Artigos de revistas sobre o tema "Biological Carbon Pum"
Siga este link para ver outros tipos de publicações sobre o tema: Biological Carbon Pum.
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores artigos de revistas para estudos sobre o assunto "Biological Carbon Pum".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja os artigos de revistas das mais diversas áreas científicas e compile uma bibliografia correta.
1
O'Neill, Cameron M., Andrew McC Hogg, Michael J. Ellwood, Bradley N. Opdyke e Stephen M. Eggins. "Sequential changes in ocean circulation and biological export productivity during the last glacial–interglacial cycle: a model–data study". Climate of the Past 17, n.º 1 (15 de janeiro de 2021): 171–201. http://dx.doi.org/10.5194/cp-17-171-2021.
Texto completo da fonteResumo:
Abstract. We conduct a model–data analysis of the marine carbon cycle to understand and quantify the drivers of atmospheric CO2 concentration during the last glacial–interglacial cycle. We use a carbon cycle box model, “SCP-M”, combined with multiple proxy data for the atmosphere and ocean, to test for variations in ocean circulation and Southern Ocean biological export productivity across marine isotope stages spanning 130 000 years ago to the present. The model is constrained by proxy data associated with a range of environmental conditions including sea surface temperature, salinity, ocean volume, sea-ice cover and shallow-water carbonate production. Model parameters for global ocean circulation, Atlantic meridional overturning circulation and Southern Ocean biological export productivity are optimized in each marine isotope stage against proxy data for atmospheric CO2, δ13C and Δ14C and deep-ocean δ13C, Δ14C and CO32-. Our model–data results suggest that global overturning circulation weakened during Marine Isotope Stage 5d, coincident with a ∼ 25 ppm fall in atmospheric CO2 from the last interglacial period. There was a transient slowdown in Atlantic meridional overturning circulation during Marine Isotope Stage 5b, followed by a more pronounced slowdown and enhanced Southern Ocean biological export productivity during Marine Isotope Stage 4 (∼ −30 ppm). In this model, the Last Glacial Maximum was characterized by relatively weak global ocean and Atlantic meridional overturning circulation and increased Southern Ocean biological export productivity (∼ −20 ppm during MIS 3 and MIS 2). Ocean circulation and Southern Ocean biological export productivity returned to modern values by the Holocene period. The terrestrial biosphere decreased by 385 Pg C in the lead-up to the Last Glacial Maximum, followed by a period of intense regrowth during the last glacial termination and the Holocene (∼ 600 Pg C). Slowing ocean circulation, a colder ocean and to a lesser extent shallow carbonate dissolution contributed ∼ −70 ppm to atmospheric CO2 in the ∼ 100 000-year lead-up to the Last Glacial Maximum, with a further ∼ −15 ppm contributed during the glacial maximum. Our model results also suggest that an increase in Southern Ocean biological export productivity was one of the ingredients required to achieve the Last Glacial Maximum atmospheric CO2 level. We find that the incorporation of glacial–interglacial proxy data into a simple quantitative ocean transport model provides useful insights into the timing of past changes in ocean processes, enhancing our understanding of the carbon cycle during the last glacial–interglacial period.
2
Russo, Vincent M., e John Wright. "Nuclear Magnetic Resonance for Monitoring Carbon Metabolism in Sweet Corn". HortScience 30, n.º 4 (julho de 1995): 889C—889. http://dx.doi.org/10.21273/hortsci.30.4.889c.
Texto completo da fonteResumo:
Understanding carbon metabolism can provide insight into physiological processes regulating yield, senescence, and resistance to pathogens in sweet corn (Zea mays L.). This study was conducted to determine if nuclear magnetic resonance (NMR) spectroscopy could be used to monitor changes in carbon metabolism at various growth stages in the shrunken-2 sweet corn cultivar Illini Gold. The 7th, 9th, and 11th stalk internodes were excised at midwhorl (V9), tassel emergence, 50% silking, and fresh-market harvest stages. The rind was removed and the sap expressed. Carbon-NMR spectroscopy was conducted with a 200.7 MHz machine on the expressed sap. From V9 through 50% silking, peaks in spectra were uniformly grouped from ≈61 to ≈104 ppm. At fresh-market stage, additional peaks were found in the spectra at ≈17 to ≈20 ppm, with the majority of peaks found from ≈57 to ≈104 ppm. The biological importance of these changes in carbon metabolism in sweet corn are not clear. Efforts are under way to identify the carbon-based compounds associated with the peaks.
3
Buchanan, Pearse J., Richard J. Matear, Andrew Lenton, Steven J. Phipps, Zanna Chase e David M. Etheridge. "The simulated climate of the Last Glacial Maximum and insights into the global marine carbon cycle". Climate of the Past 12, n.º 12 (22 de dezembro de 2016): 2271–95. http://dx.doi.org/10.5194/cp-12-2271-2016.
Texto completo da fonteResumo:
Abstract. The ocean's ability to store large quantities of carbon, combined with the millennial longevity over which this reservoir is overturned, has implicated the ocean as a key driver of glacial–interglacial climates. However, the combination of processes that cause an accumulation of carbon within the ocean during glacial periods is still under debate. Here we present simulations of the Last Glacial Maximum (LGM) using the CSIRO Mk3L-COAL (Carbon–Ocean–Atmosphere–Land) earth system model to test the contribution of physical and biogeochemical processes to ocean carbon storage. For the LGM simulation, we find a significant global cooling of the surface ocean (3.2 °C) and the expansion of both minimum and maximum sea ice cover broadly consistent with proxy reconstructions. The glacial ocean stores an additional 267 Pg C in the deep ocean relative to the pre-industrial (PI) simulation due to stronger Antarctic Bottom Water formation. However, 889 Pg C is lost from the upper ocean via equilibration with a lower atmospheric CO2 concentration and a global decrease in export production, causing a net loss of carbon relative to the PI ocean. The LGM deep ocean also experiences an oxygenation ( > 100 mmol O2 m−3) and deepening of the calcite saturation horizon (exceeds the ocean bottom) at odds with proxy reconstructions. With modifications to key biogeochemical processes, which include an increased export of organic matter due to a simulated release from iron limitation, a deepening of remineralisation and decreased inorganic carbon export driven by cooler temperatures, we find that the carbon content of the glacial ocean can be sufficiently increased (317 Pg C) to explain the reduction in atmospheric and terrestrial carbon at the LGM (194 ± 2 and 330 ± 400 Pg C, respectively). Assuming an LGM–PI difference of 95 ppm pCO2, we find that 55 ppm can be attributed to the biological pump, 28 ppm to circulation changes and the remaining 12 ppm to solubility. The biogeochemical modifications also improve model–proxy agreement in export production, carbonate chemistry and dissolved oxygen fields. Thus, we find strong evidence that variations in the oceanic biological pump exert a primary control on the climate.
4
Soedarmanto, H., e E. Setiawati. "The Analysis of Plywood Industrial Wastewater Treatment in South Kalimantan". IOP Conference Series: Earth and Environmental Science 950, n.º 1 (1 de janeiro de 2022): 012045. http://dx.doi.org/10.1088/1755-1315/950/1/012045.
Texto completo da fonteResumo:
Abstract Plywood industrial wastewater can cause heavy pollution to the environment. The wastewater treatment system will be determined by the parameters of the liquid waste produced. This study was aimed to reduce the wastewater contamination level in the plywood industry. The method consisted of sedimentation, coagulation, flocculation, aeration, sand filtration, activated carbon adsorption, and ion exchange. The wastewater was pumped into the reservoir and conditioned to a pH of 6 – 7 and allowed to stand for 2 (two) hours for sedimentation. The blower with a speed of 50 rpm was turned for aeration. Then the wastewater was sand filtrated and absorbed by activated carbon. The wastewater flowed into the anion-cation resin tank for ion exchange. The treated effluent filtrate was analyzed for Biological Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Total Suspended Solid (TSS), Phenol, and total ammonia (NH3). The results showed that the decrease of BOD5; COD; TSS; phenol; and NH3 was from 1,426 ppm to 30,5 ppm (97.9%); 2,545.7 to 34.7 ppm (98.6%); 865 ppm to 9.65 ppm (98.9%); 56.98 ppm to 1.45 ppm (97.5%); and 1,652 ppm to 4.56 ppm (99.7%).
5
Walia, Abhishek, Preeti Mehta, Shiwani Guleria, Anjali Chauhan e C. K. Shirkot. "Impact of Fungicide Mancozeb at Different Application Rates on Soil Microbial Populations, Soil Biological Processes, and Enzyme Activities in Soil". Scientific World Journal 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/702909.
Texto completo da fonteResumo:
The use of fungicides is the continuous exercise particularly in orchard crops where fungal diseases, such as white root rot, have the potential to destroy horticultural crops rendering them unsaleable. In view of above problem, the present study examines the effect of different concentrations of mancozeb (0–2000 ppm) at different incubation periods for their harmful side effects on various microbiological processes, soil microflora, and soil enzymes in alluvial soil (pH 6.8) collected from apple orchards of Shimla in Himachal Pradesh (India). Low concentrations of mancozeb were found to be deleterious towards fungal and actinomycetes population while higher concentrations (1000 and 2000 ppm) were found to be detrimental to soil bacteria. Mancozeb impaired the process of ammonification and nitrification. Similar results were observed for nitrifying and ammonifying bacteria. Phosphorus solubilization was increased by higher concentration of mancozeb, that is, 250 ppm and above. In unamended soil, microbial biomass carbon and carbon mineralization were adversely affected by mancozeb. Soil enzymes, that is, amylase, invertase, and phosphatase showed adverse and disruptive effect when mancozeb used was above 10 ppm in unamended soil. These results conclude that, to lessen the harmful effects in soil biological processes caused by this fungicide, addition of higher amount of nitrogen based fertilizers is required.
6
Moreno, Allison R., George I. Hagstrom, Francois W. Primeau, Simon A. Levin e Adam C. Martiny. "Marine phytoplankton stoichiometry mediates nonlinear interactions between nutrient supply, temperature, and atmospheric CO<sub>2</sub>". Biogeosciences 15, n.º 9 (9 de maio de 2018): 2761–79. http://dx.doi.org/10.5194/bg-15-2761-2018.
Texto completo da fonteResumo:
Abstract. Marine phytoplankton stoichiometry links nutrient supply to marine carbon export. Deviations of phytoplankton stoichiometry from Redfield proportions (106C : 1P) could therefore have a significant impact on carbon cycling, and understanding which environmental factors drive these deviations may reveal new mechanisms regulating the carbon cycle. To explore the links between environmental conditions, stoichiometry, and carbon cycling, we compared four different models of phytoplankton C : P: a fixed Redfield model, a model with C : P given as a function of surface phosphorus concentration (P), a model with C P given as a function of temperature, and a new multi-environmental model that predicts C : P as a function of light, temperature, and P. These stoichiometric models were embedded into a five-box ocean circulation model, which resolves the three major ocean biomes (high-latitude, subtropical gyres, and tropical upwelling regions). Contrary to the expectation of a monotonic relationship between surface nutrient drawdown and carbon export, we found that lateral nutrient transport from lower C : P tropical waters to high C : P subtropical waters could cause carbon export to decrease with increased tropical nutrient utilization. It has been hypothesized that a positive feedback between temperature and pCO2, atm will play an important role in anthropogenic climate change, with changes in the biological pump playing at most a secondary role. Here we show that environmentally driven shifts in stoichiometry make the biological pump more influential, and may reverse the expected positive relationship between temperature and pCO2, atm. In the temperature-only model, changes in tropical temperature have more impact on the Δ pCO2, atm (∼ 41 ppm) compared to subtropical temperature changes (∼ 4.5 ppm). Our multi-environmental model predicted a decline in pCO2, atm of ∼ 46 ppm when temperature spanned a change of 10 °C. Thus, we find that variation in marine phytoplankton stoichiometry and its environmental controlling factors can lead to nonlinear controls on pCO2, atm, suggesting the need for further studies of ocean C : P and the impact on ocean carbon cycling.
