This document summarizes the current understanding of the rise of oxygen in Earth's early ocean and atmosphere. It discusses:
1) Evidence that oxygen levels rose between 2.4-2.1 billion years ago in an event known as the Great Oxidation Event, as seen by the appearance of oxidized minerals in rock records.
2) Debate around whether oxygen-producing photosynthesis preceded or coincided with the GOE, and the role of buffers in consuming oxygen initially to delay its accumulation.
3) Strong evidence that oxygen levels rose again after the GOE but remained low for over a billion years, resulting in an oxygen-lean deep ocean until a second rise in oxygen 600 million years ago oxygen
The document summarizes several major biogeochemical cycles - carbon, nitrogen, phosphorus, and sulfur. It describes the reservoirs, fluxes, and transformations involved in each cycle, which are driven by biological and geological processes. Microbial activity plays an important role in facilitating exchanges between different reservoirs like the atmosphere, biosphere, hydrosphere and lithosphere. The carbon, nitrogen and sulfur cycles involve gaseous forms that are exchanged between air and oceans/land. Phosphorus lacks a gaseous phase and its cycle is more sedimentary in nature.
2198456m Will Atmospheric CO2 Affect Deposition of Marine Biogenic CarbonatesMagnus McFarlane
This document discusses how rising atmospheric CO2 levels are causing ocean acidification, which affects marine life and ecosystems. Since the industrial revolution, CO2 emissions have increased atmospheric CO2 levels from 180-300 ppm to over 380 ppm currently. The ocean absorbs over 30% of this CO2 annually, which reacts to form carbonic acid and lowers ocean pH. This decreases carbonate ion concentrations by 16%, threatening calcifying organisms. Corals and plankton are especially at risk, as reduced carbonate saturation can inhibit their growth and shell formation. While some species show adaptations, overall declining carbonate levels threaten marine food webs and ecosystems humans rely on for food, income, and coastal protection from erosion and storms
The document summarizes two important biogeochemical cycles - the nitrogen cycle and the carbon dioxide-oxygen cycle.
The nitrogen cycle describes how nitrogen exists in different forms and moves between the atmosphere, living things, and the lithosphere through natural processes like nitrogen fixation, assimilation, decomposition, nitrification, and denitrification. Human activities like using nitrogen fertilizers and burning fossil fuels can impact the nitrogen cycle.
The carbon dioxide-oxygen cycle explains how carbon dioxide and oxygen are exchanged between living things and the atmosphere through photosynthesis, respiration, and combustion. Photosynthesis produces oxygen and food, respiration uses oxygen and food to produce energy, and combustion releases carbon dioxide through burning fuels. Human activities such as def
This document summarizes a study that uses geochemical modeling to constrain the possible composition of Europa's subsurface ocean and seafloor. The study models how seven different candidate bulk accretionary materials for Europa (various carbonaceous and ordinary chondrites) would alter through water-rock reactions. The models produce ocean compositions within 10% of previous estimates and indicate that precipitation of different mineral phases could depend on the rock type. Ordinary chondrites may produce higher calcium ion levels in Europa's present-day ocean compared to carbonaceous materials. Future missions could help determine Europa's actual accretionary material by detecting these mineral signatures or ocean chemistry.
The carbon cycle describes the movement of carbon between the biosphere, atmosphere, oceans, and lithosphere. Carbon is exchanged through physical, chemical, and biological processes, with the largest pools located in the oceans and lithosphere. Human activities like burning fossil fuels and deforestation have significantly increased the amount of carbon dioxide in the atmosphere, disrupting the natural carbon cycle and global climate. Understanding the carbon cycle is important for studying biological and climate processes.
Presentation on biogeochemical cycles 2naimal kainat
The document summarizes key aspects of the nitrogen and phosphorus biogeochemical cycles. It defines biogeochemical cycles and describes the major types. It then provides details on the nitrogen cycle, including its ecological and biological functions, the processes of nitrogen fixation, ammonification, nitrification, and denitrification. It also discusses how human activities have influenced the nitrogen cycle through increased nitrogen fixation and emissions. Similarly, it outlines the phosphorus cycle, its functions, processes, and how human overuse of phosphorus fertilizers has polluted bodies of water and harmed ecosystems.
The document discusses the oxygen cycle on Earth, including the major sources and sinks of oxygen. It notes that photosynthesis by plants and phytoplankton is the primary source of oxygen, producing about 30,000 teragrams of oxygen per year. Respiration by animals and decay of organic matter act as sinks and consume a similar amount, keeping atmospheric oxygen concentrations relatively stable over time.
The Great Oxygenation Event was a significant increase in atmospheric oxygen levels between approximately 2.4-2.3 billion years ago. While oxygenic photosynthesis first evolved over 2.7 billion years ago, various sinks prevented a rise in oxygen until volcanic outgassing and the oxidation of the mantle decreased around 2.4 billion years ago. Evidence from rock records shows low oxygen levels until approximately 2.2 billion years ago, when banded iron formations and other minerals indicating anoxic conditions disappear. Following the GOE, sulfate levels in the oceans increased due to more oxidative weathering balancing oxygen production from burial of organic carbon and pyrite.
The document summarizes several major biogeochemical cycles - carbon, nitrogen, phosphorus, and sulfur. It describes the reservoirs, fluxes, and transformations involved in each cycle, which are driven by biological and geological processes. Microbial activity plays an important role in facilitating exchanges between different reservoirs like the atmosphere, biosphere, hydrosphere and lithosphere. The carbon, nitrogen and sulfur cycles involve gaseous forms that are exchanged between air and oceans/land. Phosphorus lacks a gaseous phase and its cycle is more sedimentary in nature.
