Water and Carbon cycles (copy)

What is a system?

What do they help identify and what does it involve?

a group of related parts that work together for a particular function and a simplified, generalisation of reality

Fundamental relationship between each component (how they can be changed/altered). It involves stores, processes, flows, inputs and outputs.

what is a cascading system?

a chain reaction, where one event triggers a series of interconnected events

what can cryospheric change lead to?

1. More Water Flow

2. Higher Sea Levels

3. precipitation changes

what is the role of cryospheric change in the water cycle?

the water cycle is a closed system. If there is less ice in normal stores, as it has melted, it will result in higher sea levels, leading to more evapotranspiration. This will then result in greater humidity and precipitation

3 types of rainfall

convectional, relief, frontal

Why is the equator hotter than the poles?

The suns radiation is more concentrated at the equator than at the poles

What is albedo

when sunlight is reflected away from the earths surface

what is interception

vegetation stopping precipitation reaching the soil

what is infiltration

water moving through rock

what is percolation

water moving through soil

What is a drainage basin

An area of land drained by a river and its tributaries

How can deforestation affect the water cycle?

when forests are removed, there are less trees and roots. This can affect the hydrological cycle and also cause more surface runoff as less water is absorbed and evaporated. As a result, more water flows into rivers and the ocean, causing rising sea levels. This can lead to more evapotranspiration, so there are changes in precipitation patterns and an increase in humidity, as well as more floods and storm surges

Evidence backing up deforestation to amount of water in a basin

When there is 50-100% of the forest removed, there are major impacts on the level of water in the basin. These changes occur on a local scale, yet can still affect very large rivers.

How does soil drainage work?

Small plastic pipes underground with holes in to allow water through known as tiles, to drain away excess water. when the water in the water table is higher than the tiles, the tiles drain way the water from the surface so that fields aren’t flooded.

How does soil drainage affect the water cycle.

Once the excess water has been lowered to the levels of the tiles, no more water flows through them. In most years in the UK, there is no flow between June and October

What is a model?

theoretical frameworks that let us predict things like spatial relationships and interactions with or across space

what is drainage density

How many rivers and streams there are in a specific area

What is a flash flood?

A sudden and intense flood that occurs within a short period, typically within 6 hours of heavy rainfall or the sudden release of water such as a breach in a dam

What is discharge?

rate of flow measured in cubic metres per second

What factor in the Nile can impact upon the flood hydrograph?

1. construction of the Aswan Dam - reduces peak discharge. As well as this, Lake Nasser and the dam contribute to the controlled release of water from the reservoir affects downstream hydrological conditions

What is water abstraction

Withdrawing water from a store

Why do people use water abstraction

1. agriculture

2. drinking water

3. hydroelectric power

4. domestic use

5. manufacturing

How much of Egypts power does the aswan dam support

10%

what is lag time

the amount of time between peak discharge and peak rainfall

Give 5 examples of carbon stores

1. atmosphere

2. biomass

3. fossil fuels

4. oceans

5. peatbogs

Give 5 examples of carbon flows/transfers

1. combustion

2. respiration

3. decomposition

4. photosynthesis

5. deforestation

Is the carbon system open or closed on a global scale?

closed system

Give an example of the fast carbon cycle, with an explanation and time scale

Photosynthesis:
- rapid exchange of carbon between the atmosphere and living organism
- occurs over days

Give an example of the slow carbon cycle, with an explanation and time scale

Rock erosion and weathering:
- gradual breakdown of rocks, releasing carbon into the soil and water
- Long-term, occurring over thousands to millions of years

what percent of peat is made from carbon?

60%

Put the stores of carbon in order from largest to smallest:
Atmosphere, Lithosphere, fossil fuels, hydrosphere, biosphere, pedosphere

Lithosphere, hydrosphere, fossil fuels, pedosphere, atmosphere, biosphere

How does carbon dioxide become stored in deep ocean sediments?

Ocean surface waters absorb atmospheric carbon dioxide, with processes like photosynthesis and calcium carbonate formation utilizing carbon. As organisms use carbon and materials sink, carbon-rich sediments accumulate. Over millions of years, these sediments transform into rocks

where are the majority of the worlds oil reserves?

The middle east

What is the oceanic carbon pump (vertical deep mixing/upwellings and downwellings)?

When cold water returns to the surface and warms up again, it releases CO2 into the atmosphere. This circulation ensures that CO2 is constantly being exchanged between the ocean and the atmosphere

What is the biological pump?

Phytoplankton absorb carbon through photosynthesis, and as they die or are eaten, the stored carbon sinks to the deep ocean, regulating Earth's climate by removing carbon from the atmosphere

What is the physical pump?

movement of carbon from the ocean through diffusion

what is vertical deep mixing?

when warm water on the oceans surface from the warm tropics is carried to the polar regions, where the water cools down, so the water becomes denser and sinks. When the cold water warms up and rises to the surface again, it loses CO2

What is the geological component?

where the carbon cycle interacts with the rock cycle through processes such as weathering, burial, subduction and volcanic eruption

How do farming practices affect the carbon cycle?

when soil is ploughed, the soil layers invert, air mixes in and soil microbial activity increases. This results in organic matter in the soil being broken down much quicker, and carbon being lost from the soil into the atmosphere

how does carbon from tectonic plates return to the atmosphere?

