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Aircraft have captured the 'breath' of the Amazon forest — carbon emissions over the Amazon basin. The findings raise concerns about the effects of future drought and call for a reassessment of how fire is used in the region. See Letter p.76 Amazonia stores large amounts of carbon, but our understanding of the sensitivity of the tropical terrestrial carbon budget to climate anomalies remains uncertain. An analysis of seasonal and annual carbon balances based on basin-wide atmospheric measurements of carbon dioxide and monoxide for anomalously dry and wet years together with forest plot data suggest that water availability has an important role in determining the carbon balance in the Amazon basin. Drought reduced plant production and limited the amount of carbon that could be stored in vegetation; at the same time large amounts of carbon were released by fire during the dry year. The region was carbon neutral during the wet year, because of reduced carbon loss through fires and increased carbon uptake by vegetation.

[1] We suggest a way to estimate phytoplankton respiration separately from heterotrophic respiration. The analysis is based on three findings: (1) that carbon loss in the plankton overnight is mostly phytoplankton respiration; (2) that uptake of 14C estimates net primary production; and (3) that phytoplankton respiration occurs during the day at the same rate as at night. Based on these three findings, we propose that phytoplankton respiration can be estimated as twice the overnight loss of organic carbon. Heterotrophic respiration is then the difference between phytoplankton and total community respiration.

[1] The behavior of the coupled carbon cycle and physical climate system in a global warming scenario is studied using an Earth system model including the atmosphere, land, ocean, and the carbon cycle embedded in these components. A fully coupled carbon-climate simulation and several sensitivity runs were conducted for the period of 1860–2100 with prescribed IPCC-SRES-A1B emission scenario. Results indicate a positive feedback to global warming from the interactive carbon cycle, with an additional increase of 90 ppmv in the atmospheric CO2, and 0.6 degree additional warming, thus confirming recent results from the Hadley Centre and IPSL. However, the changes in various carbon pools are more modest, largely due to the multiple limiting factors constraining terrestrial productivity and carbon loss. The large differences among the three models are manifestations of some of the poorly constrained processes such as the global strength of the CO2 fertilization effect and the turnover time and rates of soil decomposition.

Soil carbon dioxide efflux resulting from microbial and root respiration is a major component of the forest carbon cycle. We undertook this investigation to better understand the nature of soil carbon dioxide efflux of plantation loblolly pine, an important ecological and economical resource in the southeastern United States. Specifically, we hoped to learn how soil carbon dioxide efflux differs both spatially and temporally for four age classes of plantation loblolly pine on the Virginia piedmont. During a 12-month period, soil carbon dioxide efflux was repeatedly measured for four age classes of plantation loblolly pine using a dynamic, closed-chamber infrared gas analyzer. The age classes examined were 1- to 2-year-old, 4- to 6-year-old, 8- to 12-year-old, and 20- to 25-year-old stands. Mean soil carbon dioxide efflux rates measured during the 12-month study were 1.72, 2.58, 2.84, and 2.90 micromole/sq m/s for 1- to 2-year-old, 4- to 6-year-old, 8- to 12-year-old, and 20- to 25-year-old stands, respectively. Stand age had a significant effect on efflux rate during 10 of the 12 monthly sampling sessions. Additionally, mean efflux rates were consistently higher near the tree and a significant positional difference was detected during 8 of the 12 monthly sampling sessions. Mean soil carbon dioxide efflux rates, by position, for the 12-month study were 2.72 and 2.28 micromole/sq m/s for the near and away measurement positions, respectively. Based on monthly mean soil carbon dioxide efflux rates, annual carbon losses were estimated at 651, 976, 1074, and 1082 g C/sq m/yr for 1- to 2-year-old, 4- to 6-year-old, 8- to 12-year-old, and 20- to 25-year-old stands, respectively. Regression analysis was used to examine the influence of soil and climatic factors on seasonal changes in soil carbon dioxide efflux. The most influential factors affecting soil carbon dioxide efflux during the 12-month study were soil temperature, soil moisture, stand age, and measurement position. We believe respiring roots significantly influence soil carbon dioxide efflux of plantation loblolly pine and account for differences observed between stands of different ages as well as spatial differences observed within a given stand. Master of Science

Extensive studies were conducted of the metastable dissociation of binary metal Met-Cars which provided confirming evidence in the case of the binary systems, of the important role of carbon loss at the point of cage closing. This strongly supports the mechanism of Met-Car formation as involving the statistical assembly of MC2 units until the point of case closure, whereupon two C2 units are lost.