2198456m Will Atmospheric CO2 Affect Deposition of Marine Biogenic CarbonatesMagnus McFarlane
This document discusses how rising atmospheric CO2 levels are causing ocean acidification, which affects marine life and ecosystems. Since the industrial revolution, CO2 emissions have increased atmospheric CO2 levels from 180-300 ppm to over 380 ppm currently. The ocean absorbs over 30% of this CO2 annually, which reacts to form carbonic acid and lowers ocean pH. This decreases carbonate ion concentrations by 16%, threatening calcifying organisms. Corals and plankton are especially at risk, as reduced carbonate saturation can inhibit their growth and shell formation. While some species show adaptations, overall declining carbonate levels threaten marine food webs and ecosystems humans rely on for food, income, and coastal protection from erosion and storms
The document summarizes two important biogeochemical cycles - the nitrogen cycle and the carbon dioxide-oxygen cycle.
The nitrogen cycle describes how nitrogen exists in different forms and moves between the atmosphere, living things, and the lithosphere through natural processes like nitrogen fixation, assimilation, decomposition, nitrification, and denitrification. Human activities like using nitrogen fertilizers and burning fossil fuels can impact the nitrogen cycle.
The carbon dioxide-oxygen cycle explains how carbon dioxide and oxygen are exchanged between living things and the atmosphere through photosynthesis, respiration, and combustion. Photosynthesis produces oxygen and food, respiration uses oxygen and food to produce energy, and combustion releases carbon dioxide through burning fuels. Human activities such as def
This document summarizes a study that uses geochemical modeling to constrain the possible composition of Europa's subsurface ocean and seafloor. The study models how seven different candidate bulk accretionary materials for Europa (various carbonaceous and ordinary chondrites) would alter through water-rock reactions. The models produce ocean compositions within 10% of previous estimates and indicate that precipitation of different mineral phases could depend on the rock type. Ordinary chondrites may produce higher calcium ion levels in Europa's present-day ocean compared to carbonaceous materials. Future missions could help determine Europa's actual accretionary material by detecting these mineral signatures or ocean chemistry.
The carbon cycle describes the movement of carbon between the biosphere, atmosphere, oceans, and lithosphere. Carbon is exchanged through physical, chemical, and biological processes, with the largest pools located in the oceans and lithosphere. Human activities like burning fossil fuels and deforestation have significantly increased the amount of carbon dioxide in the atmosphere, disrupting the natural carbon cycle and global climate. Understanding the carbon cycle is important for studying biological and climate processes.
Presentation on biogeochemical cycles 2naimal kainat
The document summarizes key aspects of the nitrogen and phosphorus biogeochemical cycles. It defines biogeochemical cycles and describes the major types. It then provides details on the nitrogen cycle, including its ecological and biological functions, the processes of nitrogen fixation, ammonification, nitrification, and denitrification. It also discusses how human activities have influenced the nitrogen cycle through increased nitrogen fixation and emissions. Similarly, it outlines the phosphorus cycle, its functions, processes, and how human overuse of phosphorus fertilizers has polluted bodies of water and harmed ecosystems.
The document discusses the oxygen cycle on Earth, including the major sources and sinks of oxygen. It notes that photosynthesis by plants and phytoplankton is the primary source of oxygen, producing about 30,000 teragrams of oxygen per year. Respiration by animals and decay of organic matter act as sinks and consume a similar amount, keeping atmospheric oxygen concentrations relatively stable over time.
The Great Oxygenation Event was a significant increase in atmospheric oxygen levels between approximately 2.4-2.3 billion years ago. While oxygenic photosynthesis first evolved over 2.7 billion years ago, various sinks prevented a rise in oxygen until volcanic outgassing and the oxidation of the mantle decreased around 2.4 billion years ago. Evidence from rock records shows low oxygen levels until approximately 2.2 billion years ago, when banded iron formations and other minerals indicating anoxic conditions disappear. Following the GOE, sulfate levels in the oceans increased due to more oxidative weathering balancing oxygen production from burial of organic carbon and pyrite.
Earth History 1: unit checks questionsRobin Seamon
This document contains review questions and answers for an Earth history unit. It includes questions about the structure of the Earth, plate tectonics, rock types, and radioactive dating. The questions cover topics like what causes the plates to move, different rock formation processes, and calculating ages using half-life decay equations.
Earth History 2: Changes in AtmosphereRobin Seamon
The document discusses the various factors that cause changes in Earth's atmosphere and climate over time. It explains that changes in one climate variable, such as the atmosphere, will affect others as they are all interconnected. The key factors identified are 1) biotic processes, 2) variations in solar radiation, 3) plate tectonics, 4) volcanic eruptions and large igneous provinces, 5) the cryosphere, 6) Milankovitch cycles, and 7) greenhouse gases. The document traces the history of scientific understanding of these climate change causes and how different evidence and techniques verified theories about ice age triggers being linked to orbital variations amplified by greenhouse gas feedbacks.
The document summarizes several important biogeochemical cycles. It discusses the water, carbon, nitrogen, phosphorus, oxygen, and sulfur cycles. For each cycle it describes the key reservoirs, assimilation, and release processes involved in recycling nutrients and moving elements through ecosystems. Maintaining these biogeochemical cycles is essential for sustaining life on Earth.
1) Changes in the atmosphere, such as variations in greenhouse gases, solar radiation levels, volcanic activity, and ice sheet size can impact climate by altering the Earth's energy balance.
2) Scientific evidence shows that small variations in the Earth's orbit and axis (known as the Milankovitch cycles) have paced climate changes over hundreds of thousands of years by changing the distribution of solar energy received in different latitudes and seasons.
