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1
Q

what size are dust particles?

A

<63 microns

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2
Q

dust is formed through interaction of -spheres. which two spheres are these?

A

lithosphere-atmosphere

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3
Q

what 4 things cause the spatial distribution of deserts?

A

1) subtropical high pressure (falling Hadley cell), 2) continentality (moisture loss as you move inland)
3) rain shadow
4) ocean currents (supresses evaporation)

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4
Q

what is dust production driven by?

A

wind due to it’s high erosivity capabilities

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5
Q

how is dust formed?

A

when the erosivity of the wind exceeds the cohesive strength of the surface

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6
Q

name 3 common sources of dust through erosion?

A

lake basins, alluvial surfaces, dunefields

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7
Q

what 3 things limit dust movement?

A

wind speed, vertical height reached, precipitative input

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8
Q

what 2 ways does dust fall out of suspension?

A

1) wet deposition through dust lost in precipitation

2) dry deposition when the carrying capacity of the wind cannot exceed gravity

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9
Q

what 3 factors increase aeolian dust production?

A

dust devils, haboobs, anthropogenic

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10
Q

name 3 hazards dust presents giving examples

A

1) visibility and transport issues (Oregon 1991 = 50 car pile up)
2) health issues = respiratory problems increase
3) moving sand creates socio-economic issues (Dust bowl, 1930s America)

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11
Q

what 4 influences does dust have on the biosphere, and name a reference for this information.

A

1) anthropogenic activity creates acid deposition, but alkaline dust deposits help mitigate soil pH change
2) dust supplies nutrients for plants and ecological health
3) dust can change topography through dust accumulation followed by removal through suspension downwind
4) dust deposition forms duricrust

(Blank et al, 1999)

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12
Q

what 4 influences does dust have on the atmosphere, and name 2 references for this information.

A

1) scattering and absorption of solar radiation
2) tropospheric ozone photolysis rates are decreased by 50% - following feedback loop of environmental degrade through increased UV
3) convectional activity is altered through dust acting as condensation nuclei, increasing precipitation events
4) dust fertilizes ocean biota, which increases carbon dioxide drawdown

(maley, 1982), (haywood et al, 2003)

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13
Q

how does Fe affect ocean productivity

A

Fe is the limiting factor in nitrogen fixing which increases primary productivity

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14
Q

what 2 influences does dust have on the hydrosphere and name 2 references for this information

A

1) marine systems are reliant on the nutrients aeolian (dust) inputs have. the nutrients from dust increase primary productivity and are important for biochemical cycling
2) coral reef depletion through dust carrying diseases in pores

(shinn et al, 2000) (sarthou et al, 2003)

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15
Q

name 3 nuclear accidents and their dates

A

Chernobyl, 1986. Fukishima, 2011. Kyshtym, 1957.

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16
Q

name the 5 countries with the most nuclear tests

A

US > USSR > France > China/UK

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17
Q

where was the Chernobyl disaster?

A

Pripyat, USSR

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18
Q

how did the Chernobyl disaster occur?

A

safety tests weren’t up to scratch and there was flawed reactor designs

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19
Q

what size area was affected by Chernobyl fallout?

A

100,000 km2

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20
Q

name 2 effects of the Chernobyl disaster

A

thyroid cancer, birth defects

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21
Q

what statement was made about nuclear testing?

A

nuclear testing has left a globally synchronous mark of carbon-14

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22
Q

what will mark the Anthropocene in future years and who claims this?

A

(waters et al, 2016)

Pt radioactive decay will create a globally synchronous layer of lead.

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23
Q

name 3 sources of radioactive contamination in uninhabited areas.

A

1) transport of medical equipment
2) nuclear powered satellites can fall back into orbit or there can be failed launches
3) radiological terrorism

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24
Q

what does PTBT stand for?

A

partial test ban treaty which bans all nuclear testing except for underground

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25
Q

when was PTBT put in place?

A

1983

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26
Q

what does CTBT stand for?

A

comprehensive test ban treaty which fully bans the testing of nuclear equipment. some countries have signed but haven’t ratified such as US

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27
Q

when was CTBT put in place?

