Methane Production Rate during Anoxic Litter Decomposition Depends on Si Mass Fractions, Nutrient Stoichiometry and Carbon Quality

While Si influences nutrient stoichiometry and decomposition of graminoid litter, it is still unclear how Si influences anoxic litter decomposition and CH4 formation in graminoid dominated fen peatlands. First, Eriophorum vaginatum plants were grown under different Si and P availabilities, then shoots and roots were characterized regarding their proportions of C, Si, N and P and regarding C quality. Subsequently the Eriophorum shoots were subjected to anoxic decomposition. We hypothesized; that (I) litter grown under high Si availability would show a higher Si but lower nutrient mass fractions and a lower share of recalcitrant carbon moieties; (II) high-Si litter would show higher CH4 and CO2 production rates during anoxic decomposition; (III) methanogenesis would occur earlier in less recalcitrant high-Si litter, compared to low-Si litter. We found a higher Si mass fraction that coincides with a general decrease in C and N mass fractions and decreased share of recalcitrant organic moieties. For high-Si litter, the CH4 production rate was higher, but there was no long-term influence on the CO2 production rate. More labile high-Si litter and a differential response in nutrient stoichiometry led to faster onset of methanogenesis. This may have important implications for our understanding of anaerobic carbon turnover in graminoid-rich fens.

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

10.5194/bg-2018-225 ◽

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.

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Proxies to adjust methane production rate of beef cattle when the quantity of feed consumed is unknown

Animal Production Science ◽

10.1071/an15477 ◽

2016 ◽

Vol 56 (3) ◽

pp. 231 ◽

Cited By ~ 5

Author(s):

R. M. Herd ◽

J. I. Velazco ◽

P. F. Arthur ◽

R. S. Hegarty

Keyword(s):

Carbon Dioxide ◽

Production Rate ◽

Methane Production ◽

Carbon Dioxide Production ◽

Open Circuit ◽

Test Results ◽

Ch4 Production ◽

Time Period ◽

Methane Production Rate ◽

Carbon Dioxide Production Rate

The aim of the present experiment was to evaluate the utility of carbon dioxide production rate (CPR; g CO2/day) and animal weight (WT) data as proxies for feed intake to adjust methane production rate (MPR; g CH4/day) in situations where dry-matter intake (DMI) is not known. This experiment measured individual-animal DMI, MPR and CPR in the feedlot, and then again on restricted quantities of grain and roughage diets in open-circuit respiration chambers. Of the 59 cattle tested in the feedlot, 41 had MPR and CPR recorded, and 59 and 57 had test results on the restricted grain and roughage rations. Methane production relative to DMI by individual animals was calculated as CH4 yield (MY; MPR/DMI) and as residual CH4 production (RMPDMI; calculated as MPR less predicted MPR based on DMI). A second form of RMP: RMPCO2, was calculated by regressing MPR against CPR to determine whether animals were producing more or less CH4 than predicted for their CPR. Carbon dioxide production rate was positively associated with DMI in all three test phases (R2 = 0.25, 0.45 and 0.47; all P < 0.001). The associations for MY with MPR : CPR were moderate and positive, as follows: R2 = 0.49 in the feedlot test; R2 = 0.37 in the restricted-grain test; and R2 = 0.59 in the restricted-roughage test, and with RMPCO2, values of R2 were 0.57, 0.34 and 0.59 in the three test phases (all P < 0.001). The R2 for RMPDMI with MPR : CPR in all three tests were 0.50, 0.79 and 0.69, and with RMPCO2, values of R2 were 0.68, 0.79 and 0.68 (all P < 0.001). The high R2 for MY with MPR : CPR and RMPCO2 and even higher R2 for RMPDMI with MPR : CPR and RMPCO2 in all three test phases showed that CPR can be used to adjust MPR data for DMI when DMI is not recorded. In the feedlot test, where animal WT data were recorded over 70 days, MPR adjusted for WT and WT gain had R2 with MY and RMPDMI of 0.60 and 0.83, respectively (P < 0.001), offering the possibility that animal WT data determined over an extended time period could also be used as a proxy for DMI in adjustment of MPR.

