Major Nutrient Cycles

Major Nutrient Cycles

Carbon Cycle

Water Cycle

Important Processes: *The water cycle is mainly powered by the evaporation of water in its liquid state through solar energy, precipitation, and condensation of water (vapor) into clouds. Water can also be moved through transpiration by terrestrial plants. *The water cycle in completed when surface flow returns water to the oceans.

Key Processes:*Photosynthesis & Phytoplankton: remove amounts of atmospheric carbon dioxide*Volcanoes: over geologic time provide carbon dioxide *Burning of fossil fuels: adds carbon dioxide to atmosphere

Forms Available: *Liquid water (most common)*Water vapor (some organisms)*Frozen water (limits how much water is available to terrestrial plants)

Importance: all organisms need water; its availability affects the speed of ecosystem processes.

Importance: Organic molecules are necessary in all organisms and carbon has the ability to form the basis for said molecules.

Reservoirs:97% in oceans2% in glaciers & polar ice caps1% in lakes, rivers, etc.

Forms Available: Organisms who are phtosynthetic use carbon dioxide during photosynthesis and change the arbon to organic forms. These forms are used by fungi, animals, and other consumers.

Reservoirs: *fossil fuels *soils *oceans*atmosphere

Terrestrial Nitrogen Cycle

Key Processes: *Nitrogen Fixation: conversion of nitrogen gas by bacterias into forms that can be used to synthesize compounds containing nitrogen *Lightning: fixes nitrogen*Ammonification *Nitrification *Denitrification

Reservoirs: *atmosphere (80% nitrogen gas)*soils and sediments of rivers, lakes, oceans*surface water and groundwater*biomass of organisms

Forms Available: *Plants: ammonium, nitrate (both inorganic) amino acids (organic)*Bacteria: all the same forms as above and nitrite*Animals : only use organic forms of nitrogen

Importance: Nitrogen is a part of amino acids, nucleic acids, and proteins.