scholarly journals Carbon mineralization dynamics of tropical peats in relation to peat characteristics

2018 ◽  
Vol 19 (4) ◽  
pp. 1413-1421 ◽  
Author(s):  
AKHMAD R. SAIDY ◽  
ZURAIDA T. MARIANA ◽  
FENGKY A. ADJI ◽  
ROSSIE W. NUSANTARA ◽  
IRMA FITRIA ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Carbon Mineralization ◽  
Close Relation ◽  
Carbohydrate Content ◽  
Co2 Production ◽  
Emission Rates ◽  
Incubation Study ◽  
Tropical Areas ◽  
Paddy Cultivation ◽  
Carbon Dioxide Co2

Saidy AR, Mariana ZT, Adji FA, Nusantara RW, Fitria I, Syahrinudin. 2018. Carbon mineralization dynamics of tropicalpeats in relation to peat characteristics. Biodiversitas 19: 1413-1421. Understanding the dynamics of carbon mineralization of peats inthe tropical areas is of essential significance in controlling carbon dioxide (CO2) gas emission rates. An incubation study of tropicalpeats sampled from 3 different sites of the Barito Basin on the Borneo Island, Indonesia (uncultivated, used for paddy cultivation for  5years and 5-10 years) was carried out to investigate a relationship between CO2 production and peat characteristics. Results of studyrevealed that land use change from uncultivated peats to paddy fields resulted in significant changes in the chemical structure of peatorganic carbon. Carbohydrate contents of the peat decreased significantly as a consequence of the conversion of natural peats to paddyfields. However, the paddy peats contained higher lignin than uncultivated peats. Changes in the chemical structure of the tropical peatsresulted in changes in carbon mineralization. Carbon mineralization of uncultivated peats ranged from 29255310 mg CO2-C kg-1 peat,while carbon mineralization of 10652678 mg CO2-C kg-1 C peat was observed for paddy peats. Moreover, carbon mineralization dataobtained from the experiment fitted properly to a two-pool C mineralization model. The developed carbon mineralization model showedthat slowly and rapidly decomposable pools have a close relation with rubbed fiber and carbohydrate content data. Thus, results of thisstudy suggested that carbon mineralization of peats could be estimated appropriately using rubbed fiber and carbohydrate content data.

Longitudinal Measurements of Resting Energy Expenditure by Indirect Calorimetry in Healthy Term Infants during the First 2 Months of Life

2018 ◽  
Vol 36 (09) ◽  
pp. 918-923
Author(s):  
Sourabh Verma ◽  
Sean M. Bailey ◽  
Pradeep V. Mally ◽  
Heather B. Howell
Keyword(s):  
Pilot Study ◽  
Energy Expenditure ◽  
Indirect Calorimetry ◽  
Resting Energy Expenditure ◽  
Co2 Production ◽  
Term Infants ◽  
Longitudinal Measurements ◽  
Expired Gas ◽  
Carbon Dioxide Co2 ◽  
Resting Energy

Objective To determine longitudinal measurements of resting energy expenditure (REE) by indirect calorimetry (IC) in healthy term infants during the first 2 months of life. Study Design An outpatient prospective pilot study was performed in healthy term infants to estimate REE by measuring expired gas fractions of oxygen (O2) and carbon dioxide (CO2) with IC in a respiratory and metabolic steady state. Results A total of 30 measurements were performed. Fourteen subjects completed measurements at both 1 and 2 months of life, and two subjects had only measurements made at 1 month of life. Mean REE values were 64.1 ± 12.7 and 58.4 ± 14.3 kcal/kg/d at 1 and 2 months of age, respectively. Mean O2 consumption and CO2 production measurements were 9.3 ± 2.0 and 7.7 ± 1.2 mL/kg/min and 8.1 ± 2.2 and 6.4 ± 1.1 mL/kg/min at 1 and 2 months of age, respectively. Conclusion This pilot study demonstrates longitudinal measurements of REE by IC in healthy term infants during the first 2 months of life. We also demonstrate that, overall, there is consistency in REE values in this population, with a likely decrease in individual longitudinal measurements over the first 2 months of life.

