soil and water Flashcards
soil
organic (rare) or inorganic
complex, heterogenous environment and immense microbial diversity
soil formation
complex, takes 1000s of years, affected by microbial (metabolic products = organic acids, co2), plant and animal activities, and physical and chemical processes (freeze-thaw, wind/water erosion, dissolution)
primary producers in aquatic env
microbes (eg phytoplankton)
organic soil
created by decomposition of organic matter in bogs and marshes, much higher level of organic matter than inorganic matter, fairly rare but v productive
inorganic soil
most common
microbial activites in soil
metabolic products, organic acids, CO2
animal contribution to soil
mixing and aerating upper layers
plant contribution to soil
taking up water, releasing organics into soil (as they die)
soil profile layers
O: exposed organic matter on surface
A: topsoil, lots of minerals, root zone, lots of microbes, active
B: subsoil, less available minerals, some microbes (spare populations), somewhat active
C: mostly inorganic matter, resembled bedrock (crumbled), sometimes have microbes (spare and metabolically inactive mostly)
Bedrock
microenvironments in soil aggregates
clay, mineral, organic matter sufaces
water, air-filled pores
determinants of microbial activity in soil
water –> affects o2 (which will affect aerobes!)
nutrient status –> microbial activity limited by C, N, or P availability
how the soil aggregate microenvironments can change
introduction of organic matter (eg fungi)
is the oxygen [] of a microenvironment constant
no; the aerobic microbes will quickly use up the O content, and then O-dependent microbes will die, or have to switch to a different form of metabolism
do all soil have the same microbial communities?
v few microbes are common to all soil samples, immense diversity
rhizosphere
soil that surrounds plant roots, significantly different than bulk soil environment –> known as rhizosphere effect
large amounts of organic carbon due to plant excretion, therefore a higher number of microbes can grow here
rhizosphere effect
the difference in bulk soil env. vs plant soil env. bc plants greatly influence soil habitat + serve as potential habitat
rhizoplane
actual root surface
source of root exudates –> sugar, AAs, hormones, vitamins
phyllosphere
surface of plant leaf
subsurface inhabitants of terrestrial env; describe them
prokaryotes and microeukaryotes; low metabolic activity (bc low nutrient habitat)
most important parts of aquatic environment composition
O2 and sunlight
freshwater environment O2 levels
O2 produced near surface, lower O2 at greater depths bc of low solubility and consumption (aka anerobic inhabitants in deeper regions)
photic zone
areas of aquatic environment that are reached by sunlight; microbes in that environment are able to photozynthesize
startified lake
at certain times of years, it forms layers and those layers don’t mix - wind and waves would mix it but this doesn’t happen
thermocline
temperature changing v quickly over a short area (bc of the sunlight not reaching the bottom anymore)
anoxygenic photosynthesis by H2S-oxidizing organisms
environment types arranged by relative # of prokaryotes (most to least)
ocean subsurface (below 200m), terrestrial subsurface, soil, ocean surface, domestic animals, atmosphere
structure of stratified lake
areobic, thermocline, anaerobic
deepest region of a lake
anaerobic, support anaerobic heterotrophic activity and NO3- reduction
anerobic decomposition in sediment
rivers as an aquatic environment features
flow and turbulence affect degree of re-oxygenation
organic matter and nutrient input may affect productivity and lead to o2 depletion
BOD
biochemical oxygen demand = change in dissolved oxygen after 5 days
a measure of amount of organic matter in water that can be oxidized by microorganisms
types of marine environemtns
open ocean
fre
types of marine environemtns
open ocean
inshore areas
open ocean as a microbial environment
low 1o productivity, often limiting N, P, Fe resulting in low heterotrophic activity
inshore ocean as a microbial env
nutrient rich, greater productivity
deep sea habitats as a microbial environment
75% of ocean water is at depths greater than 1000m
dark, cold, under high hydrostatic pressure, low nutrient input therefore low microbial activity
types of microbes in deep sea
psychrotolerant or pshcryophillic, piezotolerant (barotolerant), or piezophilic (piezotolerant)
relativity abundance of archaea and bacteria in deep sea
archaea more abundant than bacteria, bacteria are at a relatively constant low level in the deep sea
how do hydrothermal vent communities survive?
geothermal energy
H2S is used most of the time by bacteria as the form of primary energy (since there are no photons available)
CO2 and CH4 also present and can be used
what are the types of hydrothermal vent communities?
free-living microorganisms
microbe-animal symbiosis
what are the types of hydrothermal vent communities?
free-living microorganisms
microbe-animal symbiosis
types of free-living microorganisms in hydrothermal vents
S-oxidizing chemolithotrophs (Thiothrix, Beggiato, Thiobacillus) - both auto (as 1o producers) and hetero (as 2o)
may also be H2-, Fe+, Mn+ oxidizers, methanotrpohs, nitrifiers
may also be methanogens, S0-reducers, sulfate-reducers,Fe(III) reducers
types of microbe-animal symbiotes in hydrothermal vents
S-oxidizers and tube worms, clams, mussels
animals that graze directly on microbiota
tube worm features
2m long
no mouth, anus, gut
possess trophosome (spongy tissue w S granules) and S-oxidizing bacteria
will trap O2, H2S and deliver it to the S-oxidizing bacteria
byproducts of S-oxidizing bacteria supports tube worm growth
how is the hydrothermal vent habitat different from the one we’re used to thinking about?
we’re used to light + CO2 being consumed by phototrophs and autotrophs –> driven by light
hydrothermal vent communities consume H2S and CO2 by chemolithoautotrophs and autotrophs –> driven by geothermal energy
both end up being consumed by organotrophic and heterotrophic organisms
