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BIO220 Lecture 21 Flashcards

Biochemical cycles

1
Q

Connection between nuclear weapons & ecological research

A

Cold War: Us vs. USSR

  • use nuclear weapons
  • radiation enter food chains -> affect crops, fish, livestock

Use radioactive tracers to see where chemicals go in natural communities

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2
Q

___ Project is the collaborative “big science” model that ecologists try to follow.

A

Manhattan

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3
Q

Manhattan Project

A

Group that produced atomic bombs

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4
Q

N cycle is a ___ cycle

A

gaseous

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5
Q

Human intervention in N cycle

A

N fertilizer, HB process, combustion of fuels

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6
Q

P cycle is a ___ cycle

A

sedimentary

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7
Q

human intervention in P cycle

A
  • mining
  • pollution
  • fishing
  • sewage & agriculture runoff
  • erosion
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8
Q

HYDROLOGIC CYCLE

A

water cycle

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9
Q

hydrologic cycle ____ and ___

A

pools & fluxes if time permits

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10
Q

human intervention in hydrologic cycle

A

freshwater diversion (used in agriculture)

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11
Q

cycle for large organic molecules

A

synthesized, consumed, broken down

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12
Q

cycle for chemical elements

A

not synthesized, but instead move around and change oxidation states/compartments

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13
Q

cycle comprises of…

A

pools & fluxes

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14
Q

____ can persist as much as elements, but experience phase changes

A

stable, long-lived compounds (water, pollutants, etc.)

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15
Q

C, N, P cycles are all tied to ___ cycle

A

hydrologic

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16
Q

C cycle is tied with…

A

trophic webs

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17
Q

what are the 2 elements most likely to limit plant productivity?

A

N, P

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18
Q

limiting steps of C cycle

A
  • creation by photosynthesis

- respiration/combustion of organic matter

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19
Q

human intervention in C cycle

A

combustion & extraction of fossil fuel, land conversion (deforestation)

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20
Q

why do humans deforest?

A
  • easier for hunting
  • land for agriculture
  • remove agricultural waste
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21
Q

C sequestered in trees is released by…

A

fire

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22
Q

transient effect of burning cut trees

A

add NPK to soil: short-term enrichment of soil

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23
Q

Evidence that Neolithic humans cleared forests

A

pollen in lake sediments

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24
Q

in the past, most of the pollen was found in ___. now, mostly found in ___. This is because…

A

woodland species;
open-country species;
woodland cleared to grasslands

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25
People always deforested. Why is it a problem now?
we have the technology & labour power to do it faster.
26
What is 1 place where forests were restored?
Eastern North America (Rhode Island) - poor farm land - Sugar maples grew back
27
____ forests were cut for paper pulp in Maine, maritimes
coniferous
28
current deforestation is mostly in the ___
tropics (South America)
29
slash and burn
involves the cutting and burning of trees and plants in forests or woodlands to create fields - release N & microelements
30
reasons for clearing tropical forests
- slash & burn | - lumber, pulp, plantation clearning
31
oil palm plantation provides...
oil for food, biodiesel
32
Tropical forests contain great stores of... | Example?
carbon (~1000 tons/hectare in Indonesian Kalimantan swamp forest, including both alive & dead plants)
33
usually, tropical forests are too wet to burn, but ___ causes drying. Why?
Logging; | less cover, so sun & wind dry soil
34
Peat
- brown, soil-like material | - very smoky when burnt
35
Tropical forests are reservoirs for __ diversity
species
36
most recent example of tropical forest deforestation
Asian Fires (1997-1998): affected 5 million hectares
37
Effect of logging on C
- remove plants which can photosynthesize C out of atm | - dry out soil -> more easy to burn -> release stored C to atm
38
Industrial revolution was powered by...
fossil fuel combustion
39
Fossil fuel moves C from ___, burn it, and release...
stores (soil, bedrock, fossils); | CO2 & smoke into atm
40
Cars are very efficient at...
fossil fuel -> atm CO2
41
Human activities that release CO2 into atm
1. Fossil fuel burning - 6 billion tons | 2. Deforestation - 1.6 billion tons
42
Is N soluble?
Yes
43
There are ___ sedimentary pools for N
minimal
44
Limiting step of N cycle
convert atm N2 -> nitrate or ammonium
45
What usually converts atm N2?
- Legume: Rhizobium - eubacteria - cyanobacteria - lightning
46
N fixation
reduce N2 -> NH3
47
Nitrification
NH4+ -> NO3- (nitrate)
48
Denitrification
NO3- -> N2
49
How do make N fertilizers?
fix N2 using electricity/natural gas
50
N cycle is ___, meaning it cycles very fast
atmospheric
51
Combustion of fuels releases which form of N into the atm?
NO2
52
Humans are accelerating the N cycle so much that...
combustion exceeds natural production rates | - in some areas, rainwater is dilute fertilizer
53
consequences of N found in rainwater
- remove limiting nutrient for plants - reduce biodiversity - some plants favoured (weeds) - nitrate buildup in groundwater (hazard in agricultural areas) - eutrophication of costal waters -> anoxia
54
P is mostly found in...
sedimentary pools (ocean sediments)
55
Limiting step in P cycle
- weathering of rocks in soil (mycorrhizae) | - geological uplift
56
mycorrhizae helps...
plants take up phosphorus from soil (makes it soluble)
57
P has no __ forms
gaseous
58
___ is sometimes an important input of P
atm dust from Saharan Africa
59
Phosphate
PO4^-3
60
is phosphate soluble?
technically yes, but bound by soil components
61
P is a ___ cycle, so it is slow
sedimentary
62
sources of P for humans
- mining | - guano
63
P is lost from terrestrial systems by...
- run-off - erosion - over-application of fertilizers - eutrophication of rivers & lakes Ends up back in marine sediments
64
Biggest P reserves
Morocco > USA > South Africa
65
Liquid peruvian guano has higher ___% than bat guano
P
66
What areas are best sources of guano? Why?
islands off the coast of Peru - lots of seabirds, no predators - fish best in areas with cold-water upwelling - which brings P up to surface - bird eat P-rich fish - dry climate: P is not washed by rain back to ocean

BIO220 (24 decks)

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