A2 (Half assed) Flashcards
Biogeochemical Cycles
Complex cyclical transfer of nutriets from the environment to organisms and back to the environment
Hydrological Cycle
The circular movement of water from the ocean reservoir to the air (cloud), back to the Earth in the form of rain, snow, and finally back to the ocean reservoir via streams and estuaries
Evaporation
Liquid to vapor
Condensation
Water vapor to liquid
Transpiration
Water vapor loss in plant (cooling when hot)
Precipitation
Rain / Snow / Sleet / Hail falls to the ground
Runoff
More water than land can absorb runs into creek / streams / ponds
Percolation
Rain water seeps into soil and filters down
What “powers” the water cycle
Solar energy and gravity
- Solar energy causes water to evaporate from the soil, plants, ocean, lakes, streams
- Warm air rises and lifts the water into the atmosphere, where it forms clouds
- Gravity pulls it down again as rain and snow
Oxygen Cycle
The oxygen cycle is closely related to the carbon cycle as they are linked by both photosyntehsis and cellular respiration
Evidence of an oxygen rich atmosphere
Stromatolites
Dome-shaped rocks composed of thin layers of sediment pressed tightly together.
Formed by photosynthetic cyanobacteria
Cross sections show red-iron bands help reveal what the composition of the ancient atmosphere was like
Evidence of an oxygen rich atmosphere
Banded Iron Formations
Thought to have as oxygen produced by cyanobacteria reacted with dissolved iron in the oceans and precipitated out, forming a thin layer on the ocean floor
Nitrogen Cycle
- Bacteria convert N (gas) —> Ammonia via nitrogen fixation
- Ammonia –> Nitrates to be used by plants
- Animals can obtain nitrogen by eating plants
- Excess nitrates in soil –> N (gas) by bacteria (denitrification)
The movement of nitrogen through ecosystems, the soil and the atmosphere
Nitrogen Fixation
Nitrogen –> Ammonium
Nitrification
Ammonium –> Nitrites by bacteria
Assimilation
PLants absorb nitrates into roots
Consumption
Organisms eat plants
Ammonification
Organisms excrete wastes/dies
Denitrification
Nitrate (NO3) —> Nitrogen (N2) back into the atmosphere
N-fixing bacteria
Convert nitrogen to ammonium for plants and plants provide bacteria with sugars produced via photosynthesis