scholarly journals High greenhouse gas fluxes from peatlands under various disturbances in the Peruvian Amazon

2021 ◽  
Author(s):  
Jaan Pärn ◽  
Kaido Soosaar ◽  
Thomas Schindler ◽  
Katerina Machacova ◽  
Waldemar Alegría Muñoz ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Water Table ◽  
Soil Surface ◽  
N2o Emission ◽  
N2o Emissions ◽  
Swamp Forest ◽  
Ch4 Production ◽  
Peat Swamp ◽  
Nitrifier Denitrification ◽  
Carbon Dioxide Co2

Abstract. Amazonian peat swamp forests remove large amounts of carbon dioxide (CO2) but anaerobic decomposition of the peat produces methane (CH4). Drought or cultivation cuts down on the CH4 production but may increase the CO2 emission. Varying oxygen content in nitrogen-rich peat produces nitrous oxide (N2O). Despite the potentially tremendous changes, greenhouse gas emissions from peatlands under various land uses and environmental conditions have rarely been compared in the Amazon. We measured CO2, CH4 and N2O emissions from the soil surface with manual opaque chambers, and environmental characteristics in three sites around Iquitos, Peru from September 2019 to March 2020: a pristine peat swamp forest, a young forest and a slash-and-burn manioc field. The manioc field showed moderate peat respiration and N2O emission. The swamp forests under slight water table drawdown emitted large amounts of CO2 and N2O while retaining their high CH4 emissions. Most noticeably, a heavy shower after the water-table drawdown in the pristine swamp forest created a hot moment of N2O. Nitrifier denitrification was the likely source mechanism, as we rule out nitrification and heterotrophic denitrification. We base the judgement on the lack of nitrate and oxygen, and the suppressed denitrification potential in the topsoil. Overall, our study shows that even moderate drying in Peruvian palm swamps may create a devastating feedback on climate change through CO2 and N2O emissions.

Controlling CO2 and CH4 Emission in a Degraded Peat Swamp Forest Related to Water Table and Peat Characteristics

2013 ◽  
Vol 391 ◽  
pp. 202-206
Author(s):  
Leila Kalsum ◽  
null Ngudiantoro ◽  
M. Faizal ◽  
A. Halim Pks
Keyword(s):  
Water Table ◽  
Forest Fires ◽  
Ash Content ◽  
Burned Area ◽  
Gas Temperature ◽  
Swamp Forest ◽  
Closed Chamber ◽  
Peat Swamp Forest ◽  
Peat Swamp

This study focuses on factors controlling CO2and CH4emission in a peat swamp forest related to water table and peat characteristics such as peat depth, C-organic, pH, ash content and N-total. This study was conducted in the dry season at a Merang peat swamp forest that has degraded due to logging activities, forest fires and canal opening. Emission of CO2and CH4was measured by using a closed chamber made by PVC material (60 cm x 60 cm x 40 cm). This close chamber was completed with a fan inside the chamber to stir the gas, a thermometer inside the chamber to measure the gas temperature and a syringe to sample gas. This study has shown that the highest CO2emission is at an average of 438.93 mg/m2/hr occurring in land cover type (1) ferns and grasses (open burned area) and the lowest is at average of 44.45 mg/m2/hr in thegelamandbelidang-dominated land. The emission of CH4is very low between 0.0018 to 0.0069 mg/m2/hr. the main controlling factor on CO2and CH4emission is concluded to be the water table. The emission of CO2will be greater if water table, pH and C-organic increase.

Sugarcane fields: sources or sinks for greenhouse gas emissions?

1998 ◽  
Vol 49 (1) ◽  
pp. 1 ◽  
Author(s):  
K. L. Weier
Keyword(s):  
Greenhouse Gases ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Sugar Industry ◽  
N2o Emissions ◽  
Gas Emissions ◽  
Sugarcane Crop ◽  
Management Procedures ◽  
Degree Of Certainty ◽  
Carbon Dioxide Co2