Using forests to sequester carbon in response to anthropogenically induced climate change is being considered across the globe. A recent U.S. executive order mandated that all federal agencies account for sequestration and emissions of greenhouse gases, highlighting the importance of understanding how forest carbon stocks are influenced by wildfire. This paper reports the effects of the most common forest fuel reduction treatments on carbon pools composed of live and dead biomass as well as potential wildfire emissions from six different sites in four western U.S. states. Additionally, we predict the median forest product life spans and uses of materials removed during mechanical treatments. Carbon loss from modeled wildfire-induced tree mortality was lowest in the mechanical plus prescribed fire treatments, followed by the prescribed fire-only treatments. Wildfire emissions varied from 10–80 Mg/ha and were lowest in the prescribed fire and mechanical followed by prescribed fire treatments at most sites. Mean biomass removals per site ranged from approximately 30–60 dry Mg/ha; the median lives of products in first use varied considerably (from 50 years). Our research suggests most of the benefits of increased fire resistance can be achieved with relatively small reductions in current carbon stocks. Retaining or growing larger trees also reduced the vulnerability of carbon loss from wildfire. In addition, modeled vulnerabilities to carbon losses and median forest product life spans varied considerably across our study sites, which could be used to help prioritize treatment implementation.

As a part of the component development process for the particle bed reactor (PBR), it is necessary to develop coatings for fuel particles which will be time and temperature stable. These coatings must not only protect the particle from attack by the hydrogen coolant, but must also help to maintain the bed in a coolable geometry and mitigate against fission product release. In order to develop these advanced coatings, a process to produce chemical vapor reaction (CVR) coatings on fuel for PBRs has been developed.The initial screening tests for these coatings consisted of testing in flowing hot hydrogen at one atmosphere. Surrogate fuel particles consisting of pyrolytic graphite coated graphite particles have been heated in flowing hydrogen at constant temperature. The carbon loss from these particles was measured as a function of time. Exposure temperatures ranging from 2500 to 3000 K were used and samples were exposed for up to 14 minutes in a cyclical fashion, cooling to room temperature between exposures. The rate of weight loss measured as a function of time is compared to that from other tests of coated materials under similar conditions. Microscopic examination of the coatings before and after exposure was also conducted and these results are presented.

The addition of ameliorant Fe 3+ and rock phosphates containing high Fe cation can reduce effect of toxic organic acids, increase peat stability through formation of complex compounds and reduce carbon emission. The research was conducted in the laboratory and green house of the Departement of Soil Science, Faculty of Agriculture, Bogor Agriculture University. Peat samples with hemic degree of decomposition were taken from Riau. Rock phosphates were taken from the rock phosphates of PT. Petrokimia Gresik, Christmas Island phosphates, and Huinan China and FeCl 3 .6H 2 O was used as the other Fe 3+ source. The aims of the research were to study (a) the effect of the applications of ameliorant Fe 3+ and rock phosphates on the P content of plants dan (b) the effect of the application ameliorant Fe 3+ and the contribution of Fe cation in rock phosphates in the decrease of carbon emission. The results showed that the P content of plants rice increased 58 – 286 % with the applications of ameliorant Fe 3+ and rock phosphates. The estimation of carbon loss through CO 2 and CH 4 emissions from peats if planted continuously with rice was around 2.5, 2.2 and 2.6 Mg of C ha -1 year -1 respectively in field capacity condition, two times of field capacity condition, and 5 cm of saturated condition. The application of ameliorant Fe 3+ and rock phosphates containing high Fe cation increased the stability of peats and reduced the carbon loss around 1.7 Mg of C ha -1 year -1 (64%) in 5 cm of saturated condition, 1,3 Mg of C ha -1 year -1 (58%) in two times of field capacity condition, and 1.0 Mg of C ha -1 year -1 (41%) in field capacity condition.

