scholarly journals Effects of Pneumatophore Density on Methane Emissions in Mangroves

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 314
Author(s):  
Chiao-Wen Lin ◽  
Yu-Chen Kao ◽  
Wei-Jen Lin ◽  
Chuan-Wen Ho ◽  
Hsing-Juh Lin
Keyword(s):  
Soil Properties ◽  
Ghg Emissions ◽  
Avicennia Marina ◽  
Organic Content ◽  
Key Factors ◽  
Soil Redox Potential ◽  
Soil Redox ◽  
Factors Affecting ◽  
Ch4 Emissions ◽  
Mangrove Soils

Mangroves play an important role in carbon sequestration. However, mangroves can be sources of greenhouse gas (GHG) emissions. In this study, methane (CH4) emissions and related soil properties were determined in multiple mangroves in Taiwan, including Kandelia obovata and Avicennia marina mangroves. K. obovata possess prop roots, whereas pneumatophores are found in A. marina. Our results showed that mangrove soils were significant sources of CH4 emissions, which should be accounted for in mangrove carbon budgets. In particular, CH4 emissions in the A. marina mangroves were approximately 50- to 100-fold those of the K. obovata mangroves and the adjoining mudflats. Multiple regression analyses indicated that the soil salinity and pH in K. obovata mangroves and the soil redox potential and organic content in the mudflats were the key factors affecting CH4 emissions. However, the pneumatophore density alone explained approximately 48% of the variation in CH4 emissions in the A. marina mangroves. More pneumatophores resulted in higher CH4 emissions in the A. marina mangroves. Thus, compared with the assessed soil properties, the contribution of pneumatophores to the transportation of CH4 from soil was more significant. In addition to soil properties, our results demonstrated that the root structure may also affect GHG emissions from mangroves.

Environmental controls in Pacific Northwest intertidal marsh plant communities

1983 ◽  
Vol 61 (4) ◽  
pp. 1105-1116 ◽  
Author(s):  
Kern Ewing
Keyword(s):  
Redox Potential ◽  
Pacific Northwest ◽  
Soil Texture ◽  
Puget Sound ◽  
Principal Component ◽  
Organic Content ◽  
Mode Analysis ◽  
Soil Redox Potential ◽  
Soil Redox ◽  
Environmental Controls

Relationships between environmental variables and species distribution were studied in a brackish intertidal marsh formed by the Skagit River as it enters the Puget Sound bay system in Washington. Transects were established which covered the range of environmental variation in the marsh. A grid of environmental measuring stations provided information on soil texture, organic content of soil fines, macroorganic material in the soil, soil temperatures, interstitial soil water salinity, soil redox potential, and site elevation. Binary discriminant analysis, a nonparametric method using species presence–absence data, was used to construct standardized residual matrices. Principal component analysis of standardized residuals (Q mode) indicated that salinity and soil texture were strongly correlated with the first factor generated, elevation with the second, and soil redox potential with the third. The factors explained, respectively, 48, 21, and 14% of the variance in the residuals matrix. From R-mode analysis, eight community types were derived: three dominated by Carex lyngbyei, two by Scirpus americanus, one by Scirpus maritimus, and two which are highly diverse.

scholarly journals Methane Emissions from Subtropical and Tropical Mangrove Ecosystems in Taiwan

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 470
Author(s):  
Chiao-Wen Lin ◽  
Yu-Chen Kao ◽  
Meng-Chun Chou ◽  
Hsin-Hsun Wu ◽  
Chuan-Wen Ho ◽  
...  
Keyword(s):  
Soil Properties ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Carbon Storage ◽  
Organic Matter Content ◽  
Avicennia Marina ◽  
Soil Parameters ◽  
Gas Emissions ◽  
Mangrove Ecosystems ◽  
Mangrove Soils

Mangroves are one of the blue carbon ecosystems. However, greenhouse gas emissions from mangrove soils may reduce the capacity of carbon storage in these systems. In this study, methane (CH4) fluxes and soil properties of the top 10 cm layer were determined in subtropical (Kandelia obovata) and tropical (Avicennia marina) mangrove ecosystems of Taiwan for a complete seasonal cycle. Our results demonstrate that CH4 emissions in mangroves cannot be neglected when constructing the carbon budgets and estimating the carbon storage capacity. CH4 fluxes were significantly higher in summer than in winter in the Avicennia mangroves. However, no seasonal variation in CH4 flux was observed in the Kandelia mangroves. CH4 fluxes were significantly higher in the mangrove soils of Avicennia than in the adjoining mudflats; this trend, however, was not necessarily recapitulated at Kandelia. The results of multiple regression analyses show that soil water and organic matter content were the main factors regulating the CH4 fluxes in the Kandelia mangroves. However, none of the soil parameters assessed show a significant influence on the CH4 fluxes in the Avicennia mangroves. Since pneumatophores can transport CH4 from anaerobic deep soils, this study suggests that the pneumatophores of Avicennia marina played a more important role than soil properties in affecting soil CH4 fluxes. Our results show that different mangrove tree species and related root structures may affect greenhouse gas emissions from the soils.