The quantities of greenhouse gases emitted into the atmosphere from sugarcane fields, and their contribution to the total emissions from Australian agriculture, have never been estimated with any degree of certainty. This review was conducted to collate the available information on greenhouse gas emissions from the Australian sugarcane crop. Estimates were made for the emissions of the 3 major greenhouse gases―carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)―from known or suspected sources. Sinks for the sequestration of the gases also have been identified. CO2 was found to be emitted during burning of the crop and from trash-blanketed and bare sugarcane fields. Total emissions from these sources in the 1994 season were estimated at 7·6 Mt CO2-C/year. However, the sugarcane crop was identified as a major sink for C, with uptake by the crop in 1994 estimated at 13· 4 Mt CO2-C/year. N2O emanating from sugarcane soils via denitrification following application of fertiliser accounted for 45-78% of total gaseous N emissions. Estimates of N2O emissions from all land under sugarcane in 1994 totalled 4·4 kt N2O-N/year from denitrification with a further 6·3 kt N2O-N emitted from areas that are still burnt. This review suggests changes in management procedures that should limit the opportunities for denitrification in the soil and thus reduce N2O emissions. Methane evolution occurs during the smouldering phase, following burning of the crop, with production estimated at 6·7 kt CH4-C/year in 1994. CH4 oxidation in soil was identified as an important process for removal of atmospheric CH4, as were trash-blanketed soils. Although these figures are our best estimate of gaseous production from sugarcane fields, there still remains a degree of uncertainty due to sampling variability and because of the extrapolation to the entire sugarcane area. However, the coupling of new laser techniques with known micrometeorological methods will allow for a more precise sampling of greenhouse gas emissions over a larger area. Estimates would thus be more representative, resulting in a greater degree of confidence being placed in them by the sugar industry.

scholarly journals Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

2016 ◽  
Vol 13 (9) ◽  
pp. 2637-2651 ◽  
Author(s):  
Järvi Järveoja ◽  
Matthias Peichl ◽  
Martin Maddison ◽  
Kaido Soosaar ◽  
Kai Vellak ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Water Table ◽  
Gross Primary Production ◽  
Vascular Plant ◽  
Plant Cover ◽  
Climate Impacts ◽  
N2o Emissions ◽  
Extraction Area ◽  
Peat Extraction ◽  
The Impact

Abstract. Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting mean water table levels (WTLs) on the annual C and GHG balances of restoration treatments with high (ResH) and low (ResL) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in ResH relative to ResL. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in ResL compared to ResH. However, the means of the measured net ecosystem CO2 exchanges (NEE) were not significantly different between ResH and ResL. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, ResH, ResL and BP were C sources of 111, 103 and 268 g C m−2 yr−1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha−1 yr−1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments 3 years following restoration. However, the C and GHG balances in ResH and ResL were considerably lower than in BP due to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.

scholarly journals Greenhouse gas emissions resulting from conversion of peat swamp forest to oil palm plantation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hannah V. Cooper ◽  
Stephanie Evers ◽  
Paul Aplin ◽  
Neil Crout ◽  
Mohd Puat Bin Dahalan ◽  
...  
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Oil Palm ◽  
Swamp Forest ◽  
Gas Emissions ◽  
Peat Swamp Forest ◽  
Oil Palm Plantation ◽  
Peat Swamp

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 Efficient nitrification and low N2O emission in a weakly acidic bioreactor at low dissolved oxygen levels are due to comammox

2021 ◽  
Author(s):  
Deyong Li ◽  
Fang Fang ◽  
Guoqiang Liu
Keyword(s):  
Wastewater Treatment ◽  
Dissolved Oxygen ◽  
Greenhouse Gas ◽  
N2o Emission ◽  
Low Energy ◽  
Emission Source ◽  
Ammonia Oxidizer ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrifier Denitrification ◽  
Low Do

Nitrification is an essential process for nutrient removal from wastewater and an important emission source of nitrous-oxide (N2O), which is a powerful greenhouse gas and a dominant ozone-depleting substance. In this study, nitrification and N2O emissions were tested in two weakly acidic (pH = 6.3–6.8) reactors: one with dissolved oxygen (DO) over 2.0 mg/L and the other with DO approximately 0.5 mg/L. Efficient nitrification was achieved in both reactors. Compared to the high-DO reactor, N2O emission in the low-DO reactor decreased slightly by 20% and had insignificant correlation with the fluctuations of DO (P = 0.935) and nitrite (P = 0.713), indicating that N2O might not be mainly produced via nitrifier denitrification. Based on qPCR, qFISH, functional gene amplicon and metagenome sequencing, it was found that complete ammonia oxidizer (comammox) Nitrospira significantly outnumbered canonical ammonia-oxidizing bacteria (AOB) in both weakly acidic reactors, especially in the low DO reactor with the comammox/AOB amoA gene ratio increasing from 6.6 to 17.1. Therefore, it was speculated that the enriched comammox was the primary cause for the slightly decreased N2O emission under long-term low DO in weakly acidic reactor. This study demonstrated that comammox Nitrospira can survive well under the weakly acidic and low-DO conditions, implying that achieving efficient nitrification with low N2O emission as well as low energy and alkalinity consumption is feasible for wastewater treatment. Importance Nitrification in wastewater treatment is an important process for eutrophication control and an emission source for greenhouse gas of N2O. The nitrifying process is usually operated at a slightly alkaline pH and high DO (>2 mg/L) to ensure efficient nitrification. However, it consumes a large amount of energy and chemicals especially for wastewater without sufficient alkalinity. This manuscript demonstrated that comammox can adapt well to the weakly acidic and low-DO bioreactors, with a result of efficient nitrification and low N2O emission. These findings indicate that comammox are significant for sustainable wastewater treatment, which provides an opportunity to achieve efficient nitrification with low N2O production as well as low energy and chemical consumption simultaneously.

