The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Bhavik R. Bakshi - One of the best experts on this subject based on the ideXlab platform.
-
accounting for emissions and sinks from the Biogeochemical Cycle of carbon in the u s economic input output model
Journal of Industrial Ecology, 2014Co-Authors: Shweta Singh, Bhavik R. BakshiAbstract:Biogeochemical Cycles are essential ecosystem services that continue to degrade as a result of human activities, but are not fully considered in efforts toward sustainable engineering. This article develops a model that integrates the carbon Cycle with economic activities in the 2002 U.S. economy. Data about the carbon Cycle, including emissions and sequestration flows, is obtained from the greenhouse gas inventory of the U.S. Environmental Protection Agency. Economic activities are captured by the economic input-output model available from the Bureau of Economic Analysis. The resulting model is more comprehensive in its accounting for the carbon Cycle than existing methods for carbon footprint (CF) calculations. Examples of unique flows in this model include the effect of land-use and land-cover change on carbon dioxide flow within the U.S. national boundary, carbon sequestration in urban trees, and emissions resulting from liming. This model is used to gain unique insight into the carbon profile of U.S. economic sectors by providing the life Cycle emissions and sequestration in each sector. Such insight may be used to support policies, manage supply chains, and be used for more comprehensive CF calculations.
-
accounting for emissions and sinks from the Biogeochemical Cycle of carbon in the u s economic input output model
Journal of Industrial Ecology, 2014Co-Authors: Shweta Singh, Bhavik R. BakshiAbstract:type="main"> Biogeochemical Cycles are essential ecosystem services that continue to degrade as a result of human activities, but are not fully considered in efforts toward sustainable engineering. This article develops a model that integrates the carbon Cycle with economic activities in the 2002 U.S. economy. Data about the carbon Cycle, including emissions and sequestration flows, is obtained from the greenhouse gas inventory of the U.S. Environmental Protection Agency. Economic activities are captured by the economic input-output model available from the Bureau of Economic Analysis. The resulting model is more comprehensive in its accounting for the carbon Cycle than existing methods for carbon footprint (CF) calculations. Examples of unique flows in this model include the effect of land-use and land-cover change on carbon dioxide flow within the U.S. national boundary, carbon sequestration in urban trees, and emissions resulting from liming. This model is used to gain unique insight into the carbon profile of U.S. economic sectors by providing the life Cycle emissions and sequestration in each sector. Such insight may be used to support policies, manage supply chains, and be used for more comprehensive CF calculations.
-
Accounting for the Biogeochemical Cycle of nitrogen in input-output life Cycle assessment
Environmental Science and Technology, 2013Co-Authors: Shweta Singh, Bhavik R. BakshiAbstract:Nitrogen is indispensable for sustaining human activities through its role in the production of food, animal feed, and synthetic chemicals. This has encouraged significant anthropogenic mobilization of reactive nitrogen and its emissions into the environment resulting in severe disruption of the nitrogen Cycle. This paper incorporates the Biogeochemical Cycle of nitrogen into the 2002 input-output model of the U.S. economy. Due to the complexity of this Cycle, this work proposes a unique classification of nitrogen flows to facilitate understanding of the interaction between economic activities and various flows in the nitrogen Cycle. The classification scheme distinguishes between the mobilization of inert nitrogen into its reactive form, use of nitrogen in various products, and nitrogen losses to the environment. The resulting inventory and model of the US economy can help quantify the direct and indirect impacts or dependence of economic sectors on the nitrogen Cycle. This paper emphasizes the need for methods to manage the N Cycle that focus not just on N losses, which has been the norm until now, but also include other N flows for a more comprehensive view and balanced decisions. Insight into the N profile of various sectors of the 2002 U.S. economy is presented, and the inventory can also be used for LCA or Hybrid LCA of various products. The resulting model is incorporated in the approach of Ecologically-Based LCA and available online.
Jorge Eduardo Marcovecchio - One of the best experts on this subject based on the ideXlab platform.