3) Positive feedback loops involving greenhouse gases, ice sheets, and temperature amplified the effects of the Milankovitch cycles in the past, driving the Earth into ice ages. However, human emissions are now the dominant factor changing climate through increased greenhouse gases.
The document summarizes several important biogeochemical cycles, including the carbon, nitrogen, phosphorus, sulfur, and oxygen cycles. It describes how each element is cycled between the biosphere, geosphere, and atmosphere through biological and chemical processes. Microorganisms play a key role in transferring nutrients between different forms and facilitating exchange through oxidation-reduction reactions. All of the cycles are interlinked as they involve the movement of elements between living organisms and their environment.
The document discusses several biogeochemical cycles including the water, carbon, nitrogen, phosphorus, and sulfur cycles. It provides details on the reservoirs, assimilation, and release stages of each cycle. For example, it notes that the water cycle involves evaporation and precipitation moving water between oceans, air, groundwater, lakes, and glaciers. Plants absorb water from the ground and animals drink or eat plants, while transpiration and excretion release water back. The carbon cycle describes photosynthesis fixing carbon from the air and respiration releasing it, and the nitrogen cycle involves nitrogen fixation, nitrification, and denitrification moving nitrogen between air, soil, plants, and animals.
The document summarizes several biogeochemical cycles including nitrogen and phosphorus cycles. It describes how nitrogen and phosphorus cycle through ecosystems via biological and geological processes. For the nitrogen cycle, it outlines the five key steps of nitrogen fixation, assimilation, mineralization, nitrification, and denitrification. It provides details on the microorganisms involved in each step and factors that control the processes. The same level of detail is provided for the phosphorus cycle which involves mineralization, assimilation, precipitation of phosphorus compounds, and microbial solubilization of phosphorus.
This document summarizes several key biogeochemical cycles. It describes how carbon, nitrogen, sulfur, and phosphorus cycles move these elements through organisms and the biosphere. Microbes play an essential role in converting nutrients between organic and inorganic forms so they can be used by other organisms. The carbon cycle involves carbon dioxide being taken up by plants and released by respiration and volcanic activity. In the nitrogen cycle, nitrogen is fixed by bacteria, converted between nitrate and nitrogen gas by other bacteria, and used by plants and microbes to make amino acids.
This document provides an overview of the nitrogen cycle presented by a group of students from Gauhati University. It begins with an introduction to geochemical cycles and defines nitrogen. It then describes the major processes in the nitrogen cycle, including nitrogen fixation, mineralization, nitrification, and denitrification. It discusses the role of microorganisms and how human activities like fertilizer use and fossil fuel combustion have impacted the global nitrogen cycle. Reservoirs of nitrogen in the terrestrial environment and crust are also examined.
The document discusses biogeochemical cycles, specifically gaseous cycles. It provides details on the nitrogen cycle, including the steps of nitrogen fixation, nitrate assimilation, ammonification, nitrification, denitrification, and sedimentation. It also briefly summarizes the carbon cycle, noting it is a perfect gaseous cycle as carbon transfers and transformations occur quickly between the atmosphere and organisms through photosynthesis, respiration, decomposition and other processes.
A geochemical assessment of soils within oke ogun area, southwestern nigeriaAlexander Decker
This document summarizes a study that analyzed soil samples from Oke-Ogun area in southwestern Nigeria to investigate concentrations of major elements and trace metals.
Key findings include:
1. Soil samples showed elevated levels of Pb, Cr, V, Mn, and Co compared to underlying bedrock, indicating enrichment during weathering.
2. Statistical analysis revealed associations between Cu-Pb-Cd-Ni-Co and Zn-V.
3. Principal component analysis identified three factors associated with differing sources for trace metals in the soils.
This document summarizes a student research project that analyzed concentrations of arsenic, lead, manganese, and nickel in sediments from Possession Sound, which is influenced by discharge from the Snohomish River. Sediment samples were taken from two sites and analyzed for heavy metal concentrations. The student hypothesized that metal concentrations would be higher at one site due to shallower sediments and that concentrations would increase with river discharge. Statistical analysis did not find a strong correlation with discharge, suggesting other internal estuary processes influence metal mobility. The document provides background on sources and environmental impacts of each metal.
This document summarizes a study on microbial metal cycling and bioaccumulation in roadside soils and streams. The study aims to establish relationships between urbanization and pollutant concentrations in a local stream ecosystem. Researchers analyzed metal concentrations in insects, soils, and sediments from different zones of a creek. They also investigated microbial oxidation and reduction of antimony species from roadside soils and isolated bacterial strains to study metabolic pathways. Preliminary results found higher arsenic and lead levels in downstream insects and trace antimony reduction by soils microbes. The study provides background on metal pollution impacts and aims to further examine seasonal shifts and microbial antimony processing.
Carbon is essential for life and is continuously cycled through Earth's biosphere, lithosphere, hydrosphere and atmosphere. The carbon cycle involves the exchange of carbon reservoirs between the atmosphere, ocean, biomass and fossil fuels. Photosynthesis absorbs carbon from the atmosphere which enters the biosphere, and respiration and decomposition release it back into the atmosphere. Human activity such as burning fossil fuels has increased carbon dioxide levels in the atmosphere, disrupting the natural carbon cycle balance.
This study examined water quality in a small residential wetland in Spokane, Washington. Water samples were taken from sites along the drainage gradient leading to the wetland and within the wetland. Concentrations of ions like magnesium and sodium increased from upstream to within the wetland, likely due to evapoconcentration. While concentrations of major ions accumulated in the wetland, concentrations of potential heavy metals like lead and zinc remained below EPA aquatic life standards. The results indicate the wetland shows no evidence of geochemical hazards from surrounding anthropogenic activities like vehicle traffic or land use.
