The Earth System Flashcards
(292 cards)
1
Q
What are the 5 components of the Earth System ?
A
atmosphere,
biosphere,
lithosphere,
cryosphere,
hydrosphere
2
Q
Who suggested that the Earth was a functioning system?
A
Lovelock (1970) known as Gaia hypothesis. Initially rejected but then accepted
3
Q
What are the 3 timescales?
A
- Cyclic time (10 x4)
- Graded time (10 x2)
- Steady time (10 x-1)
4
Q
What are seasons induced by?
A
Orbitally induced.
5
Q
What do orbitally induced seasons mean for the earth? There are 2 things.
A
- Annually varying daylight.
- Seasonal variation in temperature.
6
Q
What is Electromagnetic energy?
A
Electromagnetic (ER) - Solar energy is radiation from thermonuclear sun.
ER becomes chemical via photosynthesis
7
Q
What is kinetic energy?
A
Motion (energy of transport)
8
Q
What is Potential energy?
A
When mass falls under gravity
9
Q
What is chemical energy?
A
(as in biological material) It is captured by photosynthesis and then converted to heat, motion
10
Q
What is heat energy?
A
It is thermal energy which is generated by vibrating molecules.
11
Q
What is heat actually?
A
The total kinetic energy of all the molecules of an object; faster molecular movement means higher temperatures.
12
Q
What is temperature actually?
A
Measure of the mean kinetic energy (speed) per molecule of an object (internal energy).
13
Q
What is conduction and convection?
A
Conduction: Heat can be transferred as conduction – directly one material to another.
Convection: upward and circulation movements in fluids.
14
Q
What occurs during the latent heat process?
A
There is an energy change. For example, vapour to water releases energy and visa versa.
15
Q
What is the 1st law of thermodynamics?
A
energy can neither be created
or destroyed, but it can change form
16
Q
What is the second law of thermodynamics?
A
Heat always moves from hotter objects to colder
objects, unless energy in some form is supplied to reverse the direction
of heat flow.
17
Q
How does solar radiation vary?
A
Solar radiation occurs as a spectrum of different wavelengths. We sense these in different ways (UV,
visible light, infra -red)
18
Q
Do clouds cause an albedo or absorb?
A
They can do both (when they absorb they re-radiate it).
19
Q
In what was is energy usually re-radiated from Earth?
A
As it is cool it radiates in longer wavelengths - mainly infra-red.
20
Q
Why are smaller wavelengths of radiation dangerous to organisms?
A
they can alter atoms = ionizing radiation (UV
upwards).
21
Q
Do atmospheric gases absorb incoming or outgoing solar radiation?
A
Both.
Absorb incoming at lower rates than they absorb outgoing radiation - particularly infra-red radiation.
22
Q
What is net radiation?
A
Net radiation is usually measured at the top of the troposphere.
Net radiation is the difference between incoming and outgoing energy. Usually balances itself out.
23
Q
What is radiative forcing?
A
This is when there is a temporary imbalance in net radiation following the rebalance of the energy which causes variation in temperature.
24
Q
What is perturbation?
A
When various evets change the energy balance.
EG: Volcano causes ash which blocks incoming radiation causing cooling.
25
What is negative radiative forcing?
When there is a change in the atmosphere resulting in less radiation and therefore decline in temp.
26
Can you give an example of positive radiative forcing?
Increasing greenhouse gas concentration. Causes upward temp adjustment such as the earth emitting enough to achieve new balance.
27
Who do you cite for any earth system atmosphere lectures?
Thomas (2023) (Atmosphere lectures)))
28
What is maritime tropical air and who experiences it?
W Europe/western N America .
It is humis.
29
What is maritime polar air and who experiences it?
W Europe and W. N. America.
It is also humid but also unstable unlike MTA.
30
What is continental polar air?
Cold, dry and stable.
31
Do air masses mix?
NO they keep their identity and don't mix.
32
What air mass is unstable in N America and what does it cause?
Gulf MT air is highly unstable due to warm Atlantic
and Gulf Stream: hurricanes are generated here.
33
What does the word monsoon mean?
The switching of wind direction as the ITCZ moves north and south through the trade wind areas.
This causes a dry monsoon season and wet monsoon season
34
What are the characteristics of the Asian monsoon?
Winter high in Asia, subsidence, dry, outflowing winds.
Summer movement N of the ITCZ causes rising air, with trade winds drawn towards the continent from the sea (blow from SW), bringing moisture (deflected by Coriolis) and precipitation.
35
What does the summer monsoon mean for Asia? 4 things.
1. Seasonal rain supports rainfed agriculture.
2. 50% India population relies on agriculture.
3. Replenishment of water stores such as snow in Himalayas.
36
What was responsible for the enhanced effected of the Australian wildfires?
The southern part of Australia should get winter rain from the westerlies, but they were flowing further south and there was little precipitation.
37
What occurs during an El nino year?
Warm pool shifts east.
Cooler water and higher pressure in west.
Reduced precipitation over eastern Australia.
38
What occurs during a La nina year?
Warmer than normal sea surface in west Pacific, cooler than normal in east Pacific.
Convection and rain affect eastern Australia.
39
What are the normal conditions of the Pacific, not during an el nino or la nina year?
Warm sea surface in west Pacific, upwelling
of cool waters off S.America.
Winds blow to the west.
40
What are fronts?
Fronts occur on different scales and are associated with precipitation and temperature changes.
41
Can you give an example of a front which would cause instability?
A cold air mass pushing into a warmer, moist one typically sets up a steep temperature gradient
(instability) and warm moist air rises far and fast – setting up the possibility of severe storms.
42
How are thunderstorms created?
Heating at surface and unstable conditions lead to rising air, cloud.
Falling rain in cloud evaporates and cools (LH), causing sinking (downdraft).