Global warming as affected by incorporation of variably aged biomass of hairy vetch for rice cultivation

Soil Research ◽  
2016 ◽  
Vol 54 (3) ◽  
pp. 346 ◽  
Author(s):  
Md Mozammel Haque ◽  
Jatish Chandra Biswas ◽  
Tatoba R. Waghmode ◽  
Pil Joo Kim
Keyword(s):  
Global Warming ◽  
Biomass Production ◽  
Animal Feed ◽  
Ghg Emissions ◽  
Rice Cultivation ◽  
Emission Rates ◽  
Hairy Vetch ◽  
Closed Chamber ◽  
Vicia Villosa ◽  
Carbon Dioxide Co2

Hairy vetch (Vicia villosa Roth) is cultivated during the cold fallow season in paddy soils of temperate countries such as South Korea and Japan, mostly as animal feed and green manure. Information on the effect of ageing of hairy vetch incorporation in relation to greenhouse gas (GHG) emissions and global warming potential (GWP) is not available. Therefore, hairy vetch biomass of ages 183, 190, 197, and 204 days was incorporated in paddy soil to estimate GWP during rice cultivation. The emission rates of methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) gases were monitored once a week by using the closed-chamber method. The net ecosystem carbon budget was used to estimate pure CO2 emission fluxes. Biomass production of hairy vetch was 6.5 Mg ha–1 at 204 days, which was similar to other treatments. The GWP was lower with the 204-day-old vetch biomass incorporation than with other treatments. High content of cellulose and lignin in 204-day-old hairy vetch might have affected decomposition rate and subsequently reduced GHGs emissions during rice cultivation. Our results suggest that hairy vetch can be allowed to grow for 204 days before incorporation at 3 Mg ha–1 without sacrificing rice yield, while maximising biomass production and minimising GWP during rice cultivation.

scholarly journals Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization

2019 ◽  
Vol 16 (3) ◽  
pp. 663-680 ◽  
Author(s):  
Jianqiu Zheng ◽  
Peter E. Thornton ◽  
Scott L. Painter ◽  
Baohua Gu ◽  
Stan D. Wullschleger ◽  
...  
Keyword(s):  
Temperature Sensitivity ◽  
Iron Reduction ◽  
Carbon Mineralization ◽  
Co2 Production ◽  
Model Framework ◽  
Binding Model ◽  
Microbial Decomposition ◽  
Carbon Decomposition ◽  
Ch4 Production ◽  
Wide Range

Abstract. Rapid warming of Arctic ecosystems exposes soil organic matter (SOM) to accelerated microbial decomposition, potentially leading to increased emissions of carbon dioxide (CO2) and methane (CH4) that have a positive feedback on global warming. Current estimates of the magnitude and form of carbon emissions from Earth system models include significant uncertainties, partially due to the oversimplified representation of geochemical constraints on microbial decomposition. Here, we coupled modeling principles developed in different disciplines, including a thermodynamically based microbial growth model for methanogenesis and iron reduction, a pool-based model to represent upstream carbon transformations, and a humic ion-binding model for dynamic pH simulation to build a more versatile carbon decomposition model framework that can be applied to soils under varying redox conditions. This new model framework was parameterized and validated using synthesized anaerobic incubation data from permafrost-affected soils along a gradient of fine-scale thermal and hydrological variabilities across Arctic polygonal tundra. The model accurately simulated anaerobic CO2 production and its temperature sensitivity using data on labile carbon pools and fermentation rates as model constraints. CH4 production is strongly influenced by water content, pH, methanogen biomass, and presence of competing electron acceptors, resulting in high variability in its temperature sensitivity. This work provides new insights into the interactions of SOM pools, temperature increase, soil geochemical feedbacks, and resulting CO2 and CH4 production. The proposed anaerobic carbon decomposition framework presented here builds a mechanistic link between soil geochemistry and carbon mineralization, making it applicable over a wide range of soils under different environmental settings.

scholarly journals Observation-based modelling of permafrost carbon fluxes with accounting for deep carbon deposits and thermokarst activity

2015 ◽  
Vol 12 (11) ◽  
pp. 3469-3488 ◽  
Author(s):  
T. Schneider von Deimling ◽  
G. Grosse ◽  
J. Strauss ◽  
L. Schirrmeister ◽  
A. Morgenstern ◽  
...  
Keyword(s):  
Organic Matter ◽  
21St Century ◽  
Radiative Forcing ◽  
Permafrost Degradation ◽  
Emission Rates ◽  
Thermokarst Lakes ◽  
Air Temperatures ◽  
Carbon Release ◽  
Pool Model ◽  
Carbon Dioxide Co2