The origin of ice ages is controversial, with two opposing theories proposed. Robert Berner believes ice ages are caused by long-term decreases in decarbonation reducing atmospheric CO2 levels. Maureen Raymo argues that uplift of mountain ranges like the Himalayas increased weathering, removing CO2 from the air and cooling the climate. Eric Sundquist later concluded both theories may operate, but on different timescales, with steady-state operating over millions of years and non-steady-state during shorter uplift events.
This document discusses using stable carbon isotope analysis to study phase transitions of soil carbonates during anaerobic biodegradation of petroleum hydrocarbons. It explains that carbonate minerals like calcite and dolomite are common in soils and can dissolve or form new minerals as conditions change. Stable carbon isotope ratios are measured to identify carbonate dissolution or addition. Laboratory experiments show that dissolving soil carbonates leads to re-formation of new carbonates during anaerobic degradation of hydrocarbons. This stable isotope method allows changes in the carbonate fraction of soil to be monitored.
Assessment of fe(ii), fe(iii) and al(iii) in a mineralogical profile of gabon...Alexander Decker
1) The study assessed the fractions of Fe(II), Fe(III) and Al(III) in four depths of a Gabonese soil through water, KCl, and aqua regia extractions and analysis.
2) Total Fe(II) decreased with depth while total Al(III) and Fe(III) increased, with metals mainly in mineralogical fractions that decreased with depth.
3) This led to increases in water-soluble and exchangeable Fe(II) fractions and the exchangeable fractions of Al(III) and Fe(III) with depth, indicating increased solubility and mobility.
Sulfur is an essential element that plays an important role in biological processes through electron transfers. Understanding sulfur metabolism in model organisms like Escherichia coli and Bacillus subtilis is important to extend knowledge to other ecological niches. Sulfur metabolism involves three main processes: synthesis of sulfur-containing amino acids and coenzymes, catabolism and equilibration of sulfur molecules, and methionine recycling. Iron-sulfur proteins and copper proteins participate in one-electron transfers involving oxidation states of iron and copper.
The Oxygen Bottleneck for TechnospheresSérgio Sacani
This document discusses the role of atmospheric oxygen in enabling the development of advanced technology on exoplanets. It argues that a minimum oxygen concentration of around 18% is required for sustainable combustion, which played a key role in processes like metallurgy that were essential for early civilizations on Earth. Periods when Earth's atmospheric oxygen dropped below this level would have inhibited the development of technology. Therefore, only planets capable of maintaining significant atmospheric oxygen over long timescales may be able to develop detectable technospheres. While complex life can evolve in low-oxygen environments, the emergence of advanced technology depends more strictly on the availability of oxygen at high concentrations through combustion.
The origin and geological history of oxygenrita martin
Oxygen third most profusely found element in the universe Commercially, oxygen can be prepared by the process of liquefaction and fractional distillation of air and through electrolysis of water
Earth History 1: unit checks questionsRobin Seamon
This document contains review questions and answers for an Earth history unit. It includes questions about the structure of the Earth, plate tectonics, rock types, and radioactive dating. The questions cover topics like what causes the plates to move, different rock formation processes, and calculating ages using half-life decay equations.
Earth History 2: Changes in AtmosphereRobin Seamon
The document discusses the various factors that cause changes in Earth's atmosphere and climate over time. It explains that changes in one climate variable, such as the atmosphere, will affect others as they are all interconnected. The key factors identified are 1) biotic processes, 2) variations in solar radiation, 3) plate tectonics, 4) volcanic eruptions and large igneous provinces, 5) the cryosphere, 6) Milankovitch cycles, and 7) greenhouse gases. The document traces the history of scientific understanding of these climate change causes and how different evidence and techniques verified theories about ice age triggers being linked to orbital variations amplified by greenhouse gas feedbacks.
The document summarizes several important biogeochemical cycles. It discusses the water, carbon, nitrogen, phosphorus, oxygen, and sulfur cycles. For each cycle it describes the key reservoirs, assimilation, and release processes involved in recycling nutrients and moving elements through ecosystems. Maintaining these biogeochemical cycles is essential for sustaining life on Earth.
1) Changes in the atmosphere, such as variations in greenhouse gases, solar radiation levels, volcanic activity, and ice sheet size can impact climate by altering the Earth's energy balance.
2) Scientific evidence shows that small variations in the Earth's orbit and axis (known as the Milankovitch cycles) have paced climate changes over hundreds of thousands of years by changing the distribution of solar energy received in different latitudes and seasons.
3) Positive feedback loops involving greenhouse gases, ice sheets, and temperature amplified the effects of the Milankovitch cycles in the past, driving the Earth into ice ages. However, human emissions are now the dominant factor changing climate through increased greenhouse gases.
The document summarizes several important biogeochemical cycles, including the carbon, nitrogen, phosphorus, sulfur, and oxygen cycles. It describes how each element is cycled between the biosphere, geosphere, and atmosphere through biological and chemical processes. Microorganisms play a key role in transferring nutrients between different forms and facilitating exchange through oxidation-reduction reactions. All of the cycles are interlinked as they involve the movement of elements between living organisms and their environment.
The document discusses several biogeochemical cycles including the water, carbon, nitrogen, phosphorus, and sulfur cycles. It provides details on the reservoirs, assimilation, and release stages of each cycle. For example, it notes that the water cycle involves evaporation and precipitation moving water between oceans, air, groundwater, lakes, and glaciers. Plants absorb water from the ground and animals drink or eat plants, while transpiration and excretion release water back. The carbon cycle describes photosynthesis fixing carbon from the air and respiration releasing it, and the nitrogen cycle involves nitrogen fixation, nitrification, and denitrification moving nitrogen between air, soil, plants, and animals.
