Carbon exchange between the atmosphere and subtropical forested cypress and pine wetlands

Abstract. Carbon dioxide exchange between the atmosphere and forested subtropical wetlands is largely unknown. Here we report a first step in characterizing this atmospheric–ecosystem carbon (C) exchange, for cypress strands and pine forests in the Greater Everglades of Florida as measured with eddy covariance methods at three locations (Cypress Swamp, Dwarf Cypress and Pine Upland) for one year. Links between water and C cycles are examined at these three sites, and methane emission measured only at the Dwarf Cypress site. Each forested wetland showed net C uptake (retained in the soil and biomass or transported laterally via overland flow) from the atmosphere monthly and annually. Net ecosystem exchange (NEE) of carbon dioxide (CO2) (difference between photosynthesis and respiration, with negative values representing net ecosystem uptake) was greatest at the Cypress Swamp (−1000 g C m-2 year-1), moderate at the Pine Upland (−900 g C m-2 year-1), and least at the Dwarf Cypress (−500 g C m-2 year-1). Methane emission was a negligible part of the C (12 g C m-2 year-1) budget when compared to NEE. However, methane (CH4) production was considerable in terms of global warming potential, as about 20 g CH4 emitted per m2 year was equivalent to about 500 g CO2 emitted per m2 year}. Changes in NEE were clearly a function of seasonality in solar insolation, air temperature and water availability from rainfall. We also note that changes in the satellite-derived enhanced-vegetation index (EVI) served as a useful surrogate for changes in net and gross atmospheric–ecosystem C exchange at these forested wetland sites.

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Carbon exchange between the atmosphere and subtropical forested cypress and pine wetlands

Biogeosciences ◽

10.5194/bg-12-2285-2015 ◽

2015 ◽

Vol 12 (8) ◽

pp. 2285-2300 ◽

Cited By ~ 10

Author(s):

W. B. Shoemaker ◽

F. Anderson ◽

J. G. Barr ◽

S. L. Graham ◽

D. B. Botkin

Keyword(s):

Carbon Dioxide ◽

Vegetation Index ◽

Overland Flow ◽

Net Ecosystem Exchange ◽

Forested Wetland ◽

Carbon Dioxide Exchange ◽

Ecosystem Carbon ◽

Heterotrophic Soil Respiration ◽

The Difference ◽

Carbon Dioxide Co2

Abstract. Carbon dioxide exchange between the atmosphere and forested subtropical wetlands is largely unknown. Here we report a first step in characterizing this atmospheric–ecosystem carbon (C) exchange, for cypress strands and pine forests in the Greater Everglades of Florida as measured with eddy covariance methods at three locations (Cypress Swamp, Dwarf Cypress and Pine Upland) for 2 years. Links between water and C cycles are also examined at these three sites, as are methane emission measured only at the Dwarf Cypress site. Each forested wetland showed net C uptake from the atmosphere both monthly and annually, as indicated by the net ecosystem exchange (NEE) of carbon dioxide (CO2). For this study, NEE is the difference between photosynthesis and respiration, with negative values representing uptake from the atmosphere that is retained in the ecosystem or transported laterally via overland flow (unmeasured for this study). Atmospheric C uptake (NEE) was greatest at the Cypress Swampp (−900 to −1000 g C m2 yr−1), moderate at the Pine Upland (−650 to −700 g C m2 yr−1) and least at the Dwarf Cypress (−400 to −450 g C m2 yr−1). Changes in NEE were clearly a function of seasonality in solar insolation, air temperature and flooding, which suppressed heterotrophic soil respiration. We also note that changes in the satellite-derived enhanced vegetation index (EVI) served as a useful surrogate for changes in NEE at these forested wetland sites.