In subduction, at a destructive plate margin, the denser, carbon rich oceanic plate is pushed under the continental plate. This causes it to melt, and the carbon rises through volcanoes as carbon dioxide

What is thermal expansion?

when water gets warmer, which causes the volume of the ocean to increase

What is sequestration?

the act of separating and storing a harmful substance such as carbon dioxide in a way that keeps it safe

How much human-caused carbon is released from fossil fuels, according to the IPCC?

90%

How much CO2 is produced per 1000kg of cement produced?

900kg

what % of global methane production comes from rice?

20%

Name 3 natural causes of change in the carbon cycle

1. photosynthesis

2. volcanic activity

3. wildfires

How many hectares of forest are cut down every year?

13 million

How much rainfall is in the amazon per year?

2000mm

what is the avreage temp in rainforests?

28 dgerees

What is the atmosphere like in rainforests?

hot and humid

how much of the worlds oxygen to rainforests emit?

20%

What percent of wood is made up of carbon?

50%

How much of earths carbon does the amazon store?

1/5

How much carbon was absorbed by the amazon in 2019 in comparison to the 1990s?

in 2019 it was 600 million tonnes, but in the 1990s, it was around 2 billion tonnes each year

How has an increase in atmospheric CO2 lead to trees dying?

Increased CO2 can favor the growth of certain plant species over others, altering competitive relationships within ecosystems. This can result in changes in species composition, potentially leading to the decline of tree species less adapted to the new conditions.

What is the average discharge of water from the amazon into the atlantic ocean?

175,000 m³/s

Of the amount of water evaporated in the amazon, how much falls again as rain?

48%

Between 2000 and 2007, what was the rate of deforestation per year?

almost 20,000 km²

How much of brazils total emissions come from deforestation?

75%

What are the effects of the deforestation method of slash and burn?

1. reduces humidity

2. sudden evaporation of water previously retained in the forest canopy

3. increased albedo and temperature

4. reduces porosity of soil, causing faster rainfall drainage, erosion and silting of rivers and lakes

What is the difference in average temperature between rainforests and the pastures that they are replaced with?

rainforests have an average temperature of 24C, but the pastures are 33C

How much of the amazon rainforest has been lost?

20%

What would the effect of a 2C rise in temperature be on the amazon?

20-40% of the amazon will die off within 100 years

What are 3 methods of mitigation in the amazon rainforest?

1. creation of national parks such as the para rainforest reserve, which is 15 million hectares

2. forest biofuel production may compete with ethanol production from sugar cane by 2030

3. afforestation

What are the effects of warming waters in the amazon?

1. kill off temperature dependent species

2. change in biodiversity

3. reduce oxygen concentration in the water, which may kill eggs and larvae

Case study river catchment at a local scale

River Itchen

At the global scale what type of system is the water cycle and why?

Closed system - Transfer of energy in and out of Earth but not matter (water) (it doesn’t cross the system’s boundary)

At the drainage basin level, what type of system is the water cycle and why?

Cascading open system

It is an open system because: Energy and matter (water) move in and out of the system via rivers/streams across the boundary into the surrounding environment

It is a cascading system as: Drainage basins link together - the output of one is the input of another

Parts of a system and examples from the water cycle

Input - Precipitation

Store/component - Ocean, clouds, rivers/lakes

Flow/transfer - Channel/GW flow

Output - River discharge, transpiration, channel flow, evaporation

(Element - A consistent part of a system)

(Attribute - The characteristics of an element)

Relationships - The way in which the elements of a system interact

Boundary - The atmosphere, watershed (the border between what lies within a system & what is outside it)

Dynamic Equilibrium

If the balance is offset what happens?

When there is a balance between the rate of inputs and outputs of a system

If there isn’t this balance the system will recalibrate to create the balance once again via positive and negative feedback

What may disrupt the dynamic equilibrium causing feedback?

• If one of the elements in the system changes e.g.

• +precipitation → +channel flows → +stores → +outputs

  OR

• +average temp → +evaporation → -Stores & flows

• A barrier slowing channel flow might lead to larger stores

What is positive feedback and it’s role in a system?

Where the effect of an action are amplified or multiplied by subsequent knock-on or secondary effects

De-stabilise a system’s dynamic equilibrium

What is negative feedback and it’s role in a system?

Where the effects of an action are nullified by its sub-sequent knock-on effect

Re-stabilise a system’s dynamic equilibrium

Example of a Positive Feedback loop (de-stabilising) and why is it one?

Global temp rise - Increased ocean temp - Warm water less able to hold dissolved gas e.g. CO₂ - Dissolved CO₂ released by warmer oceans - CO₂ back into the atmosphere - Enhanced GHG effect - Global temp rise

Global temp rise is leading to more atmospheric CO₂ which is leading to more global temp rise

Example of a negative feedback loop (re-stabilising) and why is it one?

Burning FF increases atmospheric carbon dioxide - More photosynthesis - More plant growth (carbon fertilization effect) - Reduction in atmospheric carbon dioxide

The effect of burning FF (increasing atmospheric carbon) is being reduced by the sub-sequent knock on effects

What is a threshold and it’s role in a system?

A threshold is a point in a process, that once passed, triggers some king of change

Thresholds in systems are often thought of as tipping points after which the system shifts radically and potentially irreversibly into a different equilibrium state