Seasonal dynamics of carbon dioxide exchange in a mixed grassland ecosystem

1978 ◽  
Vol 56 (17) ◽  
pp. 1999-2005 ◽  
Author(s):  
R. E. Redmann
Keyword(s):  
Carbon Dioxide ◽  
Air Temperature ◽  
Net Photosynthesis ◽  
Typical Feature ◽  
Gas Analysis ◽  
Dew Point ◽  
Carbon Dioxide Exchange ◽  
Dew Point Temperature ◽  
Growing Seasons ◽  
Dominant Grasses

Carbon dioxide exchange of a mixed grassland sward dominated by Agropyron dasystachyum and A. smithii was measured over two growing seasons using field chambers and infrared gas analysis. Net photosynthesis of the sward began in late April and rose to a peak in early July ([Formula: see text] ground area h−1). Drought during the later part of the summer, a typical feature of the climate of the region, caused net photosynthesis to decline drastically. Air temperature and reduced green leaf area inhibited photosynthesis early and late in the growing season. A multiple regression analysis showed that soil moisture and air temperature together accounted for 44% of the variability in net photosynthesis. Solar radiation and dew-point temperature explained an additional 16%. The ability of the dominant grasses to adapt to fluctuations in water availability is discussed.

Observed spatiotemporal changes in air temperature, dew point temperature and relative humidity over Myanmar during 2001–2019

2021 ◽  
Vol 134 (1) ◽  
Author(s):  
Zin Mie Mie Sein ◽  
Irfan Ullah ◽  
Vedaste Iyakaremye ◽  
Kamran Azam ◽  
Xieyao Ma ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Dew Point ◽  
Point Temperature ◽  
Dew Point Temperature ◽  
Spatiotemporal Changes

scholarly journals The Influence of Air Temperature on the Dew Point Temperature in Benin City, Nigeria

2017 ◽  
Vol 21 (4) ◽  
pp. 657 ◽  
Author(s):  
KE Ukhurebor ◽  
TB Batubo ◽  
IC Abiodun ◽  
E Enoyoze
Keyword(s):  
Air Temperature ◽  
Dew Point ◽  
Point Temperature ◽  
Dew Point Temperature ◽  
Benin City

Sensitivity of a soil-plant-atmosphere model to changes in air temperature, dew point temperature, and solar radiation

1981 ◽  
Vol 23 ◽  
pp. 115-129 ◽  
Author(s):  
R.J. Luxmoore ◽  
Janice L. Stolzy ◽  
J.T. Holdeman
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Dew Point ◽  
Point Temperature ◽  
Dew Point Temperature ◽  
Atmosphere Model

Effect of Water Deficit on Carbon Dioxide Exchange and Leaf Elongation Rate of Panicum maximum Var. trichoglume

1976 ◽  
Vol 3 (3) ◽  
pp. 401 ◽  
Author(s):  
MM Ludlow ◽  
TT Ng
Keyword(s):  
Carbon Dioxide ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Net Photosynthesis ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Carbon Dioxide Exchange ◽  
Leaf Elongation ◽  
Water Deficits ◽  
Water Potentials

The responses of carbon dioxide exchange and leaf elongation of potted P. maximum var. trichoglume plants to water deficits were investigated in controlled environments and outdoors during drying cycles down to -92 bars leaf water potential, The sensitivities of net photosynthesis and leaf elongation to water deficits were similar. The leaf water potentials at which net photosynthesis and elongation ceased (c. -12 bars), and stomatal resistance increased substantially (- 6 bars), were relatively unaffected by nitrogen supply, environmental conditions during growth, and whether plants had previously experienced stress. However, these factors influenced the rate of net photosynthesis, at high leaf water potentials by affecting stomatal resistance and at moderate water potentials by affecting both stomatal and intracellular resistances. Stomata1 resistance was more sensitive than intracellular resistance to water deficits. Dark respiration rate decreased with leaf water potential, and was higher in plants receiving additional nitrogen. At moderate leaf water potentials (-7 to -9 bars), net photosynthesis of this C4 grass exhibited light saturation and rates similar to C3 plants. We suggest that the difference in behaviour of controlled-environment-grown and field-grown plants to water deficits observed with some species is unlikely to be due to differences in the aerial environment, but may result from differences in the rate at which stress develops. The ecological significance and evolution of the C4 syndrome are discussed briefly.

CARBON DIOXIDE EXCHANGE RATES OF FRUITING SOYBEAN PLANTS EXPOSED TO OZONE AND SULPHUR DIOXIDE SINGLY OR IN COMBINATION

1984 ◽  
Vol 64 (1) ◽  
pp. 69-75 ◽  
Author(s):  
N. M. LE SUEUR-BRYMER ◽  
D. P. ORMROD
Keyword(s):  
Carbon Dioxide ◽  
Glycine Max ◽  
Exchange Rates ◽  
Sulphur Dioxide ◽  
Net Photosynthesis ◽  
Exposure Period ◽  
Carbon Dioxide Exchange ◽  
Continuous Stirred Tank Reactor ◽  
Glycine Max L ◽  
Soybean Plants

Carbon dioxide exchange rates (CER) of intact soybean (Glycine max (L.) Merr.) plants at the fruiting stage were measured in continuous stirred tank reactor (CSTR) chambers. Plants were exposed to clean air, 67 ppb ozone (O3), 300 ppb sulphur dioxide (SO2), or 67 ppb O3 plus 300 ppb SO2 for 7.5 h∙day−1 for 5 days. Carbon dioxide exchange rates were measured hourly during the last 6 h of each exposure period and decreased progressively during the first period of exposure to O3 plus SO2, dropping in hour 6 to 42% of the hour 1 rate, and to a lesser extent in the second daily exposure when the corresponding decline was to 70%. There was a declining trend in CER of SO2-treated but not O3-treated plants with increasing number of days of exposure. Carbon dioxide exchange rates of all plants generally peaked and declined during each exposure period.Key words: Air pollution, net photosynthesis, mixtures, Glycine max

scholarly journals Biophysical effects on the interannual variation in carbon dioxide exchange of an alpine meadow on the Tibetan Plateau

