Ecosystem photosynthesis inferred from measurements of carbonyl sulphide flux

Asaf, David; Rotenberg, Eyal; Tatarinov, Fyodor; Dicken, Uri; Montzka, S. A.; Yakir, Dan

doi:10.1038/ngeo1730

Cited by 163 publications

(236 citation statements)

References 28 publications

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“…Using the mean LRU of 1.5 calculated for September, the total daily sum of GEP OCS and GEP CO2 agrees to within 3.5%, a good agreement given the ∼10% uncertainty estimated for GEP CO2 (23). However, this result depends on the value of LRU assumed (8,19): varying the LRU between 2 and 1 results in a 29% underestimation or a 36% overestimation, respectively (Fig. 4).…”

Section: Internal Leaf Conductances In Series (Following Equation 3 Imentioning

confidence: 72%

“…Ecosystem-scale fluxes of OCS have been proposed as a means to directly determine the photosynthetic uptake of carbon in the biosphere, independently of soil and plant respiration (1,13,14,19). However, for this approach to work as proposed, a number of requirements must be met, many of which are not realized year-round at Harvard Forest.…”

Section: Internal Leaf Conductances In Series (Following Equation 3 Imentioning

confidence: 99%

“…Initial OCS ecosystem flux estimations were made using flask sampling followed by analysis via gas chromatography-mass spectrometry (GC-MS) (13,16), but these studies did not have sufficient resolution to examine daily or hourly controls on the OCS flux. Laser spectrometers have been developed (17,18) to enable direct, in situ measurement of OCS fluxes by eddy covariance, and measurements of OCS ecosystem fluxes have been reported, for periods of up to a few weeks, above arid forests (19) and an agricultural field (8,20).…”

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confidence: 99%

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Seasonal fluxes of carbonyl sulfide in a midlatitude forest

Commane

Meredith

Baker

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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118

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Carbonyl sulfide (OCS), the most abundant sulfur gas in the atmosphere, has a summer minimum associated with uptake by vegetation and soils, closely correlated with CO 2 . We report the first direct measurements to our knowledge of the ecosystem flux of OCS throughout an annual cycle, at a mixed temperate forest. The forest took up OCS during most of the growing season with an overall uptake of 1.36 ± 0.01 mol OCS per ha (43.5 ± 0.5 g S per ha, 95% confidence intervals) for the year. Daytime fluxes accounted for 72% of total uptake. Both soils and incompletely closed stomata in the canopy contributed to nighttime fluxes. Unexpected net OCS emission occurred during the warmest weeks in summer. Many requirements necessary to use fluxes of OCS as a simple estimate of photosynthesis were not met because OCS fluxes did not have a constant relationship with photosynthesis throughout an entire day or over the entire year. However, OCS fluxes provide a direct measure of ecosystem-scale stomatal conductance and mesophyll function, without relying on measures of soil evaporation or leaf temperature, and reveal previously unseen heterogeneity of forest canopy processes. Observations of OCS flux provide powerful, independent means to test and refine land surface and carbon cycle models at the ecosystem scale.carbonyl sulfide | carbon cycle | sulfur cycle | stomatal conductance C arbonyl sulfide (OCS) is the most abundant sulfur gas in the atmosphere (1), and biogeochemical cycling of OCS affects both the stratosphere and the troposphere. The tropospheric OCS mixing ratio is between 300 and 550 parts per trillion (ppt) (1) (10 −12 mol OCS per mol dry air), decreasing sharply with altitude in the stratosphere (2). In times of low volcanic activity, the sulfur budget and aerosol loading of the stratosphere are largely controlled by transport and photooxidation of OCS from the troposphere (3). The processes regulating emission and uptake of OCS are thus important factors in determining how changes in climate and land cover may affect the stratospheric sulfate layer.Oceans are the dominant source of atmospheric OCS (4), with smaller emissions from anthropogenic and terrestrial sources, such as wetlands and anoxic soils (e.g., refs. 5 and 6) and oxic soils during times of heat or drought stress (e.g., refs. 7 and 8). The terrestrial biosphere is the largest sink for OCS (1, 4, 9, 10) with uptake by both oxic soils (e.g., ref. 11) and vegetation (e.g., ref. 9). Once OCS molecules pass through the stomata of leaves, the uptake rate of OCS is controlled by reaction with carbonic anhydrase (CA) within the mesophyll, to produce H 2 S and CO 2 . CA is the same enzyme that hydrolyzes carbon dioxide (CO 2 ) in the first chemical step of photosynthesis (12).Studies considering the large-scale atmospheric variability of OCS have linked OCS fluxes and the photosynthetic uptake of CO 2 for regional and global scales (1, 4, 13). Leaf-scale studies have confirmed the OCS link to photosynthesis (14, 15). Initial OCS ecosystem flux estimations w...