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Understory species regulate litter decomposition and accumulation of C and N in forest soils: A long-term dual-isotope experiment

Forest Ecology and Management ◽

10.1016/j.foreco.2014.04.025 ◽

2014 ◽

Vol 329 ◽

pp. 318-327 ◽

Cited By ~ 31

Author(s):

Yunfa Qiao ◽

Shujie Miao ◽

Lucas C.R. Silva ◽

William R. Horwath

Keyword(s):

Litter Decomposition ◽

Forest Soils ◽

Understory Species ◽

Dual Isotope ◽

C And N

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Simultaneous treatment of sewage sludge and food waste by the unified high-rate anaerobic digestion system

Water Science & Technology ◽

10.2166/wst.2006.166 ◽

2006 ◽

Vol 53 (6) ◽

pp. 29-35 ◽

Cited By ~ 4

Author(s):

H.-W. Kim ◽

S.-K. Han ◽

H.-S. Shin

Keyword(s):

Anaerobic Digestion ◽

Sewage Sludge ◽

Production Rate ◽

Food Waste ◽

High Rate ◽

Organic Loading Rate ◽

Simultaneous Treatment ◽

Methanogenic Activity ◽

Ch4 Production ◽

Methane Production Rate

This study aimed to evaluate the performance of the unified high-rate anaerobic digestion (UHAD) system treating co-substrate of sewage sludge and food waste. A 24-hr operating sequence consisted of four steps including fill, react, settle, and draw. The effects of co-substrate and organic loading rate (OLR) on the performance were investigated to verify the system applicability. In each OLR, the UHAD system showed higher CH4 recovery (>70%), CH4 yield (0.3 L CH4/g VSadded) and CH4 production rate (0.6 L CH4/L/d) than the control system. In the specific methanogenic activity (SMA) tests on thermophilic biomass of the UHAD system, the average SMA of acetate (102 mL CH4/gVSS/d) was much higher than those of butyrate (85 mL CH4/g SS/d) and propionate (42 mL CH4/gVSS/d). It was demonstrated that the UHAD system for co-digestion resulted in higher methane yield and methane production rate due to sequencing batch operation, thermophilic digestion, and co-digestion. The enhanced performance could be attributed to longer retention time of active biomass, faster hydrolysis, higher CH4 conversion rate, and balanced nutrient conditions of co-substrate in the UHAD system. Consequently, this optimized unification could be a viable option for the simultaneous treatment of two types of OFMSW with high stability.

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Shift in C and N humification during legume litter decomposition in an acid tropical Ferralsol

Soil Research ◽

10.1071/sr12101 ◽

2012 ◽

Vol 50 (5) ◽

pp. 380 ◽

Cited By ~ 8

Author(s):

Jorge Sierra ◽

Natacha Motisi

Keyword(s):

Laboratory Experiment ◽

Litter Decomposition ◽

Tropical Soils ◽

Term Effect ◽

Mesocosm Experiment ◽

Short Term ◽

Soil C ◽

Long Term Effect ◽

C And N

Several long-term studies on tropical soils have shown that legume residue incorporation increases soil nitrogen (N) sequestration more than that of carbon (C), resulting in a fall in the C/N ratio. This study was designed to assess the short-term effect of legume litter addition on N supply and the long-term effect on soil organic matter (SOM) formation and soil C/N decrease. The long-term effect was evaluated in a 2-year mesocosm experiment with high and frequent organic inputs from two types of legume litter with different C/N ratios, using stable isotope techniques. The short-term effect of litter was analysed using four different litters in 3-month laboratory incubations. A model of litter decomposition was used to describe C and N kinetics in the laboratory experiment and to verify whether the long-term effect of litter may be predicted from short-term incubations. The results of the mesocosm experiment confirmed that legume inputs increased soil organic N (mean +21%) more than organic C (mean +15%) (P = 0.05). Although no differences between litters were observed for C dynamics, N sequestration (14% and 28%) and the final soil C/N (12.0 and 10.8) varied with litter C/N (34.4 and 16.1, respectively). The laboratory experiment and model outputs confirmed these findings and indicated that the higher N sequestration was due to a change in the parameters describing humification of C and N coming from litter. This change depended on litter quality and was greater for litters with low C/N—C humification 0.66 g C g–1 C and N humification 0.76 g N g–1 N for litter C/N 16.1. Carbon and N sequestration were greater in the laboratory experiment, due to a higher mineralisation of the new SOM derived from litter in the mesocosm experiment—32% and 15% for the mesocosm and the laboratory experiments, respectively. Our results indicated that the decrease in soil C/N and the rapid mineralisation of new SOM should be considered in models of litter decomposition to respond correctly to the long- and the short-term effects of legume litter inputs in tropical soils.