Publisher Summary This chapter describes the place of the use of radioisotopes in studies of mycorrhizal symbioses. A symbiotic association is by definition more complex than a single organism, and a particular component of this complexity is the fluxes of material between the two partners in the symbiosis. It is no accident that much of the use of radioisotopes is directed towards understanding these interchanges, because the interface region in mycorrhiza is almost impossible to access directly. The chapter also discusses carbon allocation and fluxes. It was believed from a very early stage that the fungal symbiont in mycorrhizal associations received its carbon nutrition from the host plant. Most of the ectomycorrhiza and ericoid mycorrhizal fungi have the potential to meet their carbon needs from external carbon sources when grown non-symbiotically in the laboratory. Nevertheless, it is generally agreed that they receive the majority of their carbon nutrition from the host plant while grown symbiotically. The chapter also explains carbon loss into soil.

ECOLOGICAL SOCIETY OF AMERICA MEETINGSPOKANE, WASHINGTON-- Some 3500 ecologists gathered here from 8 to 12 August for the annual meeting of the Ecological Society of America. Discussions ranged from the link between ancient deforestation and greenhouse warming to a sizzling ecological explanation for why peppers are hot.

The effect of NH3 addition on SO2 adsorption properties of steam activated semicoke (activated carbon) has been investigated . When activated carbon was used by repeating SO2 adsorption at 130°C and regeneration in N2 at 450°C, the amounts of surface oxide which were not decomposed at regeneration temperature increased. It was, however, found out that these surface oxides were removed easily by heating the activated carbon in the presence of NH3 at regeneration temperature .With the decrease of amounts of surface oxide, there was an increase in the specific surface area of activated carbon. In addition to the removal of surface oxide with NH3, some surface oxides were found to form basic nitrogen compounds . These compounds are estimated to be active sites for SO2 adsorption.When NH3 was added in a flue gas, both sulfuric acid and its ammonium saltswere adsorbed on activated carbon. These ammonium salts decomposed to form NH3during regeneration process at 450°C. It is concluded that the NH3 reacts with surface oxide to form H2O and N2 and this effectively decrease the carbon loss during regeneration. With adding NH3 in a flue gas, it is found out that the rate of decrease of SO2 adsorption capacity during repetition of adsorption-regeneration process can be suppressed. However, the strength of a activated carbon was found out to decrease much faster than a activated carbon used without adding NH3 in a flue gas.

The amounts of organic materials released into soil from roots during the first 4 weeks of growth were determined for 11 cultivars of wheat ( Triticum aestivum L.). Carbon loss from roots was measured by supplying 14 CO 2 continuously to the shoots and measuring the 14 C content of the roots, root-free soil, water-soluble material and CO 2 flushed from the root chamber. Six cultivars were compared in each of two experiments, with the cultivar Condor common to both experiments. There were no significant differences between cultivars, relative to Condor, for 14 C activity present in soil, roots, water-soluble material or rhizosphere CO 2 . There was a significant difference between cultivars in experiment 1, but not in experiment 2, for the variate log 10 ( 14 C lost from roots: 14 C translocated to roots). There was evidence that a reduction in growth temperature, within the range 10–15°C, increased carbon loss from wheat roots into the rhizosphere.

A comparative study of the elementary chemical composition (C, H, N) of Pontella mediterranea (males, females and copepodites) was carried out in two series: in Series 1, live copepods were briefly rinsed with distilled water, dried for one night (12 h) at 60°C, and then stored in a desiccator; in Series 2, the copepods were preserved in a 5% formalin-freshwater solution neutralized with borax; they were then rinsed with distilled water, and subsequently dried and stored in a desiccator as in Series 1. The results reveal that the dry weight of preserved copepods (Series 2) is 20 to 25% less than that of fresh, dried individuals. Carbon loss was estimated as about 10% in males and 17% in females, hydrogen loss as 14% in males and 23% in females, and nitrogen loss as 20% in males and 21% in females. The organic compounds lost seem to be mainly proteinaceous. Nevertheless, relative carbon content expressed as percent dry weight, and C:N and C:H ratios were all significantly higher in the preserved specimens. These results are compared with literature data on two other crustancean species.

