Carbon Cycle

Review flashcards covering key carbon cycle concepts: reservoirs (sinks/sources), atmosphere–ocean exchange, photosynthesis vs respiration, burial and fossil fuels, and how rapid human activities alter the cycle.

What does the carbon cycle move and between which types of reservoirs?

Movement of carbon-containing molecules (CO2, glucose, CH4) between sources and sinks (atmosphere, ocean, plants, soil, sediments) with some steps fast (e.g., combustion) and some slow (e.g., sedimentation & burial).

What is a carbon sink?

A reservoir that stores more carbon than it releases (e.g., ocean, plants, soil, sediments).

What is a carbon source?

A reservoir that releases more carbon than it takes in (e.g., fossil fuels via combustion; respiration).

What happens when atmospheric CO2 increases?

Leads to global warming due to the enhanced greenhouse effect.

How does combustion affect the carbon cycle?

Burning fossil fuels converts stored carbon into CO2, increasing atmospheric CO2 levels.

What is the direct exchange between the atmosphere and the ocean?

CO2 moves quickly between air and surface ocean via dissolution and release; occurs in both directions and tends to balance levels, but higher atmospheric CO2 also raises ocean CO2, contributing to ocean acidification.

What is ocean acidification?

The lowering of ocean pH due to increased dissolved CO2 from the atmosphere.

Photosynthesis

Process by which producers convert CO2 and H2O into glucose (C6H12O6) and O2 using sunlight; removes CO2 from the atmosphere.

Cellular respiration

Process by which organisms break down glucose with O2 to release energy, producing CO2 and H2O; releases CO2 to the atmosphere.

Long-term carbon reservoir formed by burial

Sedimentation and burial compress carbon-containing sediments on the ocean floor into sedimentary rock (e.g., limestone), storing carbon long-term.

Fossil fuels

Coal, oil, and natural gas formed from buried organic matter; their combustion releases CO2 into the atmosphere.

Extraction & combustion

Mining and burning fossil fuels releases CO2 quickly; burial forms fossil fuels slowly over geological time.

Sedimentation

Calcium carbonate precipitates and settles as sediment on the ocean floor.

Calcium carbonate exoskeletons

Organisms like coral and mollusks use CO2 to build CaCO3 shells; these become part of sediment when they die.

Role of producers/consumers/decomposers

Producers fix CO2 into sugars via photosynthesis; consumers and decomposers release CO2 via respiration and decomposition; burial/removal stores carbon long-term.

Quick vs slow carbon cycle processes

Some processes are fast (e.g., combustion, respiration, photosynthesis); others are slow (sedimentation & burial), which affects the rate of carbon transfer.