scholarly journals Annual follow-up of gross diffusive carbon dioxide and methane emissions from a boreal reservoir and two nearby lakes in Québec, Canada

2011 ◽  
Vol 8 (1) ◽  
pp. 41-53 ◽  
Author(s):  
M. Demarty ◽  
J. Bastien ◽  
A. Tremblay

Abstract. Surface water pCO2 and pCH4 measurements were taken in the boreal zone of Québec, Canada, from summer 2006 to summer 2008 in Eastmain 1 reservoir and two nearby lakes. The goal of this follow-up was to evaluate annual greenhouse gas (GHG) emissions, including spring emissions (N.B. gross emissions for reservoir), through flux calculations using the thin boundary layer model. Our measurements underscored the winter CO2 accumulation due to ice cover and the importance of a reliable estimate of spring diffusive emissions as the ice breaks up. We clearly demonstrated that in our systems, diffusive CH4 flux (in terms of CO2 equivalent) were of minor importance in the GHG emissions (without CH4 accumulation under ice), with diffusive CO2 flux generally accounting for more than 95% of the annual diffusive flux. We also noted the extent of spring diffusive CO2 emissions (23% to 52%) in the annual carbon budget.

2010 ◽  
Vol 7 (4) ◽  
pp. 5429-5461 ◽  
Author(s):  
M. Demarty ◽  
J. Bastien ◽  
A. Tremblay

Abstract. Surface water pCO2 and pCH4 measurements were made in Québec (Canada) during consecutive seasons from 2006 to 2008 in two boreal reservoirs and nearby lakes. The goal of this follow-up was to evaluate greenhouse gas emissions from the water bodies studied, through flux calculations using the Thin Boundary Layer Model. Our measurements underscored the winter CO2 accumulation due to ice cover and the importance of a reliable estimation of spring diffusive emissions as the ice breaks up. We clearly demonstrated that in our systems, CH4 diffusive fluxes (in terms of CO2 equivalent) were of minor importance in the GHG emissions, with CO2 diffusive fluxes generally representing more than 95% of the annual diffusive fluxes. We also noted the extent of CO2 spring diffusive emissions (16% to 52%) in the annual budget.


2009 ◽  
Vol 42 (1) ◽  
pp. 97-111 ◽  
Author(s):  
Maaike Y. BADER ◽  
Gerhard ZOTZ ◽  
Otto L. LANGE

AbstractEstimating carbon budgets for poikilohydric organisms, such as lichens and bryophytes, requires methods other than those for homoiohydric plants due to a strong dependency of carbon gain on fluctuating hydration. This paper provides guidance with respect to optimal sampling strategies for estimating annual carbon budgets of lichens and bryophytes, based on a one-year dataset of half-hourly CO2-exchange readings on the epilithic placodioid lichen Lecanora muralis (syn. Protoparmeliopsis muralis) and tests the effects of reduced sampling frequencies and different temporal sampling schemes on carbon budget estimates. Both fine-scale sampling (measurements within a day) and large-scale sampling (selection of days within a year) are addressed.Lowering the sampling frequency within a day caused large deviations for 24-h (diel) budget estimates. Averaged over a larger number of days, these errors did not necessarily cause a large deviation in the annual budget estimate. However, the occurrence of extreme deviations in diel budgets could strongly offset the annual budget estimate. To avoid this problem, frequent sampling (c. every 1·5 hours) is necessary for estimating annual budgets. For estimating diel budgets and patterns a more frequent sampling (every c. 0·5 hours, balancing data resolution and disturbance) is often needed.Sampling fewer than 365 days in a given year inevitably caused estimates to deviate from the ‘true’ carbon budget, i.e. the annual budget based on half-hourly measurements during 365 days. Accuracy increased with total sample frequency, and blocking days caused larger deviations than sampling randomly or regularly spaced single days. Restricting sampling to only one season led to strongly biased estimates. The sampling effort required for a reliable estimate of the annual carbon balance of lichens based on simple extrapolations of diel carbon budgets is impracticably large. For example, a relatively large sample of 52 random days yielded an estimate within 25% of the true annual budget with only 60% certainty. Supporting approaches are therefore suggested, in particular extrapolating diel budgets using ‘weather response types’, possibly aided by diel activity patterns from chlorophyll fluorescence, or modelling CO2 exchange as a function of climatic conditions.


2018 ◽  
Author(s):  
Katherine N. Braun ◽  
◽  
Ethan J. Theuerkauf ◽  
Ethan J. Theuerkauf ◽  
Andrew L. Masterson ◽  
...  

