scholarly journals Global methane and nitrous oxide emissions from non-marine waters

2021 ◽  
Author(s):  
Yajing Zheng ◽  
Shuang Wu ◽  
Shuqi Xiao ◽  
Kai Yu ◽  
Xiantao Fang ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Dominant Role ◽  
Nitrous Oxide Emissions ◽  
Inland Waters ◽  
Natural Ecosystems ◽  
Marine Waters ◽  
Order Of Magnitude ◽  
Flux Component

Abstract Non-marine waters (i.e., rivers, reservoirs, lakes, ponds, streams and estuaries) are globally significant emitters of methane (CH4) and nitrous oxide (N2O) to the atmosphere, while global estimates of these emissions have been hampered due to the lack of a worldwide comprehensive database with the collection of complete CH4 and N2O flux components. Here we synthesize 2997 in-situ flux or concentration measurements of CH4 and N2O from 277 peer-reviewed publications to examine the role of non-marine waters in shaping climate change. Here we estimate that inland waters including rivers, reservoirs, lakes and streams together release 94.49 Tg CH4 yr− 1 (ebullition plus diffusion) and 1.52 Tg N2O yr− 1 (diffusion) to the atmosphere, yielding an overall CO2-equivalent emission total of 3.05 Pg CO2 yr− 1, representing roughly 59% of CO2 emissions (5.13 Pg CO2 yr− 1) from these four aquatic ecosystems, with lakes acting as the largest emitter for both trace gases. Ebullition is noticed as a dominant flux component, contributing up to 62–84% of total CH4 fluxes across all inland waters. Chamber-derived CH4 flux rates are significantly greater than those determined by diffusion model-based methods for commonly capturing of both diffusive and ebullitive fluxes. The synthesis of global N2O measurements projected that rivers exhibit the highest indirect N2O emission factor (EF5, 0.028%), while streams have the lowest EF5 value (0.015%). Our study reveals a major oversight in regional and global CH4 budgets from inland waters, caused by neglect of the dominant role of ebullition pathways in those emissions. The indirect EF5 values established in this study generally suggest an order of magnitude downward revision is required in current IPCC default EF5 values for inland waters and estuaries. Our findings further indicate that a comprehensive understanding of the magnitude and patterns of CH4 and N2O emissions from non-marine waters is essential in defining the way that these natural ecosystems shape our climate.

scholarly journals The Vulnerability of Vessels Involved in the Role of Embolism and Hypoperfusion in the Mechanisms of Ischemic Cerebrovascular Diseases

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Yong Peng Yu ◽  
Lan Tan
Keyword(s):  
Cerebral Infarction ◽  
Dominant Role ◽  
Cerebrovascular Diseases ◽  
Effective Care ◽  
Cerebrovascular Events ◽  
Accurate Definition ◽  
Ischemic Cerebrovascular Diseases ◽  
Vascular Stenosis

Accurate definition and better understanding of the mechanisms of stroke are crucial as this will guide the effective care and therapy. In this paper, we review the previous basic and clinical researches on the causes or mechanisms of ischemic cerebrovascular diseases (ICVD) and interpret the correlation between embolism and hypoperfusion based on vascular stenosis and arterial intimal lesions. It was suggested that if there is no embolus (dynamic or in situ emboli), there might be no cerebral infarction. Three kinds of different clinical outcomes of TIA were theoretically interpreted based on its mechanisms. We suppose that there is a correlation between embolism and hypoperfusion, and which mechanisms (hypoperfusion or hypoperfusion induced microemboli) playing the dominant role in each type of ICVD depends on the unique background of arterial intimal lesions (the vulnerability of vessels). That is to say, the vulnerability of vessels is involved in the role of embolism and hypoperfusion in the mechanisms of ischemic cerebrovascular diseases. This inference might enrich and provide better understandings for the underlying etiologies of ischemic cerebrovascular events.

scholarly journals Modelling Methane and Nitrous Oxide Emissions from Rice Paddy Wetlands in India Using Artificial Neural Networks (ANNs)

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2169 ◽  
Author(s):  
Tabassum Abbasi ◽  
Tasneem Abbasi ◽  
Chirchom Luithui ◽  
Shahid Abbas Abbasi
Keyword(s):  
Nitrous Oxide ◽  
Paddy Fields ◽  
Anthropogenic Sources ◽  
Nitrous Oxide Emissions ◽  
Soil Conditions ◽  
N2o Emissions ◽  
Ch4 Emissions ◽  
Artificial Neural ◽  
Ch4 And N2o

