Geologic Time and Carbon Sinks

Geologic Time and Arctic Peat

Formation and Composition

• Scientific studies, including fossil and ice core data analysis, indicate that peat found in Arctic permafrost began forming approximately 11,000 years ago.

• This peat originated from living plants that died and have been slowly decomposing over thousands of years in cold, oxygen-poor conditions, which slows down the decomposition process.

• Composition includes partially decayed plant matter, contributing to its high carbon content.

Carbon Storage

• Estimated 1.5 trillion metric tons of organic carbon are stored in the peat within the permafrost.

• This quantity represents twice the amount of carbon currently present in the Earth's atmosphere, highlighting the significance of Arctic peat as a major carbon reservoir.

Arctic Climate 11,000 Years Ago

Climatic Conditions

• Data suggests that the Arctic was slightly warmer 11,000 years ago during the peat formation period.

• Several factors could have contributed to a warmer Arctic, including variations in Earth's tilt and orbital parameters.

Earth's Tilt and Solar Radiation

• Over geologic time, the Earth's tilt angle has changed, influencing the distribution of solar radiation across the planet.

• These changes have affected the amount of solar radiation reaching the Earth's surface, particularly in the Arctic regions.

• Currently, the Earth's tilt is at $23.5°$.

• During the period when the plants that formed the peat were actively growing, the Earth's tilt was $24.5°$.

• A greater tilt angle resulted in more solar radiation reaching the Arctic for a longer period during the year, providing more direct sunlight and energy.

• As the Earth's tilt decreased, less solar radiation became available in the Arctic.

• The Arctic cooled, receiving less direct sunlight and solar energy, leading to the gradual formation of peat and permafrost.

Obliquity Cycles

• Obliquity changes over approximately 41,000-year cycles, causing cyclical variations in solar radiation.

• Tilt ranges from $22.1°$ to $24.5°$, influencing the intensity of solar radiation in polar regions.

• A greater tilt angle corresponds to more direct solar radiation in the Arctic, resulting in warmer conditions and enhanced plant growth.

• A smaller tilt angle results in less direct solar radiation, contributing to cooler conditions and permafrost formation.

Photosynthesis and Carbon Storage

Photosynthetic Processes

• Plants convert carbon dioxide and water into sugar and oxygen through photosynthesis, utilizing solar energy as the driving force.

• More solar energy leads to more carbon dioxide being captured and stored by plants as sugar, a fundamental process in carbon sequestration.

• Plants convert excess sugar into larger carbon-based molecules like starch and cellulose, which form the building blocks of plant tissues.

• Increased solar radiation in the Arctic increased the potential for plants to capture and store carbon in chemical energy-based compounds, promoting biomass accumulation.

• Chemical energy is stored in chemical bonds in glucose and other organic molecules, providing energy for plant metabolism and growth.

• When solar radiation decreased, plants died, and their organic matter accumulated, leading to peat and permafrost formation over time.

Mechanisms Explaining Plant Matter in Arctic Peat

• Photosynthesis: Plants absorb carbon and convert it into sugar, effectively removing carbon dioxide from the atmosphere.

Changes in Energy Flow

Solar Radiation Dynamics

• The flow of energy from the sun to the Arctic has slowed over the last 11,000 years due to the decreasing tilt of the Earth.

• When the tilt was $24.5°$, there was more solar radiation, creating warmer conditions conducive to plant growth; as it decreased to $22°$, less solar radiation reached the Arctic, leading to cooling.

Effect on Photosynthesis

• The change in solar radiation directly affected photosynthesis, slowing it down due to less available energy, which impacted plant productivity and carbon uptake.

Relationships Between Variables

Types of Relationships

• Direct Relationship: As one variable increases, the other increases, indicating a positive correlation.

• Inverse Relationship: As one variable increases, the other decreases, indicating a negative correlation.

• Example: Increased use of antibiotics leads to increased antibiotic-resistant bacteria, illustrating a direct relationship where one action promotes another outcome.

Sunlight and Carbon Storage

• There is a direct relationship between available sunlight and the amount of carbon plants store through photosynthesis, highlighting the importance of solar energy in carbon sequestration.

• As the amount of sunlight increases, carbon stored in plants increases, leading to greater biomass accumulation and carbon storage in ecosystems.

• Independent Variable (cause): Sunlight.

• Dependent Variable (effect): Photosynthesis.

Photosynthesis and Cellular Respiration

Photosynthesis

• Photosynthesis: Light energy is converted to chemical energy, capturing carbon dioxide and producing oxygen and glucose.

• Inputs: $CO2$, $H2O$.

• Outputs: $C6H{12}O6$, $O2$.

Cellular Respiration

• Cellular Respiration: Glucose is broken down to release energy, consuming oxygen and producing water and carbon dioxide.

• Inputs: $C6H{12}O6$, $O2$.

• Outputs: $H2O$, $CO2$, ATP (energy).

Energy Loss in Ecosystems

Energy Transfer and Loss

• Energy is lost as heat during cellular respiration, as waste products, and when organisms die, resulting in reduced energy availability at higher trophic levels.

• This energy is released to the ecosystem, supporting scavengers and decomposers, which play a vital role in nutrient cycling.

Trophic Levels and Energy

Trophic Dynamics

• Being a quaternary consumer (fourth trophic level) is not beneficial because very little energy is available at this level (103 kcal), limiting the number of organisms that can be supported.

• There are fewer organisms at the top of the pyramid because of the decreasing amount of available energy as you move up the trophic levels, illustrating the ecological constraints on top predators.

