A versatile gas flux chamber reveals high tree stem CH4 emissions in Amazonian peatland

2021 ◽  
Vol 307 ◽  
pp. 108504
Author(s):  
Joost van Haren ◽  
Paul E. Brewer ◽  
Laura Kurtzberg ◽  
Rachel N. Wehr ◽  
Vanessa L. Springer ◽  
...  
Keyword(s):  
Flux Chamber ◽  
Gas Flux ◽  
Ch4 Emissions ◽  
Tree Stem

scholarly journals The role of termite CH<sub>4</sub> emissions on ecosystem scale: a case study in the Amazon rain forest

2020 ◽  
Author(s):  
Hella van Asperen ◽  
João Rafael Alves-Oliveira ◽  
Thorsten Warneke ◽  
Bruce Forsberg ◽  
Alessandro Carioca de Araujo ◽  
...  
Keyword(s):  
Rain Forest ◽  
Emission Factor ◽  
Field Studies ◽  
Ch4 Emission ◽  
Termite Mound ◽  
Flux Chamber ◽  
Termite Mounds ◽  
Ch4 Emissions ◽  
Amazon Rain Forest

Abstract. The magnitude of termite methane (CH4) emissions is still an uncertain part of the global CH4 budget and current emission estimates are based on limited field studies. We present in-situ CH4 emission measurements of termite mounds and termite mound sub samples, performed in the Amazon rain forest. Emissions of five termite mounds of the species Neocapritermes brasiliensis were measured by use of a large flux chamber connected to a portable gas analyser, measuring CH4 and CO2. In addition, the emission of mound sub samples was measured, after which termites were counted, so that a termite CH4 and CO2 emission factor could be determined. Mound emissions were found to range between 17.0–34.8 nmol mound−1 s−1 for CH4 and between 1.6–13.5 μmol mound−1 s−1 for CO2. A termite emission factor of 0.32 μmol CH4 gtermite−1 h−1 was found, which is twice as high as the only other reported average value for the Amazon. By combining mound emission measurements with the termite emission factor, colony sizes could be estimated, which were found to range between 50–120 thousand individuals. Estimates were similar to literature values, and we therefore propose that this method can be used as a quick non-intrusive method to estimate termite colony size in the field. The role of termites in the ecosystems CH4 budget was evaluated by use of two approaches. Termite mound emission values were combined with local termite mound density numbers, leading to an estimate of 0.15–0.71 nmol CH4 m−2 s−1 on average emitted by termite mounds. In addition, the termite CH4 emission factor from this study was combined with termite density numbers, resulting in an estimate of termite emitted CH4 of ~1.0 nmol m−2 s−1. Considering the relatively low net CH4 emissions previously measured at this ecosystem, we expect that termites play an important role in the CH4 budget of this Terra Firme ecosystem.

scholarly journals Carbon dioxide and methane exchange of a patterned subarctic fen during two contrasting growing seasons

2021 ◽  
Vol 18 (3) ◽  
pp. 873-896
Author(s):  
Lauri Heiskanen ◽  
Juha-Pekka Tuovinen ◽  
Aleksi Räsänen ◽  
Tarmo Virtanen ◽  
Sari Juutinen ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Ecosystem Respiration ◽  
Growing Season ◽  
Drought Event ◽  
Flux Chamber ◽  
Ch4 Emissions ◽  
Growing Seasons ◽  
Ecosystem Level ◽  
Community Types ◽  
Carbon Dioxide Co2