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Saltwater intrusion into tidal freshwater marshes alters the biogeochemical processing of organic carbon

Biogeosciences ◽

10.5194/bg-10-8171-2013 ◽

2013 ◽

Vol 10 (12) ◽

pp. 8171-8183 ◽

Cited By ~ 86

Author(s):

S. C. Neubauer ◽

R. B. Franklin ◽

D. J. Berrier

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Saltwater Intrusion ◽

Carbon Mineralization ◽

Tidal Freshwater ◽

Co2 Production ◽

Soil Co2 ◽

Short Term ◽

Ch4 Production

Abstract. Environmental perturbations in wetlands affect the integrated plant-microbial-soil system, causing biogeochemical responses that can manifest at local to global scales. The objective of this study was to determine how saltwater intrusion affects carbon mineralization and greenhouse gas production in coastal wetlands. Working with tidal freshwater marsh soils that had experienced ~ 3.5 yr of in situ saltwater additions, we quantified changes in soil properties, measured extracellular enzyme activity associated with organic matter breakdown, and determined potential rates of anaerobic carbon dioxide (CO2) and methane (CH4) production. Soils from the field plots treated with brackish water had lower carbon content and higher C : N ratios than soils from freshwater plots, indicating that saltwater intrusion reduced carbon availability and increased organic matter recalcitrance. This was reflected in reduced activities of enzymes associated with the hydrolysis of cellulose and the oxidation of lignin, leading to reduced rates of soil CO2 and CH4 production. The effects of long-term saltwater additions contrasted with the effects of short-term exposure to brackish water during three-day laboratory incubations, which increased rates of CO2 production but lowered rates of CH4 production. Collectively, our data suggest that the long-term effect of saltwater intrusion on soil CO2 production is indirect, mediated through the effects of elevated salinity on the quantity and quality of autochthonous organic matter inputs to the soil. In contrast, salinity, organic matter content, and enzyme activities directly influence CH4 production. Our analyses demonstrate that saltwater intrusion into tidal freshwater marshes affects the entire process of carbon mineralization, from the availability of organic carbon through its terminal metabolism to CO2 and/or CH4, and illustrate that long-term shifts in biogeochemical functioning are not necessarily consistent with short-term disturbance-type responses.

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Saltwater intrusion into tidal freshwater marshes alters the biogeochemical processing of organic carbon

Biogeosciences Discussions ◽

10.5194/bgd-10-10685-2013 ◽

2013 ◽

Vol 10 (7) ◽

pp. 10685-10720 ◽

Cited By ~ 6

Author(s):

S. C. Neubauer ◽

R. B. Franklin ◽

D. J. Berrier

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Saltwater Intrusion ◽

Carbon Mineralization ◽

Tidal Freshwater ◽

Co2 Production ◽

Soil Co2 ◽

Short Term ◽

Ch4 Production

Abstract. Environmental perturbations in wetlands affect the integrated plant-microbial-soil system, causing biogeochemical responses that can manifest at local to global scales. The objective of this study was to determine how saltwater intrusion affects carbon mineralization and greenhouse gas production in coastal wetlands. Working with tidal freshwater marsh soils that had experienced roughly 3.5 yr of in situ saltwater additions, we quantified changes in soil properties, measured extracellular enzyme activity associated with organic matter breakdown, and determined potential rates of anaerobic carbon dioxide (CO2) and methane (CH4) production. Soils from the field plots treated with brackish water had lower carbon content and higher C : N ratios than soils from freshwater plots, indicating that saltwater intrusion reduced carbon availability and increased organic matter recalcitrance. This was reflected in reduced activities of enzymes associated with the hydrolysis of cellulose and the oxidation of lignin, leading to reduced rates of soil CO2 and CH4 production. The effects of long-term saltwater additions contrasted with the effects of short-term exposure to brackish water during three-day laboratory incubations, which increased rates of CO2 production but lowered rates of CH4 production. Collectively, our data suggest that the long-term effect of saltwater intrusion on soil CO2 production is indirect, mediated through the effects of elevated salinity on the quantity and quality of autochthonous organic matter inputs to the soil. In contrast, salinity, organic matter content, and enzyme activities directly influence CH4 production. Our analyses demonstrate that saltwater intrusion into tidal freshwater marshes affects the entire process of carbon mineralization, from the availability of organic carbon through its terminal metabolism to CO2 and/or CH4, and illustrate that long-term shifts in biogeochemical functioning are not necessarily consistent with short-term disturbance-type responses.

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