Trophic Models

Ecosystem Modeling

• Different models help understand trophic levels and energy relationships in ecosystems, providing insights into energy flow and species interactions.

Ecological Pyramids

Types of Ecological Pyramids

• Numbers Pyramid: Shows the number of organisms at each trophic level. It can be inverted (more consumers than producers, like a tree supporting many insects), illustrating variations in population structure.

• Biomass Pyramid: Shows the total mass of organisms at each trophic level, usually expressed as dry weight (grams or kilograms per square meter). Generally shows a decrease in biomass at higher trophic levels but can be inverted in aquatic ecosystems where phytoplankton have a rapid turnover rate and low biomass, reflecting unique ecological dynamics in aquatic environments.

Carbon and Wildfires

Wildfire Conditions

• Large wildfires are most likely to occur in high-temperature and/or dry areas, where vegetation is parched and flammable.

• These areas have partially decomposed organic matter and stored carbon in the form of chemical energy, serving as fuel for wildfires.

Carbon Sinks

Definition and Importance

• A carbon sink is where carbon is stored deep in the earth, hidden from air or oxygen, preventing its release into the atmosphere.

Ecosystems and Carbon Sinks

• Many different ecosystems have carbon sinks created from the flow of energy and matter into plants by photosynthesis, highlighting the role of ecosystems in carbon sequestration.

Fires and Biosphere

Impact of Fires

• Fire increases the flow of matter and energy from the biosphere to the atmosphere, releasing stored carbon and altering ecosystem dynamics.

Concerns About Burning Carbon Sinks

Environmental Concerns

• Increased carbon dioxide in the air causes increased air temperature, contributing to global warming and climate change.

• Directional Hypothesis: Increased carbon dioxide concentration increases temperature, supported by global data indicating this relationship is similar at the global scale.

Wildfires and Carbon Dioxide

Effects of Wildfires

• Wildfires add more carbon dioxide to the atmosphere, exacerbating climate change and altering atmospheric composition.

• Carbon dioxide can negatively impact air quality, leading to respiratory problems and other health issues.

Earth as a Closed System

System Characteristics

• The Earth is a closed system because of the atmosphere, which prevents significant exchange of matter with outer space.

• The Earth's content (matter) doesn't move out of the Earth's atmosphere, emphasizing the importance of internal cycling of resources.

• Earth is open in terms of energy, as it receives solar radiation from the sun and emits heat into space.

Ecosystem Interconnection

Interdependencies

• What happens in one ecosystem can affect other ecosystems, highlighting the interconnectedness of ecological processes on a global scale.

Carbon Dioxide and Temperature

Correlation

• The more carbon dioxide in the atmosphere, the more the temperature rises on a global scale, illustrating the greenhouse effect and its impact on climate.

Data Analysis (1980-2018)

Data Points

• X-axis: Year (1980-2018).

• Y-axis: Global temperature anomaly in degrees Celsius.

• Y²-axis: Atmospheric CO2 concentration (ppm).

Specific Years

• 1980: CO2 concentration ~340 ppm, temperature anomaly ~0.18°C.

• 1996: CO2 concentration ~365 ppm, temperature anomaly between 0.3 and 0.4°C.

• 2018: CO2 concentration ~410 ppm, temperature anomaly ~0.9°C.

• Conclusion: There is a strong positive correlation between atmospheric CO2 concentration and global temperature anomaly. As CO2 increases, temperature increases, reinforcing the link between greenhouse gas emissions and global warming.

Earth's Systems

System Interactions

• Earth is made up of many systems that energy and matter flow through, including the atmosphere, hydrosphere, biosphere, and geosphere.

• A positive feedback effect is created as increased carbon dioxide causes increased temperature, which leads to more drought, which in turn causes more wildfires that release additional carbon dioxide into the atmosphere, accelerating climate change.

• This makes more carbon available in other spheres, altering ecosystem dynamics and climate patterns.

Earth's Spheres

Components

• Atmosphere: The layer of gases surrounding the Earth.

• Hydrosphere: All the water on Earth, including oceans, lakes, rivers, and ice.

• Biosphere: All living organisms and their interactions within the environment.

• Plants perform photosynthesis, capturing carbon dioxide and producing oxygen.

• Geosphere: The solid part of the Earth, including rocks, soil, and minerals.

Energy and Matter Flow

Processes

• Fires put more carbon dioxide into the atmosphere, releasing stored carbon and contributing to air pollution.

• Carbon goes to the atmosphere when fires in the biosphere burn, altering carbon cycling and ecosystem dynamics.

• Ice melting in the permafrost releases trapped organic matter, which decomposes and releases carbon dioxide and methane.

• Water covering plants making peat slows decomposition due to anaerobic conditions, promoting carbon storage over long periods.

• Carbon goes to the atmosphere when ice melts and decomposers do cellular respiration, releasing greenhouse gases and accelerating climate change.

• Organisms dying and decomposing release carbon into the soil and atmosphere.

• Humans/lightning causing fire starts wildfires, releasing carbon dioxide and other pollutants into the atmosphere.

• Carbon dioxide goes from the atmosphere to the biosphere when plants do photosynthesis, capturing carbon and producing oxygen.

• Decomposers in the soil break down organic matter, releasing nutrients and carbon dioxide into the environment.

• Peat decomposition releases carbon dioxide and other gases, contributing to greenhouse gas emissions.

• Carbon goes from the soil in the peat to the atmosphere when decomposers do cellular respiration, completing the carbon cycle.