Water and carbon cycles Flashcards
A system
A system is an assemblage of interrelated parts that work together by a process
Elements of a system
Things that make up a system
Attributes of a system
The perceived characteristics of the elements
Relationships of a system
Descriptions of how the various elements work together to carry out some kind of process
System key characteristics
- Have a structure which lies within a boundary
- Functions by having inputs and outputs
- Involve flow of material between components
- Generalisations of reality
Isolated systems
Have no interactions with anything outside the system boundary. No inputs or outputs of energy or matter.
Closed systems
Transfers of energy across system boundary but not the transfer of matter.
Open systems
Transfer of matter and energy across system boundary
Stores
The amount of the total material held within parts of the system. A set of interrelated components working together towards a process.
Inputs
The transfer of energy or matter into a system
Outputs
The movement of energy or matter out of a system, the result of processes within a system.
Dynamic equilibrium
A balance between inputs and outputs of a system
Positive feedback
The amplifications of an action by subsequent knock off effects causing a further, continuation change.
Negative feedback
Lessening the effect of an original change and ultimately reversing it. Nullifying the impacts of action.
Example of positive feedback
-Temperatures warm due to enhanced greenhouse effect
-Sea ice cover melts and shrinks
-Ocean waters absorb more solar radiation than highly reflective sea ice
-Temperatures warm even more
Example of negative feedback
-Surface temperature increases slightly increasing evaporation from the oceans
-More low clouds in the atmosphere which increases the Earth’s albedo
-Surface temperature decreases slightly and so decreased evaporation from the oceans
-Fewer low clouds in the atmosphere which decreases the
Earth’s albedo
What is atmospheric water
Water found in the atmosphere (mainly water vapour) but also contain liquid water (cloud and rain droplets) with ice crystals
What is cryospheric water
The water locked up on the Earth’s surface as ice
Greenhouse gas
Any gaseous compound in the atmosphere that allows short wave ultraviolet radiation from the sun to pass through the atmosphere, yet prevents outgoing terrestrial infrared radiation from escaping to space.
Hydrosphere
A discontinuous layer of water at or near the Earth’s surface, including liquid and frozen surface waters, groundwater held in soil/rock and atmospheric water vapour
What is oceanic water
The water contained in the Earth’s oceans and seas
Terrestrial water
Groundwater, soil moisture, lakes, wetlands and rivers
Stores of water
Oceanic water
Atmospheric water
Cryospheric water
Terrestrial water
General agreement of total amount of water in hydrosphere
1.338 x 10^9 km^3
Percent of oceanic water in hydrosphere
Approximately 97% of hydrosphere made up of oceanic water however only 5% has been explored
They cover 72% of the Earth’s surface
Percent of freshwater in hydrosphere
Freshwater makes up remaining 3% of hydrosphere
Total number of water vapour found in atmosphere
12,900km^3
Why is oceanic water salty?
Contains dissolved salts which allow it to stay as liquid water below 0C
They are alkaline with average pH of 8.14
Classes of terrestrial water
Surface water, groundwater, soil water, biological water
Classes of cryospheric water
Sea ice, ice sheets, ice caps, alpine glaciers, permafrost
Land use changes affecting the water cycle
- Deforestation
Tropical South America has undergone explosive development and deforestation in the last 50 years due to national and international demand for cattle feed increasing
Over 10% of rainforest converted to cattle pasture and agriculture
Effects of deforestation / forest degradation
-Removal of forests leave new vegetation to have fewer leaves and shallower roots, using less water than previous forest.
-Less water evaporated from land surface and returned to atmosphere, increasing surface run off and so stream flow
What is soil drainage?
Installations of network of perforated tubes 60-120cm below soil surface known as ‘tiles’ (corrugated plastic tubing)
-Water table is higher in soil than tile, water flows into tubing
(lowers water table to depth of tile over course of days)
-Water table lowered to the elevation of tiles, no more water flows through
Advantages of soil drainage
- Build up of improve soil structure
- Improve aeration
- Increased aeration
- No danger of compaction
- Large numbers of animals able to graze land
Disadvantages of soil drainage
- Increased speed of throughflow
- Nitrate loss
- Wind erosion
Water abstraction
The process of pumping water from beneath the ground
Result of water abstraction
Sinking water tables
Empty wells
Higher pumping costs
Saline intrusion
What is saline intrusion?
Invasion of saltwater from the sea which degrades the saltwater.