A quantitative method is proposed to determine the amount of carbon taken from a steel substrate on forming a carbide coating when carbon is also supplied in the gas stream. Two series of experiments are necessary: one without carbon in the gas stream in order to determine the system constant and a second with carbon in the gas stream to determine the loss from the substrate. A limited number of experimental results taken from the literature show that the approach is viable. The assumptions made are reviewed and some recommendations on experimental procedure are made.

Temperature and light interact to modify the chemical and biochemical composition of a nitrogen-limited marine diatom, Thalassiosira allenii Takano, grown at a constant dilution rate in continuous culture and under a light:dark cycle. The percent of the total 14C incorporated into protein, polysaccharide and lipid, the N/C ratio and the C/cell varied with temperature in a markedly non-linear manner. The N/cell was negatively correlated to temperature. The Chl a C ratio was positively correlated with temperature under saturating light and non-saturating light for temperatures > 25 °C, but was constant under non-saturating light conditions for temperatures Productivity index (PI) was negatively correlated to temperature under saturating light conditions, but did not vary under low light. In each case, the variation in PI with temperature was governed by the variation in Chl a C . The dark carbon loss rate was exponentially related to temperature and independent of light. Variation in the percent of the total 14C incorporated into protein and polysaccharide, the N C ratio and C/cell was primarily due to the effects of N-limitation 20 °C. Variation in N/cell was primarily due to the effects of temperature over the entire range of temperature studied. Variation in Chl a C was caused by the interaction of temperature and light effects. In most cases, temperature and nutrient effects interacted to govern how a particular parameter varied with temperature while light affected the range of values over which the parameter varied. The percent of the total 14C incorporated into protein exhibited a significant linear relationship with N C . The dark carbon loss rate, N C ratio and Chl a C ratio data were used to test the applicability of a model for the physiological adaptation of unicellular algae. The model, with parameters derived from a non-linear least-squares fit of the dark carbon loss rate data, adequately described the N C ratio between 15 and 25 °C at 290 and 137 μE · m−2 · s−1, but failed to describe the data at 28 °C and at 48 μE · m−2 · s−1. The Chl a C ratio was adequately described by the model under all light and temperature conditions.

The combustion of methanol was studied in an open system. Quantitative measurement of the unburnt carbon formed during the combustion process was continuously followed by applying a semi-analytical technique based on the composition of the flue gas. The combustion of the alcohol was determined to be zero order under the experimental conditions. The change in the rate of burning, K, was found to correspond in magnitude to the change in the ratio of actual air volume flow-rate, Qa, to the stoichiometric air volume flow-rate, Qs.

Because of extensive interest in the use of granular activated carbon (GAC) for drinking water treatment, EPA’s Drinking Water Research Division has sponsored several field-scale research projects to demonstrate its use. Two of these projects, one at the Cincinnati Water Works (CWW) and the other at the Manchester Works Works (MWW), have yielded extensive information on capital and operating costs. Both projects utilized fluid-bed reactivation, and deep-bed contactors were constructed at the CWW. It was found that fluid-bed reactivation represented approximately 30% of the capital costs and 70% of the O&M costs. Carbon loss rates ranged from about 11 – 23% and represented the largest individual cost item in the GAC reactivation system. Regional reactivation was studied at the MWW in cooperation with three other smaller utilities. Regionalization was found to be cost-effective for these systems.

The response of dark respiration to temperature was measured for populations of Lathyrus japonicus collected from 39–56° N latitude. Carbon loss in dark respiration increases with latitude at all temperatures. This increased respiratory activity is attributable to concomitant increases in both the growth and maintenance components of total dark respiration. The possible adaptive significance of these respiratory responses is discussed.