-
silica content in soil solution and its relation with phytolith weathering and silica Biogeochemical Cycle in typical argiudolls of the pampean plain argentina a preliminary study
Journal of Soils and Sediments, 2010Co-Authors: Natalia Borrelli, Margarita Luisa Osterrieth, Maria Fernanda Alvarez, Jorge Eduardo MarcovecchioAbstract:Little is known on the silica Biogeochemical Cycle in terrestrial environments. The aim of this work is to assess phytolith’s role on the Biogeochemical Cycle of Si in Typical Argiudolls under different vegetation of the Pampean Plain, Argentina. The work has been developed in three plots with different vegetal cover: grasses and shelter-belt plantations of Acacia melanoxylon–Celtis tala and Eucalyptus globulus–C. tala. The heavy liquid separation in the soil samples was realized with sodium polytungstate. The silica concentration of the soil solution and groundwaters was determined by UV-VIS spectrophotometry. Acacia and eucalyptus do not produce phytoliths; instead, Dactylis glomerata (grass) is a silica-accumulating species, and their phytolith assemblage is composed basically by oblong and crenate, smooth elongate, rectangular and prickles within isolated phytoliths, and smooth long cells articulated. Phytolith content in soils decreases with depth. Total stock of phytoliths represents 5.9 to 12.9 wt.% and is higher in the arboreal plots. In the A horizons, phytolith fraction represents about 59.6 × 103 to 103.5 × 103 kg/ha. In these horizons, 90.7–94.4% of the phytolith content constitutes the labile pool and 9.3–5.6% the stable pool. In the arboreal plots, SiO2 content in soil solution is higher (406–1,106 μmol/L) and decreases with depth, while in the grass plot, SiO2 content is lesser (421–777 μmol/L) and increases with depth; probably because of differences in the nutritional requirements and root design between vegetal species, therefore, in the different depth uptake from the soil solution. In groundwaters, silica content is very high (932 μmol/L). Phytoliths are very representative in Typical Argiudolls and show a great degree of weathering so they could be into account in the Biogeochemical studies since they could contribute with silica content in the soil solution, affecting the terrestrial silica Biogeochemical Cycle.
-
Calcium biominerals in typical Argiudolls from the Pampean Plain, Argentina: An approach to the understanding of their role within the calcium Biogeochemical Cycle
Quaternary International, 2007Co-Authors: Natalia Borrelli, Margarita Luisa Osterrieth, Fabricio Oyarbide, Jorge Eduardo MarcovecchioAbstract:Abstract The aims of this work are: (a) to describe the presence of calcium oxalate crystals from fungus and vegetal origin; (b) to determine the contribution from leaves; and (c) to assess the role they could play within the calcium Biogeochemical Cycle, in typical Argiudolls with different vegetal cover in the Pampean Plain, Argentina. Two plots with different vegetation were investigated: Acacia melanoxylon – Celtis tala and Eucalyptus globulus – Celtis tala . Leaves of the vegetation species were diaphanized and cleared with sodium hypochlorite (50%). Leaves and mycelial mats of the organic horizons were analyzed by optical, petrographic and scanning electronic microscopy. Soil samples were taken to determine particle size distribution and mineralogy, and to test calcium concentration by UV–vis spectrophotometry both in the soils’ saturated paste extract and in leached soil. Different morphologies of weddellite (i.e., primary nuclei, rosettes and druses) in the fungus hyphae were observed. Calcium oxalate crystal production was highest in A. melanoxylon and C. tala . Ca–Na feldspars are the only minerals that could release calcium to the system, but show no features of weathering. Calcium concentration in soil solution was higher in the Eucalyptus plot than in the Acacia, and it decreased from the organic to the mineral soil horizons. Fungus and vegetal calcium biomineral production, in addition to their higher susceptibility to weathering than minerals of inorganic origin, represents an important contribution to the calcium Biogeochemical Cycle.
Shweta Singh - One of the best experts on this subject based on the ideXlab platform.