scholarly journals Rhizosphere to the atmosphere: contrasting methane pathways, fluxes and geochemical drivers across the terrestrial-aquatic wetland boundary

2019 ◽  
Author(s):  
Luke C. Jeffrey ◽  
Damien T. Maher ◽  
Scott Johnston ◽  
Kylie Maguire ◽  
Andrew D. L. Steven ◽  
...  
Keyword(s):  
Freshwater Wetlands ◽  
Sediment Geochemistry ◽  
Emission Rates ◽  
Redox Potentials ◽  
Habitat Variability ◽  
Soil Redox Potential ◽  
Ch4 Flux ◽  
Soil Redox ◽  
Ch4 Emissions ◽  
Seasonal Wetland

Abstract. Although wetlands represent the largest natural source of atmospheric CH4, large uncertainties remain regarding the global CH4 flux. Wetland hydrological oscillations contribute to this uncertainty, dramatically altering wetland area, water table height, soil redox potentials and CH4 emissions. This study compares both terrestrial and aquatic CH4 fluxes over two distinct seasons in both permanent and seasonal remediated freshwater wetlands in subtropical Australia. We account for aquatic CH4 diffusion and ebullition rates, and plant-mediated CH4 fluxes from three distinct vegetation communities, thereby examining seasonal, diurnal and intra-habitat variability. CH4 emission rates were related to underlying sediment geochemistry. For example, distinct negative relationships between Fe(III) and SO42− and CH4 fluxes were observed, whereas distinct positive trends occurred between CH4 emissions and Fe(II) / AVS, where sediment Fe(III) and SO42− were depleted. The highest CH4 emissions of the seasonal wetland were measured during flooded conditions and always during daylight hours, which is consistent with soil redox potential and temperature being important co-drivers of CH4 flux. The highest CH4 fluxes were consistently emitted from the permanent wetland (1.5 to 10.5 mmol m−2 d−1), followed by the Phragmites australis community within the seasonal wetland (0.8 to 2.3 mmol m−2 d−1), whilst the lowest CH4 fluxes came from a region of forested Juncus sp. (−0.01 to 0.1 mmol m−2 d−1) which also corresponded with the highest sedimentary Fe(III) and SO42−. We suggest that wetland remediation strategies should consider geochemical profiles to help to mitigate excessive and unwanted methane emissions, especially during early system recovery periods.

scholarly journals Rhizosphere to the atmosphere: contrasting methane pathways, fluxes, and geochemical drivers across the terrestrial–aquatic wetland boundary

2019 ◽  
Vol 16 (8) ◽  
pp. 1799-1815 ◽  
Author(s):  
Luke C. Jeffrey ◽  
Damien T. Maher ◽  
Scott G. Johnston ◽  
Kylie Maguire ◽  
Andrew D. L. Steven ◽  
...  
Keyword(s):  
Climatic Conditions ◽  
Freshwater Wetlands ◽  
Sediment Geochemistry ◽  
Emission Rates ◽  
Redox Potentials ◽  
Soil Redox Potential ◽  
Ch4 Flux ◽  
Soil Redox ◽  
Ch4 Emissions ◽  
Seasonal Wetland

Abstract. Although wetlands represent the largest natural source of atmospheric CH4, large uncertainties remain regarding the global wetland CH4 flux. Wetland hydrological oscillations contribute to this uncertainty, dramatically altering wetland area, water table height, soil redox potentials, and CH4 emissions. This study compares both terrestrial and aquatic CH4 fluxes in permanent and seasonal remediated freshwater wetlands in subtropical Australia over two field campaigns, representing differing hydrological and climatic conditions. We account for aquatic CH4 diffusion and ebullition rates and plant-mediated CH4 fluxes from three distinct vegetation communities, thereby examining diel and intra-habitat variability. CH4 emission rates were related to underlying sediment geochemistry. For example, distinct negative relationships between CH4 fluxes and both Fe(III) and SO42- were observed. Where sediment Fe(III) and SO42- were depleted, distinct positive trends occurred between CH4 emissions and Fe(II) ∕ acid volatile sulfur (AVS). Significantly higher CH4 emissions (p < 0.01) in the seasonal wetland were measured during flooded conditions and always during daylight hours, which is consistent with soil redox potential and temperature being important co-drivers of CH4 flux. The highest CH4 fluxes were consistently emitted from the permanent wetland (1.5 to 10.5 mmol m−2 d−1), followed by the Phragmites australis community within the seasonal wetland (0.8 to 2.3 mmol m−2 d−1), whilst the lowest CH4 fluxes came from a region of forested Juncus spp. (−0.01 to 0.1 mmol m−2 d−1), which also corresponded to the highest sedimentary Fe(III) and SO42-. We suggest that wetland remediation strategies should consider geochemical profiles to help to mitigate excessive and unwanted methane emissions, especially during early system remediation periods.

