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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
when was PTBT put in place?
1983
26
what does CTBT stand for?
comprehensive test ban treaty which fully bans the testing of nuclear equipment. some countries have signed but haven't ratified such as US
27
when was CTBT put in place?
1996
28
name 2 uses of radionuclides
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
29
when was the first nuclear test
July 16th, 1945 5.29am
30
name an example of underground nuclear testing
Banberry, Nevada, 1970 which was used to test its use in major evacuation routes
31
name an example of exoatmospheric testing
Johnston island, 1958, electromagnetic pulse shot at 250,000 ft
32
name an example of underwater nuclear testing
Marshall islands. this was the first recorded case of nuclear fallout. animals were on-board with 95 ships targeted.
33
name an example of atmospheric nuclear testing
castle bravo, 1954. 11,000 km2 affected by fallout
34
what countries have signed the CTBT but not ratified the treaty?
Iran, China, Egypt, US, Israel
35
what countries haven't signed the CTBT?
india and pakistan
36
name 4 features of the Goiania accident?
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
37
how is caesium-137 used as a tracer?
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.
38
name 4 reasons Plutonium-239 is a good marker for the Anthropocene
1) low solubility 2) binds to sediments 3) identifiable in sediments and ice for the next 100,000 years 4) absent in nature
39
what type of area is prescribed burning used in the UK?
heather moorland
40
why is there prescribed burning in the UK?
the burning prevents/combusts woody stems growing amongst the vegetation and so the areas remain suitable for grazing
41
what relationship do wildfires follow?
frequency-magnitude
42
when are the seasonal wildfire cycles in the UK?
may/april - july/august
43
name 4 impacts of wildfires
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
44
name 3 factors external factors which contribute to wildfires
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)
45
name 4 environmental effects of fire
1) changes seed germinations 2) kills pests 3) creates fire-adapted ecosystems 4) peat erosion
46
name 3 ways fire interacts with the earth system
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)
47
what are the three types of fire?
surface, crown and soil
48
how is magnitude related to frequency with respect to wildfires?
inversely
49
name 3 factors which increase the rate of fire spreas
1) topography = downslope fire burns faster 2) vegetation type (more volatile biochemistry) 3) wind (convective winds create self-sustaining fires)
50
name the 3 stages of fire formation
preheating, pyrolysis, flaming
51
name the equation for the combustion of biomass from a wildfire
C6H1206 + 6O6 = 6CO2 + 6H2O
52
name the 5 stages of slope transition and a reference
summit - shoulder - backslope - toeslope - floodplain | shutle, 2012
53
name 5 factors that affect slope processes
1) vegetation 2) climate 3) materials which construct the slope 4) tectonic activity 5) slope angle
54
what 4 forces act on slope material?
gravity, shear stress, normal stress and buoyancy
55
what is the name give to large rock mass movements?
talus
56
what is the name given to fine material mass movements?
collovium
57
what is the name given to mass movements with a mixture of material size?
taluvium
58
what 3 components that affect shear strength?
1) cohesion 2) buoyance/normal stress 3) coefficient of internal friction
59
name 4 factors which affect shear strength
1) degree of weathering 2) spaces between joints 3) orientation of fissures 4) movement of water through the material
60
name the 3 stages of mass movement
1) stable 2) conditionally unstable 3) actively unstable
61
name 3 flows of mass movements
pure flow, pure slide, pure heave
62
name the 3 types of mass movement
1) creep 2) flow - movement downslope as a viscous fluid 3) slide - material remains coherent but moves along a well defined surface
63
name a reference, and detail mass movement events in the Himalayas
(paul et al, 2000) rock slide debris flow with more than 1mil m3 of material moved 221 killed august 1998
64
what were the prepatory factors for the 1998 Himalayas mass movement?
widened joints through tectonic activity, freeze-thaw activity
65
what were the triggering factors for the 1998 Himalayas mass movement?
continuous rain, rock fall
66
name 4 ways to prevent mass movement events
1) vegetate landscape 2) regrading 3) terracing slopes 4) prevent undercutting.
67
define infiltration capacity
the maximum rate at which water can low into the soil and be absorbed
68
what is Darcy's law?
higher saturated hydraulic conductivity results in the draining of water more quickly
69
what is hortonian overflow?
hortonian overflow is when the precipitation intensity exceeds the infiltration capacity of the landscape resulting in overland flow. (Horton, 1933)
70
what is saturation excess overflow?
