Carbon cycle unit 4-7 practice Flashcards
Define the carbon cycle
The carbon cycle is a biochemical cycle by which carbon moves from one part of the planet to another
State the five main carbon stores
Biosphere (living parts)
Atmosphere (gases)
Hydrosphere (carbon in water)
Lithosphere (carbon in rocks)
Cryosphere (carbon in ice)
What are the three main processes in the slow carbon cycle?
Chemical weathering (carbonation)
Carbon storage (sequestration) on ocean floor
tectonic processes and volcanic activity
Summarise the chemical weathering of the slow carbon cycle
Atmospheric carbon is dissolved in water vapour and forms carbonic acid. Precipitation is naturally acidic (carbonic acid).
Carbonic acid reacts with rocks containing calcium carbonate (limestone) through carbonation weathering and creates calcium bicarbonate
Calcium bicarbonate is soluble in water and is carried in solution by runoff and percolating water
Soluble calcium carbonate is transferred to the ocean via runoff
What’s the pH of neutral water?
7
What’s the pH of acid rain?
anything with a pH of 5.6 or below
How do oceans store carbon?
At the bottom of oceans large amounts of dissolved inorganic carbon accumulate, known as carbon sequestration to form carbonate sediments. Some of this sediment will be from bicarbonate created by carbonation weathering.
How is calcium bicarbonate transferred to oceans?
Rivers, throughflow and groundwater transport calcium bicarbonate to the oceans
How is carbon used by marine organisms?
Marine organisms such as plankton and shellfish rely on carbonate ions to make their shells.
What happens to the carbon stored on the ocean floor?
In subduction zones at convergent plate boundaries will force carbonate rich sediments into magma which may result in volcanic eruptions, emitting CO2 back into the atmosphere by volcanoes.
Name the three main processes of the fast carbon cycle
Diffusion of CO2 between atmosphere and oceans
Photosynthesis, respiration and decomposition
Combustion of forest fires and fossil fuels
Describe the physical inorganic pump which carbon diffused in oceans follows
CO2 moves around oceans by thermohealene currents which form due to variations in ocean temp and salinity
Describe how thermohaline currents move carbon in oceans (2 points)
Carbon can be transferred from the surface to the deep oceans in areas wgere cold dense surface waters sink through downwelling - usually in polar regions (North Atlantic Drift)
Carbon can be transferred from deep oceans to the surface through upwelling - usually in equatorial regions
Describe the biological (organic) pump for carbon movement in the ocean for fast carbon cycle- full description
CO2 is diffused into ocean surfaces
Phytoplankton photosynthesise and used the diffused co2 storing it in new biomass
as part of the ocean food chain phytoplankton are eaten by zooplankton which in turn are eaten by other marine organisms, passing the carbon in carbohydrates
When organisms respire they release co2, some of which will pass back to the atmosphere
marine organisms die and sink to the seafloor adding to the carbon rich sediment on the ocean bed (sequestriation)
over millions of years organic rich sediment can form fossil fuels (oil and gas) - long term carbon cycle
Describe photosynthesis through carbon movement in the fast carbon cycle
photosynthesis is a biochemical process operating in plants that converts CO2 and water into glucose and oxygen.
Where is photosynthesis highest around the world?
High - tropics 30 degrees north and south of the equator
Moderate - areas beyond the tropics 60 degrees north and south
Low - Polar regions - lots of sun but no water
Describe the movement of carbon through respiration in the fast carbon cycle
respiration involves the release of energy from glucose so that all other processes needed for life can happen. co2 is released back into the atmosphere as a by-product of respiration.
Describe decomposition as a carbon movement in the fast carbon cycle
plants and animals die and decompose. This process of decomposition carried out by organisms known as detritivores such as earthworms aid decomposition as they feed on dead organic matter. Decomposition releases co2 and methane back into the atmosphere.
What percentage do wildfires contribute to greenhouse gas emissions?
20%
Lincolnshire 2020
Australia 2019
Define a biome
a biome is an ecological community whose global distribution corresponds with climatic regions of the earth
Describe the distribution and climate of tropical rainforests?
Equatorial regions such as the Amazon and Malaysia
Wet and warm
Describe the distribution of temperate grasslands and their climate?
high altitude regions 30 - 60 degrees north and south of the equator. Predominantly to the north of the tropic of cancer. Chine, Argentina, Middle-East
Climate varies
State the size of the carbon stored in a tropical rainforest?
2kg carbon annually per metre squared.
Trees store twice as much as they release - 200% efficiency
Up to 5000 tonnes of carbon per hectare per year
How much carbon does a primary forest store per hectare?
