Nutrient Cycling

1. Nutrient Cycling 3.3

2. Energy vs. Matter • Energy flows throughout an ecosystem in ONE direction from the sun to autotrophs to heterotrophs • Matter is recycled • WHY?

3. Biogeochemical Cycles • “Matter can cycle through ecosystems because organisms don’t USE it, they TRANSFORM it.” • Matter/Nutrient cycled includes: • Water • Nitrogen • Carbon • Phosphorous

4. Water Cycle • Processes involved: • Evaporation-water changes from liquid to atmospheric gas • Transpiration- water evaporates OUT of plant leaves • Also, condensation, precipitation, seepage, runoff…

5. Carbon Cycle • Key ingredient of living tissue, found in many places • Found in animal skeletons, rocks, carbon dioxide, carbohydrates, etc. • Processes Involved That Take Up and Release Carbon: • Biological- photosynthesis, respiration, decomposition • Geochemical- erosion, volcanic activity • Mixed- burial and decomposition coal and petroleum • Human Activities- mining, cutting and burning forests, burning fossil fuels

7. Nitrogen Cycle • All organisms require nitrogen to make amino acids • Occurs in many forms: N2 (78% atm gas), Ammonia (NH3), Nitrate and Nitrite (NO3- and NO2-) are found in waste products and fertilizers • Processes involved: • Nitrogen Fixation: conversion of nitrogen gas into ammonia by bacteria (occurs in the roots of legumes) also can occur thru lightning • Ammonia can be converted into nitrates and nitrites, which are taken up by plants and enter the food web • Denitrification: bacteria in soil convert nitrates into nitrogen gas

9. Phosphorous Cycle • All organisms require phosphorous to create DNA and RNA • Does not enter atmosphere, not very common • Exists inorganic form in land rock and soil minerals and ocean sediment • Processes involved: • Erosion: sediment washes into rivers, streams, and ocean • Absorption: Plants and marine organisms take up the phosphorous and it moves through the food web