-
accounting for emissions and sinks from the Biogeochemical Cycle of carbon in the u s economic input output model
Journal of Industrial Ecology, 2014Co-Authors: Shweta Singh, Bhavik R. BakshiAbstract:Biogeochemical Cycles are essential ecosystem services that continue to degrade as a result of human activities, but are not fully considered in efforts toward sustainable engineering. This article develops a model that integrates the carbon Cycle with economic activities in the 2002 U.S. economy. Data about the carbon Cycle, including emissions and sequestration flows, is obtained from the greenhouse gas inventory of the U.S. Environmental Protection Agency. Economic activities are captured by the economic input-output model available from the Bureau of Economic Analysis. The resulting model is more comprehensive in its accounting for the carbon Cycle than existing methods for carbon footprint (CF) calculations. Examples of unique flows in this model include the effect of land-use and land-cover change on carbon dioxide flow within the U.S. national boundary, carbon sequestration in urban trees, and emissions resulting from liming. This model is used to gain unique insight into the carbon profile of U.S. economic sectors by providing the life Cycle emissions and sequestration in each sector. Such insight may be used to support policies, manage supply chains, and be used for more comprehensive CF calculations.
-
accounting for emissions and sinks from the Biogeochemical Cycle of carbon in the u s economic input output model
Journal of Industrial Ecology, 2014Co-Authors: Shweta Singh, Bhavik R. BakshiAbstract:type="main"> Biogeochemical Cycles are essential ecosystem services that continue to degrade as a result of human activities, but are not fully considered in efforts toward sustainable engineering. This article develops a model that integrates the carbon Cycle with economic activities in the 2002 U.S. economy. Data about the carbon Cycle, including emissions and sequestration flows, is obtained from the greenhouse gas inventory of the U.S. Environmental Protection Agency. Economic activities are captured by the economic input-output model available from the Bureau of Economic Analysis. The resulting model is more comprehensive in its accounting for the carbon Cycle than existing methods for carbon footprint (CF) calculations. Examples of unique flows in this model include the effect of land-use and land-cover change on carbon dioxide flow within the U.S. national boundary, carbon sequestration in urban trees, and emissions resulting from liming. This model is used to gain unique insight into the carbon profile of U.S. economic sectors by providing the life Cycle emissions and sequestration in each sector. Such insight may be used to support policies, manage supply chains, and be used for more comprehensive CF calculations.
-
Accounting for the Biogeochemical Cycle of nitrogen in input-output life Cycle assessment
Environmental Science and Technology, 2013Co-Authors: Shweta Singh, Bhavik R. BakshiAbstract:Nitrogen is indispensable for sustaining human activities through its role in the production of food, animal feed, and synthetic chemicals. This has encouraged significant anthropogenic mobilization of reactive nitrogen and its emissions into the environment resulting in severe disruption of the nitrogen Cycle. This paper incorporates the Biogeochemical Cycle of nitrogen into the 2002 input-output model of the U.S. economy. Due to the complexity of this Cycle, this work proposes a unique classification of nitrogen flows to facilitate understanding of the interaction between economic activities and various flows in the nitrogen Cycle. The classification scheme distinguishes between the mobilization of inert nitrogen into its reactive form, use of nitrogen in various products, and nitrogen losses to the environment. The resulting inventory and model of the US economy can help quantify the direct and indirect impacts or dependence of economic sectors on the nitrogen Cycle. This paper emphasizes the need for methods to manage the N Cycle that focus not just on N losses, which has been the norm until now, but also include other N flows for a more comprehensive view and balanced decisions. Insight into the N profile of various sectors of the 2002 U.S. economy is presented, and the inventory can also be used for LCA or Hybrid LCA of various products. The resulting model is incorporated in the approach of Ecologically-Based LCA and available online.
Natalia Borrelli - One of the best experts on this subject based on the ideXlab platform.