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Spectral estimation of wetland carbon dioxide exchange

International Agrophysics ◽

10.2478/v10247-012-0061-3 ◽

2013 ◽

Vol 27 (1) ◽

pp. 1-79 ◽

Cited By ~ 3

Author(s):

B.H. Chojnicki

Keyword(s):

Carbon Dioxide ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Carbon Fluxes ◽

Vegetation Period ◽

Net Ecosystem Production ◽

Carbon Dioxide Exchange ◽

Production Values ◽

Ecosystem Production ◽

Index Value

Abstract The simultaneous measurements of broadband normalized difference vegetation index and net ecosystem production were carried out at Rzecin wetland in 2009. Additionally, carbon fluxes, ecosystem respiration and gross ecosystem production were estimated on the basis of measured net ecosystem production values. The maximum broadband normalized difference vegetation index value (0.73) was measured on the 6th of July. The minimum broadband normalized difference vegetation index value measured before and after the vegetation period was 0.40. The annual dynamics of carbon fluxes and broadband normalized difference vegetation index runs were different from each other. During the second half of vegetation period greenness of plants decreases more slowly than plants carbon dioxide uptake capacity. These differences are likely to be determined by plants aging. The results presented in this paper show potential applicability of broadband normalized difference vegetation index for the estimation of carbon dioxide exchange in wetlands.

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Carbon precursors of methane synthesis in the rumen of sheep dosed with ionophores

Animal Production Science ◽

10.1071/an14359 ◽

2014 ◽

Vol 54 (10) ◽

pp. 1787

Author(s):

M. L. Loughnan ◽

J. V. Nolan ◽

R. A. Leng

Keyword(s):

Carbon Dioxide ◽

Rumen Fluid ◽

Specific Radioactivity ◽

Infusion Site ◽

Irreversible Loss ◽

Microbial Biofilms ◽

Ch4 Production ◽

Naturally Occurring ◽

Carbon Dioxide Co2 ◽

Percentage Ratio

Rates of methane (CH4) production and the sources of carbon (C) for its synthesis were studied in four mature ewes when dosed with a CH4-mitigating ionophore ICI-111075, or monensin, or when untreated. The sheep were given 700 g/day of chaffed lucerne hay in equal portions every hour, before and during experiments in which 14C-labelled NaHCO3–, acetate, propionate, lactate and formate were infused intraruminally over 12 h and the specific radioactivity of C (SR) in each of these substrates was determined. During these infusions, the SR of material in the primary pool (the tracer infusion site) and in secondary metabolites of this material (secondary pools) approached asymptotic or ‘plateau’ values. The rate of infusion of 14CH4 (kBq/day) divided by the plateau SR value (kBq/g C) gave estimates of the rate of irreversible loss of CH4 (g C/day). These calculations indicated that CH4 production rate was reduced by 72% when sheep were dosed with ICI-111075 and by 58% when dosed with monensin. With monensin, the reduction in CH4 production was not associated with hydrogen (H2) accumulation in the rumen headspace gases whereas with ICI-111075, the decrease in CH4 production was associated with marked H2 accumulation in the headspace gases. When plateau SR were attained during the tracer infusions, the percentage ratio, (SR in any secondary pool: SR in the primary pool) gave an estimate of the fraction of C in that secondary pool derived from material of the primary pool. Calculated in this way, the percentage of CH4-C derived from rumen fluid carbon dioxide (CO2) averaged 59% in untreated sheep, and when sheep were dosed with ICI-111075, the corresponding percentage averaged 12%. These findings indicate there are sources of C for rumen CH4 synthesis other than rumen fluid CO2. However, there was no evidence that C from acetate, propionate, lactate or formate in rumen fluid were direct sources of the unidentified CH4-C. One plausible explanation for these findings is that CH4 is synthesised within naturally occurring microbial biofilms (attached to feed particles or the rumen wall) from CO2 that is produced locally by fermentation of unlabelled substrates within the biofilms. It is postulated that such pools of CO2 would be kinetically distinct and, during the infusion of 14C-labelled substrates, would exhibit a lower SR than the CO2 in the surrounding rumen fluid.