Wind shear can separate up and down drafts allowing storm to persist for hours.
43
What is wind shear?
Difference in wind speed or direction over a relatively short distance, either vertical or horizontal
44
How are tornados formed?
Warm rising air meets cooler air aloft, creating turbulence, winds rotate because of
wind shear: wind direction changes and wind speed
increases with height.
The spinning can generate sufficient strength to extend a funnel cloud down to the ground.
45
What is a mesocyclone and can you give an example of one?
A tornado is a mesocyclone (a storm
in a cloud) .
They may be up to 10 km across
46
What 3 atmospheric processes have the same processes but different names? What are 3 features?
Hurricane, cyclones, typhoons
1. Wind speed at least 74mph.
2. Sea surface temp must be 27 degree +
47
How does the Coriolis impact the spinning of hurricanes?
Spin anti-clockwise in NH, clockwise in SH.
48
How do moving troughs of low pressure impact tropical cyclones?
They can create them.
This is through these low pressure troughs denote zones of low level convergence which produces uplift and thunderstorms. May occur in the tropical Atlantic.
Storms may be created due to wind shear which may impact rotation and cause thunderstorms - which can transform into tropical depressions.
49
Why does energy redistribution occur?
Energy surplus and deficit of the planet, prior to circulation effects.
Polar regions lose net energy; equatorial regions gain net energy.
50
What is sensible heat transfer?
Conduction causes more energy in air parcel,
more molecular movement, decreasing density and
thus rising up (convection)
51
What is latent heat transfer?
The process which causes latent heat energy.
52
What are turbulent heat fluxes?
Processes which involve a movement of heat.
53
What is atmospheric pressure and what is t measured in?
The standard atmosphere is a unit of
pressure defined as 1013.25 millibar.
It reflects the weight of the atmosphere. It is approximately the average pressure at the Earths surface.
54
Is pressure even in all parts of the Earth?
No, due to rising and falling air masses.
55
What is the Coriolis effect?
Apparent deflection of winds (or other moving objects) due to the faster rotation of the Earth at the equator than higher latitudes. Air moves right in NH and Left in SH.
56
What are geostrophic winds?
In the upper troposphere, no surface friction, so winds
flow along the pressure gradient, due to Coriolis.
However, friction impacts wind at the surface.
57
What are jet streams?
In the upper atmosphere, steep pressure gradients are linked to fast flowing geostrophic winds
58
What are 5 of the major surface wind patterns?
1) The Coriolis effect deflects winds
2) Surface friction that slows winds and reduces the Coriolis effect.
4) Effects of variable heating and cooling of the oceans and land.
5) Effects of upper-level features, such as jet streams and Rossby waves, create weather systems
59
What is the ITCZ?
A global zone of circulation characterised by rising air, low pressure and convection, seasonal shifts.
60
What are tropical trade wind belts?
Easterly surface winds moving from areas of subtropical high pressure towards the ITCZ. In these areas, ocean temperatures are warm.
* At sea, winds generally predictable and useful, hence
the name (trade winds).
61
What are subtropical deserts (4 features) and why do they occur?
They are made from the descending limb of the Hadley cell.
1. High pressure, little or no rainfall
2. Clear skies
3. Large diurnal temperature fluctuations
4. At sea, calms (the “horse latitudes”)
62
What is the subtropical jet?
The subtropical jet is a fast-moving band of air high in the troposphere caused by a steep pressure gradient—warm rising air to cooling sinking air.
63
What are 3 characteristics of the polar cells?
1. Cold, dense air over the poles sinks
2. Typical weather is cold and clear, low precip.
3. Temperatures largely driven by latitudinally varying insolation (e.g. 24 hr sunlight/darkness) .
There is a low height of the troposphere over poles.
64
What is the polar front?
A latitudinally mobile region of generally variable weather.
Incursions of warmer temperate air occur in the lower latitudes of polar regions bring precipitation.
65
What are Rossby waves?
They are as result of the Earths rotation and they impact the surface weather features.
Waves tend to take certain forms more frequently, due to topographic features.
66
What is a polar vortex?
A strong flow enclosing the cold polar cell.
67
Why do people disregard the Ferrell cell?
It is an area of highly variable atmospheric movement.
Travelling lows (and intervening high-pressure “ridges”) lasting a few days are a feature and it is thus the most variable on the planet.
68
how are depressions formed at the polar front?
Warmer air from the south meets the cold polar air – zone of mixing of cold and warm air.
This causes low pressure at the surface.
69
What is cyclogenesis?
A vertical motion set up by swings in the horizontal airflow; the moving air is rotation caused by Coriolis: here, clockwise in surface highs and anticlockwise in lows (reversed in S Hemisphere)
70
What are General Circulation Models?
Depict the major movement of the atmosphere –
pressure, winds, rising and falling air masses.
71
What are weather models?
Atmospheric and surface grid cells.
The model makes sets of computations in time-steps in which all adjacent cells interact. This can be based on previous knowledge too.
72
What are climate models?
Ensembles of daily weather information, with outputs summarised as climate statistics (averages, variance and means).
Average weather maps are created for decades at a
time.
They produce long term changes.
73
Why is vertical movement in the atmosphere so important?
Upward motion transfers a significant amount of energy from the surface to the atmosphere.
74
What is humidity?
The absolute amount of water vapour in air.
75
What is the saturation point?
The amount of water that the air can hold.
Warm air holds more moisture than cold
76
What is the relative humidity?
The % of saturation.
77
What happens when unsaturated warm air cools?
When unsaturated warm air cools it becomes saturated and condenses (clouds form).
78
What is a lapse rate?
The lowering of temperature upwards in the atmosphere.
79
What is the Environmental lapse rate?
The rate of temperature fall with altitude. It implies that there is no air movement.
80
What 4 ways is heat released from the atmosphere?