7
Boufeldja, Linda, Dennis Brandt, Caroline Guzman, Manon Vitou, Frederic Boudard, Sylvie Morel, Adrien Servent et al. "Effect of Elevated Carbon Dioxide Exposure on Nutrition-Health Properties of Micro-Tom Tomatoes". Molecules 27, n.º 11 (2 de junho de 2022): 3592. http://dx.doi.org/10.3390/molecules27113592.
Texto completo da fonteResumo:
(1) Background: The anthropogenically induced rise in atmospheric carbon dioxide (CO2) and associated climate change are considered a potential threat to human nutrition. Indeed, an elevated CO2 concentration was associated with significant alterations in macronutrient and micronutrient content in various dietary crops. (2) Method: In order to explore the impact of elevated CO2 on the nutritional-health properties of tomato, we used the dwarf tomato variety Micro-Tom plant model. Micro-Toms were grown in culture chambers under 400 ppm (ambient) or 900 ppm (elevated) carbon dioxide. Macronutrients, carotenoids, and mineral contents were analyzed. Biological anti-oxidant and anti-inflammatory bioactivities were assessed in vitro on activated macrophages. (3) Results: Micro-Tom exposure to 900 ppm carbon dioxide was associated with an increased carbohydrate content whereas protein, minerals, and total carotenoids content were decreased. These modifications of composition were associated with an altered bioactivity profile. Indeed, antioxidant anti-inflammatory potential were altered by 900 ppm CO2 exposure. (4) Conclusion: Taken together, our results suggest that (i) the Micro-Tom is a laboratory model of interest to study elevated CO2 effects on crops and (ii) exposure to 900 ppm CO2 led to the decrease of nutritional potential and an increase of health beneficial properties of tomatoes for human health.
8
G. N. SHREEVANI, A.G. SREENIVAS, R.V. BELADHADI e B.S. JANAGOUDAR. "Environmental change and the phenology of Bt cotton aphid, Aphis gossypii Glover". Journal of Agrometeorology 19, n.º 4 (1 de dezembro de 2017): 312–18. http://dx.doi.org/10.54386/jam.v19i4.597.
Texto completo da fonteResumo:
Climate change in terms of increase in atmospheric carbon dioxide and temperature has impact on agriculture including insect pests that minimize the crop yields. To address these impacts, biological studies on aphid, Aphis gossypii Glover on Bt cotton was conducted for six generations during 2013-14 and 2014-15 under different climate change conditions. The results revealed that the biometry of aphid was influenced by increased carbon dioxide (550 ppm CO2) and temperature (rise in 2°C of the prevailing temperature). This was evidenced by decrease in nymphal developmental time (3.67 ± 0.21 days), longevity of adult (9.43 ± 0.41 days), increased fecundity (32.46 ± 0.95) and reduced life cycle (12.28 ± 0.23 days) in the elevated conditions (both 550 ppm CO2 with 32°C as well as in 550 ppm CO2 + 34°C). However, morphometry of aphid showed slight variations in all the treatments but, aphids under elevated conditions showed reduced body size which indicated that the fitness of aphid was effected in the enriched carbon dioxide (CO2) and temperature conditions.
9
Mphahlele, Ipoteng Justice, Soraya Phumzile Malinga e Langelihle Nsikayezwe Dlamini. "Combined Biological and Photocatalytic Degradation of Dibutyl Phthalate in a Simulated Wastewater Treatment Plant". Catalysts 12, n.º 5 (30 de abril de 2022): 504. http://dx.doi.org/10.3390/catal12050504.
Texto completo da fonteResumo:
The removal of organic pollutant in wastewater has become a major priority in water treatment. In this study, organic pollutant dibutyl phthalate (DBP) has been biologically and photocatalytically degraded in wastewater using modified transition metal dichalcogenides. The as-synthesized nanoparticles were characterized using various characterization techniques, which includes XRD, Raman, FT-IR, SEM, TEM, UV-Vis, XPS, PL, EIS, and photocurrent responses. The nanoparticles synthesized by slightly modified hydrothermal method depicted a hexagonal phase, as evidenced by XRD and Raman analyses. The biological degradation of 69% dibutyl phthalate was achieved. Moreover, the total organic carbon removal efficiency of 70% was further achieved. Incorporating biological and photocatalytic systems significantly improved dibutyl phthalate removal in secondary effluent by three folds when compared to the unilateral operating setup. The optimized parameters such as pH = 7, 5 ppm and DBP concentration with the addition of 10 mg catalysts loading were employed for the photocatalytic degradation of dibutyl phthalate in water. Pristine WS2 exhibited photocatalytic efficiencies of 46% after 60 min illumination. The use of dual system 3% Ce/Gd-WS2 exhibited the highest photodegradation of 85%, with a chemical oxygen demand of 80% and total organic carbon of 77%. The enhanced activity by the composite is attested to the formation of heterojunction exhibiting excellent charge separation and low rate of recombination. The 3% Ce/Gd-WS2 can be used up to seven times and still achieve a degradation of 56%.
10
Xue, Z., R. He, K. Fennel, W. J. Cai, S. Lohrenz, W. J. Huang e H. Tian. "Modeling <i>p</i>CO<sub>2</sub> variability in the Gulf of Mexico". Biogeosciences Discussions 11, n.º 8 (27 de agosto de 2014): 12673–95. http://dx.doi.org/10.5194/bgd-11-12673-2014.
Texto completo da fonteResumo:
Abstract. A three-dimensional coupled physical–biogeochemical model was used to simulate and examine temporal and spatial variability of surface pCO2 in the Gulf of Mexico (GoM). The model is driven by realistic atmospheric forcing, open boundary conditions from a data-assimilative global ocean circulation model, and observed freshwater and terrestrial nutrient and carbon input from major rivers. A seven-year model hindcast (2004–2010) was performed and was validated against in situ measurements. The model revealed clear seasonality in surface pCO2. Based on the multi-year mean of the model results, the GoM is an overall CO2 sink with a flux of 1.34 × 1012 mol C yr−1, which, together with the enormous fluvial carbon input, is balanced by the carbon export through the Loop Current. A sensitivity experiment was performed where all biological sources and sinks of carbon were disabled. In this simulation surface pCO2 was elevated by ~ 70 ppm, providing the evidence that biological uptake is a primary driver for the observed CO2 sink. The model also provided insights about factors influencing the spatial distribution of surface pCO2 and sources of uncertainty in the carbon budget.
11
Ödalen, Malin, Jonas Nycander, Kevin I. C. Oliver, Laurent Brodeau e Andy Ridgwell. "The influence of the ocean circulation state on ocean carbon storage and CO<sub>2</sub> drawdown potential in an Earth system model". Biogeosciences 15, n.º 5 (6 de março de 2018): 1367–93. http://dx.doi.org/10.5194/bg-15-1367-2018.
Texto completo da fonteResumo:
Abstract. During the four most recent glacial cycles, atmospheric CO2 during glacial maxima has been lowered by about 90–100 ppm with respect to interglacials. There is widespread consensus that most of this carbon was partitioned in the ocean. It is, however, still debated which processes were dominant in achieving this increased carbon storage. In this paper, we use an Earth system model of intermediate complexity to explore the sensitivity of ocean carbon storage to ocean circulation state. We carry out a set of simulations in which we run the model to pre-industrial equilibrium, but in which we achieve different states of ocean circulation by changing forcing parameters such as wind stress, ocean diffusivity and atmospheric heat diffusivity. As a consequence, the ensemble members also have different ocean carbon reservoirs, global ocean average temperatures, biological pump efficiencies and conditions for air–sea CO2 disequilibrium. We analyse changes in total ocean carbon storage and separate it into contributions by the solubility pump, the biological pump and the CO2 disequilibrium component. We also relate these contributions to differences in the strength of the ocean overturning circulation. Depending on which ocean forcing parameter is tuned, the origin of the change in carbon storage is different. When wind stress or ocean diapycnal diffusivity is changed, the response of the biological pump gives the most important effect on ocean carbon storage, whereas when atmospheric heat diffusivity or ocean isopycnal diffusivity is changed, the solubility pump and the disequilibrium component are also important and sometimes dominant. Despite this complexity, we obtain a negative linear relationship between total ocean carbon and the combined strength of the northern and southern overturning cells. This relationship is robust to different reservoirs dominating the response to different forcing mechanisms. Finally, we conduct a drawdown experiment in which we investigate the capacity for increased carbon storage by artificially maximising the efficiency of the biological pump in our ensemble members. We conclude that different initial states for an ocean model result in different capacities for ocean carbon storage due to differences in the ocean circulation state and the origin of the carbon in the initial ocean carbon reservoir. This could explain why it is difficult to achieve comparable responses of the ocean carbon pumps in model inter-comparison studies in which the initial states vary between models. We show that this effect of the initial state is quantifiable. The drawdown experiment highlights the importance of the strength of the biological pump in the control state for model studies of increased biological efficiency.
12
Bauska, Thomas K., Daniel Baggenstos, Edward J. Brook, Alan C. Mix, Shaun A. Marcott, Vasilii V. Petrenko, Hinrich Schaefer, Jeffrey P. Severinghaus e James E. Lee. "Carbon isotopes characterize rapid changes in atmospheric carbon dioxide during the last deglaciation". Proceedings of the National Academy of Sciences 113, n.º 13 (14 de março de 2016): 3465–70. http://dx.doi.org/10.1073/pnas.1513868113.
Texto completo da fonteResumo:
An understanding of the mechanisms that control CO2 change during glacial–interglacial cycles remains elusive. Here we help to constrain changing sources with a high-precision, high-resolution deglacial record of the stable isotopic composition of carbon in CO2 (δ13C-CO2) in air extracted from ice samples from Taylor Glacier, Antarctica. During the initial rise in atmospheric CO2 from 17.6 to 15.5 ka, these data demarcate a decrease in δ13C-CO2, likely due to a weakened oceanic biological pump. From 15.5 to 11.5 ka, the continued atmospheric CO2 rise of 40 ppm is associated with small changes in δ13C-CO2, consistent with a nearly equal contribution from a further weakening of the biological pump and rising ocean temperature. These two trends, related to marine sources, are punctuated at 16.3 and 12.9 ka with abrupt, century-scale perturbations in δ13C-CO2 that suggest rapid oxidation of organic land carbon or enhanced air–sea gas exchange in the Southern Ocean. Additional century-scale increases in atmospheric CO2 coincident with increases in atmospheric CH4 and Northern Hemisphere temperature at the onset of the Bølling (14.6–14.3 ka) and Holocene (11.6–11.4 ka) intervals are associated with small changes in δ13C-CO2, suggesting a combination of sources that included rising surface ocean temperature.
13
Crichton, Katherine A., Jamie D. Wilson, Andy Ridgwell e Paul N. Pearson. "Calibration of temperature-dependent ocean microbial processes in the cGENIE.muffin (v0.9.13) Earth system model". Geoscientific Model Development 14, n.º 1 (11 de janeiro de 2021): 125–49. http://dx.doi.org/10.5194/gmd-14-125-2021.
