C sequestration
- 1. TAMIL NADU AGRICULTURAL UNIVERSITY CARBON SEQUESTRATION B.KARTHIKEYAN 2019520103 SOIL SCIENCE& AGRL.CHEMISTRY AC&RI MADURAI SAC 506- SOIL BIOLOGY AND BIOCHEMISTRY (2+1)
- 2. CARBON SEQUESTRATION Carbon sequestration is the longterm storage of carbon in oceans, soils, vegetation (especially forests), to mitigate the global warming Carbon Sequestration is the placement of CO2 into a depository in such way that it remains safely and not released back to the atmosphere. Sequestration means something that is locked away for safe keeping. the trapping of a chemical in the atmosphere or environment and its isolation in a natural or artificial storage area.
- 3. WHY ATMOSPHERIC CARBON WILL SEQUESTRATED ? CO2 is one of the main greenhouse gases that is causing global warming and forcing climate change. One of the approaches to reducing CO2 Concentration in the atmosphere is carbon sequestration The CO2 concentration in the atmosphere is accelerated by human activities such as burning of fossil fuels and deforestation
- 4. (1)Sun light is absorbed and converted to heat, which warms the surface. (2) The surface emits infrared radiation to the atmosphere. (3) some of it is absorbed by greenhouse gases (4) Re-emitted toward the surface; (5) Some of the heat is not trapped by greenhouse gases and escapes into space. (6) Human activities that emit additional greenhouse gases to the atmosphere.
- 5. SOURCE OF CARBON DIOXIDE EMISSION 1. Man made sources Industries Transportation Land use change soil cultivation Biomass burning
- 6. 2. Natural sources Volcanoes Wild fires Decomposition Respiration
- 7. STEPS IN CARBON SEQUESTRATION 1)Trapping and separating of CO2 from other gases 2)Transporting of this captured CO2 to a storage location 3)Storing that CO2 away from the atmosphere ( underground or deep ocean)
- 8. WAYS THAT CARBON CAN BE SEQUESTERED 1. Geological sequestration : Underground 2. Ocean Sequestration : Deep in ocean 3. Terrestrial Sequestration : In plants and soil
- 9. 1.GEOLOGICAL SEQUESTRATION Geologic Storage involves capturing anthropogenic CO2 before it enters the atmosphere and injecting it into underground formations. Once CO2 is injected deep underground (typically more than 800 meters) it is trapped in minute pores or spaces in the rock structure. Impermeable cap rocks above the storage zones act as seals to ensure the safe storage of CO2.
- 10. 2.OCEAN SEQUESTRATION Carbon is naturally stored in the ocean via two pumps, solubility and biological and there are analogous man made methods, direct injection and ocean fertilization, respectively. At the present time, approximately one third of human generated emission are estimated to be entering the ocean.
- 11. 3.TERRESTRIAL SEQUESTRATION The process through which CO2 from the atmosphere is absorbed naturally through photosynthesis & stored as carbon in biomass & soils.
- 12. C POOL
- 14. A) ABIOTIC SEQUESTRATION Abiotic sequestration is based on physical and chemical reactions and engineering techniques without intervention of living organisms (e.g. plants, microbes). Abiotic sequestration has a larger sink capacity than biotic sequestration 1)Ocean injection 3)Scrubbing and carbonation 2)Geological injection
- 15. (I) OCEANIC INJECTION liquefied CO2 separated from industrial sources can be injected into the ocean by one of the following four techniques: it is injected below 1000 m from a manifold lying at the ocean floor, and being lighter than water, it rises to approximately 1000 m depth forming a droplet plume; it is also injected as a denser CO2–seawater mixture at 500–1000 m depth, and the mixture sinks into thedeeper ocean; it is discharged from a large pipetowed behind a ship; and it is pumped into a depression at the bottom of the ocean floor forming a CO2 lake. Liquefied CO2 injected at approximately3000 m depth is believed to remain stable
- 16. (II) GEOLOGICAL INJECTION This involves capture, liquefaction, transport and injection of industrial CO2 into deep geological strata. The CO2 may be injected in coal seams, old oil wells (to increase yield), stable rock strata or saline aquifers. Saline aquifers are underground strata of very porous sediments filled with brackish (saline) water In general, saline aquifers are located below the freshwater reservoirs with an impermeable layer in between. Industrial CO2 can be pumped into the aquifer, where it is sequestered hydrodynamically and by reacting with other dissolved salts to form carbonates.
- 18. (III) SCRUBBING AND MINERAL CARBONATION Mineral carbonation is achieved through mimicry of natural inorganic chemical transformation of CO2 It involves transformation of industrial CO2 emissions into CaCO3, MgCO3 and other minerals in the form of geologically and thermodynamically stable mineral carbonates. It is a two-stage process: scrubbing and mineral carbonation. 2MgSiO4 + CO2(g) + H20 Mg3Si2O5(OH)4 + MgCO3 CaSiO3 + CO2 CaCO3 + SiO2 Scrubbing, the process of chemical absorption of CO2 using an amine or carbonate solvent, is the most widely used method of carbon capture. Pure CO2 gas, recovered by heating the CO2-rich amine, is re-precipitated through mineral carbonation.