1. Radiation
2. Conduction
3. Convection
4. Latent heat transfer.
81
What does DALR and SALR stand for?
Dry Adiabatic Lapse Rate
and
Saturated Adiabatic Lapse rate
82
What does adiabatic mean?
Without energy loss.
83
True or false: If an air parcel is less dense but colder than surrounding air it will rise?
False, has to be lighter than the surroundings.
84
How are clouds impacted after they have rained?
Water vapour condenses to liquid water
and releases LATENT HEAT, which warms the
parcel, decreasing its rate of cooling. It
continues to rise at the SALR and clouds form
85
What is cloudseeding?
Traditional method of rain-making.
86
What is conditional instability and how is it impacted by ELR?
Where the ELR is between the DALR and SALR (MALR).
This is when a dry parcel will not move upwards, but a saturated parcel will.
However, when ELR rises slowly a saturated air parcel can rise as its rate of cooling exceeds that of the ELR.
87
At a local level, what can prevent warm air from rising?
A temperature inversion (when temperature is higher in a level higher-up). This is shown via smogs.
88
What does cold air drainage at night lead too?
Frost pockets and formation of early-morning mist or fog in cold air.
89
How do land-sea breezes impact weather and cloud formation?
Day: land warms fast and air rises over land, then, clouds may form over land (sea breeze feels cool).
Night: land cools faster than sea, cooler air sinks
and circulation reverses (land breeze feels warm)
90
What are katabatic winds and what are they caused by?
They are a topographically driven weather phenomenon.
Caused by: dense air moving under gravity.
91
What are shelter belts?
Line of trees etc used to protect vegetation or organisms from the wind speed.
92
What is the Venturi effect?
Concept that air flow can be funnelled into narrow passages between buildings.
93
What are transverse currents?
Wind currents which develop when buildings are at right angles to the wind.
94
What kind of molecule is water?
POLAR molecule.
Electron density (-ve) focused on the O atom and H atoms having a relatively more positive charge.
Unlike charges attract.
95
What are the 4 main water reservoirs?
1. Atmosphere
2. Ocean
3. Polar Ice/glaciers
4. Terrestrial
96
How much water is found in oceans?
96.5%
97
How much freshwater is there?
2.5%
98
What % of freshwater is found in glaciers and icecaps?
68.7%
99
How long does water reside in atmospheric water?
10 days
100
How long does water reside in world oceans ?
3600 years
101
How long does water reside in rivers and lakes??
Rivers: 2 weeks
Lakes: 10 years
102
How long does water reside in soil and biological water?
soil: 2-50 weeks
biological water: a few weeks
103
How long does water reside in ground water?
10,000 years
104
How long does water reside in permafrost?
1 million years +
105
How long does water reside in polar ice?
over 800,000 years ago
106
What is the Gulf Stream?
Wind-driven current that brings warm, saline waters north.
Together with dominant westerly winds the Gulf Stream helps to keep western Europe warmer than equivalent latitudes.
107
What is the Gulf stream also known as?
Atlantic Meridional Overturning Circulation (AMOC)
108
What are gyres?
Coriolis directs the warm western boundary
currents along the coasts of N and S America,
eastern Australia, Asia and Africa.
They do not move much.
Five subtropical GYRES located 30° N and S
109
What is deep ocean circulation?
Deep ocean circulation is not driven by winds but
differences in density (related to temperature and
salinity).
Water takes several centuries to circulate completely (estimates vary).
110
What is the movement found in deep water circulation?
Warm waters from the equator flow towards the high latitudes, cool, sink and return towards
the equator.
Also furthered by sea ice sheets.
111
What 6 processes can form lakes?
1. Glacial
2. tectonic
3. Thermokast
4. river erosion
5. Meteor impact
6. volcanic eruption
112
What is the largest freshwater lake on Earth?
Lake Baikal is the largest body of
(unfrozen) freshwater on Earth:
23,600 km3. It is in Siberia.
113
What were the Great Lakes formed by?
All formed by the Laurentide ice sheet during the Last Glacial Maximum – approx. 20,000 years ago.
114
What lake is an example of a tectonic lake?
Crater Lake, Oregon.
It is 600m deep and formed 7600 years ago in a
cataclysmic eruption of Mt. Mazama.
The lake lies within a Caldera – a collapsed magma reservoi6.
115
What 3 elements make up the cryosphere?
1. Glacier and ice sheets
2. Sea ice.
3. Permafrost.
116
What are sub-glacial lakes and give an exmaple?
Form under ice sheets and can remain isolated from
the hydrosphere for long periods.
The most famous is Lake Vostok, 4 km beneath the
Antarctic ice sheet.
117
What are 3 types of ground ice?
1. Segregated ice – ice lenses
2. Ice wedges – formed through thermal contraction
3. Relict Ice – buried ice from the Pleistocene
118
What are 2 types of perma-frost?
1. Continuous permafrost
2. Discontinuous permafrost
119
What is the Batagaika mega-slump, Siberia
The largest known regressive slump in the world (Murton et al 2017).
Has a 650,000 year climate record.
120
What is the Ogallala Aquifer and give 2 facts?
Largest USA aquifer and covers 8 states.
1. supports 30% all agricultural crop production.
2. water levels dropped significantly.
121
How much does agriculture contribute to total anthropogenic water withdrawals?
more than 70%
122
In the UK, how many hectares were used for crops in 2021 according to YOUGOV?
3.7million hectares.
123
IN 2019, according to WHO, how many people lack access to safely managed drinking water?
2.2 billion people.
124
How do those living on atolls get access to water?
They rely on shallow fresh-water lenses that float on sea water.
Resilience to fluctuations in rainfall has been improved with cistern catchment system.
125
According to Albert et al 2016, how many Solomon islands had disappeared from 1947-2014?
5, due to eustatic sea level rise.