scholarly journals Effects of Integrated Rice-Frog Farming on Paddy Field Greenhouse Gas Emissions

2019 ◽  
Vol 16 (11) ◽  
pp. 1930 ◽  
Author(s):  
Kaikai Fang ◽  
Xiaomei Yi ◽  
Wei Dai ◽  
Hui Gao ◽  
Linkui Cao
Keyword(s):  
Grain Yield ◽  
Greenhouse Gas ◽  
Ghg Emissions ◽  
Farming Systems ◽  
Rice Fields ◽  
Paddy Fields ◽  
N2o Emissions ◽  
Soil Redox Potential ◽  
Ch4 Emissions ◽  
Significant Difference

Integrated rice-frog farming (IRFF), as a mode of ecological farming, is fundamental in realizing sustainable development in agriculture. Yet its production of greenhouse gas (GHG) emissions remains unclear. Here, a randomized plot field experiment was performed to study the GHG emissions for various farming systems during the rice growing season. The farming systems included: conventional farming (CF), green integrated rice-frog farming (GIRF), and organic integrated rice-frog farming (OIRF). Results indicate that the cumulative methane (CH4) emissions from the whole growth period were divergent for the three farming systems, with OIRF having the highest value and CF having the lowest. For nitrous oxide (N2O) emissions, the order is reversed. IRFF significantly increased the dissolved oxygen (DO), soil redox potential (Eh), total organic carbon (TOC) content, and soil C:N ratio, which is closely related to GHG emissions in rice fields. Additionally, the average emissions of carbon dioxide (CO2) from soils during rice growing seasons ranged from 2312.27 to 2589.62 kg ha−1 and showed no significant difference in the three treatments. Rice yield in the GIRF and OIRF were lower (2.0% and 16.7%) than the control. The CH4 emissions contributed to 83.0–96.8% of global warming potential (GWP). Compared to CF, the treatment of GIRF and OIRF increased the GWP by 41.3% and 98.2% during the whole growing period of rice, respectively. IRFF significantly increased greenhouse gas intensity (GHGI, 0.79 kg CO2-eq ha−1 grain yield), by 91.1% over the control. Compared to the OIRF, GIRF decreased the GHGI by approximately 39.4% (0.59 kg CO2-eq ha−1 grain yield), which was 44.2% higher than that of the control. The results of structural equation model showed that the contribution of fertilization to CH4 emissions in paddy fields was much greater than that of frog activity. Moreover, frog activity could decrease GWP by reducing CH4 emissions from rice fields. And while GIRF showed a slight increase in GHG emissions, it could still be considered as a good strategy for providing an environmentally-friendly option in maintaining crop yield in paddy fields.

EVALUATION OF FINANCIAL SECURITY OF THE REPUBLIC OF CRIMEA

2020 ◽  
pp. 56-67
Author(s):  
Elena Evgenevna Mashyanova ◽  
Elena Aleksandrovna Smirnova
Keyword(s):  
Financial Markets ◽  
Negative Impact ◽  
Gradual Increase ◽  
Financial System ◽  
Financial Security ◽  
Key Factors ◽  
Factors Affecting ◽  
External Threats ◽  
The Republic ◽  
Global Financial System

In modern conditions of development, financial security is an integral part of the overall security of the region and is formed on the basis of the functioning of the financial system. The complication of relationships between key segments of international financial markets, as well as the limited ability to accurately predict future trends in the development of the global financial system, lead to a gradual increase in the risks that accompany the activities of economic entities, and an increase in the number and scale of internal and external threats that have a negative impact on the financial security of the state. This formulation of the issue requires generalization of approaches to determining the financial security of the region in order to further formalize this issue and determine the key factors affecting it. The article considers the types of financial security, as well as certain areas of ensuring the financial security of the region and their priority. In work the assessment of the level of socio-economic development of the region with a view to ensuring financial security on the basis of which offers the main activities and priority areas of implementation of the investment policy that will ensure financial security of the Republic of Crimea.

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