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Contrasting carbon dioxide fluxes between a drying shrub wetland in Northern Wisconsin, USA, and nearby forests

Biogeosciences ◽

10.5194/bg-6-1115-2009 ◽

2009 ◽

Vol 6 (6) ◽

pp. 1115-1126 ◽

Cited By ~ 84

Author(s):

B. N. Sulman ◽

A. R. Desai ◽

B. D. Cook ◽

N. Saliendra ◽

D. S. Mackay

Keyword(s):

Carbon Dioxide ◽

Water Table ◽

Climate Models ◽

Ecosystem Respiration ◽

Net Ecosystem Exchange ◽

Carbon Dioxide Exchange ◽

Co2 Fluxes ◽

Carbon Dioxide Fluxes ◽

Highly Correlated ◽

Shrub Wetland

Abstract. Wetland biogeochemistry is strongly influenced by water and temperature dynamics, and these interactions are currently poorly represented in ecosystem and climate models. A decline in water table of approximately 30 cm was observed at a wetland in Northern Wisconsin, USA over a period from 2001–2007, which was highly correlated with an increase in daily soil temperature variability. Eddy covariance measurements of carbon dioxide exchange were compared with measured CO2 fluxes at two nearby forests in order to distinguish wetland effects from regional trends. As wetland water table declined, both ecosystem respiration and ecosystem production increased by over 20% at the wetland, while forest CO2 fluxes had no significant trends. Net ecosystem exchange of carbon dioxide at the wetland was not correlated with water table, but wetland evapotranspiration decreased substantially as the water table declined. These results suggest that changes in hydrology may not have a large impact on shrub wetland carbon balance over inter-annual time scales due to opposing responses in both ecosystem respiration and productivity.

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Comparison between eddy covariance and automatic chamber techniques for measuring net ecosystem exchange of carbon dioxide in cotton and wheat fields

Biogeosciences Discussions ◽

10.5194/bgd-10-8467-2013 ◽

2013 ◽

Vol 10 (5) ◽

pp. 8467-8503 ◽

Cited By ~ 2

Author(s):

K. Wang ◽

C. Liu ◽

X. Zheng ◽

M. Pihlatie ◽

B. Li ◽

...

Keyword(s):

Carbon Dioxide ◽

Eddy Covariance ◽

Calcareous Soils ◽

Net Ecosystem Exchange ◽

Cotton Field ◽

Wheat Field ◽

Cropping Season ◽

Flux Measurements ◽

One Year ◽

Carbon Dioxide Co2

Abstract. Static and transparent automatic chamber (AC) technique is a~necessary choice for measuring net ecosystem exchange (NEE) of carbon dioxide (CO2) in circumstances where eddy covariance (EC) technique is not applicable. However, a comparison of the two techniques for measurements on croplands has seldom been undertaken. We carried out NEE observations in a cotton field (for one year) and a winter wheat field (for one cropping season) using both AC and EC techniques, to (a) compare the NEE fluxes measured using each technique, and (b) test the NEE measurement performance of an automatic chamber system (AMEG), which was designed for simultaneous flux measurements of multiple gases. The half-hourly NEE fluxes measured with the two techniques were in approximate agreement, with the AC fluxes being 0.78 (cotton) and 1.06 (wheat) times those of the EC. When integrated to daily timescale, the fluxes of the two techniques were in better agreement, showing an average ratio of 0.94 and 1.00 for the cotton and wheat, respectively. During the periods with comparable field conditions and normal performance of both instruments, the cumulative NEE fluxes revealed small differences between the two techniques (–9.0 ~ 6.7%, with a mean of 0.1%). The measurements resulted in annual cumulative NEE of –40 g C m–2 yr–1 (EC) and –42 g C m–2 yr–1 (AC) in the cotton field and seasonal cumulative NEE of –251 g C m–2 (EC) and –205 g C m–2 (AC) in the wheat field. Our results indicate that, for cropland populated by short plants, the AMEG system and the data processing procedures applied in this study are able to provide NEE estimates comparable to those from EC measurements, although either technique may lead to an overestimation of the loss rate (or underestimation of the gain rate) of the soil organic carbon stock of an ecosystem, in particular with calcareous soils exposed to increasing atmospheric acid deposition.