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
name a way in which each -sphere interacts with flood events
hydrosphere - replenishes groundwater lithosphere - erosion, sediment movement atmosphere - atmospheric moisture and precipitation events biosphere - redistribution of nutrients
72
how much does flooding cost the UK each year and where is this statistic found?
(environment agency, 2018) | £2.2bn
73
why is seasonal flooding a positive for the environment?
it is part of a river natural regime, and it is vital for soil fertility
74
how do antecedent conditions affect flooding
- water table depressions or ascensions - ground water storage capacity - stream flow reactiveness
75
what 3 things are soil water reliant on?
1) soil type 2) soil depth 3) precipitation
76
what conditions characterise floods in arid environments?
- intense and extreme precipitation/dry events | - hortonian overflow
77
what 4 components make arid environments susceptible to flooding?
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
name a facts about the 2012 Spanish floods
245mm fell in one morning
79
name 8 factors affecting catchment morphology
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
describe storm desmond
in some places 341mm fell in 24 hours. the high discharge increased sediment loads and reduced channel capacity thus increasing flood risk
81
what were antecedent conditions like in 2015/16 uk floods?
unusually dry autumn followed by record precipitation in December
82
what flows dominated in UK in winter 2015/16 floods?
saturation-excess overflow
83
name 3 ways in which flooding and climate change interact
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
describe the shifting paradigms in geography
``` 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
what defines a desert?
moisture balance
86
where is the largest concentration of dust production?
northern Africa e.g. Bodele
87
what are the 2 drivers of dust?
the erosivity of the wind and the erodibility of the surface (surface cohesive strength)
88
what is a haboob?
a collapsing weather front
89
name 4 health effects from dust
1) PM10 particles 2) asthma, bronchitis, silicosis 3) conjunctivitis 4) transporting bacteria
90
why is the aral sea creating toxic dust?
the dust traps along 2 transects downwind of aral sea. pesticides and PM10 accumulated
91
what is an indirect impact of dust on weather and climate?
impacts on biogeochemical cycling that influence atmospheric carbon ddioxide etc.
92
what three factors affect radiation budget with respect to dust in the atmosphere
1) particle size, shape and colour 2) vertical distribution 3) moisture content
93
why are radionuclides of particular concern?
due to their toxicity, widespread use, and their sufficiently long half lives
94
why are leaves important for trees?
carbon fixation and photosynthesis
95
why is wood important for trees?
growth and water transport (changes land cover characteristics and hydrological cycling)
96
why are roots important for trees?
nutrient acquisition and anchorage
97
name 3 symptoms of the California 19550s dieback
leaf yellowing, bark beetles, reduced photosynthesis
98
when was the Australian dieback event?
1940s
99
what is tree-to-tre dieback?
dieback whereby adjacent trees die
100
what is senescent trees?
old trees
101
what are senescence trees?
aging trees
102
give 3 other names for dieback
forest dieback, stand level dieback, canopy dieback
103
name 5 symptoms of dieback
chlorotic foliage reduced photosynthesis, death of twigs/branches, root necrosis, tree death
104
what size area was affected by the 1970s SW Australia stand level dieback?
20,000 ha
105
name 4 symptoms of the 1940s Australian dieback
crown decline, foliar wilt, root death, tree mortality
106
who created the conceptual model for dieback?
manion, 1991 (predisposing, inciting, contributing)
107
what 3 stages are there in Manion's conceptual model for dieback?
predisposing factors, inciting factors and contributing factors
108
what is the reference for mountain pine beetle dieback?
mitton and ferrenberg, 2012
109
where is the MPB native to?
north america
110
what is the MPB in symbiosis with?
blue stain fungus
111
what are 3 components of the natural MPB cycle?
1) prefer senescent trees 2) cold climate limits their activity and size 3) natural forest regeneration limits their population
112
what synergistic factors contributed to the MPB dieback event in north America?
wildfire reduction of tree population, drought stress, warming temperatures
113
how do warming temperatures affect MPB?
1) more over-winter survival 2) reproductive cycle changes 3) larger habitable areas
114
how does the MPB impact affect Canada carbon budget more widely?
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
what did Mitchell et al, 2014 state about the loss of one species in an ecosystem
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
name 6 ways to combat dieback
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
what is cavitation?
the weakening of trees
118
what did allen 2007 state about tree thresholds?
(allen, 2007) stated once physiological thresholds are passed the dieback will move beyond linear patterns.
119
name a reference for non-human induced predisposing factors
mueller-dombois, 1987
120
what is the difference between natural and non-natural dieback?
natural dieback usually pulsates and isn't continuous.

Dynamic Earth (1 decks)

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