soil and water Flashcards

1
Q

soil

A

organic (rare) or inorganic

complex, heterogenous environment and immense microbial diversity

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2
Q

soil formation

A

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)

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3
Q

primary producers in aquatic env

A

microbes (eg phytoplankton)

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4
Q

organic soil

A

created by decomposition of organic matter in bogs and marshes, much higher level of organic matter than inorganic matter, fairly rare but v productive

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5
Q

inorganic soil

A

most common

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6
Q

microbial activites in soil

A

metabolic products, organic acids, CO2

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7
Q

animal contribution to soil

A

mixing and aerating upper layers

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8
Q

plant contribution to soil

A

taking up water, releasing organics into soil (as they die)

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9
Q

soil profile layers

A

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

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10
Q

microenvironments in soil aggregates

A

clay, mineral, organic matter sufaces

water, air-filled pores

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11
Q

determinants of microbial activity in soil

A

water –> affects o2 (which will affect aerobes!)

nutrient status –> microbial activity limited by C, N, or P availability

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12
Q

how the soil aggregate microenvironments can change

A

introduction of organic matter (eg fungi)

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13
Q

is the oxygen [] of a microenvironment constant

A

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

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14
Q

do all soil have the same microbial communities?

A

v few microbes are common to all soil samples, immense diversity

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15
Q

rhizosphere

A

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

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16
Q

rhizosphere effect

A

the difference in bulk soil env. vs plant soil env. bc plants greatly influence soil habitat + serve as potential habitat

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17
Q

rhizoplane

A

actual root surface

source of root exudates –> sugar, AAs, hormones, vitamins

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18
Q

phyllosphere

A

surface of plant leaf

19
Q

subsurface inhabitants of terrestrial env; describe them

A

prokaryotes and microeukaryotes; low metabolic activity (bc low nutrient habitat)

20
Q

most important parts of aquatic environment composition

A

O2 and sunlight

21
Q

freshwater environment O2 levels

A

O2 produced near surface, lower O2 at greater depths bc of low solubility and consumption (aka anerobic inhabitants in deeper regions)

22
Q

photic zone

A

areas of aquatic environment that are reached by sunlight; microbes in that environment are able to photozynthesize

23
Q

startified lake

A

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

24
Q

thermocline

A

temperature changing v quickly over a short area (bc of the sunlight not reaching the bottom anymore)
anoxygenic photosynthesis by H2S-oxidizing organisms

25
Q

environment types arranged by relative # of prokaryotes (most to least)

A

ocean subsurface (below 200m), terrestrial subsurface, soil, ocean surface, domestic animals, atmosphere

26
Q

structure of stratified lake

A

areobic, thermocline, anaerobic

27
Q

deepest region of a lake

A

anaerobic, support anaerobic heterotrophic activity and NO3- reduction
anerobic decomposition in sediment

28
Q

rivers as an aquatic environment features

A

flow and turbulence affect degree of re-oxygenation

organic matter and nutrient input may affect productivity and lead to o2 depletion

29
Q

BOD

A

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

30
Q

types of marine environemtns

A

open ocean

fre

31
Q

types of marine environemtns

A

open ocean

inshore areas

32
Q

open ocean as a microbial environment

A

low 1o productivity, often limiting N, P, Fe resulting in low heterotrophic activity

33
Q

inshore ocean as a microbial env

A

nutrient rich, greater productivity

34
Q

deep sea habitats as a microbial environment

A

75% of ocean water is at depths greater than 1000m

dark, cold, under high hydrostatic pressure, low nutrient input therefore low microbial activity

35
Q

types of microbes in deep sea

A

psychrotolerant or pshcryophillic, piezotolerant (barotolerant), or piezophilic (piezotolerant)

36
Q

relativity abundance of archaea and bacteria in deep sea

A

archaea more abundant than bacteria, bacteria are at a relatively constant low level in the deep sea

37
Q

how do hydrothermal vent communities survive?

A

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

38
Q

what are the types of hydrothermal vent communities?

A

free-living microorganisms

microbe-animal symbiosis

39
Q

what are the types of hydrothermal vent communities?

A

free-living microorganisms

microbe-animal symbiosis

40
Q

types of free-living microorganisms in hydrothermal vents

A

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

41
Q

types of microbe-animal symbiotes in hydrothermal vents

A

S-oxidizers and tube worms, clams, mussels

animals that graze directly on microbiota

42
Q

tube worm features

A

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

43
Q

how is the hydrothermal vent habitat different from the one we’re used to thinking about?

A

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