126
How many people globally rely on meltwater?
1.9 billion
127
How many people rely on the Himalaya–Karakoram mountain ranges for water?
869 million people.
128
How is Slims River, Yukon an example of water piracy?
The Kaskawulsh Glacier—one of Canada’s largest glaciers, fed both the the Slims and Kaskawulsh rivers.
However, the Kaskawulsh Glacier has been rapidly retreating because of climate change.
In 2016, this led to the Slims river drying up.
129
By how much is the Dead Sea decreasing each year as a result of extraction of water from the River Jordan?
1.2 meters a year (Lensky et al 2005)
130
What is the Grand Ethiopian Renaissance Dam?
A dam being built across the Blue Nile in Ethiopia which will be one of the largest dams in the world. However, it will have a big impacted on people downstream (Abbas, Sudan Minister)
131
What are 4 types of drought?
1. Meterological: a degree of dryness compared
with average. Depends on region and climate.
2. Agricultural: a shortage of precipitation and
soil moisture affects crop yields
3. Hydrological: lack of precipitation affects
water supplies, river/reservoir levels,
snowpack, and/or leads to increased
groundwater extraction
4. Socioeconomic: when water shortage leads to
over-demand supplies are reduced. May take
into consideration rationing, health, fires and
loss-of-life.
132
In Zambia 209, how many people faced insecurity and what was the reason for it?
2.3 million, due to drought conditions.
133
What are mega-droughts?
Cook et al (2022) persistent, multi-year droughts. USA experiencing them since 2000 - can be seen via tree rings.
134
Why did some lakes, such as as megalake chad dry up?
Linked to changes in solar insolation.
Precession (Earths wobble) affects the perihelion – the point where the when Earth passes closest to the Sun
135
Give 2 facts about mega-lake chad?
1. It is now 10x smaller than it was previously.
2. The Bodele basin is now the worlds largest dust source.
136
What % of anthropogenic-driven warming have global oceans absorbed?
90%
137
According to Slater et al (2017), how many tonnes of ice did Earth lose between 194 and 2017?
28 trillion tonnes.
138
What are the O16 and O18 isotopes and what is there relevance to global ice mass?
Of these δ16O is by far the most common, followed by δ18O and finally δ17O .
Because δ16O is isotopically lighter it is preferentially evaporated from the oceans.
In cold stages δ16O becomes trapped in ice sheets, changing the ratio between δ16O and δ18O.
139
What was Beringia?
A sub-continent formed by lowered sea levels that acted as a corridor between Eurasia and North America.
Humans used this route.
140
What are eustacy and isostacy?
* Eustacy = global change in ocean volume
* Isostacy = tectonic change in the level of land relative to sea
141
What are 6 other eustatic controls? aka thing that change sea level etc.
(1) Thermal expansion / contraction of sea water
(2) New water accretion from volcanoes
(3) Extraction of ground water (a minor contribution)
(4) The construction of dams/reservoir
(5) Tectono-eustacy = global sea-level change caused by continental-scale tectonic activity
(6) Sedimento-eustacy = gradual in-filling of ocean basins with sediment
142
Why are some nations gaining and while others are losing it due to sea level rise?
Initially, sea level rises much faster than the land, drowning the coast.
Then sea level rise slows and the land continues to rise.
Today, that is why Norway, Finland and Sweden are gaining land area.
143
How is the UK being impacted by isostatic changes?
The crust of Britain is tilting, with the South sinking and Scotland rising.
144
Who do you reference for anything hydrosphere related?
Monteath (2023) (Hydrology Series)
145
How does topography impact precipitation?
Mountain ranges create orographic precipitation, and downwind are rain shadows.
This is when the descending wind compresses and warms.
146
What does continentality mean in regard to warmth of a continent?
The centre of the continent is warmer than the outer edges.
147
Can you give a positive and negative of geo-classification?
Positive:
1. Helps organise phenomena.
Negative:
1. Rarely possesses exact boundaries.
Instead empirical classification can be useful to map phenomena.
148
What 2 main things control primary productivity?
1. Temperature regime:
Includes ability to survive temperature extremes and the growing season.
2. Moisture availability:
Local rainfall regime, the evapotranspiration precipitation, and accessibility to groundwater etc.
149
What does zonal and azonal mean?
Zonal: Large-scale fcators
Azonal: Small-scale factors
150
What is a zonal factor influencing primary productivity?
Regional macro-climates such as monsoonal/equatorial etc
151
What is an azonal factor influencing primary productivity?
Topography and soils, drainage etc.
152
What are 6 conditions or characteristics within the tundra?
1. Less than 10'cin the warmest months.
2. Winter may plunge to -50'c.
3. Cold, dry in areas.
4. Permafrost.
5. Less extreme temperatures in costal regions.
6. Low primary productivity
153
How is the wood-frog a good example of extreme adaptation?
Freezes in winter; cells protected by glucose antifreeze (depression of freezing point), ice forms in body interstices.
154
What is polar amplification?
The fact that the polar regions are observed to be warming faster than the rest of the planet. Increases growing season, and shrubs are expanding
155
Can you give an example of polar amplification in Siberia?
In summer 2020, Siberia's temperatures were 10'c higher than usual.
156
What may happen to the ground as a result of polar amplificiation?
Thermal erosion in the form of perma-frost and slumping.
157
What are ectones?
These are the dividers between one biome and another. Could be related to mountains etc.
158
Where are shifts in vegetation often observed?
Ectones.
159
What are 4 challenges amplified by climate change in the med?
1. Increased drought
2. Limited water supplies
3. Major impact on irrigated agriculture
4. More frequent fires affecting forest growth and productivity
160
What are the 3 tropical and sub-tropical biomes?
1. Equatorial and tropical forest
2. Savanna
3. Warm desert
161
What are the 4 temperate biomes?
