Ecology Final
Terms
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- Decomposition
- breakdown of complex organic structures into more simple organic structures, breakdown of chemical bonds. Involves respiration and ultimately converts organic compounds into inorganic nutrients
- Detritus
- above and below-ground litter that provides energy (carbon) and nutrients. Litter falls to the ground, accumulates, and is decomposed.
- Litter Quality
- provides both energy (carbon) and nutrient (nitrogen) source for decomposers.
- Carbon Quality
- the faster a carbon source breaks down the higher the quality Lignin = low Glucose = high
- Nutrient Quality
- essentially C:N ration or N concentrations. If the ratio is high, the supply of a nutrient relative to the energy is low
- Relationship of simple sugars and lignins with decomposition
- Lignins have a low k b/c they break down slow Simple sugars have a high k b/c they break down fast
- Relationship between carbon quality and decomposition rate
- The higher the carbon quality (like simple sugars) the higher the decomposition rate.
- Relationship between decomposition rate and climate
- Climate = moisture/temp. Decomposers like warm and moderately moist environments.
- Turnover Rate
- k=litter fall/detrital mass This equation also represents the turnover rate
- Decomposition of carbon overtime
- Total carbon has neg. expo. Curve due to quick loss of material easily decomposed, the slope is very steep due to easy decomposition and slows as it comes upon lignin
- Litter Bags
- Mesh bags with litter in them. Moisture can come through. Measure mass prior and after the experiment to understand the carbon loss
- Sources of nitrogen for plants
- Nutrient Cycle: NH4, NO3, amino acids
- Net Mineralization
- 1) Nutrient content exceeds microbial demand 2) Nutrients released to soil in mineral form 3) Net decrease in nutrient content of litter, slow C/mass loss
- Net Immobilization
- 1) Microbes want more nutrients than available 2) Nutrients drawn from soil 3) net increase in nutrient content of litter, while C/mass drops
- Equation of net mineralization
- Net mineralization = mineralization - immobilization = rate nutrients are available for plant uptake
- Nitrogen transformations over time during decomposition
- At the start, more nitrogen is needed causing immobilization Later, mineralizing occurs