scholarly journals Annual greenhouse gas budget for a bog ecosystem undergoing restoration by rewetting

2016 ◽  
Author(s):  
Sung Ching Lee ◽  
Andreas Christen ◽  
Andy T. Black ◽  
Mark S. Johnson ◽  
Rachhpal S. Jassal ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Water Table ◽  
Time Horizon ◽  
Ecosystem Respiration ◽  
High Water ◽  
Co2 Uptake ◽  
Raised Bog ◽  
Peat Mining ◽  
Ch4 Emissions ◽  
Carbon Dioxide Co2

Abstract. Many peatlands have been drained and harvested for peat mining, which has turned them from carbon (C) sinks into C emitters. Rewetting of disturbed peatlands facilitates their ecological recovery, and may help them revert to carbon dioxide (CO2) sinks. However, rewetting may also cause substantial emissions of the more potent greenhouse gas (GHG) methane (CH4). Our knowledge on the exchange of CO2 and CH4 following rewetting during restoration of disturbed peatlands is currently limited. This study quantifies annual fluxes of CO2 and CH4 in a disturbed and rewetted area located in the Burns Bog Ecological Conservancy Area in Delta, BC, Canada. Burns Bog is recognized as the largest raised bog ecosystem on North America's West Coast. Burns Bog was substantially reduced in size and degraded by peat mining and agriculture. Since 2005, the bog has been declared a conservancy area, with restoration efforts focusing on rewetting disturbed ecosystems to recover Sphagnum and suppress fires. Using the eddy-covariance (EC) technique, we measured year-round (16th June 2015 to 15th June 2016) turbulent fluxes of CO2 and CH4 from a tower platform in an area rewetted for the last 8 years. The study area, dominated by sedges and Sphagnum, experienced a varying water table position that ranged between 7.7 (inundation) and −26.5 cm from the surface during the study year. The annual CO2 budget of the rewetted area was −179 g CO2-C m−2 year−1 (CO2 sink) and the annual CH4 budget was 16 g CH4-C m−2 year−1 (CH4 source). Gross ecosystem productivity (GEP) exceeded ecosystem respiration (Re) during summer months (June–August), causing a net CO2 uptake. In summer, high CH4 emissions (121 mg CH4-C m−2 day−1) were measured. In winter (December–February), while roughly equal magnitudes of GEP and Re made the study area CO2 neutral, very low CH4 emissions (9 mg CH4-C m−2 day−1) were observed. The key environmental factors controlling the seasonality of these exchanges were downwelling photosynthetically active radiation and 5-cm soil temperature. It appears that the high water table caused by ditch blocking which suppresses Re. With low temperatures in winter, CH4 emission was more suppressed than Re. Annual net GHG flux from CO2 and CH4 expressed in terms of CO2 equivalents (CO2e) during the study period totaled to −55 g CO2e m−2 year−1 (net CO2e sink) and 1147 g CO2e m−2 year−1 (net CO2e source) by using 100-year and 20-year global warming potential values, respectively. Consequently, the ecosystem was almost CO2e neutral during the study period expressed on a 100-year time horizon but was a significant CO2e source on a 20-year time horizon.

scholarly journals Land-use and greenhouse gas balances of peatlands in the Nordic countries – present knowledge and gaps

2009 ◽  
Vol 6 (3) ◽  
pp. 6271-6338 ◽  
Author(s):  
M. Maljanen ◽  
B. D. Sigurdsson ◽  
J. Guđmundsson ◽  
H. Óskarsson ◽  
J. T. Huttunen ◽  
...  
Keyword(s):  
Land Use ◽  
Greenhouse Gas ◽  
Present Knowledge ◽  
Nordic Countries ◽  
N2o Emissions ◽  
Peat Soils ◽  
Ecosystem Level ◽  
Co2 Balance ◽  
Carbon Dioxide Co2 ◽  
Northern Peatlands