1. Mediterranean/chaparral
2. Temperate grasslands
3. Temperate deciduous forest
4. Evergreen temperate forest (southern hemisphere)
162
What are 3 of the cold biomes?
1. Taiga
2. Tundra
3. Mountains
163
What is a climogram?
Intuitive, information-rich climate diagram.
It can be presented in many variants – often just temp curve and precipitation.
164
What are the 3 most anthropogenically-transformed biomes?
1. Prarie/Steppe: Agriculture.
2. Temperature deciduous forest: Good agriculture.
3. Mediterranean: European settlement.
165
What are the 2 least transformed biomes?
1. Desert
2. Tundra
166
According to Foley et al (2005), what % of land is now cropland or pasture?
40%
167
What is ecology?
The study of the interrelationships of plants and animals with each other and with their environment.
168
What is autecology?
The ecology of a particular species.
169
What is community ecology?
Ecology of interacting organisms in a particular environment.
170
What is taxonomy?
Taxonomy provides biologists with a common understanding of Earth’s species and a method of naming them, and also how they are related.
171
What are the 2 ways to define a species?
1. Reproductive definition
Individuals that successfully breed together form a species… But quite a few hybrids exist, so not a watertight definition
2. Molecular definition
With the advent of molecular biology and molecular genetics, the GENOME*, or parts of it, can be sequenced -- allows relationships to be assessed somewhat more objectively—based on proportions of shared gene sequences, BUT there are multiple solutions to the phylogenetic tree (at right)
172
How many species (not including microbes) does Mora et al (2011) argue there are?
8.7 million
173
What is a phenotype and a genotype?
Phenotype: Physical appearance (can lead to microevolution).
Genotype: Genetics
174
What is speciation or macro-evolution?
This is when species diverge so much they are no longer the same. They may be distantly related via convergent evolution.
175
What is the differences between a fundamental niche and a realized niche?
Fundamental niche is the areas that a species COULD live without biotic interaction, but realised niche is the observed space that they are found.
176
Who did the study about pine martins and squirrels?
Twining et al 2020
also, grey are more abundant.
177
What is intra-specific competition?
Individuals of the same species directly share the same resources. This leads to competition.
Can also lead to micro-evolution.
178
What 6 things can 'reset' the ecology of an area?
1. Fire
2. River floods, glacier advance
3. Windstorms
4. Animals eating, trampling…
5. Grazing stock of humans
6. Humans cutting, ploughing etc
179
What is succession?
The directional change in the composition and biomass of an ecological unit over time – usually with a gain in complexity.
180
What is primary succession?
This occurs after the appearance of a new substate.
181
What is secondary succession?
Occurs following disturbances on existing land – e.g. fire, wind-throw, forest clearance for pasture.
This can be in the form of old field succession whereby natural reforestation occurs.
182
What is arrested succession?
The prevention of succession for a reason. For example, grazing prevents trees from growing.
183
What are the characteristics of a rapid population growth rate?
-Temporary
-Common in invasive species
-Eventually constrained by some factor
184
What are the characteristics of a common population growth rate?
Grows until a carrying capacity is reached whereby population will fluctuate around this number. It is common.
185
What are 'R' plant species, and what are their characteristics?
‘r’ strategists (e.g., weed species, short-lived trees)
have high reproductive rates and rapid development.
1. good colonizers – common on new/disturbed sites
2. out-compete others in high-disturbance conditions
The best are annuals (ruderals) - such as poppies.
186
What are 'K' strategists and their characteristics?
Long-lived trees and plants.
1. Low reproductive rates but better competitive ability
2. Will out-compete other species in low-disturbance situations.
3. Often dominate in late-successional situations
4. K species can tolerate low light and lower nutrient situations and can grow slowly.
187
What are autotrophs?
1st trophic level.
They receive energy from the sun by photosynthesis. They include green plants, algae and some bacteria.
188
What are heterotrophs?
High trophic level.
They feed on autotrophs (so do omnivores).
Carnivores/omnivores consume herbivores.
189
What are decomposers/saprovores?
Detritus-based rather than vegetation-based food chain.
Releases energy and recycles inorganic nutrients
decay – recycling – reuse.
190
How much energy is passed between each tropic level on average?
Less than 10%. Most of the biomass is not eaten and dead material feeds the saprovore level.
191
What does Cardinale et al (2012) argue about biodiversity and productivity?
More biodiverse systems are more productive. This is for many reasons, with one being it is driven by the species within each ecosystem.
192
Are more diverse ecosystems more resilient?
Yes
193
Why are keystone species so important?
They are often predators so without them there is a lack of top-down control which may lead to tropic cascades.
This contrasts with resource constraints.
eg; sea urchins
194
How successful have agricultural-environmental schemes been at rewilding and reducing agriculturally induced poverty?
-Agri-environment schemes have tried (and largely failed) to deal with declining biodiversity in agricultural landscapes
- In the UK, major revamp of these so ALL subsidies meant to improve sustainability of agriculture post Brexit
195
Who do you cite for all biodiversity based information?
Eigenbrod (2023)(Biodiversity Lecture series)
196
What compromises Earth's critical zone?
It is an external heterogeneous layer.
1. From vegetation to groundwater
2. Includes rocks, soil, water, air, biota
Life-sustaining and critical
197
What are 3 non-ecological functions of soil?
1. Physical basis of human activities
2. Source of raw materials
3. Geogenic and cultural heritage
198
What are 3 ecological functions of soil?
1. Biomass production
2. Protection of humans and the environment.
3. Gene reservoir (1/4 earths biodiversity)
199
What is natural capital?
Natural capital can be defined as the world's stocks of natural assets which include geology, soil, air, water and all living things. It is from this natural capital that humans derive a wide range of services, often called ecosystem services, which make human life possible.