The document summarizes several biogeochemical cycles including nitrogen and phosphorus cycles. It describes how nitrogen and phosphorus cycle through ecosystems via biological and geological processes. For the nitrogen cycle, it outlines the five key steps of nitrogen fixation, assimilation, mineralization, nitrification, and denitrification. It provides details on the microorganisms involved in each step and factors that control the processes. The same level of detail is provided for the phosphorus cycle which involves mineralization, assimilation, precipitation of phosphorus compounds, and microbial solubilization of phosphorus.
This document summarizes several key biogeochemical cycles. It describes how carbon, nitrogen, sulfur, and phosphorus cycles move these elements through organisms and the biosphere. Microbes play an essential role in converting nutrients between organic and inorganic forms so they can be used by other organisms. The carbon cycle involves carbon dioxide being taken up by plants and released by respiration and volcanic activity. In the nitrogen cycle, nitrogen is fixed by bacteria, converted between nitrate and nitrogen gas by other bacteria, and used by plants and microbes to make amino acids.
This document provides an overview of the nitrogen cycle presented by a group of students from Gauhati University. It begins with an introduction to geochemical cycles and defines nitrogen. It then describes the major processes in the nitrogen cycle, including nitrogen fixation, mineralization, nitrification, and denitrification. It discusses the role of microorganisms and how human activities like fertilizer use and fossil fuel combustion have impacted the global nitrogen cycle. Reservoirs of nitrogen in the terrestrial environment and crust are also examined.
The document discusses biogeochemical cycles, specifically gaseous cycles. It provides details on the nitrogen cycle, including the steps of nitrogen fixation, nitrate assimilation, ammonification, nitrification, denitrification, and sedimentation. It also briefly summarizes the carbon cycle, noting it is a perfect gaseous cycle as carbon transfers and transformations occur quickly between the atmosphere and organisms through photosynthesis, respiration, decomposition and other processes.
A geochemical assessment of soils within oke ogun area, southwestern nigeriaAlexander Decker
This document summarizes a study that analyzed soil samples from Oke-Ogun area in southwestern Nigeria to investigate concentrations of major elements and trace metals.
Key findings include:
1. Soil samples showed elevated levels of Pb, Cr, V, Mn, and Co compared to underlying bedrock, indicating enrichment during weathering.
2. Statistical analysis revealed associations between Cu-Pb-Cd-Ni-Co and Zn-V.
3. Principal component analysis identified three factors associated with differing sources for trace metals in the soils.
This document summarizes a student research project that analyzed concentrations of arsenic, lead, manganese, and nickel in sediments from Possession Sound, which is influenced by discharge from the Snohomish River. Sediment samples were taken from two sites and analyzed for heavy metal concentrations. The student hypothesized that metal concentrations would be higher at one site due to shallower sediments and that concentrations would increase with river discharge. Statistical analysis did not find a strong correlation with discharge, suggesting other internal estuary processes influence metal mobility. The document provides background on sources and environmental impacts of each metal.
This document summarizes a study on microbial metal cycling and bioaccumulation in roadside soils and streams. The study aims to establish relationships between urbanization and pollutant concentrations in a local stream ecosystem. Researchers analyzed metal concentrations in insects, soils, and sediments from different zones of a creek. They also investigated microbial oxidation and reduction of antimony species from roadside soils and isolated bacterial strains to study metabolic pathways. Preliminary results found higher arsenic and lead levels in downstream insects and trace antimony reduction by soils microbes. The study provides background on metal pollution impacts and aims to further examine seasonal shifts and microbial antimony processing.
Carbon is essential for life and is continuously cycled through Earth's biosphere, lithosphere, hydrosphere and atmosphere. The carbon cycle involves the exchange of carbon reservoirs between the atmosphere, ocean, biomass and fossil fuels. Photosynthesis absorbs carbon from the atmosphere which enters the biosphere, and respiration and decomposition release it back into the atmosphere. Human activity such as burning fossil fuels has increased carbon dioxide levels in the atmosphere, disrupting the natural carbon cycle balance.
This study examined water quality in a small residential wetland in Spokane, Washington. Water samples were taken from sites along the drainage gradient leading to the wetland and within the wetland. Concentrations of ions like magnesium and sodium increased from upstream to within the wetland, likely due to evapoconcentration. While concentrations of major ions accumulated in the wetland, concentrations of potential heavy metals like lead and zinc remained below EPA aquatic life standards. The results indicate the wetland shows no evidence of geochemical hazards from surrounding anthropogenic activities like vehicle traffic or land use.
The origin of ice ages is controversial, with two opposing theories proposed. Robert Berner believes ice ages are caused by long-term decreases in decarbonation reducing atmospheric CO2 levels. Maureen Raymo argues that uplift of mountain ranges like the Himalayas increased weathering, removing CO2 from the air and cooling the climate. Eric Sundquist later concluded both theories may operate, but on different timescales, with steady-state operating over millions of years and non-steady-state during shorter uplift events.
This document discusses using stable carbon isotope analysis to study phase transitions of soil carbonates during anaerobic biodegradation of petroleum hydrocarbons. It explains that carbonate minerals like calcite and dolomite are common in soils and can dissolve or form new minerals as conditions change. Stable carbon isotope ratios are measured to identify carbonate dissolution or addition. Laboratory experiments show that dissolving soil carbonates leads to re-formation of new carbonates during anaerobic degradation of hydrocarbons. This stable isotope method allows changes in the carbonate fraction of soil to be monitored.
Assessment of fe(ii), fe(iii) and al(iii) in a mineralogical profile of gabon...Alexander Decker
1) The study assessed the fractions of Fe(II), Fe(III) and Al(III) in four depths of a Gabonese soil through water, KCl, and aqua regia extractions and analysis.