Abstract. The patterned microtopography of subarctic mires generates a variety of environmental conditions, and carbon dioxide (CO2) and methane (CH4) dynamics vary spatially among different plant community types (PCTs). We studied the CO2 and CH4 exchange between a subarctic fen and the atmosphere at Kaamanen in northern Finland based on flux chamber and eddy covariance measurements in 2017–2018. We observed strong spatial variation in carbon dynamics between the four main PCTs studied, which were largely controlled by water table level and differences in vegetation composition. The ecosystem respiration (ER) and gross primary productivity (GPP) increased gradually from the wettest PCT to the drier ones, and both ER and GPP were larger for all PCTs during the warmer and drier growing season 2018. We estimated that in 2017 the growing season CO2 balances of the PCTs ranged from −20 g C m−2 (Trichophorum tussock PCT) to 64 g C m−2 (string margin PCT), while in 2018 all PCTs were small CO2 sources (10–22 g C m−2). We observed small growing season CH4 emissions (< 1 g C m−2) from the driest PCT, while the other three PCTs had significantly larger emissions (mean 7.9, range 5.6–10.1 g C m−2) during the two growing seasons. Compared to the annual CO2 balance (−8.5 ± 4.0 g C m−2) of the fen in 2017, in 2018 the annual balance (−5.6 ± 3.7 g C m−2) was affected by an earlier onset of photosynthesis in spring, which increased the CO2 sink, and a drought event during summer, which decreased the sink. The CH4 emissions were also affected by the drought. The annual CH4 balance of the fen was 7.3 ± 0.2 g C m−2 in 2017 and 6.2 ± 0.1 g C m−2 in 2018. Thus, the carbon balance of the fen was close to zero in both years. The PCTs that were adapted to drier conditions provided ecosystem-level resilience to carbon loss due to water level drawdown.

Design and Performance of a Dynamic Gas Flux Chamber

2002 ◽  
Vol 31 (6) ◽  
pp. 1774-1781 ◽  
Author(s):  
Rivka Reichman ◽  
Dennis E. Rolston
Keyword(s):  
Flux Chamber ◽  
Gas Flux ◽  
And Performance

Automated Flux Chamber for Investigating Gas Flux at Water–Air Interfaces

2012 ◽  
Vol 47 (2) ◽  
pp. 968-975 ◽  
Author(s):  
Nguyen Thanh Duc ◽  
Samuel Silverstein ◽  
Lars Lundmark ◽  
Henrik Reyier ◽  
Patrick Crill ◽  
...  
Keyword(s):  
Flux Chamber ◽  
Gas Flux ◽  
Air Interfaces

scholarly journals A compact and stable eddy covariance set-up for methane measurements using off-axis integrated cavity output spectroscopy

2007 ◽  
Vol 7 (4) ◽  
pp. 11587-11619 ◽  
Author(s):  
D. M. D. Hendriks ◽  
A. J. Dolman ◽  
M. K. van de Molen ◽  
J. van Huissteden
Keyword(s):  
Eddy Covariance ◽  
Measurement Techniques ◽  
Power Spectra ◽  
Statistical Testing ◽  
Ch4 Emission ◽  
Flux Chamber ◽  
Night Time ◽  
Ch4 Emissions ◽  
Cavity Output ◽  
Set Up

Abstract. A DLT-100 Fast Methane Analyser (FMA) from Los Gatos Research (LGR) Ltd. is assessed for its applicability in a closed path eddy covariance field set-up. The FMA uses off-axis integrated cavity output spectroscopy (ICOS) combined with a highly specific narrow band laser for the detection of CH4 and strongly reflective mirrors to obtain a laser path length of 2×10³ to 20×10³ m. Statistical testing, a calibration experiment and comparison with high tower data showed high precision and very good stability of the instrument. The measurement cell response time was tested to be 0.10 s. In the field set-up, the FMA is attached to a scroll pump and combined with a Gill Windmaster Pro 3 axis Ultrasonic Anemometer and a Licor 7500 open path infrared gas analyzer. The power-spectra and co-spectra of the instrument are satisfactory for 10 Hz sampling rates. The correspondence with CH4 flux chamber measurements is good and the observed CH4 emissions are comparable with (eddy covariance) CH4 measurements in other peat areas. CH4 emissions are rather variable over time and show a diurnal pattern. The average CH4 emission is 50±12.5 nmol m−2 s−1, while the typical maximum CH4 emission is 120±30 nmol m−2 s−1 (during daytime) and the typical minimum flux is –20±2.5 nmol m−2 s−1 (uptake, during night time). Additionally, the set-up was tested for three measurement techniques with slower measurement rates, which could be used in the future to make the scroll pump superfluous and save energy. Both disjunct eddy covariance as well as slow 1 Hz eddy covariance showed results very similar to normal 10 Hz eddy covariance. Relaxed eddy accumulation (REA) only matched with normal 10 Hz eddy covariance over an averaging period of at least several weeks.