Texto completo da fonteResumo:
Abstract. Temperature is a master parameter in the marine carbon cycle, exerting a critical control on the rate of biological transformation of a variety of solid and dissolved reactants and substrates. Although in the construction of numerical models of marine carbon cycling, temperature has been long recognised as a key parameter in the production and export of organic matter at the ocean surface, its role in the ocean interior is much less frequently accounted for. There, bacteria (primarily) transform sinking particulate organic matter (POM) into its dissolved constituents and consume dissolved oxygen (and/or other electron acceptors such as sulfate). The nutrients and carbon thereby released then become available for transport back to the surface, influencing biological productivity and atmospheric pCO2, respectively. Given the substantial changes in ocean temperature occurring in the past, as well as in light of current anthropogenic warming, appropriately accounting for the role of temperature in marine carbon cycling may be critical to correctly projecting changes in ocean deoxygenation and the strength of feedbacks on atmospheric pCO2. Here we extend and calibrate a temperature-dependent representation of marine carbon cycling in the cGENIE.muffin Earth system model, intended for both past and future climate applications. In this, we combine a temperature-dependent remineralisation scheme for sinking organic matter with a biological export production scheme that also includes a dependence on ambient seawater temperature. Via a parameter ensemble, we jointly calibrate the two parameterisations by statistically contrasting model-projected fields of nutrients, oxygen, and the stable carbon isotopic signature (δ13C) of dissolved inorganic carbon in the ocean with modern observations. We additionally explore the role of temperature in the creation and recycling of dissolved organic matter (DOM) and hence its impact on global carbon cycle dynamics. We find that for the present day, the temperature-dependent version shows a fit to the data that is as good as or better than the existing tuned non-temperature-dependent version of the cGENIE.muffin. The main impact of accounting for temperature-dependent remineralisation of POM is in driving higher rates of remineralisation in warmer waters, in turn driving a more rapid return of nutrients to the surface and thereby stimulating organic matter production. As a result, more POM is exported below 80 m but on average reaches shallower depths in middle- and low-latitude warmer waters compared to the standard model. Conversely, at higher latitudes, colder water temperature reduces the rate of nutrient resupply to the surface and POM reaches greater depth on average as a result of slower subsurface rates of remineralisation. Further adding temperature-dependent DOM processes changes this overall picture only a little, with a slight weakening of export production at higher latitudes. As an illustrative application of the new model configuration and calibration, we take the example of historical warming and briefly assess the implications for global carbon cycling of accounting for a more complete set of temperature-dependent processes in the ocean. We find that between the pre-industrial era (ca. 1700) and the present (year 2010), in response to a simulated air temperature increase of 0.9 ∘C and an associated projected mean ocean warming of 0.12 ∘C (0.6 ∘C in surface waters and 0.02 ∘C in deep waters), a reduction in particulate organic carbon (POC) export at 80 m of just 0.3 % occurs (or 0.7 % including a temperature-dependent DOM response). However, due to this increased recycling nearer the surface, the efficiency of the transfer of carbon away from the surface (at 80 m) to the deep ocean (at 1040 m) is reduced by 5 %. In contrast, with no assumed temperature-dependent processes impacting production or remineralisation of either POM or DOM, global POC export at 80 m falls by 2.9 % between the pre-industrial era and the present day as a consequence of ocean stratification and reduced nutrient resupply to the surface. Our analysis suggests that increased temperature-dependent nutrient recycling in the upper ocean has offset much of the stratification-induced restriction in its physical transport.
14
Ugarte, Carmen M., e Michelle M. Wander. "The influence of organic transition strategy on chemical and biological soil tests". Renewable Agriculture and Food Systems 28, n.º 1 (3 de janeiro de 2012): 17–31. http://dx.doi.org/10.1017/s1742170511000573.
Texto completo da fonteResumo:
AbstractSoil testing strategies that include biologically based indicators in organic and alternative farming systems are needed in order to improve recommendations that balance production and environmental goals. In this study, soil samples were collected before and after soils were transitioned from conventional row crop production to organic management using rotations that varied in both their inputs and tillage intensity. Ley-, row crop- and vegetable-based farming systems were implemented using locally specific production practices. Subplots were imposed within each system to allow comparison of farming systems without amendment and with dairy manure- and compost-amendment. Soil analyses included standard chemical tests (0–15 cm) for available phosphorus, exchangeable potassium, calcium, magnesium, pH, total organic carbon (SOC) and total nitrogen (TN). Biological assays (0–15 and 15–30 cm) included particulate organic matter-C and -N (POM-C, POM-N), soil and POM C:N ratios, fluorescein diacetate (FDA) hydrolysis, potentially mineralizable N (PMN) and hydrolysable amino-N + NH4(IL-N). Even though cropping and tillage intensity varied among systems (ley < row crop < vegetable), organic matter and nutrient reserves were not statistically different. Nutrient concentrations tested medium to high, even without compost or manure application. Labile fractions of soil organic matter were more enriched in the deeper sampling depth; whereby, POM stocks within the 15–30 cm depth increased by 20% on average compared to roughly 6% in the surface depth. This and observed changes in other properties demonstrate the multiple benefits derived from use of winter annual or perennial crops. Results from our analyses suggested PMN and POM have particular promise as metrics of change in commercial soil testing facilities to assist recommendations for amendments to balance production and environmental goals.
15
Quirk, Joe, Megan Y. Andrews, Jonathan R. Leake, Steve A. Banwart e David J. Beerling. "Ectomycorrhizal fungi and past high CO 2 atmospheres enhance mineral weathering through increased below-ground carbon-energy fluxes". Biology Letters 10, n.º 7 (julho de 2014): 20140375. http://dx.doi.org/10.1098/rsbl.2014.0375.
Texto completo da fonteResumo:
Field studies indicate an intensification of mineral weathering with advancement from arbuscular mycorrhizal (AM) to later-evolving ectomycorrhizal (EM) fungal partners of gymnosperm and angiosperm trees. We test the hypothesis that this intensification is driven by increasing photosynthate carbon allocation to mycorrhizal mycelial networks using 14 CO 2 -tracer experiments with representative tree–fungus mycorrhizal partnerships. Trees were grown in either a simulated past CO 2 atmosphere (1500 ppm)—under which EM fungi evolved—or near-current CO 2 (450 ppm). We report a direct linkage between photosynthate-energy fluxes from trees to EM and AM mycorrhizal mycelium and rates of calcium silicate weathering. Calcium dissolution rates halved for both AM and EM trees as CO 2 fell from 1500 to 450 ppm, but silicate weathering by AM trees at high CO 2 approached rates for EM trees at near-current CO 2 . Our findings provide mechanistic insights into the involvement of EM-associating forest trees in strengthening biological feedbacks on the geochemical carbon cycle that regulate atmospheric CO 2 over millions of years.
16
MEDEIROS, ALDAIR DE SOUZA, ANTÔNIO ADOLFO SILVA SOARES e STOÉCIO MALTA FERREIRA MAIA. "SOIL CARBON STOCKS AND COMPARTMENTS OF ORGANIC MATTER UNDER CONVENTIONAL SYSTEMS IN BRAZILIAN SEMI-ARID REGION". Revista Caatinga 35, n.º 3 (setembro de 2022): 697–710. http://dx.doi.org/10.1590/1983-21252022v35n321rc.
Texto completo da fonteResumo:
ABSTRACT The objective of this study was to evaluate the effect of the conversion of secondary native vegetation (NV) to conventional systems (agriculture and pasture) in soil organic carbon (SOC) and carbon of fractions particulate organic matter (POM) and mineral-associated organic matter (MAOM) in the Brazilian semi-arid region. The study was carried out in the municipalities of Delmiro Gouveia, Inhapi and Pariconha, in Alagoas, Brazil. Soils were collected in the layers of 0-0.1, 0.1-0.2 and 0.2-0.3 m. The treatments analyzed were: agricultural crops with 4, 15 and 30 years and pasture with 10 years. As a reference, the secondary Caatinga was used. The results show that in soils with sandy texture (Neossolos Quartzarênico and Regolítico – Arenosols and Regosols, respectively), there were reductions in SOC levels and carbon in the compartment associated with minerals. The inverse can be observed in the clay-textured Argissolo (Acrisols), with 30 years of cultivation, in which there was an increase in SOC and C in the quantitative fractions of soil organic matter. In addition, despite the sandy texture of the Neossolo Regolítico, POM levels were increased in the pasture system in comparison to native vegetation, but it was not enough to recover the original SOC content of this system.
17
Vasumathi, K., Raja Vadivu G. Nadana, E. M. Nithiya, K. Sundar e M. Premalatha. "Analyzing and optimizing the carbon utilization and lipid yield at different light intensities for Scenedesmus arcuatus". Research Journal of Chemistry and Environment 25, n.º 11 (25 de outubro de 2021): 1–10. http://dx.doi.org/10.25303/2511rjce001010.
Texto completo da fonteResumo:
Microalgae, the photosynthetic microorganism growing abundantly in marine and aquatic ecosystems, are potential source for biological sequestration of CO2. The carbon uptake differs in the presence of other nutrients, light intensity etc. The biomass yield of Scenedesmus arcuatus var capitatus was studied based on the Face Centred Central Composite design (FCCD) of Response Surface Methodology (RSM) for nitrate, phosphate and carbonate under different conditions (laboratory, room and sunlight conditions). Various pre-treatments (osmotic shock, autoclaving, microwave and ultrasonication) were employed to find the best method for maximum lipid yield. The biomass yield reached a maximum of 1 g/L under sunlight conditions of nitrate concentration 500 ppm and carbonate 2000 ppm. The laboratory conditions resulted in a biomass yield of 0.59 g/L at 500 ppm nitrate, 1000 ppm carbonate and 250 ppm phosphate. Under room conditions, the yield was very low (0.11 g/L). Osmotic shock resulted in higher lipid yield than the other pre-treatment methods. The ability of Scenedesmus arcuatus to uptake high carbon under sunlight conditions and to adapt to high light intensity and fluctuations in light intensity concludes that this species is suitable for large-scale open pond cultivation for CO2 sequestration and production of metabolites.
18
COELHO JUNIOR, ALOISIO, e JOSE R. P. PARRA. "Effect of Carbon dioxide (CO2) on mortality and reproduction of Anagasta kuehniella (Zeller 1879), in mass rearing, aiming at the production of Trichogramma spp." Anais da Academia Brasileira de Ciências 85, n.º 2 (junho de 2013): 823–31. http://dx.doi.org/10.1590/s0001-37652013000200021.
Texto completo da fonteResumo:
Eggs of Anagasta kuehniella (Zeller 1879) are widely used for mass rearing of Trichogramma spp. and other parasitoids and predators, largely commercialized in many countries. The aim of this study is to evaluate the effect of carbon dioxide (CO2) originated from larval metabolism on the biological parameters of A. kuehniella. For that purpose, we assess the production of carbon dioxide (CO2) per rearing tray of A. kuehniella and the effect of CO2 on the viability of egg-to-adult period and oviposition of A. kuehniella. Results allow to estimate that a rearing tray, containing 10,000 larvae between the 4th and 5th instars, produces an average of 30.67 mL of CO2 per hour. The highest egg production of A. kuehniella was obtained when the larvae were kept in rooms with lower concentration of CO2 (1,200 parts per million - ppm), producing 23% more eggs than in rooms with higher CO2 concentrations. In rooms with high density of trays (70 trays/room), CO2 concentration exceeded 4,400 ppm. The viability of the egg-to-adult period was not influenced by carbon dioxide.
19
TEJINDER SINGH BRAR e SMRITI SHARMA. "Influence of temperature and carbon dioxide levels on growth and development of Spodoptera litura Fabricius on cauliflower". Journal of Agrometeorology 19, n.º 4 (1 de dezembro de 2017): 306–11. http://dx.doi.org/10.54386/jam.v19i4.596.
Texto completo da fonteResumo:
The studies on influence of temperature and carbon dioxide levels on growth and development of Spodoptera litura on cauliflower were conducted with six different temperature and carbon dioxide regimes viz. 25:11oC and 25:14oC at 350, 400, 450 ppm carbon dioxide concentrations. Observations on different biological indices were recorded to estimate the influence of elevated temperature and carbon dioxide on growth and development of S. litura. The study revealed temperature and carbon dioxide had significant effect on developmental indices of S. litura. It was observed that incubation period, larval duration, pupal duration, male adult longevity, female adult longevity decreased from 4.5, 23.4, 9.3, 6.8, 7.5, respectively at 25:11oC to 3.9, 21.2, 8.7, 6.5, 7.4 days respectively, at 25:14oC. Whereas fecundity of S litura increased from 363.6 to 420.9 with increase in temperature and carbon dioxide indicating reduced generation time which could lead to more number of generations per year.