A

1996

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28
Q

name 2 uses of radionuclides

A

1) caesium-137 can be used to track upstream erosion and downstream sedimentation through the 30 year half life and it binding to sediments (also ease of measurement)
2) radiometric dating such as cosmogenic radionuclide dating

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29
Q

when was the first nuclear test

A

July 16th, 1945 5.29am

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30
Q

name an example of underground nuclear testing

A

Banberry, Nevada, 1970 which was used to test its use in major evacuation routes

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31
Q

name an example of exoatmospheric testing

A

Johnston island, 1958, electromagnetic pulse shot at 250,000 ft

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32
Q

name an example of underwater nuclear testing

A

Marshall islands. this was the first recorded case of nuclear fallout. animals were on-board with 95 ships targeted.

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33
Q

name an example of atmospheric nuclear testing

A

castle bravo, 1954. 11,000 km2 affected by fallout

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34
Q

what countries have signed the CTBT but not ratified the treaty?

A

Iran, China, Egypt, US, Israel

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35
Q

what countries haven’t signed the CTBT?

A

india and pakistan

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36
Q

name 4 features of the Goiania accident?

A

1) old radiotherapy unit containing caesium-137 stole in 1987
2) 4 deaths
3) caused internal bleeding, vomiting and hair loss
4) it was stole to a scrap yard

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37
Q

how is caesium-137 used as a tracer?

A

due to the finite amount of caesium in the sediment layers, it’s volume in areas can give indication to areas of erosion and sedimentation.

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38
Q

name 4 reasons Plutonium-239 is a good marker for the Anthropocene

A

1) low solubility
2) binds to sediments
3) identifiable in sediments and ice for the next 100,000 years
4) absent in nature

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39
Q

what type of area is prescribed burning used in the UK?

A

heather moorland

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40
Q

why is there prescribed burning in the UK?

A

the burning prevents/combusts woody stems growing amongst the vegetation and so the areas remain suitable for grazing

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41
Q

what relationship do wildfires follow?

A

frequency-magnitude

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42
Q

when are the seasonal wildfire cycles in the UK?

A

may/april - july/august

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43
Q

name 4 impacts of wildfires

A

1) social disruption: loss of natural resources, loss of infrastructure such as housing
2) psychological impact
3) smoke impact: smog, haze, health effects resulting from the smoke, airport closures
4) economic costs

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44
Q

name 3 factors external factors which contribute to wildfires

A

1) insects increase susceptibility of vegetation to wildfires
2) land management: changes vegetation type and thus composition of fire-resistant species
3) over suppression

(bowman et al, 2017)

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45
Q

name 4 environmental effects of fire

A

1) changes seed germinations
2) kills pests
3) creates fire-adapted ecosystems
4) peat erosion

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46
Q

name 3 ways fire interacts with the earth system

A

1) combustion of vegetaion creates carbon dioxide which contributes to global warming
2) black carbon reduces albedo
3) vegetation regrowth following the fire (natural regime)

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47
Q

what are the three types of fire?

A

surface, crown and soil

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48
Q

how is magnitude related to frequency with respect to wildfires?

A

inversely

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49
Q

name 3 factors which increase the rate of fire spreas

A

1) topography = downslope fire burns faster
2) vegetation type (more volatile biochemistry)
3) wind (convective winds create self-sustaining fires)

50
Q

name the 3 stages of fire formation

A

preheating, pyrolysis, flaming

51
Q

name the equation for the combustion of biomass from a wildfire

A

C6H1206 + 6O6 = 6CO2 + 6H2O

52
Q

name the 5 stages of slope transition and a reference

A

summit - shoulder - backslope - toeslope - floodplain

shutle, 2012

53
Q

name 5 factors that affect slope processes

A

1) vegetation
2) climate
3) materials which construct the slope
4) tectonic activity
5) slope angle

54
Q

what 4 forces act on slope material?

A

gravity, shear stress, normal stress and buoyancy

55
Q

what is the name give to large rock mass movements?

A

talus

56
Q

what is the name given to fine material mass movements?

A

collovium

57
Q

what is the name given to mass movements with a mixture of material size?

A

taluvium

58
Q

what 3 components that affect shear strength?