2) Total Fe(II) decreased with depth while total Al(III) and Fe(III) increased, with metals mainly in mineralogical fractions that decreased with depth.
3) This led to increases in water-soluble and exchangeable Fe(II) fractions and the exchangeable fractions of Al(III) and Fe(III) with depth, indicating increased solubility and mobility.
Sulfur is an essential element that plays an important role in biological processes through electron transfers. Understanding sulfur metabolism in model organisms like Escherichia coli and Bacillus subtilis is important to extend knowledge to other ecological niches. Sulfur metabolism involves three main processes: synthesis of sulfur-containing amino acids and coenzymes, catabolism and equilibration of sulfur molecules, and methionine recycling. Iron-sulfur proteins and copper proteins participate in one-electron transfers involving oxidation states of iron and copper.
The Oxygen Bottleneck for TechnospheresSérgio Sacani
This document discusses the role of atmospheric oxygen in enabling the development of advanced technology on exoplanets. It argues that a minimum oxygen concentration of around 18% is required for sustainable combustion, which played a key role in processes like metallurgy that were essential for early civilizations on Earth. Periods when Earth's atmospheric oxygen dropped below this level would have inhibited the development of technology. Therefore, only planets capable of maintaining significant atmospheric oxygen over long timescales may be able to develop detectable technospheres. While complex life can evolve in low-oxygen environments, the emergence of advanced technology depends more strictly on the availability of oxygen at high concentrations through combustion.
The origin and geological history of oxygenrita martin
Oxygen third most profusely found element in the universe Commercially, oxygen can be prepared by the process of liquefaction and fractional distillation of air and through electrolysis of water
Biodiversity, Microbial Biodiversity, Bacterial Biodiveristy, Archae Biodiversity, Protozoa Biodiversity, Fungal Biodiversity, Origin of Life, Origin of Life on Earth, Chemical Evolution, Physical Evolution, Biological Evolution
The document summarizes key biogeochemical cycles - carbon, nitrogen, and phosphorus. It describes how carbon cycles between the atmosphere, organisms, oceans, and geosphere. The nitrogen cycle involves nitrogen fixation by bacteria, its use by organisms, and release back through denitrification. Unlike carbon and nitrogen, phosphorus does not have a gaseous phase and predominantly forms insoluble mineral compounds, cycling slowly between organisms and marine sediments.
Had this been the year 2013, I would have taught you that all extant.pdfaucmistry
Had this been the year 2013, I would have taught you that all extant Cyanobacteria are capable of
oxygenic photosynthesis. I also would have taught you that some of the earliest fossils of life on
earth are stromatolites, which are beach-ball-sized structures believed to have been formed by
ancient Cyanobacteria ~3.5 billion years ago. In 2013, I would have put these two facts together
and taught you that oxygenic photosynthesis must have been present by ~3.5 billion years ago
and that the Great Oxidation Event, which occurred ~2.4 billion years ago when O2 from
oxygenic photosynthesis started to accumulate in the atmosphere and oceans, was simply a long
time (~1 billion years) in the making. However, in the last ten years we have discovered two
lineages of Cyanobacteria that, much to our surprise, proved to be non-photosynthetic. The
phylogenetic relationship of these two new lineages (seen in the image below) has forced us to
reinterpret the timing of the origin of oxygenic photosynthesis. First, explain why the fossils and
phylogeny combine to make us think that oxygenic photosynthesis might not be as ancient as we
once thought. And second, why would a different pattern of phylogenetic relationshipfor
example, if these two new lineages had been nested inside of the clade of previously known
cyanobacterianot have caused us to reconsider our earlier thinking?.
58 S C I E N T I F I C A M E R I C A N M A R C H 2 0 0 6.docxtroutmanboris
58 S C I E N T I F I C A M E R I C A N M A R C H 2 0 0 6
I
n 1956 Roger Revelle and Hans Suess, geochemists at
the Scripps Institution of Oceanography in California,
pointed out the need to measure carbon dioxide in the
air and ocean so as to obtain “a clearer understanding
of the probable climatic effects of the predicted great indus-
trial production of carbon-dioxide over the next 50 years.”
In other words, they wanted to fi gure out how dire the situ-
ation would be today. That they had to argue the importance
of such observations now seems astonishing, but at the time
scientists did not know for certain whether the carbon diox-
ide spewing out of tailpipes and smokestacks would indeed
accumulate in the atmosphere. Some believed that it would
all be absorbed benignly by the sea or be happily taken up by
growing plants on land.
Revelle and the young researcher he hired for this project,
the late Charles David Keeling, realized that they had to set
up equipment at remote locations, far from local sources and
sinks of carbon dioxide, which would cause the measure-
ments to vary erratically. One spot they chose was about as
far from industrial activity and vegetation as anyone could
get: the South Pole. Another was at a newly established
weather station atop Mauna Loa in Hawaii.
The Mauna Loa monitoring has continued (with just one
brief interruption) from 1958 to this day. Being not so remote
as Antarctica, Hawaii sees carbon dioxide levels rise and fall
sharply in step with the Northern Hemisphere’s growing sea-
son, but at the end of each and every year, the concentration
of this heat-trapping gas always ends up higher than it was 12
Much of the carbon dioxide given off from the burning of fossil fuels goes into the ocean, where it changes the
acid balance of seawater. The r eper cussions for marine lif e may be enor mous B Y S C O T T C . D O N E Y
The Dangers of
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COP YRIGHT 2006 SCIENTIFIC A MERIC A N, INC.
w w w . s c i a m . c o m S C I E N T I F I C A M E R I C A N 59
months before. So it did not take long for the scientifi c com-
munity to realize that Revelle was right—much of the carbon
dioxide released into the atmosphere was destined to remain
there. But his calculations were also correct in showing that
a substantial fraction would end up in the sea. And it was clear
to Revelle long ago that the part that went into the ocean would
fundamentally alter the chemistry of seawater. Unlike some
aspects of climate change, the reality of this effect— essentially
the acidifi cation of the ocean—is not much debated, although
its full implications are just now being revealed.