200
How many microorganisms does 1g of soil contain?
1 billion microorganisms
201
What are the 4 components of soil?
1. Mineral particles
2. Soil organic matter
3. Soil water
4. Soil air (high CO2 concentration)
202
What are 4 types of soil water?
1. Gravitational water
2. Capillary water (only type of water available to plants)
3. Hygroscopic water
4. Plant available water
203
What are soil horizons?
Distinct horizontal layers in the profile.
These layers can be distinguished by translocation of material - can be through eluviation or illuviation.
204
What are the 5 main inputs of soil formation (pedogenesis)?
Parent material weathering,
Surface accumulation,
Solutes and particles from precipitation and wind, Energy from the sun,
Gases from the atmosphere
205
What are the 3 main losses of soil?
1. Wind erosion
2. Water erosion
3. Leaching
206
What 7 things cause mixing of soil?
1. Soil animals
2. Microbes/plant roots
3. Freeze-thaw cycles
4. Shrinking-swelling
5. Ploughing
6. Chemical processes
7. Translocation
207
What are luvisols/brown soils?
Where rainfall > evapotranspiration
Clay eluviated and redeposited in argillic horizons
208
What is podzolization of soil?
Where there is intense leaching and translocation (acidic).
Organic acids compound with iron and aluminium.
Freely drained sites under forests and heath plants.
209
What is gleying of soils?
Waterlogging leads to reduction, mobilization and removal or redeposition of iron compounds.
Alternate phases can result in mottling.
210
What is lateralization of soils?
Occurs in tropical and subtropical oxisols.
Heavy leaching
Depletion of base cations
211
What are the 5 factors influencing soil formation?
Climate (cl) – most influential
Determines moisture and temperature regime under the soil
Chemical reactions faster at higher temperatures
Organisms (o) – plants, animals, microorganisms and humans
Relief (r) – altitude, slope and aspect of the landscape
Catena – topographically determined soil profiles in a location
Parent material (p) – influence of the weathered material on the soil
Time (t)
212
What are the 2 main types of blocky soil?
Angular and sub-angular
213
What are the 2 main types of spheroidal soil?
Granular and crumb
214
What are the 4 main, over-arching soil types?
1. Blocky
2. Spheroidal
3. Platy
4. Prismatic
215
What causes an increase in hydrogen and aluminium in soil, and what effect does this have on soil?
Processes such as leaching, acid rain etc. This makes the soil more acidic.
The acidity or pH of the soil can impact its agricultural use and success. The best pH is between 6-7.
216
What impact does low pH and high pH have on soils?
Low pH: Reduces availability of nitrogen and phosphorus
High pH: Limits nitrogen and copper.
217
What is the most 'recent' period?
The holocene - it is 10ka to present day (warm interval).
218
What 4 things causes the tertiary global cooling?
1. Changes in land-sea distribution (increases in high latitude land masses)
2. Variations in ocean circulation – altered latitudinal temperature gradients
3. Changes in continental topography (mountain building), notably uplift of
Colorado and Tibetan plateau, and Transantarctic mountains
4. Enhanced chemical weathering, as a result of increased mountain building
219
How has ice sheet advance impacted quaternary records?
It fragmented many records from the terrestrial paleo-climatic period.
220
Where can continuous records be found nowadays?
1. Oceans
2. Surviving ice sheets
3. South of Quaternary ice sheet maximum (on the land near France).
We can also use indirect lines of evidence called proxys).
221
What are 3 types of proxy?
1. Biological (EG: pollen, plants, insects).
2. Physical
3. Chemical
222
What is taphonomy?
How fossils get preserved in sediments.
223
What is an example of a biological, aquatic indicator or proxy for geological change?
Diatoms.
These are aquatic algae found in freshwater and marine water. They are made of silica so preserve well and can be indicators of pH and salinity.
224
What is an example of a biological, aquatic and flying indicator or proxy for geological change?
Chironomids
These are most widely distributed freshwater insects (both larvae and pupal stage). They have many different applications.
They are good for changes in temperature.
225
What is ice-rafted debris important for?
Indicating past glacial activity and dynamics
226
Why are ice cores so significant?
They revolutionised climatology studies and can be found simultaneously at different location.
They led to theories about climate forcing.
227
What 4 things can ice cores record?
1. Snow accumulation or melt.
2. Atmospheric gases through bubbles.
3. Dust (shows atmospheric transport etc)
4. Water at time of formation holds oxygen isotopes so can be a temperature proxy.
228
What 4 things can ice cores record?
1. Snow accumulation or melt.
2. Atmospheric gases through bubbles.
3. Dust (shows atmospheric transport etc)
4. Water at time of formation holds oxygen isotopes so can be a temperature proxy.
229
Can you give an example of when ice-cores have been important in dating boundaries?
Only in 2009 was the boundary between the Pleistocene Epoch & the Holocene Epoch formally defined.
This was unusual as usually defined by terrestrial stratigraphic boundaries.
230
Why does atmospheric CO2 decline during a glaciation? (2 main reasons)
(1) Chemical weathering
– Greater land area in glacial conditions
– Solution of rocks by carbonic acid locks up CO2
– Possibly 50 – 100 ppmv drop in CO2
concentration attributable to chemical
weathering
(2) Changes in oceans
- Temperature change
- Productivity
231
Why does temperature change in oceans result in declining CO2 in the atmosphere during glaciation?
Oceans hold x60 more CO2 than atmosphere
CO2 more soluble in cold water
= more in glacial oceans, less in atmosphere
232
Why does productivity in oceans result in less CO2 in the atmosphere during a glaciation?
Plankton utilise CO2, but numbers increase in glacials, drawing down more CO2.
This is because in a glacial:
1. Light – northern sea ice pushes plankton belt
south, where the sun is stronger.