A

1) cohesion
2) buoyance/normal stress
3) coefficient of internal friction

59
Q

name 4 factors which affect shear strength

A

1) degree of weathering
2) spaces between joints
3) orientation of fissures
4) movement of water through the material

60
Q

name the 3 stages of mass movement

A

1) stable
2) conditionally unstable
3) actively unstable

61
Q

name 3 flows of mass movements

A

pure flow, pure slide, pure heave

62
Q

name the 3 types of mass movement

A

1) creep
2) flow - movement downslope as a viscous fluid
3) slide - material remains coherent but moves along a well defined surface

63
Q

name a reference, and detail mass movement events in the Himalayas

A

(paul et al, 2000)
rock slide debris flow with more than 1mil m3 of material moved
221 killed
august 1998

64
Q

what were the prepatory factors for the 1998 Himalayas mass movement?

A

widened joints through tectonic activity, freeze-thaw activity

65
Q

what were the triggering factors for the 1998 Himalayas mass movement?

A

continuous rain, rock fall

66
Q

name 4 ways to prevent mass movement events

A

1) vegetate landscape
2) regrading
3) terracing slopes
4) prevent undercutting.

67
Q

define infiltration capacity

A

the maximum rate at which water can low into the soil and be absorbed

68
Q

what is Darcy’s law?

A

higher saturated hydraulic conductivity results in the draining of water more quickly

69
Q

what is hortonian overflow?

A

hortonian overflow is when the precipitation intensity exceeds the infiltration capacity of the landscape resulting in overland flow. (Horton, 1933)

70
Q

what is saturation excess overflow?

A

saturation overflow is when the pore spaces in the soil are full with previously absorbed water and thus water flows as there is no space for it to be absorbed into.

71
Q

name a way in which each -sphere interacts with flood events

A

hydrosphere - replenishes groundwater
lithosphere - erosion, sediment movement
atmosphere - atmospheric moisture and precipitation events
biosphere - redistribution of nutrients

72
Q

how much does flooding cost the UK each year and where is this statistic found?

A

(environment agency, 2018)

£2.2bn

73
Q

why is seasonal flooding a positive for the environment?

A

it is part of a river natural regime, and it is vital for soil fertility

74
Q

how do antecedent conditions affect flooding

A
  • water table depressions or ascensions
  • ground water storage capacity
  • stream flow reactiveness
75
Q

what 3 things are soil water reliant on?

A

1) soil type
2) soil depth
3) precipitation

76
Q

what conditions characterise floods in arid environments?

A
  • intense and extreme precipitation/dry events

- hortonian overflow

77
Q

what 4 components make arid environments susceptible to flooding?

A

1) soil type - typically clay which has a low saturated hydraulic conductivity (darcy law)
2) waxy plant residues
3) low vegetation cover
4) intense rainfall

78
Q

name a facts about the 2012 Spanish floods

A

245mm fell in one morning

79
Q

name 8 factors affecting catchment morphology

A

1) drainage density
2) drainage basin hape
3) topography
4) drainage basin size
5) upland agriculture land is drained which creates lower drainage basin density
6) lowland area cattle ompaction increases overland flow
7) urbanisation
8) deforestation

80
Q

describe storm desmond

A

in some places 341mm fell in 24 hours. the high discharge increased sediment loads and reduced channel capacity thus increasing flood risk

81
Q

what were antecedent conditions like in 2015/16 uk floods?

A

unusually dry autumn followed by record precipitation in December

82
Q

what flows dominated in UK in winter 2015/16 floods?

A

saturation-excess overflow

83
Q

name 3 ways in which flooding and climate change interact

A

1) reforestation: sponge effect through organic matter and tree roots creating open structures and reducing saturation-excess overland flow
2) increased need for land use to provide for a population mitigating climate change impacts will increase impermeable surfaces
3) increasingly changing surfaces will increase hydraulic roughness decreasing water velocities.

84
Q

describe the shifting paradigms in geography

A 
pre-1800 = descriptive/philosophical
1800-1950 = uniformitatianist
1800-1950 = evolution of biology and landscape
post 1950 = quantitative revolution
post 1970 = looks at scientific method
85
Q

what defines a desert?