Paddy fields, which are shallow man-made wetlands, are estimated to be responsible for ~11% of the total methane emissions attributed to anthropogenic sources. The role of water use in driving these emissions, and the apportioning of the emissions to individual countries engaged in paddy cultivation, are aspects that have been mired in controversy and disagreement. This is largely due to the fact that methane (CH4) emissions not only change with the cultivar type but also regions, climate, soil type, soil conditions, manner of irrigation, type and quantity of fertilizer added—to name a few. The factors which can influence these aspects also encompass a wide range, and have origins in causes which can be physical, chemical, biological, and combinations of these. Exceedingly complex feedback mechanisms, exerting different magnitudes and types of influences on CH4 emissions under different conditions, are operative. Similar is the case of nitrous oxide (N2O); indeed, the present level of understanding of the factors which influence the quantum of its emission is still more patchy. This makes it difficult to even understand precisely the role of the myriad factors, less so model them. The challenge is made even more daunting by the fact that accurate and precise data on most of these aspects is lacking. This makes it nearly impossible to develop analytical models linking causes with effects vis a vis CH4 and N2O emissions from paddy fields. For situations like this the bioinspired artificial intelligence technique of artificial neural network (ANN), which can model a phenomenon on the basis of past data and without the explicit understanding of the mechanism phenomena, may prove useful. However, no such model for CH4 or N2O has been developed so far. Hence the present work was undertaken. It describes ANN-based models developed by us to predict CH4 and N2O emissions using soil characteristics, fertilizer inputs, and rice cultivar yield as inputs. Upon testing the predictive ability of the models with sets of data not used in model development, it was seen that there was excellent agreement between model forecasts and experimental findings, leading to correlations coefficients of 0.991 and 0.96, and root mean square error (RMSE) of 11.17 and 261.3, respectively, for CH4 and N2O emissions. Thus, the models can be used to estimate CH4 and N2O emissions from all those continuously flooded paddy wetlands for which data on total organic carbon, soil electrical conductivity, applied nitrogen, phosphorous and potassium, NPK, and grain yield is available.

scholarly journals Nitrous oxide emissions from inland waters: Are IPCC estimates too high?

2018 ◽  
Vol 25 (2) ◽  
pp. 473-488 ◽  
Author(s):  
Taylor Maavara ◽  
Ronny Lauerwald ◽  
Goulven G. Laruelle ◽  
Zahra Akbarzadeh ◽  
Nicholas J. Bouskill ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrous Oxide Emissions ◽  
Inland Waters

scholarly journals Beyond denitrification: the role of microbial diversity in controlling nitrous oxide reduction and soil nitrous oxide emissions

2021 ◽  
Author(s):  
Jun Shan ◽  
Robert A. Sanford ◽  
Joanne Chee‐Sanford ◽  
Sean Khan Ooi ◽  
Frank E. Löffler ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Microbial Diversity ◽  
Nitrous Oxide Emissions ◽  
Oxide Reduction ◽  
Nitrous Oxide Reduction

Biochar Incorporation into Pasture Soil Suppresses in situ Nitrous Oxide Emissions from Ruminant Urine Patches

2011 ◽  
Vol 40 (2) ◽  
pp. 468-476 ◽  
Author(s):  
Arezoo Taghizadeh-Toosi ◽  
Tim J. Clough ◽  
Leo M. Condron ◽  
Robert R. Sherlock ◽  
Craig R. Anderson ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrous Oxide Emissions ◽  
Pasture Soil

scholarly journals Nitrous oxide emissions from the Arabian Sea: A synthesis

2001 ◽  
Vol 1 (1) ◽  
pp. 61-71 ◽  
Author(s):  
H. W. Bange ◽  
M. O. Andreae ◽  
S. Lal ◽  
C. S. Law ◽  
S. W. A. Naqvi ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Arabian Sea ◽  
Sea Surface ◽  
Nitrous Oxide Emissions ◽  
N2o Emissions ◽  
Coastal Zones ◽  
N2o Flux ◽  
In Situ Data ◽  
Data Coverage

Abstract. We computed high-resolution (1º latitude x  1º longitude) seasonal and annual nitrous oxide (N2O) concentration fields for the Arabian Sea surface layer using a database containing more than 2400 values measured between December 1977 and July 1997. N2O concentrations are highest during the southwest (SW) monsoon along the southern Indian continental shelf. Annual emissions range from 0.33 to 0.70 Tg N2O and are dominated by fluxes from coastal regions during the SW and northeast monsoons. Our revised estimate for the annual N2O flux from the Arabian Sea is much more tightly constrained than the previous consensus derived using averaged in-situ data from a smaller number of studies. However, the tendency to focus on measurements in locally restricted features in combination with insufficient seasonal data coverage leads to considerable uncertainties of the concentration fields and thus in the flux estimates, especially in the coastal zones of the northern and eastern Arabian Sea. The overall mean relative error of the annual N2O emissions from the Arabian Sea was estimated to be at least 65%.