-
silica Biogeochemical Cycle in temperate ecosystems of the pampean plain argentina
Journal of South American Earth Sciences, 2015Co-Authors: Margarita Osterrieth, Natalia Borrelli, Maria Fernanda Alvarez, Mariana Fernandez HonaineAbstract:Abstract Silicophytoliths were produced in the plant communities of the Pampean Plain during the Quaternary. The biogeochemistry of silicon is scarcely known in continental environments of Argentina. The aim of this work is to present a synthesis of: the plant production and the presence of silicophytoliths in soils with grasses, and its relationship with silica content in soil solution, soil matrix and groundwaters in temperate ecosystems of the Pampean Plain, Argentina. We quantified the content of silicophytoliths in representative grasses and soils of the area. Mineralochemical determinations of the soils' matrix were made. The concentration of silica was determined in soil solution and groundwaters. The silicophytoliths assemblages in plants let to differenciate subfamilies within Poaceae. In soils, silicophytoliths represent 40–5% of the total components, conforming a stock of 59–72 × 103 kg/ha in A horizons. The concentration of SiO2 in soil solution increases with depth (453–1243 μmol/L) in relation with plant communities, their nutritional requirements and root development. The average concentration of silica in groundwaters is 840 umol/L. In the studied soils, inorganic minerals and volcanic shards show no features of weathering. About 10–40% of silicophytoliths were taxonomically unidentified because of their weathering degrees. The matrix of the aggregates is made up by microaggregates composed of carbon and silicon. The weathering of silicophytoliths is a process that contributes to the formation of amorphous silica-rich matrix of the aggregates. So, silicophytoliths could play an important role in the silica Cycle being a sink and source of Si in soils and enriching soil solutions and groundwaters.
-
silica content in soil solution and its relation with phytolith weathering and silica Biogeochemical Cycle in typical argiudolls of the pampean plain argentina a preliminary study
Journal of Soils and Sediments, 2010Co-Authors: Natalia Borrelli, Margarita Luisa Osterrieth, Maria Fernanda Alvarez, Jorge Eduardo MarcovecchioAbstract:Little is known on the silica Biogeochemical Cycle in terrestrial environments. The aim of this work is to assess phytolith’s role on the Biogeochemical Cycle of Si in Typical Argiudolls under different vegetation of the Pampean Plain, Argentina. The work has been developed in three plots with different vegetal cover: grasses and shelter-belt plantations of Acacia melanoxylon–Celtis tala and Eucalyptus globulus–C. tala. The heavy liquid separation in the soil samples was realized with sodium polytungstate. The silica concentration of the soil solution and groundwaters was determined by UV-VIS spectrophotometry. Acacia and eucalyptus do not produce phytoliths; instead, Dactylis glomerata (grass) is a silica-accumulating species, and their phytolith assemblage is composed basically by oblong and crenate, smooth elongate, rectangular and prickles within isolated phytoliths, and smooth long cells articulated. Phytolith content in soils decreases with depth. Total stock of phytoliths represents 5.9 to 12.9 wt.% and is higher in the arboreal plots. In the A horizons, phytolith fraction represents about 59.6 × 103 to 103.5 × 103 kg/ha. In these horizons, 90.7–94.4% of the phytolith content constitutes the labile pool and 9.3–5.6% the stable pool. In the arboreal plots, SiO2 content in soil solution is higher (406–1,106 μmol/L) and decreases with depth, while in the grass plot, SiO2 content is lesser (421–777 μmol/L) and increases with depth; probably because of differences in the nutritional requirements and root design between vegetal species, therefore, in the different depth uptake from the soil solution. In groundwaters, silica content is very high (932 μmol/L). Phytoliths are very representative in Typical Argiudolls and show a great degree of weathering so they could be into account in the Biogeochemical studies since they could contribute with silica content in the soil solution, affecting the terrestrial silica Biogeochemical Cycle.