20
Moreno, Marta M., Carmen Moreno, Carlos Lacasta e Ramón Meco. "Evolution of Soil Biochemical Parameters in Rainfed Crops: Effect of Organic and Mineral Fertilization". Applied and Environmental Soil Science 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/826236.
Texto completo da fonteResumo:
In organic farming, crop fertilization is largely based on the decomposition of organic matter and biological fixation of nutrients. It is therefore necessary to develop studies conducted to know and understand the soil biological processes for the natural nutrient supplies. The effect of three fertilizer managements (chemical with synthetic fertilizers, organic with 2500 kg compost ha−1, and no fertilizer) in a rainfed crop rotation (durum wheat-fallow-barley-vetch as green manure) on different soil biochemical parameters in semi-arid conditions was investigated. Soil organic matter, microbial biomass carbon, organic matter mineralization, CO2production-to-ATP ratio, and NO3-N content were analysed. Fertilization was only applied to cereals. The results showed the scarce effect of the organic fertilization on soil quality, which resulted more dependent on weather conditions. Only soil organic matter and NO3-N were affected by fertilization (significantly higher in the inorganic treatment, 1.28 g 100 g−1and 17.3 ppm, resp.). Soil organic matter was maintained throughout the study period by the inclusion of a legume in the cropping system and the burying of crop residues. In fallow, soil microbial biomass carbon increased considerably (816 ng g−1), and NO3-N at the end of this period was around 35 ppm, equivalent to 100 kg N ha−1.
21
LUTHFIANA, Ifa Dwi, Hersanti HERSANTI e Fitri WIDIANTINI. "The Potency of Lysinibacillus Sp. in Carbon Fiber and Zinc Oxide Nanoparticles Mixture to Suppress Ralstonia Solanacearum in Vitro". International Journal of Environmental, Sustainability, and Social Science 4, n.º 1 (31 de janeiro de 2023): 250–55. http://dx.doi.org/10.38142/ijesss.v4i1.453.
Texto completo da fonteResumo:
Ralstonia solanacearum is the cause of bacterial wilt on many Solanaceous crops. Antagonistic bacterium can be used to biologically control the pathogen. Lysinibacillus sp. was proven to be able to control R. solanacearum. To formulate the biopesticide, beside the active ingredients, a carrier materials is needed. The carrier material used in this study was 5% of 80 mesh carbon fiber as the site for the bacteria to attach, and enriched with ZnO nanoparticles (ZnO Nps) as one of the plant micro nutrients. The objective of the study was to determine the concentration of ZnO Nps that is viable for Lysinibacillus sp. and able to suppress the in vitro growth of R. Solanacearum. The antagonism test was carried out by using the completely randomized design with 11 treatments and 3 repetitions. The results showed that the largest inhibition zone, 8,30 mm, was caused by the treatment ZLd (ZnO NPs 1000 ppm + Lysinibacillus) without carbon, and 2,12 mm in the treatment of ZLKa ( (ZnO NPs 250 ppm + Lysinibacillus + carbon fiber) with carbon.
22
Biru, Fikadu N., Christopher I. Cazzonelli, Rivka Elbaum e Scott N. Johnson. "Contrasting effects of Miocene and Anthropocene levels of atmospheric CO 2 on silicon accumulation in a model grass". Biology Letters 16, n.º 11 (novembro de 2020): 20200608. http://dx.doi.org/10.1098/rsbl.2020.0608.
Texto completo da fonteResumo:
Grasses are hyper-accumulators of silicon (Si), which they acquire from the soil and deposit in tissues to resist environmental stresses. Given the high metabolic costs of herbivore defensive chemicals and structural constituents (e.g. cellulose), grasses may substitute Si for these components when carbon is limited. Indeed, high Si uptake grasses evolved in the Miocene when atmospheric CO 2 concentration was much lower than present levels. It is, however, unknown how pre-industrial CO 2 concentrations affect Si accumulation in grasses. Using Brachypodium distachyon , we hydroponically manipulated Si-supply (0.0, 0.5, 1, 1.5, 2 mM) and grew plants under Miocene (200 ppm) and Anthropocene levels of CO 2 comprising ambient (410 ppm) and elevated (640 ppm) CO 2 concentrations. We showed that regardless of Si treatments, the Miocene CO 2 levels increased foliar Si concentrations by 47% and 56% relative to plants grown under ambient and elevated CO 2 , respectively. This is owing to higher accumulation overall, but also the reallocation of Si from the roots into the shoots. Our results suggest that grasses may accumulate high Si concentrations in foliage when carbon is less available (i.e. pre-industrial CO 2 levels) but this is likely to decline under future climate change scenarios, potentially leaving grasses more susceptible to environmental stresses.
23
Santos, Jéssica de Oliveira, Francislene Angelotti e Tiago Cardoso da Costa-Lima. "Does elevated CO2 affect the biological aspects of Liriomyza sativae in melon plants?" Semina: Ciências Agrárias 42, n.º 4 (20 de maio de 2021): 2151–62. http://dx.doi.org/10.5433/1679-0359.2021v42n4p2151.
Texto completo da fonteResumo:
An increase in the carbon dioxide concentration (CO2) in the atmosphere has occurred in recent years, influencing the different biological aspects of herbivorous insects. The present study aimed to evaluate the effect of CO2 increase on the biological aspects of Liriomyza sativae Blanchard leafminer in melon plants. For this, two experiments were carried out: (i) to evaluate the effect of melon plants grown in CO2-enriched environments on the immature developmental stages of L. sativae and L. sativae adult longevity, and (ii) to verify the impact of increased CO2 concentration on L. sativae adult survival, feeding punctures, and oviposition. The experiments were carried out in growth chambers maintained in the temperature regime of 20-26-33 °C (simulating the minimum, average, and maximum daily temperature) and under two CO2 concentrations (400 ppm and 770 ppm). The immature stages and the egg-adult period of L. sativae were longer when they developed on plants grown in high CO2 levels (770 ppm), but no difference in adult longevity was observed. The viability of the immature phases was not different between the two CO2 concentrations. Furthermore, there was no difference in the number of eggs and feeding punctures between treatments. Thus, the increase in CO2 concentration prolongs the duration of the immature stages of L. sativae; however, it does not affect their viability. Adult survival, fertility, and feeding punctures were also unmodified by the environment enriched with CO2.
24
Quirk, J., J. R. Leake, S. A. Banwart, L. L. Taylor e D. J. Beerling. "Weathering by tree root-associating fungi diminishes under simulated Cenozoic atmospheric CO<sub>2</sub> decline". Biogeosciences Discussions 10, n.º 10 (9 de outubro de 2013): 15779–807. http://dx.doi.org/10.5194/bgd-10-15779-2013.
Texto completo da fonteResumo:
Abstract. Trees dominate terrestrial biotic weathering of silicate minerals by converting solar energy into chemical energy that fuels roots and their ubiquitous nutrient-mobilising fungal symbionts. These biological activities regulate atmospheric CO2 ([CO2]a) over geologic timescales by driving calcium and magnesium fluvial ion export and marine carbonate formation, but the important stabilising feedbacks between [CO2]a and biotic weathering anticipated by geochemical carbon cycle models remain untested. We report experimental evidence for a negative feedback across a declining Cenozoic [CO2]a range from 1500 ppm to 200 ppm, whereby low [CO2]a curtails mineral surface alteration via trenching and etch pitting by arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) fungal partners of tree roots. Optical profile imaging using vertical scanning interferometry reveals changes in nanoscale surface topography consistent with a dual mode of attack involving delamination and trenching by AM and EM fungal hyphae on phyllosilicate mineral flakes. This is consistent with field observations of micropores in feldspar, hornblende and basalt, purportedly caused by EM fungi, but with little confirmatory evidence. Integrating these findings into a process-based biotic weathering model revealed that low [CO2]a effectively acts as a "carbon starvation" brake, causing a three-fold drop in tree-driven fungal weathering fluxes of calcium and magnesium from silicate rock grains as [CO2]a falls from 1500 ppm to 200 ppm. The feedback is regulated through the action of low [CO2]a on host tree productivity and provides empirical evidence for the role of [CO2]a starvation in diminishing the contribution of trees and mycorrhizal fungi to rates of biological weathering. More broadly, diminished tree-driven weathering under declining [CO2]a may provide an important contributory mechanism stabilising Earth's [CO2]a minimum over the past 24 million years.
25
Morée, Anne L., Jörg Schwinger, Ulysses S. Ninnemann, Aurich Jeltsch-Thömmes, Ingo Bethke e Christoph Heinze. "Evaluating the biological pump efficiency of the Last Glacial Maximum ocean using <i>δ</i><sup>13</sup>C". Climate of the Past 17, n.º 2 (6 de abril de 2021): 753–74. http://dx.doi.org/10.5194/cp-17-753-2021.
Texto completo da fonteResumo:
Abstract. Although both physical and biological marine changes are required to explain the 100 ppm lower atmospheric pCO2 of the Last Glacial Maximum (LGM, ∼21 ka) as compared to preindustrial (PI) times, their exact contributions are debated. Proxies of past marine carbon cycling (such as δ13C) document these changes and thus provide constraints for quantifying the drivers of long-term carbon cycle variability. This modeling study discusses the physical and biological changes in the ocean needed to simulate an LGM ocean in satisfactory agreement with proxy data, here focusing especially on δ13C. We prepared a PI and LGM equilibrium simulation using the ocean model NorESM-OC with full biogeochemistry (including the carbon isotopes δ13C and radiocarbon) and dynamic sea ice. The modeled LGM–PI differences are evaluated against a wide range of physical and biogeochemical proxy data and show agreement for key aspects of the physical ocean state within the data uncertainties. However, the lack of a simulated increase of regenerated nutrients for the LGM indicates that additional biogeochemical changes are required to simulate an LGM ocean in agreement with proxy data. In order to examine these changes, we explore the potential effects of different global mean biological pump efficiencies on the simulated marine biogeochemical tracer distributions. Through estimating which biological pump efficiency reduces LGM model–proxy biases the most, we estimate that the global mean biological pump efficiency increased from 38 % (PI) to up to 75 % (LGM). The drivers of such an increase in the biological pump efficiency may be both biological and related to circulation changes that are incompletely captured by our model – such as stronger isolation of Southern Source Water. Finally, even after considering a 75 % biological pump efficiency in the LGM ocean, a remaining model–proxy error in δ13C exists that is 0.07 ‰ larger than the 0.19 ‰ data uncertainty. This error indicates that additional changes in ocean dynamics are needed to simulate an LGM ocean in agreement with proxy data.
26
Prayitno, Prayitno, Nanik Hendrawati e Indrazno Siradjuddin. "Penyisihan Pencemar Air Limbah Industri Rumput Laut Menggunakan Nano Karbon Aktif". Jurnal Teknik Kimia dan Lingkungan 5, n.º 2 (29 de outubro de 2021): 175. http://dx.doi.org/10.33795/jtkl.v5i2.252.
Texto completo da fonteResumo:
Air limbah yang dihasilkan oleh industri pengolahan rumput laut memiliki volume yang cukup besar dengan karakteristik pH: 11-13 (alkalis), BOD: 200-300 ppm, COD: 500-700 ppm sehingga kurang efisien jika diolah menggunakan proses biologi dan adsorpsi kimiawi. Penelitian bertujuan untuk menganalisa kemampuan nano karbon aktif mengadsorpsi bahan-bahan pencemar (pollutans) dalam suatu kolom adsorpsi alir kontinyu. Penelitian dilakukan dengan cara mengalirkan air limbah rumput laut ke dalam kolom adsorpsi yang berisi adsorben nano karbon aktif pada ukuran 1-25 nm. Variabel percobaan yang digunakan adalah tekanan operasi (2 dan 4 MPa), serta berat adsorben nano karbon aktif (50, 100 dan 150 g) dengan lama adsorpsi 1 jam. Hasil percobaan menunjukkan bahwa pada tekanan 4 MPa dan berat adsorpben nano karbon aktif 150 g dengan waktu adsorpsi selama 25 menit memberikan penyisihan BOD, COD dan TSS maksimal masing-masing sebesar 96,4; 96,4 dan 94,5%.Wastewater produced by the seaweed processing industry has a large enough volume with the characteristics of pH: 11-13 (alkaline), BOD: 200-300 ppm, COD: 500-700 ppm so it is less efficient if treated using biological processes and chemical adsorption. The aim of this research is to analyze the ability of activated carbon nano to adsorb pollutants in a continuous flow adsorption column. The study was conducted by flowing wastewater seaweed into the adsorption column containing the adsorbent activated carbon nano in size 1-25 nm. The experimental variables used were operating pressure (2 and 4 MPa), as well as weight of activated carbon nano adsorbent (50, 100 and 150 g) with adsorption time of 1 hour. The experimental results showed that at pressure of 4 MPa and weight of activated carbon nano adsorbent of 150 g with an adsorption time of 25 minutes gave the maximum removal of BOD, COD and TSS were 96.4, 96.4 and 94.5%, respectively.