- 19. (B) BIOTIC SEQUESTRATION Biotic sequestration is based on managed intervention of higher plants and micro- organisms in removing CO2 from the atmosphere Oceanic sequestration Terrestrial sequestration Soil C sequestration as Secondary carbonates Bio fuel
- 20. (I) OCEANIC SEQUESTRATION There are several biological processes leading to C sequestration in the ocean through photosynthesis. Phytoplankton photosynthesis is one such mechanism (Rivkin & Legendre 2001), which fixes approximately 45 Pg C /yr. Some of the particulate organic material formed by phytoplankton is deposited at the ocean floor and is thus sequestered
- 21. (II) TERRESTRIAL SEQUESTRATION Transfer of atmospheric CO2 into biotic and pedologic C pools is called terrestrial C sequestration. Terrestrial ecosystems constitute a major C sink owing to the photosynthesis and storage of CO2 in live and dead organic matter. Owing to its numerous ancillary benefits (e.g. improved soil and water quality, restoration of degraded ecosystems, increased crop yield), Terrestrial C sequestration is often termed as win–win or no-regrets strategy It offers multiple benefits even without the threat of global climate change.
- 22. Forest ecosystems store C as lignin and other relatively resistant polymeric C compounds. Presently, the net rate of C sequestration in forest ecosystems (other than those being deforested) is 1.7 ± 0.5 Pg C/yr Afforestation is one of the viable options of C sequestration in terrestrial ecosystems Establishment of productive and monoculture plantations of Pinus, Eucalyptus and Acacia can enhance the terrestrial C pool in these ecosystems There are three principal components of terrestrial C sequestration: FOREST ECOSYSTEMS SOILS WETLANDS. FORESTS
- 23. Wetlands and the associated soils or histosols constitute a large pedologic pool estimated at approximately 450 Pg .Wetland soils may contain as much as 200 times more C than the associated vegetation Soil C sequestration, Implies enhancing the concentration/ pools of SOC and SIC as secondary carbonates through land-use conversion and adoption of recommended management practices (RMPs) in agricultural, pastoral and forestry ecosystems SOIL WETLANDS
- 24. STRATEGIES OF SOC SEQUESTRATION RESTORATION OF SOIL DEGRADED BY pollution and contamination Erosion salinization and alkalization Nutrient depletion acidification and leaching competition, crusting and structural decline Restoring physical, chemical and biological quality of degraded soils ADOPTION OF RMPS ON AGRICULTURAL &FOREST SOILS INM no-till farming with residue mulch and cover crops diverse crop rotations, agroforestry and charcoal precision farming and fertilization integrated pest management (IPM) Agricultural intensification to increase productivity converting surplus agricultural land for nature conservancy and environmental improvements
- 25. ADVANTAGES OF TERRESTRIAL C SEQUESTRATION • Improved soil structure • Better water use and storage • Less erosion • Increased soil fertility • Improved biodiversity • Healthier ecology • Improved agricultural performance.
- 26. (III) SECONDARY CARBONATES Soil C sequestration may also occur in SIC as secondary carbonates, and leaching of bicarbonates into the ground water. Secondary carbonates occur in various forms as films, threads, concretions and pedants. There are four principle mechanisms of formation of secondary carbonates 1st mechanism Secondary carbonates are formed through dissolution of CO2 in the surface layer followed by translocation and re-precipitation with CaCO3 and MgCO3 in the subsoil
- 27. 2nd mechanism In contrast, Sobecki & Wilding (1983) described the second mechanism based on capillary rise of CaC2 from shallow ground water and its re-precipitation in the surface layer. 3rd mechanism The third mechanism is in situ dissolution and re-precipitation (Rabenhorst & Wilding) (1986). 4th mechanism Monger (2002) observed that pedogenic/secondary carbonates are of biogenic origin and are formed by activity of soil fauna (e.g. termites).
- 28. Chemical reactions describing the dissolution of CO2 are shown in the following Secondary carbonates are formed in the soil pH range of 7.3–8.5. There must, however, be sufficient quantity of CaC2 and MgC2 present in the soil system. CO2 (gas) + H2O CO2(aq) + H2O CO2 (aq) + H2O H2CO3 H2CO3 H+ + HCO3- HCO3- H+ + CO3 2- H2CO3 2H+ + CO3 2- Ca2+ (aq) + 2 HCO3-(aq) CaCO3 (Calcite) + H2O + CO2
- 29. 4. BIOFUELS Converting biomass-derived sugars to ethanol and plant-derived oils and fats into bio- diesel is a viable strategy to reduce use of fossil fuels and develop alternate / sustainable sources of energy They are related to C sequestration in two distinct but interrelated aspects 1) C sequestration through restoration of the depleted SOC pool, especially when agriculturally degraded/ marginal soils are converted to energy plantations,and 2) Recycling of atmospheric CO2 into biomassbased biofuels