Hank describes the desperate need many organisms have for nutrients (specifically nitrogen and phosphorus) and how they go about getting them via the nitrogen and phosphorus cycles.

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Table of Contents

Nitrogen Cycle 1:46
Nitrogen Fixing Bacteria 2:32
Nitrifying Bacteria 3:24
Denitrifying Bacteria 4:34
Phosphorous Cycle 5:16
Lithosphere 5:27
Plants 5:56
Animals 5:56
Decomposers 5:56
Aquatic & Marine Ecosystems 6:24
Sedimentation & Weathering 6:55
Synthetic Fertilizers 7:23

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