2. Nutrients – more dust in glacial (less vegetation),
supplying more iron to oceans.
233
What was a major reason for the changes in methane levels in a glacial atmosphere?
Quantity of CH4 in atmosphere controlled
by sources and sinks.
Changes in wetland composition and extent – major factor driving change in CH4.
234
What are the 3 hypothesis to describe the longer term climatic change? - which has a pattern
(1) Geographical changes in the Earth’s surface
- Mountain building
(2) Changes in the atmosphere
-Atmospheric changes
(3) Changes in solar radiation receipt
1 and 2 fail to explain regular cycles though
235
What is the aphelion and the perihelion?
* Aphelion = Earth at most distant part of elliptical orbit
* Perihelion = Earth closest to sun
236
What are the 3 long-term changes in the Earths orbit? These are knwon as the Milankovitch cycles,
* Eccentricity
* Obliquity
* Precession
237
What is Eccentricity?
The change in the shape of the orbit from circular to elliptical. This causes a slight change in the total radiation received in summer/winter.
Changes over 100,000 year cycle.
238
What is obliquity?
The tilt of the Earth. It varies by 4 degrees and it changes the contrast between the seasons.
It changes on a 41,000 year cycle.
239
What is the precession of the equinoxes?
Precession is caused by a ‘wobble’ in the Earth’s axis which results in progressive change in the direction in which the Earths axis of rotation points. It takes about 21,000 years to complete.
240
What are 3 issues regarding the astronomical theory of climate change?
1. Doesn’t explain long-term Tertiary cooling
2. Main pacing of the ice ages has shifted from 41ka (early Quaternary ) to 100ka.
– Shift occurred after c.800ka.
– Glaciations also intensified
3. Shifts in period and intensity of the ice ages can’t be solely orbital in origin.
241
What 5 things can cause a deepening of glacial activity?
(1) Albedo = more reflection of sunlight
(2) Reduced sea level = larger land area for ice
(3) Sea area small (moderates temps)
(4) Ice sheet height increases height of land
(5) CO2 reduced in the atmosphere
242
What 5 things drive sub-Milankovitch climate change?
* Volcanism
* Solar irradiance
* Ice sheet dynamics
* Changes to Ocean circulation
* Human impacts
243
How does volcanism impact climate?
Volcanic aerosols cause relatively short-term climatic
cooling:
* Increased volcanic activity in the last 600 years correlates well with proxy climate data showing N. hemisphere cooling.
* Abrupt rise in N. hemisphere temperatures between 1920- 50 coincides with phase of reduced volcanic activity.
* Modelling suggests that volcanism accounts for 22% of temp. variability over the last 1000 years
244
How does solar irradiance impact climate?
* Radiation output of the sun changes cyclically
* E.g. 11, 200, 1500 yrs
* Reduced sunspot activity = less solar output + weaker
solar wind
245
Why can the sun not be blamed for the increase in global temperatures?
1. Sun’s energy hitting top of atmosphere has not increased (measurements started since 1978).
2. Warming is only at the surface of the planet, not throughout the atmosphere (stratosphere is cooler). Consistent with warming caused by trapped gases near earth’s surface - not linked to the sun.
246
What 3 changes, not linked to the Milankovitch cycle may be responsible for the rising temperature of Earth?
1. Thermohaline ocean circulation
2. Atlantic Meridional Overturning Circulation
- If the North Atlantic Deep Water NADW is impacted, it has impact the thermohaline circulation.
-Ice sheet collapse has impacted this but could cause cooling as heat transfer to northern latitudes is vastly reduced.
3. Heinrich event: AMOC is off due to the ice sheet collapse.
247
Who do you cite for anything geosphere related?
Langdon (2023) Geosphere Lecture Series.
248
How many essential soil nutrients are there? Give 3 examples
16.
1. Carbon
2. Hydrogen
3. Oxygen
249
What are the 3most essential biochemical nutrients' cycles?
1. Phosphorous
2. Nitrogen
3. Carbon
250
What are molecules and what are compounds?
Molecules refer to substances where two or more
atoms have combined (e.g. H2)
Compounds are where at least two different elements (H2O) combine.
251
What are ions?
Atom or molecules that have lost electrons producing a net +ve charge, or gained an electron which creates a negative charge.
252
What are cations and what are anions?
Ions with a negative charge - ANIONS
Ions with a positive charge - CATIONS
253
What is Liebig's law of the minimum?
The concept that something can only grow to a certain level when it has the correct nutrients - a lack of one thing will impact growth.
254
Where can you find natural phosphorous?
Often found in some rocks (apatite) and guano (bird droppings).
255
Why is phosphorous critical to life?
It is vital for all energy metabolisms, a part of DNA and found in animal bones.
256
How is phosphorous transferred?
Phosphorous is insoluble but is transported through water via absorption on organic or minerogenic particles.
Humans can also transfer it into soil from rocks through fertilizers etc.
257
How much nitrogen is found int he atmosphere?
79% but most is unreactive due to small size. (trace concentration)
258
Where does nitrogen come from?
Process called nitrogen fixation.
Lightning causes reaction between oxygen and nitrogen which creates nitrogen oxide, then reaches the ground as ammonium.
259
In what 2 forms do plants use nitrogen?
nitrate (NO3− *) and ammonium (NH4 + *)
260
What is biological fixation?
It is the creation of nitrogen availability for plants and animals.
261
How does biological fixation occur and what is N cycle?
1. Oxidising-nitrifying bacteria in plant roots (mainly legumes, e.g. pea and bean family) à NH3 (NH4
+) direct to plants.
2. Oxidising-nitrifying bacteria in soil fix N2 from atmosphere, initially as NH4 + (ammonium) then other
(oxidising) bacteria nitrify NH4 + to NO2- (nitrite) then to NO3 − (nitrate).