Experiments with the composting of municipal sewage sludge were made to examine the effect of different bulking agents and of the oxygen supply on the process. The bulking agents have been chopped straw, milled bark and sawdust as organic materials and Styropor—foamed polystyrene as a synthetic material. The bulking agents have been dried at 105°C and then mixed with the same quantity of digested municipal sewage sludge. Because of the different water capacity of each material different structures were reached. i.e. the free air space in the mixture differed, because each material extracted a different quantity of water out of the sludge. This effect can be seen in Table 1, while a scheme of the experiment is given in Figures 1 and 2. In a second run the oxygen content was changed from 21 Vol-% to 50 Vol-% in dry air at the same rate of 17 1/h for 3 min in each hour. In both runs the composting process was followed by measuring the temperatures and the CO2-rate in the exit air. For comparison two parameters have been calculated, the energy production and the carbon loss which are shown in Table 2. These results show that bark was the best bulking agent (2608 kJ and 45.4 g carbon loss), while the synthetic material produced almost no activity (326 kJ and 4.2 g carbon loss). The effect of the higher oxygen content can be seen by comparing the curves of the temperatures in Figs 3 and 4 showing the characteristic form. After reaching the maximum, the temperatures stayed for a longer time on a higher level during the second run, marking a higher activity of the process. The curves of the CO2-rate given in the Figs 5 and 6 show the same effect. Overall it is evident, that the structure of the mixture, i.e. the bulking agent has a greater effect on the composting process than the increased oxygen content.

The marine diatom Thalassiosira jluvintilis was grown in a continuous culture system at 20°C on a 12:12 L:D cycle over a series of nutrient- and light-limited dilution rates. Bannister’s theoretical model describing nutrient-saturated growth gave an excellent fit to the light-limited data. A simple extension of the model allows description of nutrient-limited growth as well. Dark carbon loss rates were in the range lo-20% of daytime production rates at dilution rates >0.25*d-‘. The relationship hctwcen Chl n:C ratios and dilution rate was linear under nutrient limitation and independent of the type of limiting nutrient. Productivity indices under nutrient limitation were found to be a hyperbolic function of dilution rate. N:C ratios were linearly correlated with dihltion rate llnder both light and nutrient limitation, but with the regressions having opposite signs.

The daily total CO2-exchange of an aspen population (32 trees) was measured using a growth chamber gas analysis system which had been shown to measure accurately the actual carbon gain of the population. The CO2-exchange rates of the components (e.g. roots, stems, leaves) were measured in the light and dark and these rates were used to calculate the total CO2-exchange of the population using a computer model. The carbon gain during the photoperiod was underestimated by 25% in the simulation while the carbon loss during the nyctoperiod was overestimated 100% by the simulation.

Decarburization of two white cast irons, differing only in microstructure, has been studied using a 20% carbon dioxide-80% carbon monoxide atmosphere. Carbon loss and depth of decarburization at 1000°C and 1050°C were measured as a function of time. A mathematical analysis of decarburization is developed and from a comparison of this with the experimental results it is concluded that the diffusion of carbon in austenite is the rate controlling process.

The rate, extent, and spatial variation of carbon loss from a graphite cylinder exposed to steam has been calculated as a function of time. The geometrical arrangement considered was a hollow cylin...

Climate-change impacts can be mitigated through greater use of bioenergy, but the extent to which specific options actually reduce overall impacts needs to be assessed. Most bioenergy assessments have used proxy measures for assessing its merits. Here, a new approach is presented, whereby the contribution of bioenergy use is assessed through quantifying marginal changes in climate-change impacts that result from the implementation of a bioenergy option. Marginal climate-change impacts were calculated for one specific example of a bioenergy option, conversion of an unutilised mature forest into a production forest harvested repeatedly for bioenergy over successive 25-year rotations. The overall benefit of the option was assessed by including stand-level carbon dynamics, global carbon-cycle feedback, progressively changing radiative efficiency and marginal impact sensitivity of warming. It also includes a differentiated assessment of three kinds of climatic impacts: direct-warming, rate-of-warming and cumulative-warming impacts. Marginal impacts were calculated and summed over 100 years to assess the overall marginal impact of this bioenergy option. Bioenergy use in this specific example led to a large initial loss of biomass carbon followed by an ongoing and accumulating benefit through fossil-fuel substitution. This caused adverse climatic impacts over the first two rotations as the effects of the on-site carbon loss dominated the overall impact, but the option became increasingly beneficial over longer time frames as the benefit of fossil-fuel substitution accrued and eventually dominated. Summed over 100 years, the bioenergy option reduced direct-temperature and rate-of-warming impacts whilst increasing cumulative-warming impacts. The average of the three kinds of impacts showed a slight mitigation benefit by reducing overall impacts. In the particular example, bioenergy use was assessed to have a more beneficial effect if the analysis was carried out under the assumption of higher-emission concentrations pathways, or if it assumed a steeper relationship between climate perturbations and impacts. The usefulness of any climate-change mitigation option ultimately relates to the marginal climate-change impacts it can avert. It is shown here that marginal impacts can be calculated in routine operation and that they can provide an objective and methodologically consistent assessment of the mitigation potential of bioenergy use.