Abstract. High-latitude soils store vast amounts of perennially frozen and therefore inert organic matter. With rising global temperatures and consequent permafrost degradation, a part of this carbon stock will become available for microbial decay and eventual release to the atmosphere. We have developed a simplified, two-dimensional multi-pool model to estimate the strength and timing of future carbon dioxide (CO2) and methane (CH4) fluxes from newly thawed permafrost carbon (i.e. carbon thawed when temperatures rise above pre-industrial levels). We have especially simulated carbon release from deep deposits in Yedoma regions by describing abrupt thaw under newly formed thermokarst lakes. The computational efficiency of our model allowed us to run large, multi-centennial ensembles under various scenarios of future warming to express uncertainty inherent to simulations of the permafrost carbon feedback. Under moderate warming of the representative concentration pathway (RCP) 2.6 scenario, cumulated CO2 fluxes from newly thawed permafrost carbon amount to 20 to 58 petagrams of carbon (Pg-C) (68% range) by the year 2100 and reach 40 to 98 Pg-C in 2300. The much larger permafrost degradation under strong warming (RCP8.5) results in cumulated CO2 release of 42 to 141 Pg-C and 157 to 313 Pg-C (68% ranges) in the years 2100 and 2300, respectively. Our estimates only consider fluxes from newly thawed permafrost, not from soils already part of the seasonally thawed active layer under pre-industrial climate. Our simulated CH4 fluxes contribute a few percent to total permafrost carbon release yet they can cause up to 40% of total permafrost-affected radiative forcing in the 21st century (upper 68% range). We infer largest CH4 emission rates of about 50 Tg-CH4 per year around the middle of the 21st century when simulated thermokarst lake extent is at its maximum and when abrupt thaw under thermokarst lakes is taken into account. CH4 release from newly thawed carbon in wetland-affected deposits is only discernible in the 22nd and 23rd century because of the absence of abrupt thaw processes. We further show that release from organic matter stored in deep deposits of Yedoma regions crucially affects our simulated circumpolar CH4 fluxes. The additional warming through the release from newly thawed permafrost carbon proved only slightly dependent on the pathway of anthropogenic emission and amounts to about 0.03–0.14 °C (68% ranges) by end of the century. The warming increased further in the 22nd and 23rd century and was most pronounced under the RCP6.0 scenario, adding 0.16 to 0.39 °C (68% range) to simulated global mean surface air temperatures in the year 2300.

Correlations of methane and carbon dioxide concentrations from feedlot cattle as a predictor of methane emissions

2016 ◽  
Vol 56 (1) ◽  
pp. 108 ◽  
Author(s):  
Mei Bai ◽  
David W. T. Griffith ◽  
Frances A. Phillips ◽  
Travis Naylor ◽  
Stephanie K. Muir ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Concentration Ratio ◽  
Co2 Concentration ◽  
Feedlot Cattle ◽  
Mitigation Strategies ◽  
Co2 Production ◽  
Ch4 Emissions ◽  
Carbon Dioxide Concentrations ◽  
Carbon Dioxide Co2 ◽  
Animal Diet

Accurate measurements of methane (CH4) emissions from feedlot cattle are required for verifying greenhouse gas (GHG) accounting and mitigation strategies. We investigate a new method for estimating CH4 emissions by examining the correlation between CH4 and carbon dioxide (CO2) concentrations from two beef cattle feedlots in Australia representing southern temperate and northern subtropical locations. Concentrations of CH4 and CO2 were measured at the two feedlots during summer and winter, using open-path Fourier transform infrared spectroscopy. There was a strong correlation for the concentrations above background of CH4 and CO2 with concentration ratios of 0.008 to 0.044 ppm/ppm (R2 >0.90). The CH4/CO2 concentration ratio varied with animal diet and ambient temperature. The CH4/CO2 concentration ratio provides an alternative method to estimate CH4 emissions from feedlots when combined with CO2 production derived from metabolisable energy or heat production.

scholarly journals Greenhouse gas production in degrading ice-rich permafrost deposits in northeast Siberia