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Ozone effects on Sphagnum mosses, carbon dioxide exchange and methane emission in boreal peatland microcosms

The Science of The Total Environment ◽

10.1016/s0048-9697(01)01012-9 ◽

2002 ◽

Vol 289 (1-3) ◽

pp. 1-12 ◽

Cited By ~ 20

Author(s):

Riikka Niemi ◽

Pertti J. Martikainen ◽

Jouko Silvola ◽

Toini Holopainen

Keyword(s):

Carbon Dioxide ◽

Methane Emission ◽

Carbon Dioxide Exchange ◽

Sphagnum Mosses

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Comparison between eddy covariance and automatic chamber techniques for measuring net ecosystem exchange of carbon dioxide in cotton and wheat fields

Biogeosciences ◽

10.5194/bg-10-6865-2013 ◽

2013 ◽

Vol 10 (11) ◽

pp. 6865-6877 ◽

Cited By ~ 38

Author(s):

K. Wang ◽

C. Liu ◽

X. Zheng ◽

M. Pihlatie ◽

B. Li ◽

...

Keyword(s):

Carbon Dioxide ◽

Eddy Covariance ◽

Net Ecosystem Exchange ◽

Cotton Field ◽

Wheat Field ◽

Cropping Season ◽

Flux Measurements ◽

One Year ◽

Carbon Dioxide Co2 ◽

B Test

Abstract. Static and transparent automatic chamber (AC) technique is a necessary choice for measuring net ecosystem exchange (NEE) of carbon dioxide (CO2) in circumstances where eddy covariance (EC) technique is not applicable. However, a comparison of the two techniques for measurements on croplands has seldom been undertaken. We carried out NEE observations in a cotton field (for one year) and a winter wheat field (for one cropping season) using both AC and EC techniques, to (a) compare the NEE fluxes measured using each technique, and (b) test the NEE measurement performance of an automatic chamber system (AMEG), which was designed for simultaneous flux measurements of multiple gases. The half-hourly NEE fluxes measured with the two techniques were in approximate agreement, with the AC fluxes being 0.78 (cotton) and 1.06 (wheat) times the size of the EC fluxes. When integrated to daily timescale, the fluxes of the two techniques were in better agreement, showing an average ratio of 0.94 and 1.00 for the cotton and wheat, respectively. During the periods with comparable field conditions and normal performance of both instruments, the cumulative NEE fluxes revealed small differences between the two techniques (−9.0% ~ 7%, with a mean of 0.1%). The measurements resulted in an annual cumulative NEE of −40 g C m−2 yr−1 (EC) and −42 g C m−2 yr−1 (AC) in the cotton field, and a seasonal cumulative NEE of −251 g C m−2 (EC) and −205 g C m−2 (AC) in the wheat field. Our results indicate that, for cropland populated by short plants, the AMEG system and the data processing procedures applied in this study are able to provide NEE estimates comparable to those from EC measurements.

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Effect of the 2018 drought on methane and carbon dioxide exchange of northern mire ecosystems

10.5194/egusphere-egu2020-7329 ◽

2020 ◽

Author(s):

Janne Rinne ◽

Juha-Pekka Tuovinen ◽

Leif Klemendtsson ◽

Mika Aurela ◽

Jutta Holst ◽

...

Keyword(s):

Carbon Dioxide ◽

Greenhouse Gas ◽

Water Table ◽

Methane Emission ◽

Radiative Forcing ◽

Western Europe ◽

Terrestrial Ecosystems ◽

Carbon Dioxide Exchange ◽

The North ◽

Ghg Fluxes

In 2018, North-Western Europe experienced very dry and warm summer. These conditions can have considerable effects on the functioning and greenhouse gas exchange of terrestrial ecosystems. Peat-forming wetlands, or mires, are a characteristic component of the North-European boreal landscape, and crucial for long-term carbon storage as well as for methane emission. We have analyzed the effect of the drought on greenhouse gas (GHG) exchange of five North European mire ecosystems in Sweden and Finland in 2018. The low precipitation and high summer temperatures in Fennoscandia led to a lowered water table in majority of the mires. This lowered both carbon dioxide (CO2) uptake and methane (CH4) emission during 2018, turning many of the mires from CO2sinks to sources during this year. The changes in methane emission and total GHG exchange, expressed as CO2equivalent, were significantly correlated with change in water table position. The calculated time-evolving radiative forcing due to the changes in GHG fluxes in 2018 showed that the drought-induced changes in GHG fluxes first resulted in a cooling effect lasting 15-50 years, due to the lowered CH4emission, which was followed by longer-term warming phase due to the lower CO2&#160;uptake in 2018.&#160;

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