EFFECT OF ENRICHED CO2 ON RICE UNDER OPEN TOP CHAMBER CONDITION AT KHUMALTAR
Description:
The effect of CO2
enrichment in raising the temperature was realized in the Open Top Chamber
(OTC) experiment. The elevated CO2 with this level of temperature
raised grain yield and yield components of rice but varied greatly by year. The
CO2 enriched plot had lesser N, P, and K in grain, straw, and root
but higher organic carbon (OC) in the root compared to the Ambient and the
Field. The study indicated that this rise of temperature due to the elevated CO2
could not adversely affect the yield.
Author's Names: K. Sherchand, G. Malla, A. Sharma and S. Shrestha
Filesize: 53.20 Kb
Added on: 04-Aug-2005 Downloads: 64
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EFFECT OF ELEVATED CO2 ON GROWTH, BIOMASS PRODUCTION AND PHOTOSYNTHESIS OF PANICUM MAXIMUM AND ...
Description:
In P. maximum the
cumulative dry biomass production in two cuttings showed an increase of 59.24%
and 43.17% in open top chambers (OTC) with elevated CO2 (600±50
ppm) (C600) and without elevated CO2 (COTC)
respectively over the open field grown corps (Ca). In S. hamata the dry matter increased by
39.79% under C600 and 31.02% in COTC over Ca. The canopy
photosynthesis (PN x LAI) increased significantly in both the crop
species with elevated CO2. The increased rate of canopy
photosynthesis indicated that there was higher assimilation of CO2,
which has intern maximum biomass production. The increase in fresh and dry
matter accumulation in C600 indicating that these crop species
should be promoted for higher biomass production and carbon sequestration in
the semi arid tropical environmental conditions.
Author's Names: R. K. Bhatt, M.J. Baig, Jyoti Dubey and H. S. Tiwari
Filesize: 90.35 Kb
Added on: 05-Aug-2005 Downloads: 64
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EFFECT OF ELEVATED ATMOSPHERE CO2 CONCENTRATION ON COTTONWOOD TREE GROWTH AND SOIL RESPIRATORY ...
Description: The effect of three atmospheric CO2 concentrations (ambient –
400 ppm, doubled – 800 ppm and tripled – 1200 ppm) has been studied (1) on the
productivity of cottonwood tree (Populus
deltoides Barr.), (2) on the activity of soil microbial biomass in rooting
zone. It has been shown, that the total biomass of cottonwood trees increase under
elevated CO2 (2.61, 5.59 and 4 kg/tree for 400, 800 and 1200 ppm
respectively). The highest production had the stem and coarse roots at 800 ppm (in
3 and 2 times higher as compared to ambient CO2). Under 1200 ppm CO2
we observed increased the roots biomass, but the biomass of leaves and branches
was insignificant or didn’t changed at all. The shoot/root ratio changed as
following: 400 ppm – 1.8, 800 ppm – 2.3, 1200 ppm – 1.4. The rate of С-СО2
flux from soil samples being incubated for 70 days increased in the row 1200>800>400
ppm CO2, the average values of CO2 emission were 2.76, 2.33,
2.02 mg 100g-1·day-1, respectively. The largest amount of
C microbial biomass (Cmb) was in the variant with triple CO2
concentration (75.1 mg 100g-1), and the lowest – under ambient
concentration (53.7 mg 100g-1).
Author's Names: V.N.Kudeyarov, K.Biel, S.A.Blagodatsky, V.M.Semenov, et al
Filesize: 108.71 Kb
Added on: 01-Aug-2005 Downloads: 66
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EFFECT OF ECTOMYCORRHIZAL INFECTION ON THE GROWTH AND PHOTOSYNTHETIC CHARACTERISTICS OF THREE ...
Description: After 18 weeks, elevated CO2 (720 μmol·mol-1) increased significantly the
ectomycorrhizal development. The phosphate concentration (P) in needles of Pinus densiflora and Larix kaempferi inoculated with Pt or EC was significantly higher than that without
inoculation at both CO2 concentrations. Pt or EC inoculation had led to significantly increase the
physiological activities, such as the PAR
saturated net photosynthetic rates (Psat),
maximum net photosynthetic rate at saturated CO2 concentration (Pmax), carboxylation efficiency (CE), RuBP
regeneration rate of A/Ci curve and
water use efficiency (WUE) of P. koraiensis,
P. densiflora and L. kaempferi seedlings grown at both CO2
concentrations (360 and 720 μmol·mol-1) relative to non-inoculated
seedlings. Moreover, dry mass and
stem diameter of inoculated P. koraiensis,
P. densiflora and L. kaempferi seedlings significantly
higher than those non-inoculated seedlings.