300
How much carbon is stored in a temperate grassland compared to a tropical rainforest?
compared to tropical rainforests where NPP averages around 2kg per metre squared per year, temperature grasslands store around 600 grams per metre squared per year
What diagram must be drawn in an essay for carbon stores in either grassland or tropical rainforests?
Gershmehl diagram
State the stores of carbon in a tropical rainforest and a temperate grassland
Biomass
Litter
Soil
State the three influences on a carbon store in either tropical rainforest or temperate grassland
temperature
precipitation
light
Name three ways humans change the use of land in either TR or Grasslands
Deforestation (Borneo)
Afforestation (Brazil)
Agricultural activity (Dust Bowl)
Describe the distribution of peat formation
Peat is mostly found in the northern hemisphere including parts of north America and northern Europe. countries include Scotland, Ireland, Denmark, Russia.
What are the three main types of peatlands in the UK?
Fen Peatlands - where groundwater meets the surface
Blanket peatlands - occur on flat hill tops where rainfall is high
Raised Bogs - occurs in valley bottoms where soils saturated
(Whixhall Moss)
How does carbon accumulate through peat formation?
Peat forms in waterlogged areas, lacking in oxygen and where the water is acidic. In these conditions, decomposition is restricted so that dead organic matter doesn’t decompose. Over thousands of years peat accumulates at the rate of about 1mm per year. Consequently, carbon is preserved and makes up 50% of the dead organic matter.
What does sphagnum moss do?
Holds 20x its own weight in water and makes the water acidic - 4.5 which means theres a potential for hydrogen ions
State the two ways the carbon store in peat is reduced
peat extraction and drainage
Discuss human activities which reduce carbon stored in peat
Cutting peat and burning as a fuel
Cutting peat and use in horticulture
Drainage of peat and use for agriculture of forestry
State three ways a peatland can be restored and managed
Blocking drainage channels
Removing invasive shrub and tree species
Re-seeding damage areas with sphagnum moss.
What are the causes of recent increases in the atmospheric carbon store. What did IPCC say?
According to the Inter-governmental panel on climate change (IPCC) in so23, ‘human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming, with global surface temperatures reaching 1.1 degrees above 1850-1900 in 2011-2020.
Give a specific cause for the increase in atmospheric carbon
linked to increased concentrations of greenhouse gases, namely carbon dioxide and methane. Methane is the second most important greenhouse gas. It is 25x more potent than CO2.
Which graph represents the increase in average global temperature?
The Hockey Stick Graph by Mann, Bradley and Hughes in 1999. The graph shows the rise in global temperatures since the industrial revolution.
Define the energy budget
The balance between incoming radiation from the sun and outgoing radiated heat plus reflected radiation from the sun.
Describe the relationship between recent increases in the atmospheric carbon store and the energy budget
Greenhouse gases absorb heat energy released from the Earth’s surface, retaining heat.
Changes to patterns and levels of precipitation/extreme weather events - more convectional rainfall
Sea level rise and acidification of oceans
State the impacts of recent increases in the atmospheric carbon store on the water cycle and oceans
Collectively, we have had 8/10 of the warmest year since 2002 and 7/10 wettest years since 1998
Flooding (River Fargo)
Extreme rain (Boscastle)
Drought (1976 UK)
Forest fires (Lincolnshire 2020)
What’s a feedback system?
A feedback system is a series of responses that change the ‘steady-state equilibrium’ of a system.
Positive feedback - increases or amplifies the initial change
Negative feedback - stops or reverse the initial change
Name the four types of feedback loops
Methane feedback
Cryosphere feedback
Marine carbon feedback
Terrestrial ecosystem feedback
Describe the methane feedback loop (5 steps)
High levels of greenhouse gases in the atmosphere cause global temperatures to increase
Increasing temperatures cause permafrost to thaw
Thawing exposes previously frozen organic matter to decay
As organic matter decays it releases CO2 into the atmosphere
Atmospheric CO2 and methane levels increase
State the cryosphere feedback loop (4 steps)
Increase in atmospheric temps
Melting of sea ice and glaciers
Reduced albedo of earths surface
Increased insolation absorption
State a marine feedback loop (7 steps)
Warmer ocean water absorbs less atmospheric carbon by diffusion
There is less carbonate ions for shell production and for producers to survive on
Impacts entire food chain
Kills marine life
Decomposition
Releases CO2 and CH4
Greenhouse effect
Global warming
Define ocean acidification
As oceans absorb CO2 by diffusion, surface water becomes more acidic. Carbonic acid is created when water diffuses with carbon.
Need to do a terrestrial feedback loop!
Deforestation of tropical rainforests (Borneo)
Deforested trees release CO2 - IPCC statement
Increaseses greenhouse conc
Does the carbon or water cycle affect the plant most?
Carbon cycle seen as most effects of the water cycle is a result of the carbon cycle.