How Unnatural?
t h e h a l f - c e n t u r y r e c o r d that Keeling produced is
extremely valuable, but it is too short to place the current
situation in context. Scientists have, however, been able to
obtain a longer-term perspe.
1. Biogeochemistry is the study of the cycles of chemical elements like carbon and nitrogen through biological and geological systems over space and time. Key cycles include the carbon, nitrogen, phosphorus, and sulfur cycles.
2. These biogeochemical cycles involve the movement of elements between living and non-living components of the Earth system, including the atmosphere, lithosphere, hydrosphere, and biosphere.
3. Microbes play an important role in transforming elements between their various chemical forms and facilitating their movement between different Earth reservoirs as part of these global element cycles.
The future life span of Earth’s oxygenated atmosphereSérgio Sacani
Earth’s modern atmosphere is highly oxygenated and is a remotely detectable signal of
its surface biosphere. However, the lifespan of oxygen-based biosignatures in Earth’s
atmosphere remains uncertain, particularly for the distant future. Here we use a
combined biogeochemistry and climate model to examine the likely timescale of
oxygen-rich atmospheric conditions on Earth. Using a stochastic approach, we find that
the mean future lifespan of Earth’s atmosphere, with oxygen levels more than 1% of the
present atmospheric level, is 1.08 ± 0.14 billion years (1σ). The model projects that a
deoxygenation of the atmosphere, with atmospheric O2 dropping sharply to levels
reminiscent of the Archaean Earth, will most probably be triggered before the inception
of moist greenhouse conditions in Earth’s climate system and before the extensive loss
of surface water from the atmosphere. We find that future deoxygenation is an
inevitable consequence of increasing solar fluxes, whereas its precise timing is
modulated by the exchange flux of reducing power between the mantle and the ocean–
atmosphere–crust system. Our results suggest that the planetary carbonate–silicate cycle
will tend to lead to terminally CO2-limited biospheres and rapid atmospheric
deoxygenation, emphasizing the need for robust atmospheric biosignatures applicable
to weakly oxygenated and anoxic exoplanet atmospheres and highlighting the potential
importance of atmospheric organic haze during the terminal stages of planetary
habitability.
The document examines various hypotheses regarding the origin of life on Earth, such as abiogenesis, the RNA world, and panspermia. It discusses early Earth conditions and the emergence of the earliest life forms. While panspermia provides a favored hypothesis for how life began on our planet, the document concludes that delivery of organic molecules by comets alone was likely not sufficient and that additional triggers were needed to initiate life.
1) Early Earth had a different atmosphere than today and was bombarded by asteroids and comets. 2) Miller-Urey experiments showed how organic molecules could form in early Earth conditions. 3) RNA may have come before DNA and led to early life forms. Photosynthetic bacteria later produced oxygen that changed Earth's atmosphere.
Greenhouse gases are compounds in Earth's atmosphere that absorb and emit infrared radiation, trapping heat in the lower atmosphere. The major greenhouse gases are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. While some occur naturally, human activities like burning fossil fuels have increased their atmospheric concentrations since the industrial revolution. This occurs as these activities release carbon that was previously stored in solid form back into the atmosphere as a gas. The increased greenhouse gases are enhancing the natural greenhouse effect and contributing to global climate change.
1) Early Earth had a different atmosphere than today and was bombarded by asteroids and comets. 2) Experiments in the 1950s suggested that organic molecules could form from inorganic compounds on the early Earth. 3) By 3.8 billion years ago, protein-like microspheres may have formed and taken on some characteristics of living cells.
The Antarctic ozone hole refers to the seasonal depletion of stratospheric ozone over Antarctica. It was determined that CFCs from refrigerants and aerosols were the main cause by depleting ozone. Less ozone allows more UV radiation to reach the Earth's surface, affecting human health and marine ecosystems. The ozone hole forms due to chemical reactions on polar stratospheric clouds that release reactive radicals to catalytically destroy ozone in the Antarctic vortex. Increased UV radiation threatens phytoplankton and marine food webs in Antarctica, with potential global impacts.
Presentation is about the "Origin of Life". Many theories being proposed to clearly explains how does Life actually came into existence on our planet Earth.
J. Sequeira Ocean Acidification SoA ReviewJohn Sequeira
This document summarizes research on ocean acidification and its effects. It discusses how increased CO2 absorption by oceans leads to acidification, affecting calcium carbonate availability and organisms that use it in shells and skeletons. While most research focuses on single species responses, one study found increased calcification in coccolithophores during winter when pH is lowest, contradicting hypotheses. Experts agree ocean acidification due to CO2 emissions will continue for centuries and exceed past rates, but have less consensus on specific biogeochemical issues.
The document discusses the astronomical origins of life and how the basic chemical elements necessary for life were created in stars before being incorporated into planets like Earth. It outlines how carbon, hydrogen, oxygen, and nitrogen came together on Earth to form the first living organisms around 4 billion years ago. The document also explores extremophile microorganisms that can survive in extreme environments and how their ability to inhabit harsh conditions contributes to our understanding of possible life in other parts of the solar system like Mars or Europa.