Atmosphere ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 465 ◽  
Author(s):  
Kiwamu Ishikura ◽  
Untung Darung ◽  
Takashi Inoue ◽  
Ryusuke Hatano

This study investigated spatial factors controlling CO2, CH4, and N2O fluxes and compared global warming potential (GWP) among undrained forest (UDF), drained forest (DF), and drained burned land (DBL) on tropical peatland in Central Kalimantan, Indonesia. Sampling was performed once within two weeks in the beginning of dry season. CO2 flux was significantly promoted by lowering soil moisture and pH. The result suggests that oxidative peat decomposition was enhanced in drier position, and the decomposition acidify the peat soils. CH4 flux was significantly promoted by a rise in groundwater level, suggesting that methanogenesis was enhanced under anaerobic condition. N2O flux was promoted by increasing soil nitrate content in DF, suggesting that denitrification was promoted by substrate availability. On the other hand, N2O flux was promoted by lower soil C:N ratio and higher soil pH in DBL and UDF. CO2 flux was the highest in DF (241 mg C m−2 h−1) and was the lowest in DBL (94 mg C m−2 h−1), whereas CH4 flux was the highest in DBL (0.91 mg C m−2 h−1) and was the lowest in DF (0.01 mg C m−2 h−1), respectively. N2O flux was not significantly different among land uses. CO2 flux relatively contributed to 91–100% of GWP. In conclusion, it is necessary to decrease CO2 flux to mitigate GWP through a rise in groundwater level and soil moisture in the region.


2021 ◽  
Vol 13 (15) ◽  
pp. 8532
Author(s):  
Michael M. Blanke ◽  
Sabine D. Golombek

(1) Background: Black plastics pose a general problem in sustainability issues, as the recycling is hampered by the black colour disguising the type of plastics in the NIR scanner on the garbage sorting belt, as the black colour absorbs NIR radiation. Sorting flower/plant pots suffer from their additional soil contamination in the strive for sustainable flower production in horticulture. As these black plastic flowerpots are currently rarely recycled, a study was instigated of reusing them based on Heino Schwarz’s innovative idea. (2) Methods: In the first step, the carbon footprint was calculated for the flowerpots of two sizes employed in the nursery, their customised production from virgin polypropylene and the delivery from the Netherlands to the nursery in Bavaria. In step 2, the carbon footprint was calculated based on PAS 2050-1 for the number of flowerpots in circulation and return rates in 2019 and in 2020 to assess the GHG saved by the innovation. (3) Results: The innovative concept of Heino Schwarz is a discount on returning the customised used flowerpots, with a 40% increase from 24,533 returned flowerpots in 2019 to 39,797 in 2020. This shows the increasing acceptance and environmental awareness of the consumer and the great success. (4) Conclusions and outlook: The present case study has shown that innovative approaches such as discounts for reused/returned flowerpots of the Schwarz nursery can save 3.85–4.56 t CO2eq, a valuable contribution to reducing GHG emissions, creating environmental awareness among the consumers and building a close B2C relationship. The amount of CO2eq saved is equivalent to ca. 40% of the annual carbon burden of a European/German citizen or ca. 23,000 km driven in a private vehicle, the average mileage driven privately in two years.


2011 ◽  
Vol 8 (11) ◽  
pp. 3219-3230 ◽  
Author(s):  
K. Kuliński ◽  
J. Pempkowiak

Abstract. This paper presents the results of a comprehensive study of the Baltic Sea carbon budget. The Baltic Sea is very much influenced by terrestrial carbon input. Rivers are the largest carbon source, and their input amounts to 10.90 Tg C yr−1 (Tg = 1012 g) with a 37.5% contribution of organic carbon. On the other hand, carbon is effectively exported from the Baltic to the North Sea (7.67 Tg C yr−1) and is also buried in bottom sediments (2.73 Tg C yr−1). The other sources and sinks of carbon are of minor importance. The net CO2 emission (1.05 Tg C yr−1) from the Baltic to the atmosphere was calculated as the closing term of the carbon budget presented here. There is a net loss of organic carbon, which indicates that the Baltic Sea is heterotrophic.


2020 ◽  
Vol 42 ◽  
pp. e7
Author(s):  
Ricardo Acosta ◽  
Gustavo Pujol Veeck ◽  
Tiago Bremm ◽  
Débora Regina Roberti ◽  
Osvaldo Luiz Leal de Moraes

Annual carbon estimation of the most diverse ecosystems is a recurring theme in meetings that address climate change mitigation, as it is essential to have a realistic inventory of carbon stock in the biosphere and the ability to assimilate atmospheric carbon. Measurements of CO2 flux over ecosystems after being taken undergo rigorous post-processing to remove spurious and unrealistic data. In addition, a correction for low turbulence situations, where the eddy-covariance technique may be underestimated, is to take the friction velocity (u*) as a threshold to establish valid measurements, especially at night. This method, although widely used by the scientific community, is not unanimous. Especially since u* is itself a flow and consequently its value correlates with the time scale used for the analysis. This paper presents the annual carbon estimate of a natural pasture ecosystem, Pampa biome, in an experimental site established in Santa Maria - RS. We evaluated three distinct situations in the annual carbon estimate (NEP): i) without a u* filter; ii) with a fixed filter u* for all evaluated years and; iii) with the filter u* varying seasonally. The methodology used to estimate u* is the same as that used by Papale et al. (2006). The results show a total annual carbon sequestration variability of up to 10% depending on the methodology employed. The ecosystem in question, regardless of the method used, proved to be a carbon sink. However, the use of one methodology or another in ecosystem situations that are close to carbon assimaltion neutral should be closely scrutinized for an accurate annual balance.