2018 ◽  
Author(s):  
Josefine Walz ◽  
Christian Knoblauch ◽  
Ronja Tigges ◽  
Thomas Opel ◽  
Lutz Schirrmeister ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Greenhouse Gas ◽  
Late Glacial ◽  
Gas Production ◽  
Depositional Environments ◽  
Co2 Production ◽  
Glacial Deposits ◽  
Ch4 Production ◽  
Carbon Dioxide Co2

Abstract. Permafrost deposits have been a sink for atmospheric carbon for millennia. Thaw-erosional processes, however, can lead to rapid degradation of ice-rich permafrost and the release of substantial amounts of organic carbon (OC). The amount of the OC stored in these deposits and their potential to be microbially decomposed to the greenhouse gases carbon dioxide (CO2) and methane (CH4) depends on climatic and environmental conditions during deposition and the decomposition history before incorporation into the permafrost. Here, we examine potential greenhouse gas production in degrading ice-rich permafrost deposits from three locations in the northeast Siberian Laptev Sea region. The deposits span a period of about 55 kyr and include deposits from the last glacial and Holocene interglacial periods. Samples from all three locations were aerobically and anaerobically incubated for 134 days at 4 °C. Greenhouse gas production was generally higher in glacial than Holocene deposits. In permafrost deposits from the Holocene and the late glacial transition, only 0.1–4.0 % of the initially available OC could be decomposed to CO2, while 0.2–6.1 % could be decomposed in glacial deposits. Within the glacial deposits from the Kargin interstadial period (Marine Isotope Stage 3), local depositional environments, especially soil moisture, also affected the preservation of OC. Sediments deposited under wet conditions contained more labile OC and thus produced more greenhouse gases than sediments deposited under drier conditions. To assess the long-term production potentials, deposits from two locations were incubated for a total of 785 days. However, more than 50 % of the aerobically produced and more than 80 % of anaerobically produced CO2 after 785 days of incubation were already produced within the first 134 days, highlighting the quantitative importance of the slowly decomposing OC pool in permafrost. CH4 production was generally observed in active layer samples but only sporadically in permafrost samples and was several orders of magnitude smaller than CO2 production.

scholarly journals Greenhouse gas production in degrading ice-rich permafrost deposits in northeastern Siberia

2018 ◽  
Vol 15 (17) ◽  
pp. 5423-5436 ◽  
Author(s):  
Josefine Walz ◽  
Christian Knoblauch ◽  
Ronja Tigges ◽  
Thomas Opel ◽  
Lutz Schirrmeister ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Greenhouse Gas ◽  
Late Glacial ◽  
Gas Production ◽  
Depositional Environments ◽  
Co2 Production ◽  
Anaerobic Conditions ◽  
Northeastern Siberia ◽  
Carbon Dioxide Co2 ◽  
Glacial Periods

Abstract. Permafrost deposits have been a sink for atmospheric carbon for millennia. Thaw-erosional processes, however, can lead to rapid degradation of ice-rich permafrost and the release of substantial amounts of organic carbon (OC). The amount of the OC stored in these deposits and their potential to be microbially decomposed to the greenhouse gases carbon dioxide (CO2) and methane (CH4) depends on climatic and environmental conditions during deposition and the decomposition history before incorporation into the permafrost. Here, we examine potential greenhouse gas production as a result of degrading ice-rich permafrost deposits from three locations in the northeastern Siberian Laptev Sea region. The deposits span a period of about 55 kyr from the last glacial period and Holocene interglacial. Samples from all three locations were incubated under aerobic and anaerobic conditions for 134 days at 4 ∘C. Greenhouse gas production was generally higher in deposits from glacial periods, where 0.2 %–6.1 % of the initially available OC was decomposed to CO2. In contrast, only 0.1 %–4.0 % of initial OC was decomposed in permafrost deposits from the Holocene and the late glacial transition. Within the deposits from the Kargin interstadial period (Marine Isotope Stage 3), local depositional environments, especially soil moisture, also affected the preservation of OC. Sediments deposited under wet conditions contained more labile OC and thus produced more greenhouse gases than sediments deposited under drier conditions. To assess the greenhouse gas production potentials over longer periods, deposits from two locations were incubated for a total of 785 days. However, more than 50 % of total CO2 production over 785 days occurred within the first 134 days under aerobic conditions, while 80 % were produced over the same period under anaerobic conditions, which emphasizes the nonlinearity of the OC decomposition processes. Methanogenesis was generally observed in active layer samples but only sporadically in permafrost samples and was several orders of magnitude smaller than CO2 production.

