#21-Nutrient Supply And Cycling Flashcards
What are nutrients?
Chemical elements required for metabolism and growth
- has to be in certain forms for uptake
Do animals or plants have a higher C:N ratio?
Animals have lower ratios
How do plants take up nutrients?
In simple soluble forms
How do animals take up nutrients ?
As large complex molecules that are broken down through digestion
-some can just be absorbed
What are minerals?
Solid substances with characteristic chemical properties
What is mechanical weathering?
The physical breakdown of rocks
What is chemical weathering?
Chemical reactions release soluble forms of the mineral element
What is soil?
A mix of organic matter and mineral particles water and organisms
What is a soil solution?
Water contains dissolved organic matter morals and gases
-plant roots absorb this solution
What is sand?
The coarsest particles
What is clay?
The smallest particles
What is the cation exchange capacity?
The ability of s soil to hold and exchange cations
- related to the amount and type of clay present
What happens to soil with a high portion of sand?
Can’t hold water well, all drains through
What is parent material?
The Rock and mineral material that was broken down by weathering to form soil
What does the structure of the parent material determine?
Rate of weathering
Amount of chemical released
- can influence abundance, growth and diversity of plants
Where is soil development the fastest?
Warm and wet conditions
Can nutrients be reused and recycled?
Yes
What is litter?
Fresh undecomposed organic matter on the soil surface
What is mineralization?
Chemical conversions or organic matter into inorganic nutrients
What controls decomposition?
Abiotic and biotic
What does mineralization determine?
Nutrient availability
What inhibits detrivores in soil?
Low O2 concentration in wet soils
What is lignin?
Strengthens plant cell walls
- can affect how well it can be broken down by detrivores
What is Nitrification?
NH3 and 4 –> NO3-
By bacteria in anaerobic conditions
What is denitrification?
NO3- –> N2
Under anoxic conditions
How do you estimate soil fertility?
Concentration of inorganic forms of Nitrogen
How can plants avoid competition of nitrogen?
Can take up different forms of it
What is nutrient cycling?
Movement of nutrients in ecosystems as they undergo biological and chemical and physical transformations
What are pools?
Total amount of nutrients in a component of the ecosystem
What is the mean residence time?
Turnover rate
- amount of time on average that a molecules lens in the pool
How are nutrients lost from an ecosystem?
Leach out of the root zone into ground water and streams
Lost as gases
Converted to chemical forms
What is a watershed?
The land area that is drained by a single stream is often used
How do nutrients get into a watershed?
Atmospheric deposition and nitrogen fixations
How are nutrients transferred through ecosystems?
Herbivory
Predation
Decomposition
Weathering
How does an ecosystem lose nutrients?
Streams
Atmosphere
Organisms moving
What is atmospheric deposition?
Elements in precipitation or aerosols and fine dust
Equation for the total amount of element entering the watershed
Concentration of element x volume of precipitation in watershed
What’s harder to measure, dry or wet deposition?
Dry
- done less often
What is primary succession?
Little organic matter in soil and little N
Where does P originate?
From weathering of the mineral apatite
What is occlusion?
Soluble P may combine with iron, calcium or aluminum to form insoluble compounds that are unavailable as nutrients
What is biogeochemistry?
The study of physical chemical and biological factors that influence the movement and transformation of elements
