chapter 4 Flashcards
What are nutrients?
Nutrients are substances necessary for healthy physiology of organisms
What are macronutrients? What are micro nutrients?
Nutrients required in large quantities: like Carbon, Oxygen, Hydrogen
Micro nutrients are required in low quantities (less than 0.01% of plant biomass): iron manganese boron zinc chlorine sodium… (lack=deficiency too much causes toxicity (nickle and copper)
What is hyperaccumulation?
Some plants neutralize toxic substances by accumulating them in vacuoles (mangroves)
Bioremediation exploits this property of plants to help collect pollutant
Do we ever add new nutrients to a system?
No they are always cycled
Carbon cycle
Backbone of life (50%)
- Carbon (CO2) is fixed from the atmosphere through photosynthesis
* Carbon is released (CO2) through decomposition and respiration
* Storage as biomass (e.g.
peat, coal, oil, gas
- Found in ground!!!
When is there more carbon in the atmosphere and when is there less?
More carbon winter, less summer (plants)
(in temperate, boreal, and arctic latitudes of the Northern Hemisphere)
Tropical latitudes have relatively consistent rates of net production throughout the year\
What are the anthropogenic effects of carbon?
fossicl fule goes up
NItrogen cycle
Nitrogen: A critical component of all proteins
* Nitrogen is often growth-limiting
* Some forms of nitrogen are plant-available nutrients
Nitrogen is found in the atmosphere
What is phosphorous
It is a critical component of adenosine triphosphate (ATP), the energy source of cells, among other biomolecules
* Phosphorus is often growth-limiting in lakes
- It can be found in marine sediments
- it’s often a growth limiting factor
- Phosphorus returns to land using stuff like pacific salmon or sea birds
Explain the sulphur cycle
a critical component of
proteins and other biochemicals
* Gaseous sulphur is emitted by volcanos
* Some sulphur is produced by bacteria
- 78% of emissions are anthropogenic
- creates acid rain
- if it’s at 0.5 or higher, it’s toxic
What are the Soil types and how is it formed?
Soil is formed from parent material using climate and biological processes
*Clay-dominated soils drain poorly
* Sandy soils drain well, but prone to drought
* Organic matter (humus) increases water- and nutrient-holding capacity (tilth)
Principle of limiting factors
Growth may be determined by the factor in the shortest supply (often nutrients)
ex.
Phosphorus limits productivity in aquatic ecosystems
Nitrogen fixation
78% of nitrogen is in an N2 form, which can’t be used
- nitrogen fixation is the process in which n2 is separated to n so it can be useful
- Nitrogen is fixed by bacteria, free-living or in
symbiosis with plant hosts (root nodules containing Rhizobium and Bradyrhizobium
bacteria)
- oftenhappens in the legume family
* Nitrogen is fixed through oxidation by lightning
* Nitrogen can be fixed industrially
What is Denitrification?
free-living bacteria are involved in the
process of denitrification, in which nitrate is metabolically
converted to gaseous N2
or N2
O, which are released
to the atmosphere. D
Soil designations
- Coarse gravel (>20 mm)
- Gravel (2-20 mm)
- Sand (0.05-2 mm)
- Silt (0.002-0.05 mm)
- Clay (<0.002 mm)
Water moves nutrients
through soils - hummus= made of dead biomass
Contributes to tilth like qualities