27
Saravanane, Pasoubady, Ali Ahsan Bajwa, Maduraimuthu Djanaguiraman e Steve W. Adkins. "Biological Response of Invasive Parthenium Weed to Elevated Concentration of Atmospheric Carbon Dioxide and Soil Salinity". Sustainability 15, n.º 2 (5 de janeiro de 2023): 1025. http://dx.doi.org/10.3390/su15021025.
Texto completo da fonteResumo:
Climate change elements including elevated atmospheric carbon dioxide (CO2) concentration and soil salinity significantly impact weed biology and management. In this study, we evaluated the performance of a highly invasive plant species, parthenium weed (Parthenium hysterophorus L.) grown at various soil salinity levels (ranging from 0 to 16 dS m−1) at two CO2 concentrations (ambient: 400 ppm and elevated: 700 ppm). The CO2 concentration and soil salinity individually affected various early growth attributes of parthenium weed. The interaction between CO2 and salinity was significant for chlorophyll index, stem dry weight and phenolics content. Parthenium weed plants grew taller (13%), achieved greater leaf area (28%) and produced more dry weight (24%) when raised under elevated as compared with the ambient CO2. Soil salinity had a dose-dependent, negative effect on various growth attributes, chlorophyll index, relative water content and phenolics content. Even the modest levels of salinity (4.2 to 4.6 dS m−1) caused 50% reduction in dry weights of leaves, roots and whole plants. Sodium ion (Na+) concentration peaked at the highest salinity level (16 dS m−1) as compared with the lower salinity levels (0 to 12 dS m−1). Overall, salinity had a negative effect on different growth variables but elevated CO2 improved growth and phenolics content regardless of the salt stress regime. Hence, parthenium weed could benefit from future atmospheric CO2 concentration and may invade some salt-affected areas.
28
Ou, Shih-Fu, Ya-Yun Zheng, Sin-Jen Lee, Shyi-Tien Chen, Chien-Hui Wu, Chien-Te Hsieh, Ruey-Shin Juang, Pei-Zhen Peng e Yi-Huang Hsueh. "N-Doped Carbon Quantum Dots as Fluorescent Bioimaging Agents". Crystals 11, n.º 7 (6 de julho de 2021): 789. http://dx.doi.org/10.3390/cryst11070789.
Texto completo da fonteResumo:
Graphene quantum dots, carbon nanomaterials with excellent fluorescence characteristics, are advantageous for use in biological systems owing to their small size, non-toxicity, and biocompatibility. We used the hydrothermal method to prepare functional N-doped carbon quantum dots (N-CQDs) from 1,3,6-trinitropyrene and analyzed their ability to fluorescently stain various bacteria. Our results showed that N-CQDs stain the cell septa and membrane of the Gram-negative bacteria Escherichia coli, Salmonellaenteritidis, and Vibrio parahaemolyticus and the Gram-positive bacteria Bacillus subtilis, Listeria monocytogenes, and Staphylococcus aureus. The optimal concentration of N-CQDs was approximately 500 ppm for Gram-negative bacteria and 1000 ppm for Gram-positive bacteria, and the exposure times varied with bacteria. N-Doped carbon quantum dots have better light stability and higher photobleaching resistance than the commercially available FM4-64. When excited at two different wavelengths, N-CQDs can emit light of both red and green wavelengths, making them ideal for bioimaging. They can also specifically stain Gram-positive and Gram-negative bacterial cell membranes. We developed an inexpensive, relatively easy, and bio-friendly method to synthesize an N-CQD composite. Additionally, they can serve as a universal bacterial membrane-staining dye, with better photobleaching resistance than commercial dyes.
29
Antonucci, Bárbara, Renata Gonçalves Aguiar, Leonardo José Gonçalves Aguiar e Nara Luísa Reis de Andrade. "Fluxos de CO2 em uma área de floresta tropical úmida na Amazônia Ocidental em um ano de El Niño". Ciência e Natura 40 (22 de março de 2018): 119. http://dx.doi.org/10.5902/2179460x30718.
Texto completo da fonteResumo:
The objective this paper was to quantify the hourly variability of CO2 fluxes in the year of the El Niño, in 2015, in a tropical rain forest in the Western Amazon. Data of CO2 fluxes collected at 63.5 m height in a tower of the Large-Scale Biosphere–Atmosphere Experiment in Amazonia in the Jaru Biological Reserve, composed of the Open Ombrophilous forest, were analyzed. Data from the dry-wet period were used, which by convention, the negative and positive values indicate absorption and emission of CO2, respectively. The CO2 uptake in the forest had higher levels between 9:30 a.m. and 4:00 p.m., with mean values between -19 and -13 μmol m-2 s-1, however the peak absorption occurs at 1:00 p.m. with -30 μmol m-2 s-1, considering that at this time the sun's rays are most intense. In average, the Rebio Jaru absorbs more than the areas of the transition Amazonia-Cerrado, indicating that the physiological activities in Ombrophilous forest require a greater amount of carbon. The average daily behavior of CO2 fluxes showed higher concentrations of absorption during the day than emissions overnight, behaving as a carbon sink, corroborating the importance of the forest in assimilation of the atmospheric carbon.
30
Байсаров (Baysarov), Габиден (Gabiden) Маратович (Maratovich), Айдана (Аjdana) Рахманиякызы (Rakhmaniyakyzy) Жуматаева (Zhumatayeva), Гулим (Gulim) Кенесбековна (Kenesbekovna) Мукушева (Mukusheva), Эльвира (El'vira) Эдуардовна (Eduardovna) Шульц (Shul'ts), Роза (Roza) Батталовна (Battalovna) Сейдахметова (Seydakhmetova) e Сергазы (Sergazy) Мынжасарович (Mynzhasarovich) Адекенов (Adekenov). "FLAVONOID COMPOUNDS FROM ARTEMISIA GLABELLA KAR. ET. KIR., SYNTHESIS ON THEIR BASIS AND BIOLOGICAL ACTIVITY". chemistry of plant raw material, n.º 3 (23 de maio de 2018): 215–22. http://dx.doi.org/10.14258/jcprm.2018033766.
Texto completo da fonteResumo:
As a result of complex chemical processing of medicinal raw materials of Artemisia glabella Kar. et Kir., including CO2 extraction and lactones isolation, we have investigated the chemical composition of flavonoids to select the biologically active ones and carry out modifications on their basis. Two flavonoids pectolinaringenin and cirsilineol have been isolated by partition chromatography from the secondary raw materials of Artemisia glabella Kar. et. Kir. and identified. To obtain new biologically active compounds, we have synthesized new amino derivatives of cirsilineol by the Mannich reaction with secondary amines (piperidine and N-methylpiperazine) in isopropanol with the presence of dimethylaminopyridine. In proton NMR spectrum of the synthesized compounds there are proton signals of the initial cirsilineol fragment; however, there is no N-8 proton signal, besides other signals typical for amines’ benzene ring have been observed at 1.53–3.90 ppm. It means that reaction occurred at the C-8 position of carbon in ring A. The synthesized compounds have been studied for various types of biological activity typical for this class, including hepatoprotective and anti-inflammatory activities. Amino derivatives of cirsilineol exhibit a moderate activity against HepG2 cell line, while cirsilineol at a dose of 5 mg/ml expresses a pronounced hepatoprotective activity. Moreover, all samples at a dose of 25 mg/kg show poor anti-inflammatory effects on the model of acute exudative reaction in vivo.
31
Rosset, Jean Sérgio, Maria do Carmo Lana, Marcos Gervasio Pereira, Jolimar Antonio Schiavo, Leandro Rampim e Marcos Vinicius Mansano Sarto. "Organic matter and soil aggregation in agricultural systems with different adoption times". Semina: Ciências Agrárias 40, n.º 6Supl3 (16 de outubro de 2019): 3443. http://dx.doi.org/10.5433/1679-0359.2019v40n6supl3p3443.
Texto completo da fonteResumo:
In conservation management systems, such as no-till (NT), it is important to analyze the pattern of changes in soil quality as a function of the time since adoption of the system. This study evaluated the physical fractions of organic matter and soil aggregation in management systems in areas cultivated with different times since implementation of NT: 6, 14, and 22 successive years of soybean and maize/wheat crops (NT6, NT14, and NT22, respectively); 12 years of no-till with successive years of soybean and maize/wheat crops, and the last 4 years with integration of maize and ruzi grass (Brachiaria ruziziensis) - (NT+B); pasture; and forest. Physical fractionation of organic matter determined the total carbon (TC), particulate organic matter (POM), and mineral organic matter (MOM) by calculating the carbon management index (CMI) and variables related to soil structural stability. Forest and pasture areas showed the highest contents of TC, POM, and MOM, as well as higher stocks of POM and MOM. Among the cultivated areas, higher TC and particulate fractions of organic matter and the best CMI values were observed in the area of NT22. There were changes in aggregation indices, depending on the time since implementation of NT. Areas of NT22, pasture, and forest showed the greatest evolution in C-CO2, indicating increased biological activity, with positive effects on soil structural stability.
32
Tamilselvan, C., S. John Joseph, G. Mugunthan, A. Sathish Kumar e S. Syed Musthaq Ahamed. "Biological Degradation of Metribuzin and Profenofos by some Efficient Bacterial Isolates". International Letters of Natural Sciences 14 (abril de 2014): 26–39. http://dx.doi.org/10.18052/www.scipress.com/ilns.14.26.
Texto completo da fonteResumo:
The soil sample was collected from the paddy field of Sriperumbudur, Tamilnadu which is having a history of repeated pesticide applications. The isolation of efficient pesticide degrading bacteria was identified as Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis. The growth of the three pesticide degrading isolates was assessed in Minimal salt broth containing 25 ppm of pesticides. Two popularly used pesticides Metribuzin and Profenofos were selected for this study. Among the three bacterial isolates, the bacteria Bacillus subtilis utilized the pesticides effectively and showed maximum growth. The growth of the three pesticides degrading isolates Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis was assessed in Minimal salt broth containing 25 ppm of pesticides at different temperature levels (25 °C, 30 °C, 35 °C, 40 °C, 45 °C, 50 °C & 55 °C) and pH levels (pH 4, pH 5, pH 6, pH 7 & pH 8) and carbon sources (Lactose, Dextrose, Fructose, Mannose & Galactose) and nitrogen sources Peptone, Yeast extract, Beef extract, Malt extract and Casein respectively. The maximum growth rate of bacteria was recorded at 35 °C and pH 6. The maximum growth of bacteria was in the presence of Dextrose followed by Fructose, Galactose and Mannose. The least growth was recorded in Lactose broth culture. The maximum growth of bacteria was in the presence of Malt extract followed by Peptone, Yeast extract and Casein. The least growth was recorded in Beef extract broth culture. The bacterial isolates showed maximum growth in the Minimal salt broth containing Profenofos followed by Metribuzin
33
Tamilselvan, C., S. John Joseph, G. Mugunthan, A. Sathish Kumar e S. Syed Musthaq Ahamed. "Biological Degradation of Metribuzin and Profenofos by some Efficient Bacterial Isolates". International Letters of Natural Sciences 14 (29 de abril de 2014): 26–39. http://dx.doi.org/10.56431/p-67z2iz.