scholarly journals The full greenhouse gas balance of an abandoned peat meadow

2007 ◽  
Vol 4 (3) ◽  
pp. 411-424 ◽  
Author(s):  
D. M. D. Hendriks ◽  
J. van Huissteden ◽  
A. J. Dolman ◽  
M. K. van der Molen
Keyword(s):  
Greenhouse Gas ◽  
Ecosystem Respiration ◽  
Net Ecosystem Exchange ◽  
Co2 Uptake ◽  
Flux Chamber ◽  
Greenhouse Gas Balance ◽  
Dry Land ◽  
Ch4 Emissions ◽  
Growing Seasons ◽  
Ch4 And N2o

Abstract. Globally, peat lands are considered to be a sink of CO2, but a source when drained. Additionally, wet peat lands are thought to emit considerable amounts of CH4 and N2O. Hitherto, reliable and integrated estimates of emissions and emission factors for this type of land cover have been lacking and the effects of wetland restoration on methane emissions have been poorly quantified. In this paper we estimate the full greenhouse gas (GHG) balance of a restored natural peat land by determining the fluxes of CO2, CH4 and N2O through atmosphere and water, while accounting for the different Global Warming Potentials (GWP's). The site is an abandoned agricultural peat meadow, which has been converted into a wetland nature reserve ten years ago, after which the water level was raised. GHG fluxes were measured continuously with an eddy covariance system (CO2) and flux chamber measurements (CH4 and N2O). Meteorological and hydrological measurements were collected as well. With growing seasons of respectively 192, 168 and 129 days, the annual net ecosystem exchange of CO2 (NEE) was −446+±83 g C m−2 yr−1 for 2004, −311±58 g C m−2 yr−1 for 2005 and −232±57 g m−2 yr−1 for 2006. Ecosystem respiration (Reco) was estimated as 869±668 g C m−2 yr−1 for 2004, 866±666 g C m−2 yr−1 for 2005 and 924±711 g C m−2 yr−1 for 2006. CH4 emissions from the saturated land and water surfaces were high compared to the relatively dry land. Annual weighted CH4 emissions were 31.27±20.40 g C m−2 yr−1 for 2005 and 32.27±21.08 g C m−2 yr−1 for 2006. N2O fluxes were too low to be of significance. The water balance of the area was dominated by precipitation and evapotranspiration and therefore fluxes of carbon and CH4 through seepage, infiltration and drainage were relatively small (17.25 g C m−2 yr−1). The carbon-balance consisted for the largest part of CO2 uptake, CO2 respiration and CH4 emission from water saturated land and water. CO2 emission has decreased significantly as result of the raised water table, while CH4 fluxes have increased. In GWP's the area was a small net GHG sink given as CO2-equiv. of −86 g m−2 yr−1 (over a 100-year period).

scholarly journals The role of termite CH<sub>4</sub> emissions on the ecosystem scale: a case study in the Amazon rainforest

2021 ◽  
Vol 18 (8) ◽  
pp. 2609-2625
Author(s):  
Hella van Asperen ◽  
João Rafael Alves-Oliveira ◽  
Thorsten Warneke ◽  
Bruce Forsberg ◽  
Alessandro Carioca de Araújo ◽  
...  
Keyword(s):  
Emission Factor ◽  
Field Studies ◽  
Amazon Rainforest ◽  
Ch4 Emission ◽  
Termite Mound ◽  
Flux Chamber ◽  
Termite Mounds ◽  
Ch4 Emissions ◽  
Current Emission