Nitrous Oxide Emissions from In Situ Deposition of 15 N-Labeled Ryegrass Litter in a Pasture Soil

2013 ◽  
Vol 42 (2) ◽  
pp. 323-331 ◽  
Author(s):  
Pranoy Pal ◽  
Tim J. Clough ◽  
Francis M. Kelliher ◽  
Robert R. Sherlock
Keyword(s):  
Nitrous Oxide ◽  
Nitrous Oxide Emissions ◽  
Pasture Soil ◽  
In Situ Deposition

Low-Temperature Halo-Carbon Homoepitaxial Growth of 4H-SiC: Morphology, Doping, and Role of HCl Additive

2007 ◽  
Vol 556-557 ◽  
pp. 133-136 ◽  
Author(s):  
Huang De Lin ◽  
Galyna Melnychuk ◽  
Jeffery L. Wyatt ◽  
Yaroslav Koshka
Keyword(s):  
Low Temperature ◽  
Nitrogen Concentration ◽  
Aluminum Concentration ◽  
Silicon Cluster ◽  
Vapor Species ◽  
Aluminum Doping ◽  
Homoepitaxial Growth ◽  
Order Of Magnitude

Low-temperature epitaxial growth of 4H-SiC with CH3Cl carbon precursor was further developed. In-situ doping with nitrogen and aluminum was investigated. The nitrogen concentration in epitaxial layers grown on the C face was almost two orders of magnitude higher than that in the Si-face epilayers grown in the same growth run at 13000C. The opposite trend was observed for intentional aluminum doping, with more than an order of magnitude higher aluminum concentration incorporated in Si-face epilayers. High values of nitrogen and aluminum doping well in excess of 1020 cm-3 without any obvious epilayer morphology degradation can be achieved on C-face and Siface respectively. Addition of HCl during halo-carbon growth at 13000C resulted in drastic improvement of the surface morphology. Also, a significant increase of the growth rate took place confirming that the improvement in the epilayer morphology during HCl-assisted growth is predominantly related to silicon cluster etching by additional Cl-containing vapor species.

scholarly journals Nitrous Oxide Emissions from Paddies: Understanding the Role of Rice Plants

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 180
Author(s):  
Arbindra Timilsina ◽  
Fiston Bizimana ◽  
Bikram Pandey ◽  
Ram Kailash Prasad Yadav ◽  
Wenxu Dong ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Rice Plant ◽  
Soil Microorganisms ◽  
N2o Emission ◽  
Nitrous Oxide Emissions ◽  
Agricultural Activity ◽  
N2o Formation ◽  
Rice Plants ◽  
Potential Source

Paddies are a potential source of anthropogenic nitrous oxide (N2O) emission. In paddies, both the soil and the rice plants emit N2O into the atmosphere. The rice plant in the paddy is considered to act as a channel between the soil and the atmosphere for N2O emission. However, recent studies suggest that plants can also produce N2O, while the mechanism of N2O formation in plants is unknown. Consequently, the rice plant is only regarded as a channel for N2O produced by soil microorganisms. The emission of N2O by aseptically grown plants and the distinct dual isotopocule fingerprint of plant-emitted N2O, as reported by various studies, support the production of N2O in plants. Herein, we propose a potential pathway of N2O formation in the rice plant. In rice plants, N2O might be formed in the mitochondria via the nitrate–nitrite–nitric oxide (NO3–NO2–NO) pathway when the cells experience hypoxic or anoxic stress. The pathway is catalyzed by various enzymes, which have been described. So, N2O emitted from paddies might have two origins, namely soil microorganisms and rice plants. So, regarding rice plants only as a medium to transport the microorganism-produced N2O might be misleading in understanding the role of rice plants in the paddy. As rice cultivation is a major agricultural activity worldwide, not understanding the pathway of N2O formation in rice plants would create more uncertainties in the N2O budget.

Dominant role of aortic baroreceptors in the cardiac baroreflex of the rat in situ

2008 ◽  
Vol 142 (1-2) ◽  
pp. 32-39 ◽  
Author(s):  
Anthony E. Pickering ◽  
Annabel E. Simms ◽  
Julian F.R. Paton
Keyword(s):  
Dominant Role ◽  
Aortic Baroreceptors
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