Texto completo da fonteResumo:
The soil sample was collected from the paddy field of Sriperumbudur, Tamilnadu which is having a history of repeated pesticide applications. The isolation of efficient pesticide degrading bacteria was identified as Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis. The growth of the three pesticide degrading isolates was assessed in Minimal salt broth containing 25 ppm of pesticides. Two popularly used pesticides Metribuzin and Profenofos were selected for this study. Among the three bacterial isolates, the bacteria Bacillus subtilis utilized the pesticides effectively and showed maximum growth. The growth of the three pesticides degrading isolates Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis was assessed in Minimal salt broth containing 25 ppm of pesticides at different temperature levels (25 °C, 30 °C, 35 °C, 40 °C, 45 °C, 50 °C & 55 °C) and pH levels (pH 4, pH 5, pH 6, pH 7 & pH 8) and carbon sources (Lactose, Dextrose, Fructose, Mannose & Galactose) and nitrogen sources Peptone, Yeast extract, Beef extract, Malt extract and Casein respectively. The maximum growth rate of bacteria was recorded at 35 °C and pH 6. The maximum growth of bacteria was in the presence of Dextrose followed by Fructose, Galactose and Mannose. The least growth was recorded in Lactose broth culture. The maximum growth of bacteria was in the presence of Malt extract followed by Peptone, Yeast extract and Casein. The least growth was recorded in Beef extract broth culture. The bacterial isolates showed maximum growth in the Minimal salt broth containing Profenofos followed by Metribuzin
34
Betts, Richard A., Chris D. Jones, Jeff R. Knight, Ralph F. Keeling, John J. Kennedy, Andrew J. Wiltshire, Robbie M. Andrew e Luiz E. O. C. Aragão. "A successful prediction of the record CO 2 rise associated with the 2015/2016 El Niño". Philosophical Transactions of the Royal Society B: Biological Sciences 373, n.º 1760 (8 de outubro de 2018): 20170301. http://dx.doi.org/10.1098/rstb.2017.0301.
Texto completo da fonteResumo:
In early 2016, we predicted that the annual rise in carbon dioxide concentration at Mauna Loa would be the largest on record. Our forecast used a statistical relationship between observed and forecast sea surface temperatures in the Niño 3.4 region and the annual CO 2 rise. Here, we provide a formal verification of that forecast. The observed rise of 3.4 ppm relative to 2015 was within the forecast range of 3.15 ± 0.53 ppm, so the prediction was successful. A global terrestrial biosphere model supports the expectation that the El Niño weakened the tropical land carbon sink. We estimate that the El Niño contributed approximately 25% to the record rise in CO 2 , with 75% due to anthropogenic emissions. The 2015/2016 CO 2 rise was greater than that following the previous large El Niño in 1997/1998, because anthropogenic emissions had increased. We had also correctly predicted that 2016 would be the first year with monthly mean CO 2 above 400 ppm all year round. We now estimate that atmospheric CO 2 at Mauna Loa would have remained above 400 ppm all year round in 2016 even if the El Niño had not occurred, contrary to our previous expectations based on a simple extrapolation of previous trends. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.
35
Segschneider, J., A. Beitsch, C. Timmreck, V. Brovkin, T. Ilyina, J. Jungclaus, S. J. Lorenz, K. D. Six e D. Zanchettin. "Impact of an extremely large magnitude volcanic eruption on the global climate and carbon cycle estimated from ensemble Earth System Model simulations". Biogeosciences Discussions 9, n.º 7 (18 de julho de 2012): 8693–732. http://dx.doi.org/10.5194/bgd-9-8693-2012.
Texto completo da fonteResumo:
Abstract. The response of the global climate-carbon cycle system to an extremely large Northern Hemisphere mid latitude volcanic eruption is investigated using ensemble integrations with the comprehensive Earth System Model MPI-ESM. The model includes dynamical compartments of the atmosphere and ocean and interactive modules of the terrestrial biosphere as well as ocean biogeochemistry. The MPI-ESM was forced with anomalies of aerosol optical depth and effective radius of aerosol particles corresponding to a super eruption of the Yellowstone volcanic system. The model experiment consists of an ensemble of fifteen model integrations that are started at different pre-ENSO states of a contol experiment and run for 200 yr after the volcanic eruption. The climate response to the volcanic eruption is a maximum global monthly mean surface air temperature cooling of 3.8 K for the ensemble mean and from 3.3 K to 4.3 K for individual ensemble members. Atmospheric pCO2 decreases by a maximum of 5 ppm for the ensemble mean and by 3 ppm to 7 ppm for individual ensemble members approximately 6 yr after the eruption. The atmospheric carbon content only very slowly returns to near pre-eruption level at year 200 after the eruption. The ocean takes up carbon shortly after the eruption in response to the cooling, changed wind fields, and ice cover. This physics driven uptake is weakly counteracted by a reduction of the biological export production mainly in the tropical Pacific. The land vegetation pool shows a distinct loss of carbon in the initial years after the eruption which has not been present in simulations of smaller scale eruptions. The gain of the soil carbon pool determines the amplitude of the CO2 perturbation and the long term behaviour of the overall system: an initial gain caused by reduced soil respiration is followed by a rather slow return towards pre-eruption levels. During this phase, the ocean compensates partly for the reduced atmospheric carbon content in response to the land's gain. In summary, we find that the volcanic eruption has long lasting effects on the carbon cycle: after 200 yr, the ocean and the land carbon pools are still different from the pre-eruption state, and the land carbon pools (vegetation and soil) show some long lasting local anomalies that are only partly visible in the global signal.
36
Kožíšková, Jarmila, e Jana Goliáš. "Influence of ripening on the ethylene and carbon dioxide production during storage of plum fruits". Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 60, n.º 8 (2012): 133–40. http://dx.doi.org/10.11118/actaun201260080133.
Texto completo da fonteResumo:
The fruits of 13 plum cultivars were analysed at two different stages of maturity: first when they were ready for picking according to conventional commercial criteria, and again after seven days of maturation at 20 °C in a normal oxygen atmosphere during shelf life. Firmness, soluble solids concentration (SSC), respiration rate and the production of ethylene were measured. In the period of over-ripening SSC increased, and no differences were found in relation to the cultivar. The fruits in this period were physiologically in a phase of reduced intensity of respiration, while production of ethylene increased and was associated with the earliness of the cultivar. Cultivars with a short vegetation period produce more ethylene while late-maturing cultivars have a low potential for ethylene production. Based on post-harvest changes in the tested quality factors, the late-ripening plum cultivars (cv.) ‘Jojo’, ‘Topend’, ‘President’, ‘Tophit’ and ‘Elena’ have higher storage potential. Changes in ethylene production in response to shelf life seem to play a regulatory role in fruit firmness. A high significant negative correlation was detected between levels of skin firmness and ethylene production.
37
P Kalaiselvi, RM Devi, E Parameswari, SP Sebastian, V Dayamani e T Ilakiya. "The ocean carbon pool: a vital component of the global carbon cycle". Journal of Agriculture and Ecology 17 (10 de novembro de 2023): 80–84. http://dx.doi.org/10.58628/jae-2317-314.
Texto completo da fonteResumo:
The global carbon cycle is an integral part of the Earth System. Of the land, atmosphere, and ocean components of the global carbon cycle that exchange carbon on the timescales of decades to centuries, the ocean contains more than 90% of carbon. The ocean carbon pool represents a critical component of the Earth's carbon cycle, playing a pivotal role in regulating atmospheric carbon dioxide (CO2) levels and influencing climate dynamics. The exponential increase of total anthropogenic CO2 emissions in the industrial era implies the ocean's uptake has increased exponentially, reaching 2.5 ± 0.6 Pg C yr-1 for 2009-2018. Without the ocean and land sinks, atmospheric CO2 levels would be close to 600 ppm. The ocean carbon pool comprises dissolved inorganic carbon (DIC), organic carbon, and particulate organic matter, collectively responsible for the sequestration and release of carbon into the atmosphere. Phytoplankton, the microscopic marine plants, play a fundamental role in the oceanic carbon cycle by photosynthesizing and fixing atmospheric CO2 into organic matter. This organic matter can be transferred to the deep ocean through the biological pump, further contributing to the storage of carbon in the form of sinking particles. The bulk of the global ocean margin represents a carbon sink of ~0.1-0.2 Pg C. Oceanic processes, such as ocean circulation and upwelling, help redistribute carbon from surface waters to the deep ocean. The solubility pump, which is driven by changes in temperature and salinity, also affects the solubility of CO2 in seawater. These natural processes work to mitigate the increase in atmospheric CO2 concentrations and help regulate global temperatures.
38
Lüdde, Hans Jürgen, Alba Jorge, Marko Horbatsch e Tom Kirchner. "Net Electron Capture in Collisions of Multiply Charged Projectiles with Biologically Relevant Molecules". Atoms 8, n.º 3 (17 de setembro de 2020): 59. http://dx.doi.org/10.3390/atoms8030059.
Texto completo da fonteResumo:
A model for the description of proton collisions from molecules composed of atoms such as hydrogen, carbon, nitrogen, oxygen and phosphorus (H, C, N, O, P) was recently extended to treat collisions with multiply charged ions with a focus on net ionization. Here we complement the work by focusing on net capture. The ion–atom collisions are computed using the two-center basis generator method. The atomic net capture cross sections are then used to assemble two models for ion–molecule collisions: An independent atom model (IAM) based on the Bragg additivity rule (labeled IAM-AR), and also the so-called pixel-counting method (IAM-PCM) which introduces dependence on the orientation of the molecule during impact. The IAM-PCM leads to significantly reduced capture cross sections relative to IAM-AR at low energies, since it takes into account the overlap of effective atomic cross sectional areas. We compare our results with available experimental and other theoretical data focusing on water vapor (H2O), methane (CH4) and uracil (C4H4N2O2). For the water molecule target we also provide results from a classical-trajectory Monte Carlo approach that includes dynamical screening effects on projectile and target. For small molecules dominated by a many-electron atom, such as carbon in methane or oxygen in water, we find a saturation phenomenon for higher projectile charges (q=3) and low energies, where the net capture cross section for the molecule is dominated by the net cross section for the many-electron atom, and the net capture cross section is not proportional to the total number of valence electrons.
39
Tiburu, Elvis K., Ali Salifu, Edmund O. Aidoo, Heidimarie N. A. Fleischer, Gloria Manu, Abu Yaya, Han Zhou e Johnson K. Efavi. "Formation of Chitosan Nanoparticles Using Deacetylated Chitin Isolated from Freshwater Algae and Locally Synthesized Zeolite A and their Influence on Cancer Cell Growth". Journal of Nano Research 48 (julho de 2017): 156–70. http://dx.doi.org/10.4028/www.scientific.net/jnanor.48.156.
Texto completo da fonteResumo:
This work reports the isolation and characterization of chitin from green algae using XRD, 13C CP/MAS NMR, FTIR and Microscopy. The XRD diffraction pattern confirmed orthorhombic structure of the crystalline polysaccharide, whereas the FTIR spectra revealed strong absorption bands at 896.9 cm-1 and 852 cm-1 typical of C–H axial and C–H equatorial vibrations within the anomeric center of the glucopyranosicyclic moiety. Another strong absorption band was observed at 1039.9 cm-1 and was assigned to C–O–C, C–O stretching bands. The purity and structure of the deacetylated chitin was confirmed using 13C NMR, showing overlapping peaks around 65 ppm assigned to both the sugar carbon at C2, as well as a methylene carbon at C6. An intense peak at 74 ppm is assigned to C3 and C5 with corresponding resonances at 81 and 104 ppm assigned to C4 and C1 respectively. Zeolite/Chitosan nanocomposites were synthesized by ionic cross-linking of chitosan with sodium tripolyphosphate. Chitosan nanoparticles and LTA of different concentrations were incubated with HeLa cancer cells to investigate their cytotoxicity effects. The exposure of the cells to chitosan nanoparticles resulted in a decreased in cell growth and this was concentration-dependent. Our results revealed the utility of locally available materials to produce new biodegradable nanoparticles to investigate their biological nanotoxicity.
