Water and Carbon Cycles Flashcards
1
Q
Water and carbon cycles as natural systems
-Inputs
A
- The addition of matter and energy into a system
- Water cycle inputs= precipitation
- Carbon cycle inputs= atmospheric CO2
2
Q
Water and carbon cycles as natural systems
-Outputs
A
- The removal of matter and/or energy from a system
- Water cycle outputs=Transpiration, evaporation, river discharge
- Carbon cycle outputs= Fossils and fossil fuels
3
Q
Water and carbon cycles as natural systems
-Stores and components
A
- A part of the system where energy/matter is held for a long time or transformed
- Water cycle stores= interception, ground water storage and soil moisture storage
- Carbon cycle stores=ocean carbon store, lithosphere, hydrosphere, pedosphere, cryosphere, atmosphere, biosphere
4
Q
Water and carbon cycles as natural systems
-Flows/transfers
A
- A link between one store and another that involves movement of energy or mass
- Water cycle flows=Stem flow, percolation, channel flow
- Carbon cycle flows= Photosynthesis, respiration, combustion, decomposition, ocean uptake and loss, weathering and sequestration
5
Q
Water and carbon cycles as natural systems
-Positive feedback
A
-Where the effects of an action are amplified or multiplied by subsequent knock-on or secondary effects
6
Q
Water and carbon cycles as natural systems
-Negative feedback
A
-Where the effects of an action are nullified by its subsequent knock-on effects
7
Q
Water and carbon cycles as natural systems
-Dynamic equilibrium
A
-A balance between inputs and outputs within a system
8
Q
Water and carbon cycles as natural systems
-Isolated systems
A
-These have no interactions with anything outside the system boundary. There is no input or output of energy or matter
9
Q
Water and carbon cycles as natural systems
-Closed systems
A
-These have transfers of energy both into and beyond the system boundary but not transfer of matter
10
Q
Water and carbon cycles as natural systems
-Open systems
A
-These are where matter and energy can be transformed from the system across the boundary into the surrounding environment
11
Q
The water cycle
-Hydrosphere
A
-All the water on the Earth’s surface, such as lakes and seas, and sometimes including water over the Earth’s surface, such as clouds
12
Q
The water cycle
-Cryosphere
A
-The cryosphere contains the frozen parts of the planet
-This sphere helps maintain Earth’s climate by reflecting incoming solar radiation back into space
-The cryosphere contains 5 locations, including:
sea ice, permafrost, alpine glaciers, ice sheets and ice caps
13
Q
The water cycle
-Atmosphere
A
- Atmospheric water is found in the atmosphere; mainly as water vapour with some liquid water and ice crystals
- The atmosphere contains 12,900 km3 of water (as vapour)
14
Q
The water cycle
-Lithosphere
A
- It is bounded by the atmosphere above and the asthenosphere
- Water held in rocks is stored in aquifers
- Layers of permeable rock which allow the percolation of water
15
Q
The water cycle
-Water on planet Earth
A
- There is roughly 1,320,000,000 to 1,370,000,000 km 3 of water on Earth, with an average depth of 3,682m
- The ocean contains 97% of the Earth’s water, with 3% as fresh water
- Oceanic water tastes salty because it contains dissolved salts. These salts allow it stay as liquid water below 0 ^C
16
Q
The water cycle
-Cloud formation
A
- There are millions of tiny droplets around us. They are either tiny gas particles, known as water vapour, or aerosols which are tiny particles of salt and dust
- The water vapour and the aerosols are constantly bumping into each other. When the air is cooled, they sometimes stick together- this is called condensation
- Eventually, bigger water droplets form around these aerosol particles and these water droplets start sticking to other droplets, forming clouds
- Clouds will either be composed of ice or water droplets, depending on the height of the cloud and the temperature of the atmosphere. Because the droplets are small, they can remain in liquid from in temperatures as low as -30 C.
- Clouds from when the air is saturated and cannot hold any more water vapor. The warmer the air is, the more water vapour it can hold. As the air rises it cools, reducing the temperature and then resulting in condensation
- As the tiny water droplets group together, they grow heavy and gravity pulls them down as raindrops. If it is cold enough, the rainfall can either be sleet, freezing rain or hail
17
Q
The water cycle
-Causes of precipitation (frontal rainfall)
A
- When a warm air mass meets a cold air mass, they don’t mix as they have different densities
- Instead, the warm less dense air is pushed is over the cold dense air creating the ‘front’
- The warm air cools and the water vapour condenses and falls as raindrops
18
Q
The water cycle
-Causes of precipitation (orographic, relief, rainfall)
A
- Where there is high ground, moist air is forced upwards producing precipitation
- Mountainous areas close to prevailing westerly winds are most likely to experience this type of rainfall
19
Q
The water cycle
-Causes of precipitation (convectional rain)
A
- The ground is heated by the sun, causing moisture in the ground to evaporate and rise, as the hot ground also heats the air above it
- As the water vapour rises, it cools and condenses into clouds and eventually rain
20
Q
The water cycle
-Drainage basins
A
Input:
-Precipitation
Stores:
- Interception
- Surface storage
- Soil moisture
- Ground water
Flows:
- Infiltration
- Percolation
- Ground water flow
- Throughflow
- Surface runoff
Outputs:
- Transpiration
- Evaporation
- River channel
21
Q
The water cycle
-Drainage basins description
A
- Drainage basins can be viewed as open, local hydrological cycles
- A river’s drainage basin is the area surrounding the river where the rain falling on the land flows into the river (the river catchment)
- Drainage basins are open systems with inputs and outputs
- The boundary of a drainage basin is the watershed
22
Q
The water cycle
-The water balance
A
- The water balance is worked out from inputs and outputs. The water balance affects how much water is stored in the basin
- In wet seasons, precipitation exceeds evapotranspiration. This creates a water surplus.
