Carbon Cycle & Photosynthesis

• Cycles of matter circulate matter between the Earth, atmosphere, and living organisms.
• Natural matter cycles enable the transport and storage of matter, providing essential elements to living things for biosynthesis.
• Prominent matter cycles include the carbon and nitrogen cycles.

Carbon Cycle

• The carbon cycle involves the movement of carbon among the Earth, atmosphere, and living things.
• Disruption of this cycle via human activities contributes to global warming.
• Carbon cycles through Earth and living things via photosynthesis, respiration, combustion, and dissolution.
• Carbon is essential to living organisms; life on Earth is carbon-based.
• Carbon's electron configuration enables it to form up to four bonds, creating diverse molecules, such as nucleic acids, proteins, carbohydrates, and lipids.

Photosynthesis

• Photosynthesis is the process some organisms use to produce food from carbon dioxide, sunlight, and water, yielding oxygen and glucose.
• Photosynthesis removes carbon dioxide from the atmosphere, incorporating it into chemical structures like glucose.
• Carbon assimilated by plants is distributed through the ecosystem when primary consumers eat the plants.
• Carbon is released back into the atmosphere and soil upon the death of living things.
• Deforestation disrupts this cycle by reducing the amount of carbon dioxide removed from the atmosphere, increasing atmospheric carbon.
• Excess carbon dioxide, a greenhouse gas, contributes to global warming and climate change.

Respiration

• Respiration is the process that organisms use to exchange gases with the environment.
• During cellular respiration, organisms use oxygen and glucose to produce ATP, carbon dioxide, and water.
• Carbon dioxide is released into the atmosphere through respiration, which is used by humans and other animals for energy.

Combustion

• Combustion is the process of burning matter, releasing carbon dioxide into the atmosphere.
• Fossil fuels, derived from carbon, power vehicles and electricity production, releasing carbon dioxide when burned.
• Combustion also occurs during forest fires, deforestation, and volcanic eruptions.

Cycling of Carbon in the Ocean

• The ocean is a significant carbon sink, absorbing carbon dioxide from the air, which dissolves into carbonic acid.
• Over time, carbonic acid can be compressed into rock on the ocean floor or incorporated into the shells of sea animals as calcium carbonate.
• Calcium carbonate in shells accumulates on the ocean floor, forming limestone, Earth's largest carbon reservoir.
• Excessive atmospheric carbon dioxide leads to an excess of carbonic acid in the ocean, causing ocean acidification and disrupting the marine ecosystem.

Nitrogen Cycle

• The nitrogen cycle involves the movement of nitrogen among the Earth, atmosphere, and living organisms.
• Nitrogen is a vital element for living things, a key component of proteins and nucleic acids.
• The atmosphere is 78% nitrogen gas, but this form is unusable for most organisms and must be "fixed" into usable forms.

Nitrogen Fixation

• Nitrogen fixation converts atmospheric nitrogen into a usable form through lightning or special soil bacteria.
• Nitrogen-fixing bacteria convert nitrogen gas into ammonia, which is then transformed into nitrites and nitrates by nitrifying bacteria.
• These forms are usable by plants with some bacteria living in the soil, and others in plant root nodules in a symbiotic relationship.

Assimilation

• Assimilation is the process where plants absorb nitrogen to create biomolecules.
• Plants are consumed by organisms in the ecosystem and pass nitrogen through the food web.
• When organisms die, nitrogen is released back into the atmosphere and soil, recycling it back into the nitrogen cycle.
• Human activities, such as fertilizing crops, disrupt the nitrogen cycle by adding excess nitrogen to ecosystems.
• Excess nitrogen leads to eutrophication, disrupting the balance of ecosystems, especially in aquatic environments, causing algal blooms.

Comparing Nitrogen and Carbon Cycles

Explore the carbon cycle's movement between Earth, atmosphere, and life. Understand the process of photosynthesis, where organisms create food from carbon dioxide, sunlight, and water, producing oxygen and glucose. Learn how carbon's unique bonding properties enable complex molecules essential for life.