40
Zaehle, Sönke, Chris D. Jones, Benjamin Houlton, Jean-Francois Lamarque e Eddy Robertson. "Nitrogen Availability Reduces CMIP5 Projections of Twenty-First-Century Land Carbon Uptake*". Journal of Climate 28, n.º 6 (13 de março de 2015): 2494–511. http://dx.doi.org/10.1175/jcli-d-13-00776.1.
Texto completo da fonteResumo:
Abstract Coupled carbon cycle–climate models in the Coupled Model Intercomparison Project, phase 5 (CMIP5), Earth system model ensemble simulate the effects of changes in anthropogenic fossil-fuel emissions and ensuing climatic changes on the global carbon (C) balance but largely ignore the consequences of widespread terrestrial nitrogen (N) limitation. Based on plausible ranges of terrestrial C:N stoichiometry, this study investigates whether the terrestrial C sequestration projections of nine CMIP5 models for four representative concentration pathways (RCPs) are consistent with estimates of N supply from increased biological fixation, atmospheric deposition, and reduced ecosystem N losses. Discrepancies between the timing and places of N demand and supply indicated increases in terrestrial N implicit to the projections of all nine CMIP5 models under all scenarios that are larger than the estimated N supply. Omitting N constraints leads to an overestimation of land C sequestration in these models between the years 1860 and 2100 by between 97 Pg C (69–252 Pg C; RCP 2.6) and 150 Pg C (57–323 Pg C; RCP 8.5), with a large spread across models. The CMIP5 models overestimated the average 2006–2100 fossil-fuel emissions required to keep atmospheric CO2 levels on the trajectories described in the RCP scenarios by between 0.6 Pg C yr−1 (0.4–2.2 Pg C yr−1; RCP 2.6) and 1.2 Pg C yr−1 (0.5–3.3 Pg C yr−1; RCP 8.5). If unabated, reduced land C sequestration would enhance CO2 accumulation in the ocean and atmosphere, increasing atmospheric CO2 burden by 26 ppm (16–88 ppm; RCP 2.6) to 61 ppm (29–147 ppm; RCP 8.5) by the year 2100.
41
Segschneider, J., A. Beitsch, C. Timmreck, V. Brovkin, T. Ilyina, J. Jungclaus, S. J. Lorenz, K. D. Six e D. Zanchettin. "Impact of an extremely large magnitude volcanic eruption on the global climate and carbon cycle estimated from ensemble Earth System Model simulations". Biogeosciences 10, n.º 2 (1 de fevereiro de 2013): 669–87. http://dx.doi.org/10.5194/bg-10-669-2013.
Texto completo da fonteResumo:
Abstract. The response of the global climate-carbon cycle system to an extremely large Northern Hemisphere mid-latitude volcanic eruption is investigated using ensemble integrations with the comprehensive Earth System Model MPI-ESM. The model includes dynamical compartments of the atmosphere and ocean and interactive modules of the terrestrial biosphere as well as ocean biogeochemistry. The MPI-ESM was forced with anomalies of aerosol optical depth and effective radius of aerosol particles corresponding to a super eruption of the Yellowstone volcanic system. The model experiment consists of an ensemble of fifteen model integrations that are started at different pre-ENSO states of a control experiment and run for 200 years after the volcanic eruption. The climate response to the volcanic eruption is a maximum global monthly mean surface air temperature cooling of 3.8 K for the ensemble mean and from 3.3 K to 4.3 K for individual ensemble members. Atmospheric pCO2 decreases by a maximum of 5 ppm for the ensemble mean and by 3 ppm to 7 ppm for individual ensemble members approximately 6 years after the eruption. The atmospheric carbon content only very slowly returns to near pre-eruption level at year 200 after the eruption. The ocean takes up carbon shortly after the eruption in response to the cooling, changed wind fields and ice cover. This physics-driven uptake is weakly counteracted by a reduction of the biological export production mainly in the tropical Pacific. The land vegetation pool shows a decrease by 4 GtC due to reduced short-wave radiation that has not been present in a smaller scale eruption. The gain of the soil carbon pool determines the amplitude of the CO2 perturbation and the long-term behaviour of the overall system: an initial gain caused by reduced soil respiration is followed by a rather slow return towards pre-eruption levels. During this phase, the ocean compensates partly for the reduced atmospheric carbon content in response to the land's gain. In summary, we find that the volcanic eruption has long-lasting effects on the carbon cycle: After 200 years, the ocean and the land carbon pools are still different from the pre-eruption state by 3 GtC and 4 GtC, respectively, and the land carbon pools (vegetation and soil) show some long-lasting local anomalies that are only partly visible in the global signal.
42
RAMALHO, TEODORICO C., ELAINE F. F. DA CUNHA e RICARDO BICCA DE ALENCASTRO. "THEORETICAL STUDY OF ADIABATIC AND VERTICAL ELECTRON AFFINITY OF RADIOSENSITIZERS IN SOLUTION PART 2: ANALOGUES OF TIRAPAZAMINE". Journal of Theoretical and Computational Chemistry 03, n.º 01 (março de 2004): 1–13. http://dx.doi.org/10.1142/s0219633604000866.
Texto completo da fonteResumo:
Tirapazamine is a radiosensitizer, whose biological activity is associated to its electron affinity (EA). The electron affinity can be divided in two main processes: Vertical and Adiabatic. In this work, we calculated the EAs of nitroimidazoles (Fig. 2) using HF and DFT methods and evaluated solvent effects (water and carbon tetrachloride) on EAs. For water, we combined the Polarized Continuum Model (PCM) and free energy perturbation (Finite Difference Thermodynamic Integration, FDTI) methods. For carbon tetrachloride, we used the FDTI method. The values of adiabatic EA obtained are in agreement with experimental data (deviations of 13.25 meV). The vertical EA were calculated according to Cederbaum's Outer Valence Green Function (OVGF) method. This study, which relays on theoretical aspects of free energy calculations on charged molecules in solution, could be helpful in the rational design of new and more selective bioreductive anticancer drugs.
43
Kulchar, Rachel J., Yusuke Kakiuchi, Vania Sanchez-Gamarra, Jie Deng e Francis Mante. "Abstract 6035: Fluoride effects on thermal properties of irradiated dentin and enamel". Cancer Research 84, n.º 6_Supplement (22 de março de 2024): 6035. http://dx.doi.org/10.1158/1538-7445.am2024-6035.
Texto completo da fonteResumo:
Abstract Aim: Radiation therapy to treat oral cancer introduces various harms, including decreased hardness of dentin and enamel. Fluoride treatments, including silver diamine fluoride (SDF), have been used as a tool to combat these harms, but its influences on the thermal properties of dentin and enamel prior to and after radiation therapy are not well understood. Thus, this study analyzed how SDF influences the thermal stability of dentin and enamel that has been exposed to radiation therapy intended for head and neck cancer patients. Methods: Forty human posterior teeth were collected, cleaned of debris and soft tissue, and then mounted into acrylic resin molds. The teeth were divided into two equal groups, with one group being the control (no treatment) and the other group receiving SDF treatment. Using an X-Rad 320ix biological irradiator, all teeth were subjected to two grays of radiation therapy every day for six weeks. Afterwards, the dentin and enamel were pulverized a SPEX freezer mill. Samples were heated in a NETZSCH Thermal Analysis instrument, and the amount of carbon dioxide and water released was determined. All teeth were heated to 1429 °C from room temperature. Results: The SDF-treated dentin released the most carbon dioxide (49,611.82 ppm/mg), followed by irradiated dentin (47,672.76 ppm/mg) and untreated dentin (45,249.66 ppm/mg). In contrast, the SDF-treated enamel released less carbon dioxide (7,367.62 ppm/mg) than the control enamel (8,172.01 ppm/mg). The pattern of release of water was different from that of carbon dioxide. The control dentin group released the most water (45.56 ppt/mg), followed by the SDF-treated (39.72 ppt/mg) and irradiated dentin (23.51 ppt/mg). Similarly, the control enamel also released the highest amount of water (0.83 ppt/mg), as well as the highest amount of carbon dioxide. The SDF-treated enamel released around 65% of the water compared to the control enamel group (0.54 ppt/mg). Furthermore, the irradiated dentin had the largest heat reversal temperatures for carbon dioxide (85.19 °C) and water (86.57 °C). Conclusions: The impacts of SDF treatment and radiation vary between dentin and enamel. Comparatively, dentin has a higher content of combustible material than enamel. Radiation treatment reduces the water content of both enamel and dentin, which may make teeth more susceptible to fracture. Therefore, regular dental check-ups and frequent fluoride treatment to increase the strength of the teeth are recommended for patients undergoing radiation therapy. Citation Format: Rachel J. Kulchar, Yusuke Kakiuchi, Vania Sanchez-Gamarra, Jie Deng, Francis Mante. Fluoride effects on thermal properties of irradiated dentin and enamel [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6035.
44
Geyer, Kevin M., Cristina D. Takacs-Vesbach, Michael N. Gooseff e John E. Barrett. "Primary productivity as a control over soil microbial diversity along environmental gradients in a polar desert ecosystem". PeerJ 5 (25 de julho de 2017): e3377. http://dx.doi.org/10.7717/peerj.3377.
Texto completo da fonteResumo:
Primary production is the fundamental source of energy to foodwebs and ecosystems, and is thus an important constraint on soil communities. This coupling is particularly evident in polar terrestrial ecosystems where biological diversity and activity is tightly constrained by edaphic gradients of productivity (e.g., soil moisture, organic carbon availability) and geochemical severity (e.g., pH, electrical conductivity). In the McMurdo Dry Valleys of Antarctica, environmental gradients determine numerous properties of soil communities and yet relatively few estimates of gross or net primary productivity (GPP, NPP) exist for this region. Here we describe a survey utilizing pulse amplitude modulation (PAM) fluorometry to estimate rates of GPP across a broad environmental gradient along with belowground microbial diversity and decomposition. PAM estimates of GPP ranged from an average of 0.27 μmol O2/m2/s in the most arid soils to an average of 6.97 μmol O2/m2/s in the most productive soils, the latter equivalent to 217 g C/m2/y in annual NPP assuming a 60 day growing season. A diversity index of four carbon-acquiring enzyme activities also increased with soil productivity, suggesting that the diversity of organic substrates in mesic environments may be an additional driver of microbial diversity. Overall, soil productivity was a stronger predictor of microbial diversity and enzymatic activity than any estimate of geochemical severity. These results highlight the fundamental role of environmental gradients to control community diversity and the dynamics of ecosystem-scale carbon pools in arid systems.
45
PISAREK, IZABELLA, e KATARZYNA GRATA. "The Influence of the Organic Matter of Sewage Sediments on Biological Activity of Microorganisms which Carry Out the Transformations of Carbon and Nitrogen Compounds". Polish Journal of Microbiology 62, n.º 4 (2013): 445–52. http://dx.doi.org/10.33073/pjm-2013-061.
Texto completo da fonteResumo:
Soil microorganisms play an important role in the organic matter transformation process. The soil microorganisms also are in symbiotic relationship with plants. At the same time, soil microorganisms are sensitive to both anthropogenic and natural habitat changes. Particular characteristics of organic matter (the C:N relation, pH, the content the content of assimilated nutrients, the xenobiotics etc.) modify the biotic conditions of the soils. This particularly concerns the microorganisms which carry out the changes in the mineral and organic nitrogen compounds and the transformation of the external organic matter. The first aim of this work was to assess the influence of the sewage sediments and the manure on the phytosanitary potential of the soil environment. The second aim of this article was to estimate the number and activity of microorganisms which carry out the transformation of carbon and nitrogen compounds. This work showed the stimulating effect of the external organic matter both on the number and on the activity of most of the physiological groups. The manure mainly stimulated ammonificators, amylolitic microorganisms and Azotobacter sp. The sewage sediments mainly stimulated ammonificators, nitrifiers of I phase and cellulolytic microorganisms. The statistically significant impact of the physio-chemical soil habitat on the biological activity of the analyzed groups of microbes was also noted.