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Section: Internal Leaf Conductances In Series (Following Equation 3 Imentioning

confidence: 72%

Section: Internal Leaf Conductances In Series (Following Equation 3 Imentioning

confidence: 99%

mentioning

confidence: 99%

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Seasonal fluxes of carbonyl sulfide in a midlatitude forest

Commane

Meredith

Baker

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

118

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“…For example, recent work by Campbell et al (2008) suggests that carbonyl sulfide is a good photosynthetic tracer. A study by Asaf et al (2013) concludes that OCS flux could provide a constraint on estimates of gross primary productivity (GPP).…”

Section: Introductionmentioning

confidence: 99%

Characterization of Aura TES carbonyl sulfide retrievals over ocean

et al. 2014

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Abstract. We present a description of the NASA Aura Tropospheric Emission Spectrometer (TES) carbonyl sulfide (OCS) retrieval algorithm for oceanic observations, along with evaluation of the biases and uncertainties using aircraft profiles from the HIPPO (HIAPER Pole-to-Pole Observations) campaign and data from the NOAA Mauna Loa site. In general, the OCS retrievals (1) have less than 1.0 degree of freedom for signals (DOFs), (2) are sensitive in the mid-troposphere with a peak sensitivity typically between 300 and 500 hPa, (3) but have much smaller systematic errors from temperature, CO 2 and H 2 O calibrations relative to random errors from measurement noise. We estimate the monthly means from TES measurements averaged over multiple years so that random errors are reduced and useful information about OCS seasonal and latitudinal variability can be derived. With this averaging, TES OCS data are found to be consistent (within the calculated uncertainties) with NOAA ground observations and HIPPO aircraft measurements. TES OCS data also captures the seasonal and latitudinal variations observed by these in situ data.

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“…Gross primary production (GPP) from photosynthesis has been well understood at leaf and canopy levels; however, ecosystem level estimation of GPP has not yet been well investigated (Asaf et al, 2013;Barman, Jain, & Liang, 2014). Since the 1990s, the eddy covariance method has been used as an important tool to measure heat, water, and CO 2 exchanges as well as trace green-house gases (Baldocchi, 2014).…”

Section: Introductionmentioning

confidence: 99%

Comparison of four EVI-based models for estimating gross primary production of maize and soybean croplands and tallgrass prairie under severe drought

Dong

Xiao

Wagle

et al. 2015

Remote Sensing of Environment

102

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Berrien III, "Comparison of four EVI-based models for estimating gross primary production of maize and soybean croplands and tallgrass prairie under severe drought" (2015). Accurate estimation of gross primary production (GPP) is critical for understanding ecosystem response to climate variability and change. Satellite-based diagnostic models, which use satellite images and/or climate data as input, are widely used to estimate GPP. Many models used the Normalized Difference Vegetation Index (NDVI) to estimate the fraction of absorbed photosynthetically active radiation (PAR) by vegetation canopy (FPAR canopy ) and GPP. Recently, the Enhanced Vegetation Index (EVI) has been increasingly used to estimate the fraction of PAR absorbed by chlorophyll (FPAR chl ) or green leaves (FPAR green ) and to provide more accurate estimates of GPP in such models as the Vegetation Photosynthesis Model (VPM), Temperature and Greenness (TG) model, Greenness and Radiation (GR) model, and Vegetation Index (VI) model. Although these EVI-based models perform well under non-drought conditions, their performances under severe droughts are unclear. In this study, we run the four EVI-based models at three AmeriFlux sites (rainfed soybean, irrigated maize, and grassland) during drought and non-drought years to examine their sensitivities to drought. As all the four models use EVI for FPAR estimate, our hypothesis is that their different sensitivities to drought are mainly attributed to the ways they handle light use efficiency (LUE), especially water stress. The predicted GPP from these four models had a good agreement with the GPP estimated from eddy flux tower in non-drought years with root mean squared errors (RMSEs) in the order of 2.17 (VPM), 2.47 (VI), 2.85 (GR) and 3.10 g C m −2 day −1 (TG). But their performances differed in drought years, the VPM model performed best, followed by the VI, GR and TG, with the RMSEs of 1.61, 2.32, 3.16 and 3.90 g C m −2 day −1 respectively. TG and GR models overestimated seasonal sum of GPP by 20% to 61% in rainfed sites in drought years and also overestimated or underestimated GPP in the irrigated site. This difference in model performance under severe drought is attributed to the fact that the VPM uses satellite-based Land Surface Water Index (LSWI) to address the effect of water stress (deficit) on LUE and GPP, while the other three models do not have such a mechanism. This study suggests that it is essential for these models to consider the effect of water stress on GPP, in addition to using EVI to estimate FPAR, if these models are applied to estimate GPP under drought conditions.

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Ecosystem photosynthesis inferred from measurements of carbonyl sulphide flux

Cited by 163 publications

References 28 publications

Seasonal fluxes of carbonyl sulfide in a midlatitude forest

Seasonal fluxes of carbonyl sulfide in a midlatitude forest

Characterization of Aura TES carbonyl sulfide retrievals over ocean

Comparison of four EVI-based models for estimating gross primary production of maize and soybean croplands and tallgrass prairie under severe drought

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