Author's Names: D.S. Choi, Y. Maruyama, H.O Jin, K. Sasa and T. Koike
Filesize: 94.25 Kb
Added on: 28-Jul-2005 Downloads: 53
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CORAL REEF CALCIFICATION AND CLIMATE CHANGE: THE EFFECT OF OCEAN WARMING
Description:
Coral
reefs are constructed of calcium carbonate (CaCO3). Deposition of
CaCO3 (calcification) by corals and other reef organisms is
controlled by the saturation state of CaCO3 in seawater (Ω) and sea
surface temperature (SST). Previous studies have neglected the effects of ocean
warming in predicting future coral reef calcification rates. In this study we take into account both these
effects by combining empirical relationships between coral calcification rate
and Ω and SST with output from a climate model to predict changes in coral reef
calcification rates. Our analysis suggests
that annual average coral reef calcification rate will increase with future
ocean warming and eventually exceed pre-industrial rates by about 35% by 2100.
There is evidence however to suggest that different corals display different
sensitivities to changes in Ωarag and SST [Reynaud et al., 2003]. Considering that both these environmental
parameters are likely to change considerably in the future, additional
experiments on a variety of differing coral species will be crucial to obtain a
better understanding of future coral reef stability.
Author's Names: B. I. McNeil, R. J. Matear and D. J. Barnes
Filesize: 154.39 Kb
Added on: 02-Aug-2005 Downloads: 95
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CLIMATE CHANGE FEEDBACKS ON OCEANIC pH AND Ω
Description: Anthropogenic CO2 uptake by the ocean will decrease both the pH
and the aragonite saturation state (Ωarag) of seawater. However, the factors controlling future changes
in pH and Ωarag are independent and will respond differently to oceanic
climate change feedbacks such as ocean warming, circulation and biological
changes. We examine the sensitivity of
these CO2-related parameters to climate change feedbacks within a
coupled atmosphere-ocean model. Although surface pH is projected to decrease
relatively uniformly by ~0.25 by the year 2100, we find pH to be insensitive to
climate change feedbacks, whereas Ωarag is buffered by ~15%. The independent
climate change response between pH and Ωarag is attributed solely to
the opposing effects associated with ocean warming, which increases Ωarag
but lowers pH. Our result implies that
future climate change projections for surface ocean pH can be adequately
simulated using ocean-only models, however for Ωarag more complex
coupled atmosphere-ocean models are required.
Author's Names: B. I. McNeil and R. J. Matear
Filesize: 181.80 Kb
Added on: 02-Aug-2005 Downloads: 48
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CALCITE AND ARAGONITE UNDERSATURATION UNDER RISING ATMOSPHERIC CARBON DIOXIDE CONCENTRATIONS ...
Description:
Increasing atmospheric CO2
concentrations lowers oceanic pH and carbonate ion concentrations, thereby
decreasing the level of saturation of calcium carbonate [Feely et
al., 2004]. This acidification will eventually lead to
undersaturation and dissolution of calcium carbonate in parts of the surface
ocean. Besides affecting the global carbon cycle, these changes threaten marine
organisms that form their exoskeletons out of CaCO3, which are
essential components of the marine food web [Orr et al.,
2005]. We investigate magnitude and pattern of ocean acidification due to
increasing atmospheric CO2 concentrations and global warming, both
for the recent past and the near future, using the reduced complexity, Bern 2.5-D
physical-biogeochemical climate model and a series of CO2 emission
scenarios and CO2 stabilization profiles provided by the
Intergovernmental Panel on Climate Change (IPCC). The focus of the study is on
the impact of global warming and induced ocean circulation changes on the
projected oceanic pH and carbonate ion reductions.
Author's Names: G.-K. Plattner, F. Joos, T. Stocker, and J. C. Orr
Filesize: 24.71 Kb
Added on: 03-Aug-2005 Downloads: 53
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BAYSIAN INVERSION OF A TERRESTRIAL ECOSYSTEM MODEL AND UNCERTAINTY ANALYSIS
Description:
We applied the Bayesian
probability inversion and a Markov Chain Monte Carlo (MCMC)
technique to a terrestrial ecosystem model and analyzed uncertainties of
estimated carbon transfer coefficients and simulated carbon pool sizes. The
study used six data sets of soil respiration, woody biomass, foliage biomass,
litterfall, carbon content in the litter layers, carbon content in mineral soil
measured under both ambient CO2 (350 ppm) and elevated CO2
(550 ppm) plots from 1996 to 2000 at the Duke Forest Free-Air CO2
Experiment (FACE) site.
Author's Names: Tao Xu, Yiqi Luo
Filesize: 244.22 Kb
Added on: 09-Aug-2005 Downloads: 45
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A PAEO PERSPECTIVE ON THE OCEAN'S ROLE IN THE CARBON CYCLE
Description: Recently developed proxies for the seawater carbonate ion concentration
were used to reconstruct the vertical gradient in the carbonate ion
concentration for times in the past corresponding to the
glacial-interglacial cycles. The reconstructed changes leave little
doubt that the ocean drove the large natural variations in atmospheric
carbon dioxide that accompanied the glacial cycles, most likely through
the combined influence of changes in the biological pump and deep ocean
circulation. Below 1500 m the carbonate ion concentration changes
little, evidence of the ocean’s ability to buffer changes in carbon
chemistry over thousands of years.
Author's Names: David M. Anderson
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Added on: 26-Aug-2005 Downloads: 59
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