The carbon loss due to oxidation during arc spraying of steels depends on the heat input of the arc. In order to retain as much as carbon in the coating, the heat input should be kept as low as possible. Even so, the carbon loss is still as high as 42%. Using nitrogen as the atmizing gas could lower the carbon loss to the level of 23The coating sprayed by nitrogen is very coherent and has much better wear resistance than that of the compressed air sprayed coatings.

Peatlands are especially important but fragile tropical landscapes. The importance of peatlands is owing to their ability to 1) sequester a considerable amount of terrestrial carbon, 2) store freshwater, and 3) regulate floods during the rainy season. Nowadays, extensive peatland degradation occurs because of peatland utilization for agriculture purposes, causing severe environmental consequences such as carbon emission, loss of biodiversity, risk of flooding, and peat fire. Meanwhile, local planners and decision makers tend to overlook the long-term strategic function of peatlands for carbon storage and hydrological regulation, preferring peatland utilization for short-term economic benefits. The objective of our study is to quantify the total ecosystem services (except biodiversity) of a tropical peatland landscape in various peat-utilization scenarios to help build awareness among local planners and decision makers on the strategic tradeoff between peatland utilization and restoration. Studies on the total ecosystem services in a tropical peatland landscape involving hydrological regulation are still rare. Based on the net present value calculation, provisioning services, carbon regulation, and hydrological regulation in our study area account for 19, 70, and 11% of the total ecosystem services, respectively. Based on uncertainty analysis, at any combination of the social cost of carbon emission (within a range of USD 52.7–USD 107.4) and discount rate (within a range of 5–10%), the enrichment of peatlands with paludiculture crops (e.g., jelutong) shows superior ecosystem services compared to other peatland-utilization scenarios. Conversely, planting peatlands with monoculture crops, which are associated with peatland drainage, shows a rapid decrease in the total ecosystem services. The fluvial carbon export in our study, which is often neglected in a peatland carbon budget, increases the estimate of the total carbon budget by 8%. Restoring undrained peatlands with paludiculture crops such as jelutong contributes positively to carbon sequestration and potentially reduces carbon emissions by 11%. These quantitative findings can help local planners and decision makers in understanding the tradeoff between the long-term benefits of peatland restoration and the short-term economic benefits of peatland utilization for monoculture crops.

Large amounts of carbon are stored in the permafrost of the northern high latitude land. As permafrost degrades under a warming climate, some of this carbon will decompose and be released to the atmosphere. This positive climate-carbon feedback will reduce the natural carbon sinks and thus lower anthropogenic CO2 emissions compatible with the goals of the Paris Agreement. Simulations using an ensemble of the JULES-IMOGEN intermediate complexity climate model (including climate response and process uncertainty) and a stabilization target of 2 °C, show that including the permafrost carbon pool in the model increases the land carbon emissions at stabilization by between 0.09 and 0.19 Gt C year−1 (10th to 90th percentile). These emissions are only slightly reduced to between 0.08 and 0.16 Gt C year−1 (10th to 90th percentile) when considering 1.5 °C stabilization targets. This suggests that uncertainties caused by the differences in stabilization target are small compared with those associated with model parameterisation uncertainty. Inertia means that permafrost carbon loss may continue for many years after anthropogenic emissions have stabilized. Simulations suggest that between 225 and 345 Gt C (10th to 90th percentile) are in thawed permafrost and may eventually be released to the atmosphere for stabilization target of 2 °C. This value is 60–100 Gt C less for a 1.5 °C target. The inclusion of permafrost carbon will add to the demands on negative emission technologies which are already present in most low emissions scenarios.