2012 ◽  
Vol 9 (2) ◽  
pp. 1439-1482 ◽  
Author(s):  
D. Y. F. Lai ◽  
N. T. Roulet ◽  
E. R. Humphreys ◽  
T. R. Moore ◽  
M. Dalva

Abstract. Accurate quantification of soil-atmosphere gas exchange is essential for understanding the magnitude and controls of greenhouse gas emissions. We used an automatic closed dynamic chamber system to measure the fluxes of CO2 and CH4 for several years at the ombrotrophic Mer Bleue peatland near Ottawa, Canada and found that atmospheric turbulence and chamber deployment period had a considerable influence on the observed flux rates. With a short deployment period of 2.5 min, CH4 flux exhibited strong diel patterns and both CH4 and nighttime CO2 effluxes were highly and negatively correlated with friction velocity as were the CO2 concentration gradients in the top 20 cm of peat. This suggests winds were flushing the very porous and relatively dry near surface peat layers, altering the concentration gradient and resulting in a 9 to 57% underestimate of CH4 flux at any time of day and a 13 to 21% underestimate of nighttime CO2 fluxes in highly turbulent conditions. Conversely, there was evidence of an overestimation of ~100% of CH4 and nighttime CO2 effluxes in calm atmospheric conditions possibly due to enhanced near-surface gas concentration gradient by mixing of chamber headspace air by fans. These problems were resolved by extending the deployment period to 30 min. After 13 min of chamber closure, the flux rate of CH4 and nighttime CO2 became constant and were not affected by turbulence thereafter, yielding a reliable estimate of the net biological fluxes. The measurement biases we observed likely exist to some extent in all chamber flux measurements made on porous and aerated substrate, such as peatlands, organic soils in tundra and forests, and snow-covered surfaces, but would be difficult to detect unless high frequency, semi-continuous observations are made.


2016 ◽  
Vol 13 (10) ◽  
pp. 2959-2969 ◽  
Author(s):  
Raphael Felber ◽  
Daniel Bretscher ◽  
Andreas Münger ◽  
Albrecht Neftel ◽  
Christof Ammann

Abstract. Carbon (C) sequestration in the soil is considered as a potential important mechanism to mitigate greenhouse gas (GHG) emissions of the agricultural sector. It can be quantified by the net ecosystem carbon budget (NECB) describing the change of soil C as the sum of all relevant import and export fluxes. NECB was investigated here in detail for an intensively grazed dairy pasture in Switzerland. Two budget approaches with different system boundaries were applied: NECBtot for system boundaries including the grazing cows and NECBpast for system boundaries excluding the cows. CO2 and CH4 exchange induced by soil/vegetation processes as well as direct emissions by the animals were derived from eddy covariance measurements. Other C fluxes were either measured (milk yield, concentrate feeding) or derived based on animal performance data (intake, excreta). For the investigated year, both approaches resulted in a small near-neutral C budget: NECBtot −27 ± 62 and NECBpast 23 ± 76 g C m−2 yr−1. The considerable uncertainties, depending on the approach, were mainly due to errors in the CO2 exchange or in the animal-related fluxes. The comparison of the NECB results with the annual exchange of other GHG revealed CH4 emissions from the cows to be the major contributor in terms of CO2 equivalents, but with much lower uncertainty compared to NECB. Although only 1 year of data limit the representativeness of the carbon budget results, they demonstrate the important contribution of the non-CO2 fluxes depending on the chosen system boundaries and the effect of their propagated uncertainty in an exemplary way. The simultaneous application and comparison of both NECB approaches provides a useful consistency check for the carbon budget determination and can help to identify and eliminate systematic errors.


Atmosphere ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 504 ◽  
Author(s):  
Fumiaki Takakai ◽  
Masahiro Kobayashi ◽  
Takashi Sato ◽  
Kentaro Yasuda ◽  
Yoshihiro Kaneta

The effects of conversion from staple rice to forage rice on carbon and greenhouse gas (GHG) balances in a paddy field were evaluated. A staple rice plot without the application of livestock manure compost (LMC, S − M plot) and forage rice plots with and without the application of LMC, derived mainly from cattle (2 kg−FW m−2, F + M and F − M plots, respectively), were established. CH4 and N2O fluxes and CO2 flux from a bare soil plot for organic matter decomposition (OMD) were measured. The carbon budget was calculated by subtracting the OMD, CH4 emission, and harvested grain and straw (forage rice only) from the net primary production and LMC. The net GHG balance was calculated by integrating them as CO2 equivalents. There were no significant differences in GHG flux among the plots. Compared to the carbon loss in the S − M plot, the loss increased by harvesting straw and was mitigated by LMC application. The net GHG emission in the F + M plot was significantly lower than that in other plots (1.78 and 2.63−2.77 kg CO2-eq m−2 year−1, respectively). There is a possibility that GHG emissions could be suppressed by forage rice cultivation with the application of LMC.


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