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
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NITROGEN REGULATION OF CARBON SEQUESTRATION IN TERRESTRIAL ECOSYSTEMS IN RESPONSE TO RISING ...
Description:
A highly controversial issue in global change
research is the regulation of terrestrial carbon (C) sequestration by soil
nitrogen (N) availability. The Third Assessment IPCC Report predicts rising atmospheric CO2
alone could stimulate terrestrial carbon (C) sequestration by 350 – 980 Pg (=1015
g) C in the 21st Century. Sequestering 350 – 980 Gt C in terrestrial
ecosystems requires 7.7 – 37.5 Pg (N) based on a stoichiochemical relationship
that approximately 0.005 g N is required for 1 g C stored in long-lived plant
biomass (i.e., wood) and 0.067 g N for 1 g C sequestered in soil organic matter
(SOM). Thus, to realistically predict
future C sequestration in terrestrial ecosystems, we have to understand how
closely C and N processes are coupled in response to rising Ca.
Author's Names: Yiqi Luo
Filesize: 24.39 Kb
Added on: 01-Aug-2005 Downloads: 158
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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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THE POTENTIAL OF UPPER OCEAN ALKALINITY CONTROLS FOR ATMOSPHERIC CARBON DIOXIDE CHANGES
Description:
Extreme
global model scenarios of complete preservation and degradation of biogenic
particulate CaCO3 (calcium carbonate) in open ocean waters which are
supersaturated with respect to CaCO3 were carried out. According to
these experiments, the theoretical potential of upper ocean alkalinity controls
for changing the atmospheric pCO2 (CO2 partial pressure)
amounts to several hundred μatm on time scales of several 104 years.
Up to a timescale of 103 years, however, the respective influence is
minor as compared to an expected anthropogenic increase of the atmospheric pCO2
in the order of 500-1000
μatm.
Author's Names: Christoph Heinze
Filesize: 80.15 Kb
Added on: 29-Jul-2005 Downloads: 162
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FOREST MICROMETEOROLOGICAL RESPONSES TO INCREASED CO2 AND O3 CONCENTRATIONS
Description: The
Forest-Atmosphere Carbon Transfer and Storage (FACTS-II) Project in northern
Wisconsin is examining the interacting effects of elevated carbon dioxide (CO2)
and ozone (O3) concentrations on the productivity, sustainability,
and competitive interactions in a regenerating northern hardwood
ecosystem. A key component of this
project involves an examination of the micrometeorological feedback mechanisms
that can alter atmospheric environments within and above vegetation layers
exposed to elevated CO2 and O3 concentrations. This paper provides a brief summary of some
of the observed forest micrometeorological responses to elevated CO2
and O3 concentrations at the FACTS-II study site over the 1999-2004
period.
Author's Names: W.E. Heilman, and R.M. Teclaw
Filesize: 58.80 Kb
Added on: 29-Jul-2005 Downloads: 41
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GROWTH AND PHOTOSYNTHETIC RESPONSE OF DECIDUOUS TREE SAPLINGS IN A FREE AIR CO2 ENRICHMENT SYSTEM
Description:
We
examined the photosynthetic and growth traits of two woody species (birch) that
are dominant in northern Japan
under elevated CO2 concentration ([CO2]), using a free
air CO2 enrichment (FACE) system. Our results suggest that it is necessary to consider not only leaf-level
photosynthesis but also the entire plant physiology when using photosynthesis
to evaluate the growth response of two birch saplings under elevated [CO2].
Author's Names: N. Eguchi, K. Karatsu, T. Ueda, R. Funada, et al
Filesize: 123.78 Kb
Added on: 28-Jul-2005 Downloads: 42
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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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SUBSTRATE INDUCED GROWTH RESPONSE OF SOIL AND RHIZOSPHERE MICROBIAL COMMUNITIES UNDER ELEVATED CO2
Description: The
maximal specific growth rate of microorganisms from rhizospheres of Populus deltoides grown under normal CO2 concentration
in the atmosphere (400 ppm) was lower compared to the assessments made for
plots under elevated CO2 (800 and 1200 ppm). A similar conclusion
was made for microbial communities from soil under winter wheat and sugar beets
grown under 370 and 550 ppm CO2 in the atmosphere. Three to four
years fumigation of field plots with elevated CO2 has been shown to
result in the formation of rhizosphere microbial communities characterized by
faster specific growth rates as compared to microbial community under control
plants.
Author's Names: S.A. Blagodatsky, E.V. Blagodatskaya, T.-H. Anderson, et al
Filesize: 147.23 Kb
Added on: 26-Jul-2005 Downloads: 196
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IMPACT OF ELEVATED CO2 AND TEMPERATURE ON SOIL CARBON SEQUESTRATION POTENTIAL OF TWO CONTRASTING...
Description: Carbon sequestration in soils might offset part
of the increase of CO2 in the atmosphere. Two contrasting
subtropical grassland species, bahiagrass (BG), Paspalum notatum Flügge, and rhizoma perennial peanut (PP), Arachis glabrata Benth., a legume, were
grown at Gainesville, Florida, USA, in field soil plots in four temperature
zones (baseline-ambient, +1.5, +3.0, and +4.5 °C) in four temperature-gradient
greenhouses, two each at 360 and 700 ppm CO2. The soil had been in
continuous cultivation for more than 20 years before plant establishment. Samples
from the top 20 cm of each plot were collected before plant establishment and six
years later, after the study ended. Soil organic carbon (SOC) increases across
the six years were greater for BG than PP, 1.396 and 0.746 g/kg, respectively. Belowground
biomass was also greater for BG than PP. Mean SOC gains in BG plots at 700 and
360 ppm CO2 were 1.450 and 1.343 g/kg, respectively (no CO2
effect). Mean SOC increases in PP plots at 700 and 360 ppm CO2 were
0.949 g/kg and 0.544 g/kg, respectively (significant CO2 effect).
Overall, SOC increased only for the first temperature increment, and thereafter
declined. Soil organic nitrogen (SON) accumulation patterns were similar to SOC
increases. Mean annual SOC accumulation was 475 kg/ha per year, comparable with
other studies. We conclude that carbon can be accumulated in soils converted to
grassland species in humid, subtropical environments. The SOC accumulation will
be greatest for species that have greater belowground biomass accumulation.
Author's Names: L.H. Allen, Jr, S.L. Albrecht, K.J. Boote, J.M.G. Thomas, and K.W. Skirvin
Filesize: 29.38 Kb
Added on: 25-Jul-2005 Downloads: 36
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