46
Flowers, B. A., H. H. Powers, M. K. Dubey e N. G. McDowell. "Field inter-comparison of two high-accuracy fast-response spectroscopic sensors of carbon dioxide". Atmospheric Measurement Techniques Discussions 4, n.º 5 (15 de setembro de 2011): 5837–55. http://dx.doi.org/10.5194/amtd-4-5837-2011.
Texto completo da fonteResumo:
Abstract. Tunable diode laser absorption (TDL) and cavity ring-down spectroscopic (CRDS) sensors for atmospheric carbon dioxide were co-deployed during summer and fall of 2010 in the field at Los Alamos National Laboratory. Both sensors were characterized for accuracy and precision for ambient carbon dioxide measurements at ground level and are compared using both laboratory and atmospheric data. After a four point laboratory cross calibration, the mean [12C16O2]TDL = 392.05 ± 8.92 ppm and [12C16O2]CRDS' = 392.22 ± 9.05 ppm between 29 July and 16 August 2010 (mean difference = 0.04 ± 0.04 ppm). The slope of the cross-calibrated linear regression analysis between the two sensors is 1.000. The CRDS sensor is capable of measuring ambient [12C16O2] to a relative precision of 23 ppb Hz−1/2 for a 1-min time constant and this decreases to 6.5 ppb Hz−1/2 for a 58-min time constant. At one and 58-min time constants, the TDL exhibits precisions of 29 ppb Hz−1/2 and 53 ppb Hz−1/2. The CRDS is compact, fast, and stable. The TDL is larger and requires frequent calibrations that limit its time resolution. Field observations show that 1-min averaged data measured by the two instruments agree almost perfectly, for the 19-day period the CRDS/TDL ratio is a Gaussian distribution at x0 = 1.000 ± 3.38 × 10−5. The sensors also exhibit consistent hourly averaged diurnal values underscoring the interplay of biological, anthropogenic, and transport processes regulating CO2 at the site.
47
Yamamoto, Akitomo, Ayako Abe-Ouchi, Rumi Ohgaito, Akinori Ito e Akira Oka. "Glacial CO<sub>2</sub> decrease and deep-water deoxygenation by iron fertilization from glaciogenic dust". Climate of the Past 15, n.º 3 (4 de junho de 2019): 981–96. http://dx.doi.org/10.5194/cp-15-981-2019.
Texto completo da fonteResumo:
Abstract. Increased accumulation of respired carbon in the deep ocean associated with enhanced efficiency of the biological carbon pump is thought to be a key mechanism of glacial CO2 drawdown. Despite greater oxygen solubility due to seawater cooling, recent quantitative and qualitative proxy data show glacial deep-water deoxygenation, reflecting increased respired carbon accumulation. However, the mechanisms of deep-water deoxygenation and contribution from the biological pump to glacial CO2 drawdown have remained unclear. In this study, we report the significance of iron fertilization from glaciogenic dust in glacial CO2 decrease and deep-water deoxygenation using our numerical simulation, which successfully reproduces the magnitude and large-scale pattern of the observed oxygen changes from the present to the Last Glacial Maximum. Sensitivity experiments show that physical changes contribute to only one-half of all glacial deep deoxygenation, whereas the other one-half is driven by iron fertilization and an increase in the whole ocean nutrient inventory. We find that iron input from glaciogenic dust with higher iron solubility is the most significant factor in enhancing the biological pump and deep-water deoxygenation. Glacial deep-water deoxygenation expands the hypoxic waters in the deep Pacific and Indian oceans. The simulated global volume of hypoxic waters is nearly double the present value, suggesting that glacial deep water was a more severe environment for benthic animals than that of the modern oceans. Our model underestimates the deoxygenation in the deep Southern Ocean because of enhanced ventilation. The model–proxy comparison of oxygen change suggests that a stratified Southern Ocean is required for reproducing the oxygen decrease in the deep Southern Ocean. Iron fertilization and a global nutrient increase contribute to a decrease in glacial CO2 of more than 30 ppm, which is supported by the model–proxy agreement of oxygen change. Our findings confirm the significance of the biological pump in glacial CO2 drawdown and deoxygenation.
48
Indis, Nadhifah Al, Nadiyah Nur Haliza, Ajun Prayitno e Nunuk Helilusiatiningsih. "ANALISIS KADAR AIR, KARBON ORGANIK, FOSFOR, NITROGEN, KALIUM, pH DAN TEKSTUR PADA CONTOH TANAH DI LABORATORIUM TANAH - BPTP JAWA TIMUR". Agrika 16, n.º 2 (30 de novembro de 2022): 106. http://dx.doi.org/10.31328/ja.v16i2.4025.
Texto completo da fonteResumo:
ABSTRAKAnalisis tanah merupakan kegiatan berskala laboratorium yang bertujuan mengetahui serta menetapkan kualitas atau kesuburan tanah. Kualitas dan kesuburan tanah dipengaruhi oleh sifat-sifat fisika, kimia, dan biologi. Penelitian ini menguji beberapa parameter fisika dan kimia, di antaranya adalah kadar air, karbon organik, fosfor, nitrogen, kalium, pH, dan tekstur tanah. Parameter biologi tanah, yaitu jumlah mikroorganisme di dalam tanah, tidak diukur pada penelitian ini. Hal ini dikarenakan berdasarkan hasil penelitian sebelumnya kadar C-organik berbanding lurus dengan jumlah mikroorganisme tanah. Contoh tanah diperoleh dari Kota Batu Jawa Timur pada bulan Februari-Mei 2022. Penelitian dilakukan di Laboratorium Tanah BPTP Jawa Timur dengan menggunakan metode analisis sebagai berikut: gravimetri, spektrofotometri UV-Vis, Kjeldahl, perkolasi, atomic absorption spectroscopy (AAS), dan hydrometer. Hasil analisis contoh tanah dengan kode 66, 67, dan 115, berturut-turut adalah: kadar air 11,65%; 6,62%; dan 8,25%; karbon organik 0,95% (rendah), 1,43% (rendah) dan 0,93% (rendah); fosfor 12,69 ppm (sedang), 6,00 ppm (rendah) dan 34,75 ppm (tinggi); nitrogen 0,15% (rendah), 0,17% (rendah) dan 0,13% (rendah); kalium 0,36 cmol(+)/kg (rendah), 0,54 cmol (+)/kg (sedang), dan 0,66 cmol (+)/kg (tinggi); pH 4,6 (masam), 5,1 (masam), dan 5,5 (masam); tekstur liat, lempung berliat, dan liat. Hasil analisis contoh tanah tidak dikorelasikan dengan pertumbuhan tanaman, karena setiap jenis tanaman memiliki kondisi yang berbeda-beda. Secara umum hasil analisis tanah angka yang rendah, sehingga perlu dilakukan pemupukan secara berkala pada tanah tersebut, baik menggunakan pupuk organik ataupun campuran antara pupuk organik dan pupuk kimia, dengan dosis yang sesuai dengan kebutuhan tanaman. ABSTRACTSoil analysis is a laboratory-scale activity that aims to knows and determine the quality and fertility of soil. Soil quality and fertility are influenced by physical, chemical, and biological properties. This study tested several physical and chemical parameters, including water content, organic carbon, phosphorus, nitrogen, potassium, pH, and soil texture. Soil biological parameters, namely the number of microorganisms in the soil, were not measured in this study, because based on the results of previous studies, the content of organic carbon was directly proportional to the amount of soil microorganisms. Soil samples were taken from Batu Regency, East Java, from February to Mei 2022. This research was conducted at Soil Laboratory – BPTP East Java, using the following analytical methods: gravimetric, UV-Vis spectrophotometry, Kjeldahl, percolation, atomic absorption spectroscopy (AAS), and hydrometer. The results of analysis soil samples in this research with codes 66, 67, and 115, respectively were: water content 11.65%; 6.62%; and 8.25%; organic carbon 0.95% (low), 1.43% (low) and 0.93% (low); phosphorus 12.69 ppm (medium), 6.00 ppm (low) and 34.75 ppm (high); nitrogen 0.15% (low), 0.17% (low) and 0.13% (low); potassium 0.36 cmol(+)/kg (low), 0.54 cmol(+)/kg (moderate), and 0.66 cmol(+)/kg (high); pH 4.6 (sour), 5.1 (sour), and 5.5 (sour); soil textures are clay, loamy clay, and clay. The results of soil sample analysis in this research were not correlated with plant growth, because in every plant had a different conditions.
49
Hewett, Peter W., Takeshi Fujisawa, Samir Sissaoui, Meng Cai, Geraldine Gueron, Bahjat Al-Ani, Melissa Cudmore et al. "Carbon monoxide inhibits sprouting angiogenesis and vascular endothelial growth factor receptor-2 phosphorylation". Thrombosis and Haemostasis 113, n.º 02 (março de 2015): 329–37. http://dx.doi.org/10.1160/th14-01-0002.
Texto completo da fonteResumo:
SummaryCarbon monoxide (CO) is a gaseous autacoid known to positively regulate vascular tone; however, its role in angiogenesis is unknown. The aim of this study was to investigate the effect of CO on angiogenesis and vascular endothelial growth factor (VEGF) receptor-2 phosphorylation. Human umbilical vein endothelial cells (HUVECs) were cultured on growth factor-reduced Matrigel and treated with a CO-releasing molecule (CORM-2) or exposed to CO gas (250 ppm). Here, we report the surprising finding that exposure to CO inhibits vascular endothelial growth factor (VEGF)-induced endothelial cell actin reorganisation, cell proliferation, migration and capillary-like tube formation. Similarly, CO suppressed VEGF-mediated phosphorylation of VEGFR-2 at tyrosine residue 1175 and 1214 and basic fibroblast growth factor- (FGF-2) and VEGF-mediated Akt phosphorylation. Consistent with these data, mice exposed to 250 ppm CO (1h/day for 14 days) exhibited a marked decrease in FGF-2-induced Matrigel plug angiogenesis (p<0.05). These data establish a new biological function for CO in angiogenesis and point to a potential therapeutic use for CO as an anti-angiogenic agent in tumour suppression.
50
Stefanova, Assia, Pichaya In-na, Gary Stephen Caldwell, Ben Bridgens e Rachel Armstrong. "Photosynthetic textile biocomposites: Using laboratory testing and digital fabrication to develop flexible living building materials". Science and Engineering of Composite Materials 28, n.º 1 (1 de janeiro de 2021): 223–36. http://dx.doi.org/10.1515/secm-2021-0023.
Texto completo da fonteResumo:
Abstract Urban development and the construction industry account for a considerable proportion of global carbon dioxide (CO2) emissions. Emerging biological materials, such as those proposed in this paper, seek to utilize the metabolic functions of living microorganisms to reduce some of the negative impacts of humans on the environment. The material explorations demonstrated in this paper propose a living photosynthetic carbon capture textile for the built environment. We demonstrate making practices that integrate living microorganisms within experimental methods of digital fabrication; specifically, harnessing photosynthetic microalgae that feed on waste and are capable of sequestering CO2 from internal building settings. These new biocomposites incorporate flexible textile substrates, i.e. cotton, hessian, polyester, and canvas, which provide a range of algae laden matrices that continue to develop and change during the useful part of the material’s lifecycle. This paper explores biological 3D printing fabrication processes and studies the development of mixtures that are compatible with the fabrication method and support microalgae (Chlorella vulgaris) metabolic processes. A range of incubation methods are assessed, highlighting the need for a support environment. The biocomposites’ performance is tested using imaging pulse amplitude modulation fluorometry (Imaging-PAM) to investigate changes in microalgae chlorophyll fluorescence over a 14 day period.