scholarly journals High methane emissions dominated annual greenhouse gas balances 30 years after bog rewetting

2015 ◽  
Vol 12 (14) ◽  
pp. 4361-4371 ◽  
Author(s):  
M. Vanselow-Algan ◽  
S. R. Schmidt ◽  
M. Greven ◽  
C. Fiencke ◽  
L. Kutzbach ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Carbon Sink ◽  
Plant Litter ◽  
Time Span ◽  
Initial Increase ◽  
Emission Rates ◽  
Ch4 Emissions ◽  
Long Time ◽  
Ch4 And N2o ◽  
Carbon Dioxide Co2

Abstract. Natural peatlands are important carbon sinks and sources of methane (CH4). In contrast, drained peatlands turn from a carbon sink to a carbon source and potentially emit nitrous oxide (N2O). Rewetting of peatlands thus potentially implies climate change mitigation. However, data about the time span that is needed for the re-establishment of the carbon sink function by restoration are scarce. We therefore investigated the annual greenhouse gas (GHG) balances of three differently vegetated sites of a bog ecosystem 30 years after rewetting. All three vegetation communities turned out to be sources of carbon dioxide (CO2) ranging between 0.6 ± 1.43 t CO2 ha−2 yr−1 (Sphagnum-dominated vegetation) and 3.09 ± 3.86 t CO2 ha−2 yr−1 (vegetation dominated by heath). While accounting for the different global warming potential (GWP) of CO2, CH4 and N2O, the annual GHG balance was calculated. Emissions ranged between 25 and 53 t CO2-eq ha−1 yr−1 and were dominated by large emissions of CH4 (22–51 t CO2-eq ha−1 yr−1), with highest rates found at purple moor grass (Molinia caerulea) stands. These are to our knowledge the highest CH4 emissions so far reported for bog ecosystems in temperate Europe. As the restored area was subject to large fluctuations in the water table, we assume that the high CH4 emission rates were caused by a combination of both the temporal inundation of the easily decomposable plant litter of purple moor grass and the plant-mediated transport through its tissues. In addition, as a result of the land use history, mixed soil material due to peat extraction and refilling can serve as an explanation. With regards to the long time span passed since rewetting, we note that the initial increase in CH4 emissions due to rewetting as described in the literature is not inevitably limited to a short-term period.

scholarly journals Methane and Carbon Dioxide Emission of Beef Heifers in Relation with Growth and Feed Efficiency

Animals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1136 ◽  
Author(s):  
Gilles Renand ◽  
Aurélie Vinet ◽  
Virginie Decruyenaere ◽  
David Maupetit ◽  
Dominique Dozias
Keyword(s):  
Carbon Dioxide ◽  
Methane Production ◽  
Feed Efficiency ◽  
Average Daily Gain ◽  
Carbon Dioxide Emission ◽  
Methane Yield ◽  
Emission Rates ◽  
Beef Heifers ◽  
Positive Correlations ◽  
Carbon Dioxide Co2

Reducing enteric methane production and improving the feed efficiency of heifers on roughage diets are important selection objectives for sustainable beef production. The objective of the current study was to assess the relationship between different methane production and feed efficiency criteria of beef heifers fed ad libitum roughage diets. A total of 326 Charolais heifers aged 22 months were controlled in two farms and fed either a grass silage (n = 252) or a natural meadow hay (n = 74) diet. Methane (CH4) and carbon dioxide (CO2) emission rates (g/day) were measured with GreenFeed systems. The dry matter intake (DMI), average daily gain (ADG), CH4 and CO2 were measured over 8 to 12 weeks. Positive correlations were observed among body weight, DMI, ADG, CH4 and CO2. The residual feed intake (rwgDMI) was not related to CH4 or residual methane (rwiCH4). It was negatively correlated with methane yield (CH4/DMI): Rp = −0.87 and −0.83. Residual gain (rwiADG) and ADG/DMI were weakly and positively related to residual methane (rwiCH4): Rp = 0.21 on average. The ratio ADG/CO2 appeared to be a useful proxy of ADG/DMI (Rp = 0.64 and 0.97) and CH4/CO2 a proxy of methane yield (Rp = 0.24 and 0.33) for selecting low-emitting and efficient heifers.

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