Abstract. This article provides an overview of the effects of land-use on the fluxes of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) of peatlands in the Nordic countries presented in about 100 studies. In addition, the article identifies the gaps in the present knowledge on the greenhouse gas (GHG) balances associated with the land-use of these northern ecosystems. Northern peatlands have accumulated, as peat, a vast amount of carbon from the atmosphere since the last glaciation. However, past land-use and the present climate have evidently changed their GHG balance. The mean annual GHG balances of undisturbed ombrotrophic and minerotrophic peatlands were surprisingly positive (net sources) of 140 and 380 g CO2 eq m−2, respectively, even if the former was a sink of 63 g CO2 eq m−2 when only the CO2 balance was considered. Drainage of such peatlands for agriculture resulted in the most disadvantageous land-use option for the atmosphere, with the net annual GHG balance increasing to 2190, 2280 and 3140 g CO2 eq m−2 for areas drained for grass swards, cereals or those left fallow, respectively. Even after ceasing of the cultivation practices, N2O emissions remained high and together with the other GHGs resulted in net emissions of 1570 and 500 g CO2 eq m−2, in abandoned and afforested peatlands, respectively. Peat extraction sites were also net sources, 730 g CO2 eq m−2. The cultivation of reed canary grass turned the site to net sink of −330 g CO2 eq m−2 but restoration did not (source of 470 g CO2 eq m−2). Data for afforested extraction sites is lacking. Peat soils originally drained for forestry may act as net sinks of 780 g CO2 eq m−2, and when those sites were restored the sink was 190 g CO2 eq m−2. However, more data is needed to confirm this point. Peat soils submerged under water reservoirs had a mean annual emission of 240 g CO2 eq m−2. In general, there is a lack of studies where all three GHGs have been measured at an ecosystem level, especially in the forested peatlands.

scholarly journals Effect of Biochar on Soil Greenhouse Gas Emissions at the Laboratory and Field Scales

Soil Systems ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 8 ◽  
Author(s):  
Rivka Fidel ◽  
David Laird ◽  
Timothy Parkin
Keyword(s):  
Field Study ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Cropping Systems ◽  
Cropping System ◽  
N2o Emission ◽  
N2o Emissions ◽  
Gas Emissions ◽  
Continuous Corn ◽  
The Impact

Biochar application to soil has been proposed as a means for reducing soil greenhouse gas emissions and mitigating climate change. The effects, however, of interactions between biochar, moisture and temperature on soil CO2 and N2O emissions, remain poorly understood. Furthermore, the applicability of lab-scale observations to field conditions in diverse agroecosystems remains uncertain. Here we investigate the impact of a mixed wood gasification biochar on CO2 and N2O emissions from loess-derived soils using: (1) controlled laboratory incubations at three moisture (27, 31 and 35%) and three temperature (10, 20 and 30 °C) levels and (2) a field study with four cropping systems (continuous corn, switchgrass, low diversity grass mix and high diversity grass-forb mix). Biochar reduced N2O emissions under specific temperatures and moistures in the laboratory and in the continuous corn cropping system in the field. However, the effect of biochar on N2O emissions was only significant in the field and no effect on cumulative CO2 emissions was observed. Cropping system also had a significant effect in the field study, with soils in grass and grass-forb cropping systems emitting more CO2 and less N2O than corn cropping systems. Observed biochar effects were consistent with previous studies showing that biochar amendments can reduce soil N2O emissions under specific but not all, conditions. The disparity in N2O emission responses at the lab and field scales suggests that laboratory incubation experiments may not reliably predict the impact of biochar at the field scale.

Towards a benchmarking tool for minimizing wastewater utility greenhouse gas footprints

2012 ◽  
Vol 66 (11) ◽  
pp. 2483-2495 ◽  
Author(s):  
L. Guo ◽  
J. Porro ◽  
K. R. Sharma ◽  
Y. Amerlinck ◽  
L. Benedetti ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Greenhouse Gas ◽  
Ghg Emissions ◽  
Treatment Plant ◽  
N2o Emission ◽  
Mitigation Strategies ◽  
N2o Emissions ◽  
N2o Production ◽  
Average Value ◽  
And Control

A benchmark simulation model, which includes a wastewater treatment plant (WWTP)-wide model and a rising main sewer model, is proposed for testing mitigation strategies to reduce the system's greenhouse gas (GHG) emissions. The sewer model was run to predict methane emissions, and its output was used as the WWTP model input. An activated sludge model for GHG (ASMG) was used to describe nitrous oxide (N2O) generation and release in activated sludge process. N2O production through both heterotrophic and autotrophic pathways was included. Other GHG emissions were estimated using empirical relationships. Different scenarios were evaluated comparing GHG emissions, effluent quality and energy consumption. Aeration control played a clear role in N2O emissions, through concentrations and distributions of dissolved oxygen (DO) along the length of the bioreactor. The average value of N2O emission under dynamic influent cannot be simulated by a steady-state model subjected to a similar influent quality, stressing the importance of dynamic simulation and control. As the GHG models have yet to be validated, these results carry a degree of uncertainty; however, they fulfilled the objective of this study, i.e. to demonstrate the potential of a dynamic system-wide modelling and benchmarking approach for balancing water quality, operational costs and GHG emissions.

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