Biomass (TTB), Crop biomass (CB), Total Biomass (TB), Total biomass carbon (TBC), soil organic carbon (SOC), and total carbon stock (TC) status were estimated and variables were compared using one-way analysis of variance (ANOVA).The result indicated that AGB, BGB, TTB, CB , TB, TBC, SOC, and TC varied significantly (p < 0.05) across the altitudes. Results showed that total carbon stock followed the order upper altitude ˃ middle altitudes ˃ lower altitude. The upper altitude (2000-2800 m) AGB, BGB,TTB, TBC,SOC, and TC stock was estimated as 2.11 Mg ha-1 , 0.52 Mg ha-1, 2.63 Mg ha-1, 2.633 Mg ha-1, 1.18 Mg ha-1 , 26.53 Mg ha-1, 38.48 Mg ha-1 respectively, and significantly higher than the other altitudes. It was concluded that agrisilviculture system hold a high potential for carbon storage at temperate zones. Quercus lucotrichophora, Grewia oppositifolia and Melia azadirach contributed maximum carbon storage which may greatly contribute to the climate resilient green economy strategy and their conservation should be promoted.

scholarly journals Spatiotemporal Evolution and Genesis of the Late Ordovician—Early Silurian Marine Euxinia in Northeastern Upper Yangtze Basin, South China

2021 ◽  
Vol 9 ◽  
Author(s):  
Chaoyong Wang ◽  
Zaitian Dong ◽  
Xuehai Fu ◽  
Qing Chen ◽  
Xiaofan Liu ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Sea Level ◽  
South China ◽  
Accumulation Rate ◽  
Water Area ◽  
Late Ordovician ◽  
Redox Conditions ◽  
Water Columns ◽  
Yangtze Basin ◽  
Upper Yangtze Basin

Marine redox conditions and their dynamic changes were a major factor that controlled the formation of black shale and caused the late Ordovician marine extinction in the Upper Yangtze Basin (South China). However, the spatiotemporal variation and potential controlling factors of marine redox conditions in this area remain unclear. We analyzed whole-rock geochemistry and pyrite sulfur isotopes (δ34Spy) of 47 shale samples from the Late Katian to Rhuddanian in a shelf-to-slope (Qianjiang Shaba section and Wc-1 well) region of northeastern Upper Yangtze Basin, and reconstructed water column redox conditions during the Late Ordovician–Early Silurian Transition. The geochemical characteristics of shale, including the ratio of elements, discriminant function and ternary diagram location in the study area suggest a passive continental margin sedimentary environment, wherein the terrigenous detritus is mainly derived from felsic igneous rocks in the upper crust, showing characteristics of near-source deposition. The redox indices (Fe speciation, Corg/P, UEF, and MoEF) showed that the development of anoxic water, especially euxinia, has obvious spatiotemporal heterogeneity. Under conditions of high availability of active organic carbon and limited sulfate supply, high active Fe input and strong biological irrigation in the shallow water area may effectively remove H2S produced by microbial sulfate reduction, conducive to the prevalence of ferruginous water columns. However, for this deep water area, the rapid accumulation rate of organic matter, decrease in dissolved Fe (caused by upwelling in the open sea), and seawater stratification (caused by the rising of sea level) promoted the development of a euxinic water column. This inference is supported by the covariant relationship between organic carbon accumulation rate, chemical index of alteration, Co × Mn, and δ34Spy. Our study highlights the potential control effects of sea level change, continental weathering and upwelling on the development of euxinic water columns.

scholarly journals Changes of lake organic carbon sinks from closed basins since the Last Glacial Maximum and quantitative evaluation of human impacts

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yu Li ◽  
Xinzhong Zhang ◽  
Lingmei Xu ◽  
Yuxin Zhang ◽  
Wangting Ye ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Carbon Storage ◽  
Human Impacts ◽  
Carbon Sinks ◽  
Closed Basin ◽  
The Past ◽  
Closed Basins ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract Background Closed basins occupy 21% of the world’s land area and can substantially affect global carbon budgets. Conventional understanding suggests that the terminal areas of closed basins collect water and carbon from throughout the entire basin, and changes in lake organic carbon sinks are indicative of basin-wide organic carbon storages. However, this hypothesis lacks regional and global validation. Here, we first validate the depositional process of organic carbon in a typical closed-basin region of northwest China using organic geochemical proxies of both soil and lake sediments. Then we estimate the organic carbon sinks and human impacts in extant closed-basin lakes since the Last Glacial Maximum (LGM). Results Results show that 80.56 Pg organic carbon is stored in extant closed-basin lakes mainly found in the northern mid-latitudes. Carbon accumulation rates vary from 17.54 g C m−2 yr−1 during modern times, 6.36 g C m−2 yr−1 during the mid-Holocene and 2.25 g C m−2 yr−1 during the LGM. Then, we evaluated the influence by human activities during the late Holocene (in the past three thousand years). The ratio of human impacts on lake organic carbon storage in above closed basins is estimated to be 22.79%, and human-induced soil organic carbon emissions in the past three thousand years amounted to 207 Pg. Conclusions While the magnitude of carbon storage is not comparable to those in peatland, vegetation and soil, lake organic carbon sinks from closed basins are significant to long-term terrestrial carbon budget and contain information of climate change and human impact from the whole basins. These observations improve our understanding of carbon sinks in closed basins at various time scales, and provide a basis for the future mitigation policies to global climate change.

scholarly journals Organic Carbon Storage in the Tropical Peat Soils and Its Impact on Climate Change

2019 ◽  
Vol 08 (01) ◽  
pp. 94-109 ◽  
Author(s):  
Md. Jashim Uddin ◽  
A. S. M. Mohiuddin ◽  
Masud Hassan
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Carbon Storage ◽  
Peat Soils ◽  
Tropical Peat ◽  
Organic Carbon Storage
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