Carbon cycle and global concerns on environmentRajat Nainwal
Carbon is the primary building block of life and cycles through different carbon pools in the biosphere, lithosphere, hydrosphere, and atmosphere. The global carbon cycle involves fluxes of carbon between these pools through natural processes like photosynthesis, respiration, and geological processes. However, human activities like burning fossil fuels and deforestation have significantly increased carbon dioxide levels in the atmosphere, disrupting the natural carbon cycle and causing global climate change. Rising global temperatures will lead to problems like rising sea levels, food shortages, and threats to biodiversity.
The document summarizes two mesoscale iron enrichment experiments conducted in the Southern Ocean to investigate the effects of iron enrichment in regions with high and low concentrations of silicic acid. The experiments found that iron plays a pivotal role in controlling carbon uptake and regulating atmospheric carbon dioxide levels. Iron enrichment led to increased phytoplankton growth and biomass in both the high silicic acid waters of the south and the low silicic acid waters of the north, demonstrating that large increases in nitrate-based photosynthesis and carbon export can occur across the Southern Ocean with added iron.
1) Nutrient cycling involves the movement of elements like carbon, nitrogen, oxygen, and water through biotic and abiotic components of the biosphere.
2) There are two main types of nutrient cycles - gaseous cycles like carbon and nitrogen that occur globally in the atmosphere, and sedimentary cycles like phosphorus that tend to accumulate in sediments.
3) Nutrient cycles can operate globally, with gases circulating worldwide, or locally within ecosystems, with nutrients like phosphorus and calcium cycling within soils. Photosynthesis and respiration drive the global carbon cycle, while nitrogen is transformed between chemical forms by both biological and non-biological processes.
Matthew Professional CV experienced Government LiaisonMattGardner52
As an experienced Government Liaison, I have demonstrated expertise in Corporate Governance. My skill set includes senior-level management in Contract Management, Legal Support, and Diplomatic Relations. I have also gained proficiency as a Corporate Liaison, utilizing my strong background in accounting, finance, and legal, with a Bachelor's degree (B.A.) from California State University. My Administrative Skills further strengthen my ability to contribute to the growth and success of any organization.
Lifting the Corporate Veil. Power Point Presentationseri bangash
"Lifting the Corporate Veil" is a legal concept that refers to the judicial act of disregarding the separate legal personality of a corporation or limited liability company (LLC). Normally, a corporation is considered a legal entity separate from its shareholders or members, meaning that the personal assets of shareholders or members are protected from the liabilities of the corporation. However, there are certain situations where courts may decide to "pierce" or "lift" the corporate veil, holding shareholders or members personally liable for the debts or actions of the corporation.
Here are some common scenarios in which courts might lift the corporate veil:
Fraud or Illegality: If shareholders or members use the corporate structure to perpetrate fraud, evade legal obligations, or engage in illegal activities, courts may disregard the corporate entity and hold those individuals personally liable.
Undercapitalization: If a corporation is formed with insufficient capital to conduct its intended business and meet its foreseeable liabilities, and this lack of capitalization results in harm to creditors or other parties, courts may lift the corporate veil to hold shareholders or members liable.
Failure to Observe Corporate Formalities: Corporations and LLCs are required to observe certain formalities, such as holding regular meetings, maintaining separate financial records, and avoiding commingling of personal and corporate assets. If these formalities are not observed and the corporate structure is used as a mere façade, courts may disregard the corporate entity.
Alter Ego: If there is such a unity of interest and ownership between the corporation and its shareholders or members that the separate personalities of the corporation and the individuals no longer exist, courts may treat the corporation as the alter ego of its owners and hold them personally liable.
Group Enterprises: In some cases, where multiple corporations are closely related or form part of a single economic unit, courts may pierce the corporate veil to achieve equity, particularly if one corporation's actions harm creditors or other stakeholders and the corporate structure is being used to shield culpable parties from liability.
Guide on the use of Artificial Intelligence-based tools by lawyers and law fi...Massimo Talia
This guide aims to provide information on how lawyers will be able to use the opportunities provided by AI tools and how such tools could help the business processes of small firms. Its objective is to provide lawyers with some background to understand what they can and cannot realistically expect from these products. This guide aims to give a reference point for small law practices in the EU
against which they can evaluate those classes of AI applications that are probably the most relevant for them.
सुप्रीम कोर्ट ने यह भी माना था कि मजिस्ट्रेट का यह कर्तव्य है कि वह सुनिश्चित करे कि अधिकारी पीएमएलए के तहत निर्धारित प्रक्रिया के साथ-साथ संवैधानिक सुरक्षा उपायों का भी उचित रूप से पालन करें।
Genocide in International Criminal Law.pptxMasoudZamani13
Excited to share insights from my recent presentation on genocide! 💡 In light of ongoing debates, it's crucial to delve into the nuances of this grave crime.
Sangyun Lee, 'Why Korea's Merger Control Occasionally Fails: A Public Choice ...Sangyun Lee
Presentation slides for a session held on June 4, 2024, at Kyoto University. This presentation is based on the presenter’s recent paper, coauthored with Hwang Lee, Professor, Korea University, with the same title, published in the Journal of Business Administration & Law, Volume 34, No. 2 (April 2024). The paper, written in Korean, is available at <https://shorturl.at/GCWcI>.
Defending Weapons Offence Charges: Role of Mississauga Criminal Defence LawyersHarpreetSaini48
Discover how Mississauga criminal defence lawyers defend clients facing weapon offence charges with expert legal guidance and courtroom representation.
To know more visit: https://www.saini-law.com/
What are the common challenges faced by women lawyers working in the legal pr...lawyersonia
The legal profession, which has historically been male-dominated, has experienced a significant increase in the number of women entering the field over the past few decades. Despite this progress, women lawyers continue to encounter various challenges as they strive for top positions.