- In drier seasons, precipitation is lower than evapotranspiration. Ground stores are depleted as some water is used and some flows into the river channel, but isn’t replaced by precipitation.
23
Q
The water cycle
-Flood hydrographs (description)
A
- River discharge is the volume of water (m3) that flows in a river per second
- High levels of runoff increase the discharge of a river because more water makes it into a river, increasing it’s volume
- Hydrographs are graphs of river discharge over time. They show how the volume of water flowing at a certain point in a river changes over a period of time.
24
Q
The water cycle
-Hydrographs and runoff
A
- The amount of runoff and the shape of the hydrograph depends on various factors, such as:
- Size of drainage basin-> larger drainage basins catch more precipitation, so they have a higher peak discharge than smaller basins
- Shape of drainage basins ->Circular basins are more likely to have a flashy hydrograph than long, narrow basins
- Ground steepness -> Water flows more quickly downhill in steep-sided drainage basins, shortening lag time
- Rock and soil type-> Impermeable rocks and soils don’t store water or let water infiltrate
25
The water cycle
| -Physical factors affecting the water cycle
Storms and precipitation:
- Intense storms generate more precipitation and greater peak discharges than light rain showers
- the larger input of water causes flows, e.g. runoff, to increase in size
Seasonal changes and vegetation:
- The size of the inputs, flows and stores in the water cycle varies within the seasons
- The more vegetation there is, the more water is lost before it reaches the river channel. reducing runoff and peak discharge
26
The water cycle
| -Human activities affecting the water cycle
Farming practices:
- Ploughing breaks up the surface so that more water can infiltrate, reducing the amount of runoff
- Livestock, such as cattle, trample and compact the soil, decreasing infiltration and increasing runoff
Land use change:
- Deforestation reduces the amount of water that is intercepted by vegetation, increasing the amount that reaches the surface
- Construction of new buildings and roads creates an impermeable layer over the land, preventing infiltration
Water abstraction:
- More water is abstracted to meet demand in areas where population density is high
- During dry seasons, even more water is abstracted from stores for consumption and irrigation, so stores are depleted further
27
The carbon cycle
| -Global distribution of carbon
- Carbon is found in both organic stores and inorganic stores
- Carbon can be found in each of the Earth's systems in some form or another:
- Lithosphere=Over 99.9% of the carbon on Earth is stored in sedimentary rock such as limestone
- Atmosphere= Carbon is stores in CO2 and as small quantities as methane in the atmosphere
- Hydrosphere=CO2 is dissolved in rivers, lakes and oceans
- Biosphere= Carbon is stored in the tissues of living organisms
- Cryosphere=The cryosphere contains less than 0.1% of Earth's carbon
28
The carbon cycle
| -Carbon transfer between stores
- The carbon cycle is a closed system, where there are inputs and outputs of energy, but the amount of carbon in the system remains the same
- There are lots of flows between stores:
- Photosynthesis-> Photosynthesis transfers carbon stored in the atmosphere to biomass
- Combustion-> Combustion transfers carbon stored in living dead or decomposed biomass to the atmosphere by burning
- Respiration-> Respiration transfers carbon from living organisms to the atmosphere
- Decomposition-> Decomposition transfers carbon from dead biomass to the atmosphere and the soil
- Ocean uptake and loss-> CO2 is directly dissolved from the atmosphere into the ocean
- Weathering-> Chemical weathering transfers carbon from from dead biomass to the atmosphere and the soil
- Sequestration-> Carbon from the atmosphere can be captured and held in sedimentary rocks or as fossil fuels
28
The carbon cycle
| -Carbon transfer between stores
- The carbon cycle is a closed system, where there are inputs and outputs of energy, but the amount of carbon in the system remains the same
- There are lots of flows between stores:
- Photosynthesis-> Photosynthesis transfers carbon stored in the atmosphere to biomass
- Combustion-> Combustion transfers carbon stored in living dead or decomposed biomass to the atmosphere by burning
- Respiration-> Respiration transfers carbon from living organisms to the atmosphere
- Decomposition-> Decomposition transfers carbon from dead biomass to the atmosphere and the soil
- Ocean uptake and loss-> CO2 is directly dissolved from the atmosphere into the ocean
- Weathering-> Chemical weathering transfers carbon from from dead biomass to the atmosphere and the soil
- Sequestration-> Carbon from the atmosphere can be captured and held in sedimentary rocks or as fossil fuels
29
Water, carbon, climate and life on Earth
| -Stores essential for life (carbon)
- Carbon is a fundamental building block of life-all living things contain carbon
- Water is also essential for life-> all living things need water to survive
30
Water, carbon, climate and life on Earth
| -Stores essential for life (plants/vegetation)
- Plants form the base of most food chains-> when photosynthesis occurs, they use energy from the sunlight to convert CO2 and water into biomass that gets passed up the food chain
- Photosynthesis requires inputs of both water and carbon
31
Water, carbon, climate and life on Earth
| -Stores essential for life (greenhouse gases)
- Water is present in the atmosphere as water vapour (and water droplets), and carbon dioxide exists as CO2 and methane.