3. Denitrifying (reducing) bacteria return N2 to atmosphere, completing cycle (burning releases
further NO, NO2). Decomposers return N to soil as NH4 +
262
In what 3 ways have humans impacted the nitrogen cycle?
1. The industrial fixation (Haber–Bosch process-1913) of N2 to ammonium and N-fertilizers (half of all food dependent on N-fertilizers)
2. The internal combustion engine – NOx emissions
3. Animal rearing is associated with the emission of NH3, produced by the decomposition of urine
and faeces
263
What does the enhanced, anthropogenically driven nitrogen cycle impact? Give an exmaple.
The consequence of increased formation of NH3 and oxides of nitrogen is an enhanced rate of ammonium and nitrate deposition to land and waters
More N now entering atmosphere
through human activity than through
all natural processes.
Dominance of nettles along roadsides as a result of emissions.
264
Can you give a positive of the human impact on the nitrogen cycle?
overall plant growth may be enhanced and lead to
higher rates of C-uptake (e.g., some forests)
265
What is an example of the impact the human induced nitrogen cycle has had on the environment?
Great Atlantic Sargassum Belt: 5,500 mile algal belt which keeps growing. (eutrophication)
266
What is the total anthropogenic burden of Carbon on the atmosphere per year?
7.5-8.5 gt C a year (fossil fuels 6.5 and deforestation is 1-2).
267
What is happening to the excess carbon which is not being taken up by the atmosphere?
Atmosphere only takes about 3gt extra a year. It is being taken up by terrestrial photosynthesis or through dissolving in the ocean.
268
What was the Early Holocene climate instability including the 8200 BP event?
8.2ky event
This was an Atlantic wide cooling effect - associated with iceberg release.
In 8200 there was a release of a flood (150,000km3) to Hudson bay which shaped Great Lakes.
269
What did the Early Holocene climate instability including the 8200 BP event lead too?
1.4m of sea level rise as a result of the cancelling of the gulf stream (due to cold water). This may have displaced rural communities, but could've causes the beginning of agriculture (Turney and Brown 2007)
270
What is the Browning of the Sahara an example of?
An example of a tipping point, triggered by the weakening of the African monsoon.
271
Why did the browning of the Sahara occur?
The AHP (African Humid period) began 14.5ka BP as the monsoon strengthened due to orbital parameters (equinoxes)
- This is because they impacted dust and solar insolation.
As the N. Atlantic cooled as a result of the dust, the Sahara becomes dry (mid-holocene). This continued due to the decrease in solar radiation.
272
What impacts did the browning of the Sahara have on the earth?
A decline in vegetation led to changes in soil structure. This causes less vegetation and drier conditions - an example of a positive feedback loop as the initial climate signal was amplified.
273
What was the medieval climate anomoly?
This was the drying of Europe between 950-1250 AD, this was shown by the expansion of vineyards in Europe.
274
What were the effects of the medieval climate anomaly on the environment?
Drying of the climate could have led to the collapse of the Mayan society - for example the drying of lakes could evidence 4 drying events.
275
What were the effects of the medieval climate anomaly on humans?
Led to rapid migration into the Pacific in 2 phases (Melanesia to Oceana) and then a pause before movement into Polynesia/South America. The Cook islands were important during this transition.
This may have led to migration into E. Pacific due to push for resources.
276
What was the little ice age?
Cooling from 1150-1460 but with cold spells from 1560-1850.
277
What were the effects of the little ice age on humans?
1. Reduced growing season by 15-20%
2. Year without summer (1816) poor grain/wine harvest
3. 1788 French Rev triggered by bread riots - no harvest
4. Malnutrition and disease
Also led to abandonment of uplands, severity of storms increasing and evidence for the N. Hemisphere drying.
278
Why did the Little ice age occur?
Corresponds to sunspot periods (Dalton period 1900) however has to be for other reasons.
1. Volcanic activity
- Tree ring evidence
-1816 year w/o summer following Indonesian eruption
279
Who do you evidence for anything linked to impacts on climate etc?
Langdon (2023) Impact Lecture Series.
280
What happened 21000 years ago in regard to the holocene?
Maximum of last ice age
281
What happened 14000 years ago in respect to the holocene?
Ice retreats, advances and then retreats for good
282
What happened 11000 years ago in regard to the holocene?
Beginning of the holocene
283
What happened 6000-5000 years ago?
The Sahara switch
284
What happened 6500 years ago?
The neolithic period (first agriculture)
285
What happened 4500 years ago?
Bronze age (first metal)
286
What happened 2700 years ago?
Iron age
287
From 43-410 AD what was happening?
Romans
288
Who was around from 800-1066 AD
Vikings and Saxons
289
What happened in the late 1700s?
Industrial revolution
290
How are cosmogenic isotopes 14C and 10Be proxies for reduced solar output?
The solar irradiance reduced the cosmic waves which causes these isotopes (linked to sun-spots). However, this doesn't justify all global change
291
What di the IPCC (2023) argue about observed warming and its causes?
Human activities, principally through emissions of greenhouse gases, have unequivocally caused global
warming, with global surface temperature reaching 1.1°C above 1850–1900 in 2011–2020. Global
greenhouse gas emissions have continued to increase, with unequal historical and ongoing contributions
arising from unsustainable energy use, land use and land-use change, lifestyles and patterns of consumption
and production across regions, between and within countries, and among individuals
292
How has El NIno and La Nina impacted global temperatures?
During the warm phase of ENSO (El Niño), global temperatures tend to be warmer than ENSO-neutral or La Niña years, while global temperatures tend to be slightly cooler during cold phase ENSO episodes (La Niña).
Despite the last two years (2021 and 2022) not ranking among the five warmest years on record, the global annual temperature increased at an average rate of 0.08°C per decade since 1880 and over twice that rate
(0.18°C) since 1981