Abstract. The magnitude of termite methane (CH4) emissions is still an uncertain part of the global CH4 budget and current emission estimates are based on limited field studies. We present in situ CH4 emission measurements of termite mounds and termite mound subsamples performed in the Amazon rainforest. Emissions from five termite mounds of the species Neocapritermes brasiliensis were measured by use of a large flux chamber connected to a portable gas analyser measuring CH4 and CO2. In addition, the emissions of mound subsamples were measured, after which the termites were counted so that a termite CH4 and CO2 emission factor could be determined. Mound emissions were found to range between 17.0 and 34.8 nmol mound−1 s−1 for CH4 and between 1.1 and 13.0 µmol mound−1 s−1 for CO2. A termite emission factor of 0.35 µmol CH4 gtermite-1 h−1 was found, which is almost twice as high as the only other reported value for the Amazon. By combining mound emission measurements with the termite emission factor, colony sizes could be estimated, which were found to range between 55–125 thousand individuals. Estimates were similar to literature values, and we therefore propose that this method can be used as a quick non-intrusive method to estimate termite colony size in the field. The role of termites in the ecosystem's CH4 budget was evaluated by use of two approaches. Termite mound emission values were combined with local mound density numbers, leading to an estimate of 0.15–0.71 nmol CH4 m−2 s−1, on average, emitted by termite mounds. In addition, the termite CH4 emission factor from this study was combined with termite biomass numbers, resulting in an estimate of termite-emitted CH4 of ∼1.0 nmol m−2 s−1. Considering the relatively low net CH4 emissions previously measured at this ecosystem, we expect that termites play an important role in the CH4 budget of this terra firme ecosystem.

Towards a better understanding of soil- and tree stem-atmosphere exchanges of greenhouse gases, i.e. CO2, CH4, N2O, in a tropical rainforest

2020 ◽  
Author(s):  
Laëtitia Brechet ◽  
Warren Daniel ◽  
Clément Stahl ◽  
Benoît Burban ◽  
Jean-Yves Goret ◽  
...  
Keyword(s):  
Climate Change ◽  
Tropical Rainforest ◽  
Temporal Variations ◽  
Automated System ◽  
Flux Chamber ◽  
Wet Season ◽  
Environmental Controls ◽  
C Cycle ◽  
Ghg Fluxes ◽  
Tree Stem

