Cultivation: Terrestrial and Aquatic Microbes Flashcards
Soil may be . . .
Organic (rarely) or inorganic (common)
What contributes to soil formation?
Physical/chemical processes and microbial activities, animals living in soil mix and aerate upper layers
How to do photorophs play a role in soil formation?
Phototrophs (lichens) grow on bare rock and produce organic matter
Water availability affects . . .
O2 availability
Nutrient status
Microbial activity may be limited by C, N or P
O2 availability is high in
well-drained soil
O2 availability is low in
water-logged soil - anorexic area
Surface soil is . . .
nutrient rich, very high microbe activity
Deeper the soil the . . .
lower the nutrient concentration, microbes present but not very productive
Near soil pores
Microbial cells accumulate
Culture-dependent methods create
enrichment bias
Rhizosphere
Soil that surrounds plant roots, plants roots release nutrients, causing higher microbial numbers
Rhizosphere microbes produce
Rhizosphere microbes to stimulate plant growth and antibiotics to prevent growth of pathogens
Rhizosphere microbes fix
Atmospheric nitrogen for plant root uptake
Rhizosphere microbes solubilize
Phosphate for plant root uptake
Rhizoplane
Actual root surface - source of root exudates
Phyllosphere
Surface of plant leaf
Biosphere extends
~ 1km below ground surface
Deep terrestrial subsurface microbiomes house
Primarily prokaryotes
In aquatic environments, niches are based on
Light and oxygen
Algal blooms are initially beneficial because:
Takes up excess nutrients and produces lots of oxygen, grows quickly and consume all nutrients
Algal blooms become harmful when
They begin to die, decomposition requires consumption of oxygen by bacteria
Biochemical oxygen demand equation:
Initial DO - final DO
Biochemical oxygen demand (BOD5)
Changes in dissolved oxygen after 5 days at 20C
Open oceans have
Low primary productivity because of limitedinorganic nutrients
Inshore areas have
High primary productivity because nutrient rich