A

moisture balance

86
Q

where is the largest concentration of dust production?

A

northern Africa e.g. Bodele

87
Q

what are the 2 drivers of dust?

A

the erosivity of the wind and the erodibility of the surface (surface cohesive strength)

88
Q

what is a haboob?

A

a collapsing weather front

89
Q

name 4 health effects from dust

A

1) PM10 particles
2) asthma, bronchitis, silicosis
3) conjunctivitis
4) transporting bacteria

90
Q

why is the aral sea creating toxic dust?

A

the dust traps along 2 transects downwind of aral sea. pesticides and PM10 accumulated

91
Q

what is an indirect impact of dust on weather and climate?

A

impacts on biogeochemical cycling that influence atmospheric carbon ddioxide etc.

92
Q

what three factors affect radiation budget with respect to dust in the atmosphere

A

1) particle size, shape and colour
2) vertical distribution
3) moisture content

93
Q

why are radionuclides of particular concern?

A

due to their toxicity, widespread use, and their sufficiently long half lives

94
Q

why are leaves important for trees?

A

carbon fixation and photosynthesis

95
Q

why is wood important for trees?

A

growth and water transport (changes land cover characteristics and hydrological cycling)

96
Q

why are roots important for trees?

A

nutrient acquisition and anchorage

97
Q

name 3 symptoms of the California 19550s dieback

A

leaf yellowing, bark beetles, reduced photosynthesis

98
Q

when was the Australian dieback event?

A

1940s

99
Q

what is tree-to-tre dieback?

A

dieback whereby adjacent trees die

100
Q

what is senescent trees?

A

old trees

101
Q

what are senescence trees?

A

aging trees

102
Q

give 3 other names for dieback

A

forest dieback, stand level dieback, canopy dieback

103
Q

name 5 symptoms of dieback

A

chlorotic foliage reduced photosynthesis, death of twigs/branches, root necrosis, tree death

104
Q

what size area was affected by the 1970s SW Australia stand level dieback?

A

20,000 ha

105
Q

name 4 symptoms of the 1940s Australian dieback

A

crown decline, foliar wilt, root death, tree mortality

106
Q

who created the conceptual model for dieback?

A

manion, 1991 (predisposing, inciting, contributing)

107
Q

what 3 stages are there in Manion’s conceptual model for dieback?

A

predisposing factors, inciting factors and contributing factors

108
Q

what is the reference for mountain pine beetle dieback?

A

mitton and ferrenberg, 2012

109
Q

where is the MPB native to?

A

north america

110
Q

what is the MPB in symbiosis with?

A

blue stain fungus

111
Q

what are 3 components of the natural MPB cycle?

A

1) prefer senescent trees
2) cold climate limits their activity and size
3) natural forest regeneration limits their population

112
Q

what synergistic factors contributed to the MPB dieback event in north America?

A

wildfire reduction of tree population, drought stress, warming temperatures

113
Q

how do warming temperatures affect MPB?

A

1) more over-winter survival
2) reproductive cycle changes
3) larger habitable areas

114
Q

how does the MPB impact affect Canada carbon budget more widely?

A

the area affected by MPB stand level decline is equivalent to the input of 900m otns of carbon dioxide which is 5x the annual transport emissions of Canada.

115
Q

what did Mitchell et al, 2014 state about the loss of one species in an ecosystem

A

there is damaging effects around the whole ecosystem with the loss of one species through the interconnected nature of the ecosystem and it’s services

116
Q

name 6 ways to combat dieback

A

1) monitoring programmes
2) phytosanitary inspection
3) containment of diseases
4) treatment of diseased areas
5) destruction of diseased populations
6) irrigation/nutrient management

117
Q

what is cavitation?

A

the weakening of trees

118
Q

what did allen 2007 state about tree thresholds?

A

(allen, 2007) stated once physiological thresholds are passed the dieback will move beyond linear patterns.

119
Q

name a reference for non-human induced predisposing factors

A

mueller-dombois, 1987

120
Q

what is the difference between natural and non-natural dieback?

A

natural dieback usually pulsates and isn’t continuous.

Dynamic Earth (1 decks)

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