Earth Environment - Chapter 4 Flashcards
describe the terrestrial environment from an integrated physical, biological and chemical perspective .
- increase O.matter, H2O and nutrients = increased microbial activity
- surface area affects ration : adsorptions and retention of H2O
- air pockets/porous envi and H2O carrier nutrients needed for aerobic microbial growth
- Cation exchange: bac = -, charged metal (PB2+)= +, soil=- charge
Why might water move so quickly into the saturated zone?
- pores
- mineral particles are layer, therefor, doesn’t hold up H2O
What are some sources of increased acidity in the soil?
- microbes metabolite(fermentation–> acid)
- increased nitrogen(anthropogenic)–> nitracficiation (add lime to neutralize)
- increase with time
- acid rain
- base cation(Ca2+, K+, Na+) are more easilu released than acid cation
Define surface soil
- weathered end product
- high O Carbon content
Define vadose zone
- low O.carbon content
- decreased H2O movement
Define saturated zone
- shallow or intermediate/ deep aquifers
- porous parent materials
- wetlands
- oligotrophic condition
Id components of soil as it related to microbial activity
- texture: size of mineral particles
- pore size distribution:
- organic matter
- soil structure: aggreigate/size
- interaggregrate pore
- intra-aggregrate pore
- cation exchange
- soil H2O potential
How can the components of soil vary?
- O matter varies
- pores can vary based on mineral type (sand/small space vs. clay/large spores)
explain how microbial activity can influence the soil atmosphere
- bac attach to porous media
- leaching: micro-pore exclusion, competitive affinity
- precipitation of minerals/pesticides–> affect soil solution chem
- microbial alters N2, O2 and CO2 gases [ ] in saturated levels
soil properties
- texture: size mineral particles
- structure: aggrigate /size
- porosity: H2O movement
- chemistry: cation exchange capacity
- colour:O..contents, minerals
Soil forming factores
- parent material: rock/mineral that is weathered
- climate: precipitation +temp
- Organisms
- Topography: slide angle and length
- Time
Weathering created what? and what is released
- sand, silt, clay
- releases:
1. minerals in solution
2. oxides of Fe and Al (negative charge)
3. silica
4. stable waste
Phases of typical soil
- pore space
- mineral
- organic material
Phases of typical soil
- pore space
- mineral
- organic material
Distinguish b/n soil particles and soil aggregrate
- particles: makes up pore
- Aggregrate: inter/intra aggregrate pores
Why do bogs have low microbial activity
- high acidity levels (decrease cation exchange)
- high O.matters b/e of low microbial activity
- little H2O movement
Why do bogs have low microbial activity
- high acidity levels (decrease cation exchange)
- high O.matters b/e of low microbial activity
- little H2O movement
Cation exchange capacity
- sum of exchangeable based on soil
- isomorphic sub
- Ionization (pH dependent)
field Capacity ?
- # of H2O in sol w/ natural saturation
- h2o held naturally with sufficient O2
field Capacity ?
- # of H2O in sol w/ natural saturation
- h2o held naturally with sufficient O2
- wilt point, h2o films thin around particles (opposite to field capacity )
water potential
- work responsible to move a H2O
- water bound by matric forces, gravity, surface tension, osmosis
- predicts the ability of env. to move microbes and nutrients
Biotic stress
competition
predation
parasatism
antibiotice production
Abiotic stress
light moisture Temp pH redox potential (not enough E from terminal e-, maintenance not growth
Redox potential @ 800
O2 to h2o
aerobes
Redox potential @ 740
no3 to n2 or n2o
facultative anaerobes, nitrate reductions
Redox potential @ -220
so4 to s
anaerobes, sulfate reduction
Redox potential @ -300
co2 to ch4
anaerobes, methanogenesis