&lt;p&gt;The importance of greenhouse gas (GHG) emissions in global climate change is undisputed, but our understanding of the daily and seasonal variations of the GHG fluxes is far from complete and detailed flux estimates are unequally distributed among ecosystems worldwide. Carbon dioxide (77%; CO&lt;sub&gt;2&lt;/sub&gt;), methane (14%; CH&lt;sub&gt;4&lt;/sub&gt;) and nitrous oxide (8%; N&lt;sub&gt;2&lt;/sub&gt;O) are the three main GHGs that trap infrared radiations and contribute to climate change. While CO&lt;sub&gt;2&lt;/sub&gt; has been largely studied, a considerable effort is still required to quantify the magnitude and drivers of CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O, which have radiative effects 25 and 298 times greater than CO&lt;sub&gt;2&lt;/sub&gt;, respectively. Tropical forests play a pivotal role in global carbon (C) balance and climate change mitigation, accounting for 68% of global C stock and representing up to 30% of total forest soil C sink. In the tropics, soils are main contributors to the ecosystem GHG fluxes. In fact, tropical forest soils are the largest natural source of soil CO&lt;sub&gt;2&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O and are overwhelmingly reported as important sink of CH&lt;sub&gt;4&lt;/sub&gt;. More recently, studies reported that tree stems can also emit CO&lt;sub&gt;2&lt;/sub&gt;, CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O and act, via passive transport through the soil xylem stream, as a pathway for these gas emissions to the atmosphere.&lt;/p&gt;&lt;p&gt;Although accurate estimates of GHG sources and sinks are of great importance for reducing the uncertainties of C cycle - climate feed-backs, we are only just beginning to understand the role of tropical tree stems as producers and / or conduits of soil-produced GHG.&lt;/p&gt;&lt;p&gt;I present first results of soil and tree stem GHG fluxes estimated over a six-month period, including a dry and a wet season, of continuous high frequency measurements with automated GHG flux systems in a tropical rainforest, in French Guiana. We adapted and extended an existing soil GHG flux system, combining a commercial automated soil CO&lt;sub&gt;2&lt;/sub&gt; flux chamber system (LI-8100A) and CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O analyser (Picarro G2308), to include tree stem chambers. Different closure times were applied to ensure reliable flux estimates, especially for low CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O fluxes. I show that the new automated system operated successfully, allowing for robust long-term measurements to examine temporal variations and ultimately calculate budgets of CO&lt;sub&gt;2&lt;/sub&gt;, CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O fluxes at soil and tree stem levels. Our results indicated that soils and tree stems acted exclusively as source for CO&lt;sub&gt;2&lt;/sub&gt;, whereas soils and tree stems exhibited distinct patterns for both CH&lt;sub&gt;4&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O, which highlights the importance of partitioning GHG fluxes to better determine environmental controls regulating ecosystem GHG exchanges.&lt;/p&gt;

scholarly journals Assessing the spatial and temporal variability of GHG emissions from different configurations of on-site wastewater treatment system using discrete and continuous gas flux measurement

2021 ◽  
Author(s):  
Jan Knappe ◽  
Celia Somlai ◽  
Laurence Gill
Keyword(s):  
Wastewater Treatment ◽  
Ghg Emissions ◽  
Soil Surface ◽  
Soil Treatment ◽  
Septic Tank ◽  
Spatial And Temporal Variability ◽  
Flux Chamber ◽  
Treatment Unit ◽  
Gas Flux ◽  
Ch4 And N2o

Abstract. Global emissions linked to wastewater treatment are estimated to account for up to 1.5 % of total greenhouse gas (GHG) emissions globally. However, few studies have measured GHG emissions from domestic on-site treatment systems (DWWTSs) directly. In this study, two DWWTSs were monitored for 446 days and > 42,000 gas flux measurements were conducted using both discrete spot measurements and continuous flux chamber deployments. The observed GHG fluxes from biological activity in the soil and water phase were found to be highly spatially and temporally variable and correlated to environmental factors, water usage patterns and system design. In total, the results show that a septic tank discharging effluent into a well-designed soil treatment unit is estimated to emit a net 9.99 kg-CO2eq cap−1 yr−1, with approximately 63 %, 27 % and 10 % of the total CO2-equivalent net emissions in the form of CO2, CH4 and N2O, respectively. Emissions from the septic tank surface contributed over 50 % of total emissions and tended to be strongly underestimated by one-off discrete measurements, especially when episodic ebullitive events are to be considered. Fluxes from the soil treatment unit (STU) stemmed from both the soil surface and the vent system, but were also found to be periodically negative, i.e. net uptakes. Soil fluxes were mostly influenced by temperature but peaked regularly under conditions of rapidly changing soil water content. Vent fluxes were mostly governed by effluent quality and a low number of high emission events was responsible for the majority of total observed vent emissions. Owing to the strong overall spatial and temporal heterogeneity of observed fluxes from DWWTSs across all modules, future studies should focus on continuous deployments of a number of flux chambers over discrete measurements to accurately assess GHG emissions from on-site systems. This study also provided insights into managing GHG emissions from DWWTSs by different system configuration design, as well as indicating that the current IPCC emission factors for CH4 and N2O are significantly overestimating emissions for on-site wastewater treatment systems.

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