-
Calcium biominerals in typical Argiudolls from the Pampean Plain, Argentina: An approach to the understanding of their role within the calcium Biogeochemical Cycle
Quaternary International, 2007Co-Authors: Natalia Borrelli, Margarita Luisa Osterrieth, Fabricio Oyarbide, Jorge Eduardo MarcovecchioAbstract:Abstract The aims of this work are: (a) to describe the presence of calcium oxalate crystals from fungus and vegetal origin; (b) to determine the contribution from leaves; and (c) to assess the role they could play within the calcium Biogeochemical Cycle, in typical Argiudolls with different vegetal cover in the Pampean Plain, Argentina. Two plots with different vegetation were investigated: Acacia melanoxylon – Celtis tala and Eucalyptus globulus – Celtis tala . Leaves of the vegetation species were diaphanized and cleared with sodium hypochlorite (50%). Leaves and mycelial mats of the organic horizons were analyzed by optical, petrographic and scanning electronic microscopy. Soil samples were taken to determine particle size distribution and mineralogy, and to test calcium concentration by UV–vis spectrophotometry both in the soils’ saturated paste extract and in leached soil. Different morphologies of weddellite (i.e., primary nuclei, rosettes and druses) in the fungus hyphae were observed. Calcium oxalate crystal production was highest in A. melanoxylon and C. tala . Ca–Na feldspars are the only minerals that could release calcium to the system, but show no features of weathering. Calcium concentration in soil solution was higher in the Eucalyptus plot than in the Acacia, and it decreased from the organic to the mineral soil horizons. Fungus and vegetal calcium biomineral production, in addition to their higher susceptibility to weathering than minerals of inorganic origin, represents an important contribution to the calcium Biogeochemical Cycle.
Eiichi Tajika - One of the best experts on this subject based on the ideXlab platform.
-
conditions required for oceanic anoxia euxinia constraints from a one dimensional ocean Biogeochemical Cycle model
Earth and Planetary Science Letters, 2011Co-Authors: Kazumi Ozaki, Shigeo Tajima, Eiichi TajikaAbstract:article i nfo Widespread black shale depositional intervals termed oceanic anoxic events (OAEs) occurred repeatedly during the Phanerozoic Eon. Here we developed a new vertical one-dimensional ocean Biogeochemical Cycle model that involves several chemical reactions in an oxic-anoxic-sulfidic water column. To explore the theoretical constraints for global oceanic anoxia/euxinia quantitatively and systematically, we conducted sensitivity analyses of the proposed causal mechanisms, including elevated rates of riverine phosphorus (P) input, ocean stagnation, and lowered oxygen solubility due to climate warming. We gave special attention to the vertical chemical structure of the ocean and also to the characteristic behaviors of the marine P Cycle under anoxic conditions, because the relationship between the depth of anoxia and the benthic phosphorus flux could be important for the occurrence of oceanic anoxia/euxinia. Steady-state simulations indicated that (1) a decrease in ocean stagnation or oxygen solubility is not enough by itself to achieve widespread anoxia with the present reactive P river input rate, and (2) shallow water anoxia followed by massive P liberation from surface sediments can lead to widespread eutrophication and anoxia/euxinia. We conclude that elevated riverine flux of reactive P is the most important factor for triggering global anoxic events via a positive feedback loop among ocean anoxia, phosphorus regeneration, and surface biological productivity.
-
role of dissolved organic matter in the marine Biogeochemical Cycle studies using an ocean Biogeochemical general circulation model
Global Biogeochemical Cycles, 1997Co-Authors: Yasuhiro Yamanaka, Eiichi TajikaAbstract:A Biogeochemical general circulation model which includes production and consumption processes of dissolved organic matter (DOM) is developed. The semilabile and the refractory DOM are taken into account. The vertical distribution of the dissolved organic carbon (DOC) concentration and the Δ 14 C value obtained in our model compares well with the recent observations. It is found that the double DOC maximum zone (DDMZ) extends in the east-west direction in the equatorial Pacific. Case studies, which change the decay time and production ratio constant, show that the horizontal distribution of DOC in the surface layer can be reproduced only when the decay time of the semilabile DOM is about half a year. The semilabile DOM exists only above a depth of 400 m, and its vertical and horizontal transport plays an important role in the marine Biogeochemical Cycle in the surface layer. However, below that depth, only the inert refractory DOM exists, and the role of the refractory DOM in the Biogeochemical Cycle is not important. The global export production due to the particulate organic matter (POM) and DOM at a depth of 100 m is estimated to be about 8 Gt C/yr and about 3 Gt C/yr, respectively. The vertical transport below 400 m is due almost entirely to POM.