2016 ◽  
Author(s):  
Lei Wang ◽  
Huizhi Liu ◽  
Jihua Sun ◽  
Yaping Shao
Keyword(s):  
Carbon Dioxide ◽  
Tibetan Plateau ◽  
Air Temperature ◽  
Interannual Variation ◽  
Alpine Meadow ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Seasonal Pattern ◽  
Carbon Dioxide Exchange ◽  
The Tibetan Plateau

Abstract. Eddy covariance measurements from 2012 to 2015 were used to investigate the interannual variation in carbon dioxide exchange and its control over an alpine meadow on the southeast margin of the Tibetan Plateau. The annual net ecosystem exchange (NEE) from 2012 to 2015 was −114.2, −158.5, −159.9 and −212.6 g C m−2 yr−1 and generally decreased with the mean annual air temperature (MAT). An exception occurred in 2014, which had the highest MAT. This was attributed to higher ecosystem respiration (RE) and similar gross primary production (GPP) in 2014 because the GPP increased with MAT but became saturated due to the photosynthesis capacity limit. In the spring (March to May) of 2012, lower air temperature (Ta) and drought events delayed grass germination and reduced GPP. In the late wet season (September to October) of 2012 and 2013, the lower Ta in September and its negative effects on vegetation growth caused earlier grass senescence and significantly lower GPP. This indicates that the seasonal pattern of Ta greatly affected the annual total GPP, which is consistent with the result of the homogeneity-of-slopes model. The model shows that the climatic seasonal variation explained 48.6 % of the GPP variability, and the percentage of climatic interannual variation and the ecosystem functional change were 9.7 % and 10.6 %, respectively.

scholarly journals The relationship of atmospheric air temperature and dew point temperature to extreme rainfall

2019 ◽  
Vol 14 (7) ◽  
pp. 074025 ◽  
Author(s):  
Andrew Bui ◽  
Fiona Johnson ◽  
Conrad Wasko
Keyword(s):  
Air Temperature ◽  
Extreme Rainfall ◽  
Dew Point ◽  
Point Temperature ◽  
Atmospheric Air ◽  
Dew Point Temperature ◽  
Relationship Of ◽  
The Relationship

scholarly journals Biophysical effects on the interannual variation in carbon dioxide exchange of an alpine meadow on the Tibetan Plateau

2017 ◽  
Vol 17 (8) ◽  
pp. 5119-5129 ◽  
Author(s):  
Lei Wang ◽  
Huizhi Liu ◽  
Jihua Sun ◽  
Yaping Shao
Keyword(s):  
Carbon Dioxide ◽  
Tibetan Plateau ◽  
Air Temperature ◽  
Interannual Variation ◽  
Alpine Meadow ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Seasonal Pattern ◽  
Carbon Dioxide Exchange ◽  
The Tibetan Plateau

Abstract. Eddy covariance measurements from 2012 to 2015 were used to investigate the interannual variation in carbon dioxide exchange and its control over an alpine meadow on the south-east margin of the Tibetan Plateau. The annual net ecosystem exchange (NEE) in the 4 years from 2012 to 2015 was −114.2, −158.5, −159.9 and −212.6 g C m−2 yr−1, and generally decreased with the mean annual air temperature (MAT). An exception occurred in 2014, which had the highest MAT. This was attributed to higher ecosystem respiration (RE) and similar gross primary production (GPP) in 2014 because the GPP increased with the MAT, but became saturated due to the limit in photosynthetic capacity. In the spring (March to May) of 2012, low air temperature (Ta) and drought events delayed grass germination and reduced GPP. In the late wet season (September to October) of 2012 and 2013, the low Ta in September and its negative effects on vegetation growth caused earlier grass senescence and significantly lower GPP. This indicates that the seasonal pattern of Ta has a substantial effect on the annual total GPP, which is consistent with results obtained using the homogeneity-of-slopes (HOS) model. The model results showed that the climatic seasonal variation explained 48.6 % of the GPP variability, while the percentages explained by climatic interannual variation and the ecosystem functional change were 9.7 and 10.6 %, respectively.

Carbon dioxide exchange by native Great Plains grasses

1971 ◽  
Vol 49 (8) ◽  
pp. 1341-1345 ◽  
Author(s):  
Robert E. Redmann
Keyword(s):  
Carbon Dioxide ◽  
Soil Respiration ◽  
Water Potential ◽  
Plant Communities ◽  
Great Plains ◽  
Net Photosynthesis ◽  
Moisture Stress ◽  
Bouteloua Gracilis ◽  
Carbon Dioxide Exchange ◽  
Western North Dakota

Carbon dioxide exchange in relation to light and moisture stress was determined for dominants of three grassland plant communities of western North Dakota. These range from Bouteloua gracilis on very dry sites to Stipa viridula on less dry positions to Sporobolus heterolepis in moist ravines. Maximum net photosynthesis of sod transplants ranged from 10 to 12 mg CO2 g−1 h−1 (6 × 104 lx), corrected for soil respiration of about 3 mg CO2 dm−1 h−1. In B. gracilis and S. viridula, net photosynthesis declined steadily to 25% of maximum when moisture stress was increased to −30 bars soil matric water potential. Net photosynthesis declined less rapidly in S. heterolepis when moisture stress increased to −10 bars, but decreased to zero when stress reached −30 bars. The implications regarding distribution of the species are discussed.

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