NRE 509
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- Henry's Law and sources and sinks
- if concentration > henry's saturation value then atmosphere is a sink if concentration < saturation concentration: atmosphere is a source
- Name 2 species of bacteria that are involved in the nitrogen cycle
- Nitrosomonas Nitrobacter
- What function does Nitrosomonas serve in the N cycle?
- Converts ammonium to nitrite
- What function does Nitrobacter serve in the N cycle?
- Converts nitrite to nitrate
- Describe Photoautotroph metabolism
- Uses two parts - synthesis and metabolism. Uses photons to split water molecules, then catalyze the reduction of a CO2 molecule to form HCO2. Water and oxygen are byproducts. Uses sunlight as primary energy source for synthesis of organic compounds. Aerobic respiration. Oxidation of organic compounds yields useful biochemical energy (ATP units) Notice its just the reverse reaction of photosynthesis.
- Describe Chemoautotroph metabolism
- Uses chemosynthesis to get its energy. Degrades inorganic compounds into energy. For example - nitrifying bacteria that oxidize reduced nitrogen and yield energy and a free proton.
- Describe Photoheterotroph metabolism
- Uses light energy and raw materials
- Describe Chemoheterotroph metabolism
- uses high energy molecules and raw material. Examples: methanogenesis, denitrification, sulphate reduction.
- auto means: hetero means:
- - OWN - DIFFERENT
- What process do photoautotrophs do?
- Photosynthesis!
- What is Lindeman efficiency?
- Idea that get about a 10% level of energy transfer from one trophic level to the next.
- growth efficiency
- energy stored per unit converted
- Energy exploitation efficiency
- how much energy can be captured from what’s available – predators are good at this. Obtain 10-50% - get what try for. For plants, less high – 1-2%, but are better at assimilation of energy.
- metabolic scope
- currently available energy for growth and maintenance and activity
- Energy Balance - what two components are there?
- Rate of energy acquisition Rate of energy dissipation
- If energy dissipation and acquisition are equal what is the scope?
- 0 = org. is as good as dead - "incipient lethal threshold"
- If energy acquisition is less than energy dissipation, what is scope?
- approaching lethal threshold.
- If energy acquisition is greater than energy dissipation, what is scope?
- Scope is >0 - energy is being stored.
- energy assimilation efficiency
- difference between amount consumed and the amount actually assimilated
- chemoautotrophs and photoautotrophs generate what kind of production?
- primary production
- photoheterotrophs and chemoheterotrophs generate what kind of production?
- secondary production
- Ecological efficiencies - averages
- -exploitation: 33% -assimiliation: 60% -growth: 50%
- Rank plants, herbivores and predators in terms of growth efficiency
- plant; then herbivore and predtor tied at 40-60%.
- rank plants herbivores and predators in terms of assimilation efficiency
- plants, predators, herbivores
- rank plants herbivores and predators in terms of exploitation efficiency
- predators, herbivores, plants
- Ecosystem metabolism is measured as
- NPP/R where R is total respiration or destruction of carbon. And NPP is generally thought of as photosynthesis. If P/R > 1, system is a net producer of energy and carbon.
- Inorganic compounds in water
- -anions: carbonates and bicarbonates, chloride, sulfate, and hydroxide -cations: sodium, calcium, magnesium (these three are most common cations), phosphorous, iron
- Henry's Law equation
- saturation concentration [c] = solubility*partial pressure
- Henry's law
- Gives the concentration a system will reach if left alone. note - it is independent of the starting concentration
- Of N, CO2, and O2, which is most soluble in water (Henry's Law)
- CO2 is most, then O2, then N.
- Fick's Law
- Gives rate at which gasses and water saturate/diffuse
- Fick's Law equation
- diffusion rate = K([saturation]-[O2]) where k is the diffusivity constant
- Fick's Law in terrestrial vs. aquatic systems
- diffusion is up to 10,000 times faster in terrestrial systems than aquatic b/c of density of air
- What form(s) of carbon are constrained by Henry's Law?
- Only dissolved CO2.
- What forms of carbon can aquatic plants use for photosynthesis?
- CO2, bicarbonate, and carbonate
- Carbonate
- CO3 =
- Bicarbonate
- HCO3-
- What function do carbonates serve in an aquatic system?
- They buffer acids - HCO3- can take one proton, CO3= can take two. Dominant form of carbonate at a given time is related to pH.
- How do photosynthesis and pH relate in aquatic systems?
- Photosynthesis drives pH up during the day. (Respiration drives it down at night).
- How do aquatic plants use bicarbonate and carbonate for photosynthesis?
- They convert it to Co2 and release hydroxide ions.
- What type of carbon occurs at what pH?
- Free CO2 at lower pHs, HCO3 at middle pHs, CO3= at higher pHs.
- Carbonate system conversions
- know the conversions in aquatic systems
- Ammonification
- -anaerobic and aerobic -organic N to NH4
- Nitrogen Fixation
- -aerobic -N2 to organic N
- N Assimilation
- -aerobic -NO3, NH4 to organic N
- Nitrification
- -aerobic -NH4 to NO2 to NO3
- Denitrification
- -anaerobic -NO3 to NO2 to NH4
- Three domains of life
- Archea, Bacteria, Eukarya
- Monod's model equation
- growth rate = max*(S/S+K) where S is input concentration and K is 1/2 the saturation constant and max is the maximum rate
- Monod take-homes
- Biological responses respond in a non-linear fashion to changes in all essential inputs small changes in availability of rare inputs can induce large responses, but large changes in availability of common inputs can have relatively small consequences
- Leibig's Law of the minimum
- yield or growth of an organisms is determined by the abundance of that substance which, in relationship to the needs of the organism, is least abundant in the environment [i.e.,at a minimum]
- Average total annual C production
- 2 kg/square meter /year, or a total of ~ 1.02 x 1012 kg
- Define Evolution
- Change in genotypic frequencies within populations
- lambda =
- per capita geometric rate of increase (in a population)
- little r =
- r=(b+i)-(d+e) r=per capita exponential growth rate r= INSTANTANEOUS rate of change r= relative rate of change r=loge*Lambda and Lambda=e^r
- strictly speaking, little r is:
- instantaneous per capita rate of change in population size over time.
- Biotic factors that change population size
- -predation -competition -parasitism -mutualism -disease
- Abiotic factors that change population size
- -temperature -disturbance -pH -precipitation -pollution -salinity
- Ro=
- -net reproductive rate -number of daughters born per female
- Difference between Ro and W
- W is fitness of a genotype. Ro is fitness of a population.
- When does Ro = W?
- When generation time is 1.
- What is stable age structure and when does it occur?
- It's when proportions of individuals in age classes within a population remain the same (even if overall, population is growing). Happens when age-specific fecundities and mortalities remain the same.
- lx
- survival
- survival
- lx
- age
- x, in leslie matrices, etc.
- age-specific survival
- Px
- Px
- age-specific survival
- mx
- fecundity
- fecundity
- mx
- intraspecific competition
- within a species - self-limiting
- interspecific competition
- between species
- scramble competition
- -aka exploitation competition -resources allocated equally in a group
- contest competition
- -aka interference competition -some individuals get all the resources