- These are greenhouse gases-> they cause a natural greenhouse gas effect that prevents some energy from escaping into space and reflects it back to Earth
- This causes temperatures on Earth to be higher than they would be-> without the natural greenhouse effct the Earth would be frozen and uninhabitable
32
Water, carbon, climate and life on Earth
| -Stores essential for life (human activities/greenhouse effect)
- Human activities are increasing the concentration of greenhouse gases in the atmosphere
- Most scientists agree that this is causing an enhanced greenhouse effect
- This is where the additional greenhouse gases reflect more energy back to the Earth than in the natural greenhouse effect, so temperature increases even further. This is thought to be causing global warming and other changes to the climate
33
Water, carbon, climate and life on Earth
| -Carbon and water cycles depending on each other
- Carbon combines with water in the atmosphere. This allows chemical weathering, which removes carbon from the atmosphere
- Water is needed for photosynthesis, which removes carbon from the atmosphere
- The amount of CO2 in the atmosphere affects global temperatures, which affect the amount of evaporation that can take place, which affects the amount of precipitation
34
Water, carbon, climate and life on Earth
| -How climate change affects life on Earth
Climate change is predicted to have major impacts on plants, animals and people, for example:
- The pattern of precipitation is expected to change-> wet areas becoming wetter, dry areas becoming more drier
- Extreme weather events-> storms, floods, droughts becoming more frequent
- Agricultural productivity-> decreasing in some areas, leading to food shortages
- Sea levels-> They are expected to rise and may flood low-lying areas
- The geographical range of some species will change as climate changes-> some species may become extinct
- Plankton numbers may decline-> may have a knock-on effect on marine food chains
35
Water, carbon, climate and life on Earth
| -Human influence on the carbon cycle
- Humans have influenced the carbon cycle for centuries, particularly by extracting and burning fossil fuels. There is now more than 40% more CO2 in the atmosphere than in 1750
- The International Panel on Climate Change (IPCC) is an international organisation set up by the UN to share knowledge about climate change. The IPCC states that countries need to reduce the amount of CO2 emitted by human activities in order to prevent large temperature rises
- People are trying to mitigate the impacts of climate change by reducing transfers of carbon to the atmosphere
36
Water, carbon, climate and life on Earth
| -Human influence on the carbon cycle (individual)
- People can choose to use their car less and buy more fuel efficient cars
- They can also make their homes more energy efficient, e.g. with double glazing, insulation and more efficient appliances
37
Water, carbon, climate and life on Earth
| -Human influence on the carbon cycle (regional and national)
- Governments can reduce reliance on fossil fuels for heating and powering homes by increasing the availability and reducing the cost of renewable energy sources such as wind, tidal and solar
- Afforestation and restoring degraded forests can increase carbon uptake by the biosphere
38
Water, carbon, climate and life on Earth
| -Human influence on the carbon cycle (Global)
- Countries can work together to reduce emissions. For example, the Kyoto Protocol (1997) and the Paris Agreement (2015) are international treaties to control the total amount of greenhouse gases released
- There are also international carbon trading schemes. Countries and businesses are given a limit on the emissions they can produce-> if they produce less they can sell the extra credits, if they produce more they need to buy more credits
39
Example of a positive feedback cycle in the carbon cycle
Temperatures rise ->
- > Plant respiration increases ->
- > Amount of CO2 in the atmosphere increases->
- > Greenhouse effect increases
40
Example of a negative feedback cycle in the carbon cycle
CO2 in the atmosphere increases->
- > Extra CO2 causes plants to to increase growth->
- >Plants remove and store more CO2 from atmosphere-> Amount of CO2 in atmosphere reduces
41
Example of a positive feedback cycle in the water cycle
Temperatures rise->
- > Evaporation increases ->
- > Amount of water in the atmosphere increases->
- > Greenhouse effect increases ->
42
Example of a negative feedback cycle in the water cycle
Temperature rise ->
- > Evaporation increases ->
- > Amount of water vapour in atmosphere increases, causing more clouds to form->
- > Increased cloud cover reflects more of Sun's energy back into space->
- > Temperatures fall
