Geochemical Cycles MP 1.5 Water Cycle = Hydrological Cycle • A series of events where water is stored and/or transferred. Water Storage • Water is stored in lakes, rivers, clouds, snow, and glaciers. Methods of Transfer • Precipitation (rain), rain runoff, condensation, sublimation, evaporation, transpiration, and snowmelt. The Carbon Cycle • Shows where all carbon comes from and goes to. • All animals and most cells release CO2. Plants use it to make food. • Only photosynthesis and decomposition return carbon to the earth most other processes release it to the atmosphere Carbon Cycle • CO2 is a greenhouse gas that traps heat in the atmosphere. The Greenhouse Effect Section 4-1 Sunlight Some heat escapes into space Greenhouse gases trap some heat Earth’s surface The Nitrogen Cycle 4 Processes of Nitrogen Cycle • Fixation – breaks stable nitrogen molecule apart so it can be attached, done by lightning and bacteria. • Decay – when plants and animals break down they return their nitrogen to the earth as ammonia. • Nitrification – conversion of ammonia from waste and decomposition to nitrates that plants must consume to grow (like fertilizer). • Denitrification – Nitrates are turned back into gas and released to atmosphere. The Nitrogen Cycle The Phosphorus Cycle Phosphorus Cycle • Important for plants and animals because it is a major constituent of DNA • Unlike other cycles it does not have a gaseous state at normal temperatures so it cycles through soil, water and sediments. • Plants pick it up through soil and animals get it from eating plants or eating animals that eat plants. • Stored in rocks and sediments for millions of years until released by weathering.