- Widespread along Mediterranean coastlines of Italy, Spain and Turkey (popular tourist location)
Water abstraction in Malta
Most groundwater is now unable for domestic consumption and irrigation due to saline intrusion, with country resorting to expensive desalination plants
Water abstraction - Irrigation
Main cause of groundwater overexploitation in agricultural areas
-Greek Argolid plain of eastern Peloponnesus
Common to find boreholes 400m deep contaminated by saline
-Italy, Po River
Region of Milan aquifer has led to a 25-40m decrease in
groundwater levels over last 80 years.
Anthropogenic CO2
Carbon dioxide generated by human activity
Stores of carbon
Lithosphere
Hydrosphere
Biosphere
Atmosphere
Carbon sequestration
The capture of carbon dioxide from the atmosphere or capturing anthropogenic CO2 from large scale stationary sources before released to atmosphere. Once captured, CO2 is placed in long term storage
Impact of changing carbon budget on the land
The National Ocean and Atmospheric Administration
- Permafrost in the Northern Hemisphere holds between 1460 and 1600 GtC. If 10% of this permafrost were to thaw it could release enough extra CO2 to atmosphere to raise temperatures an extra 0.7% by 2100
Impact of changing carbon budget on the oceans
Ocean acidification
Ocean warming
Melting sea ice
Ocean salinity
Sea level rise
Impact of changing carbon budget on the atmosphere
Enhanced greenhouse effect
- Radiative forcing
Enhanced greenhouse effect
The impact on the climate from the additional heat retained due to the increased amounts of CO2 and other greenhouse gases that humans have released into Earth’s atmosphere since the Industrial Revolution
Radiative forcing
The imbalance between energy flowing into the atmosphere in the form of sunlight which is reflected back into space or absorbed back by the planet.
- Current level is 2.8 watts/m^2 (IPCC)
What is a drainage basin?
An area of land that supplys river with water and is drained by a river and its tributaries. It includes water found on the
surface, in the soil and in near-surface geology.
Groundwater flow
The slow movement of water through underlying rocks.
Infiltration
The downward movement of water from
the surface into soil.
Stemflow
The portion of precipitation intercepted by
the canopy that reaches the ground by flowing down stems, stalks or tree boles.
Throughfall
The portion of the precipitation that reaches the ground directly through gaps in the vegetation canopy and drips from leaves, twigs and stems. This occurs when the canopy-surface rainwater storage exceeds its storage capacity.
Throughflow
The movement of water downslope
through the subsoil under the influence of gravity. It is particularly effective when underlying permeable rock prevents further downward movement.
Percolation
Following infiltration, water moves vertically down through the soil and unsaturated rock
Water balance
The balance between inputs (precipitation) and outputs (run-off, evapotranspiration,
soil and groundwater storage)
Precipitation (P) = discharge (Q) + evapotranspiration (E) ± changes in storage (S)
What is potential evapotranspiration?
Is the amount of water that could be evaporated or transpired (or both) from an area if there was sufficient water available.
River regime
‘the variability in its discharge throughout the course of a year in response to precipitation, temperature, evapotranspiration and drainage basin characteristics.’
Storm hydrograph
Graph of the discharge of a river leading up to and following a storm or rainfall event (storm flow)
- they are important because they can
predict how a river might respond to a rainstorm
- this can help in managing the river.
Urban growth’s impact on the carbon cycle
The urban population is expected to reach 60 per cent by 2030.
The CO2 emissions resulting from energy consumption for transport, industry and domestic use, the cement manufacture required for all the buildings and infrastructure, have increased.
- In 2019, according to the United Nations Community Programme, urban areas were estimated to be responsible for around 75 per cent of global carbon emissions.
The Amazon Rainforest
- Mitigation
- The creation of national parks and forest reserves. E.g. the Pará Rainforest reserve (15 million hectares)
- Forest biofuel production could compete with ethanol production from sugar cane by 2030
- Reforestation: much of Brazil’s industrial (roundwood) timber comes from planted forests which make up only 2 percent of the forest area
- Enrichment of degraded forests using native species
- Amazon Cooperation Treaty Organisation (ACTO) to promote harmonious development
- The Latin American Technical Cooperation Network on Watershed Management (REDLACH)
The Amazon Rainforest
- Impacts of warming water temperatures
● kill off temperature-dependent species
● change the biodiversity of the river system by introducing new species and killing others
● reduce water-dissolved oxygen concentrations, which
could destroy eggs and larvae, which rely on dissolved
oxygen for survival.
