Topic 1: Part 2 Flashcards
(24 cards)
What are the spheres of the earth system?
Four main spheres with subspheres; the atmosphere, hydrosphere, biosphere, and geosphere.
What allows the ingredients for life to move through spheres?
Biogeochemical cycles involving chemical reactions or phase changes. The ingredients can be stored in one sphere for a period before inevitably moving to another.
How does the hydrologic cycle work?
Water is stored in different reservoirs for different periods of time before moving through various processes to other reservoirs. These processes have different rates depending on wind, temperature, humidity, and other factors.
How does the carbon cycle work?
Carbon has been on Earth since it was formed and recycled over the eons. It moves through photosynthesis (atmosphere -> biosphere), cellular respiration (biosphere -> atmosphere), and decomposition (biosphere -> pedosphere). Carbon also dissolves into oceans from the atmosphere (atmosphere -> hydrosphere) and is incorporated into shells and skeletal structures of living organisms (Calcium carbonate, hydrosphere -> biosphere). Burial, compaction, and cementation (lithification) of these organisms leads to the formation of limestone (biosphere -> geosphere). Lastly, ocean cycling transfers carbon between surface and deep oceans. So, in summary, carbon is temporarily stored in different reservoirs within each sphere and transferred to other reservoirs through various processes!
What are some carbon reservoirs?
Atmosphere, vegetation, soils, surface of the ocean, deep ocean, rocks and sediments. The size of the reservoir increases through this list.
What rock type stores most of the world’s carbon?
Carbonate rocks (e.g. limestone)
What impacts the rate of carbon exchange (flux) from reservoir to reservoir?
Generally, the larger the reservoir the longer it takes to exchange its carbon with another reservoir.
Are large fluxes approximately balanced from year to year?
Yes. Annual carbon in approximately = annual carbon out.
What are scientific models?
Physical, mathematical, or conceptual representations of a system of ideas, events, or processes. They are simplified versions of reality.
What is the residence time?
The length of time carbon stays in any given reservoir.
What are carbon sinks?
Reservoirs that remove more carbon from the atmosphere than they release and that then store that carbon for long periods of time.
What are some other crucial cycles in the Earth system?
The nitrogen cycle, the sulfur cycle, and the phosphorus cycle.
What is the rock cycle?
A cycle that describes the process of one rock type becoming another when it enters a new tectonic environment.
Weathering and volcanism are two major processes that allow elements to exchange between the geosphere, hydrosphere and atmosphere.
What is the difference between weathering and erosion?
Weathering is the breakdown of rock into smaller particles through physical or chemical means. Erosion is the transportation of these weathered particles by wind, water, gravity, and glaciers.
What is physical weathering and what are some examples of it?
Physical weathering is the mechanical breakdown of rocks into smaller pieces. Some examples are frost wedging, root wedging, ventifaction (blowing wind sandblasting rocks), thermal expansion (and contraction), salt crystal growth, and bioturbation.
What controls the rates of physical weathering?
- Local climactic/environmental conditions
- Rock type, textures, structures
- Biological activity
- Time
What is chemical weathering and what are the chemical processes involved?
Chemical weathering alters rocks and minerals at Earth’s surface as they react with water, oxygen and carbon dioxide. This produces new minerals and dissolved elements and compounds.
4 main processes lead to chemical weathering:
1. Dissolution/Solution
2. Oxidation
3. Hydration
4. Hydrolysis
What is a karst and how are they formed?
A karst is an underground cave system formed by the dissolution of sulfur dioxide or carbon dioxide with water to produce acid, which dissolves carbonate rocks to create a solution of calcium and bicarbonate ions. This process also causes surface weathering.
What are speleothems?
Travertine: carbonate rock precipitated directly from solution
Dripstones: Stalactites and stalagmites
What minerals are most susceptible to oxidation?
Pyroxene, amphibole, magnetite, pyrite and olivine are most susceptible to oxidation
because they are high in iron
What is hydration?
Hydration occurs when minerals combine with water, changing their structures.
What is hydrolysis?
A complex weathering reaction that produces clays, commonly K feldspar reacts with H+ and OH- solutions in water to produce clay minerals, potassium ions, and silica in solution.
What is the main chemical reaction that removes carbon from the atmosphere?
Hydrolysis.
What controls the rate of chemical weathering?
- Surface environment (underwater or not)
- Exposed surface area
- Grain size
- Climate
- Nature of rocks and minerals
