Tundra soils are mainly composed of peat that forms in the extreme cold conditions found within this ecosystem. Peat contains large amounts of carbon which is released when the tundra soils thaw during warmer seasons. Scientists investigated the amount of carbon released from tundra soils at one location, that were thawed to different extents over the course of three years. The results from this investigation can be seen in the graph below.
Calculate the difference in the mean carbon loss that occurred in tundra soils that were thawed considerably and those that were thawed slightly. Show your working.
The following data show fluxes in carbon between different storage reserves in an ecosystem, measured in gigatonnes per year (GT yr-1). A gigatonne equals 1 billion tonnes.
Process of carbon transfer
Flux / GT yr-1
Release from the oceans
101
Ocean dissolving
104
Release from soil
62
Incomplete decomposition
52
Respiration of terrestrial organisms
53
Photosynthesis
117
Deforestation
2.0
Combustion of fossil fuels
4.9
i)
Calculate the net flux of carbon. Show your working.
[2 marks]
ii)
State the direction of this movement with regards to the atmosphere.
Methane is an example of a greenhouse gas that commonly occurs in the atmosphere. The graph below shows the main sources of methane as well as the percentage contribution of the different components of each source. A teragram (Tg) equals 1012 grams and is equivalent to one megatonne (1 million tonnes).
Calculate the amount of methane, in Tg year-1, that is released from wetlands. Show your working.
Recent studies predict a decrease in levels of hydroxyl radicals in the atmosphere of between 10% and 16%. Hydroxyl radicals are often called the 'detergent of the atmosphere' and plays an important part in regulating atmospheric levels of gases such as methane.
i)
Predict the possible long-term effect these decreased levels of hydroxyl radicals could have on atmospheric concentrations of methane.
Carbon dioxide is one of the main greenhouse gases in the atmosphere. The graph below shows the changes of carbon dioxide levels in the atmosphere, as well as the change in global temperatures over a period of time.
The amount of carbon in the atmosphere is constantly changing over time. Carbon dioxide and methane gases contribute to carbon levels in the atmosphere and have important impacts on the planet.
Discuss the importance of obtaining reliable data on the atmospheric concentration of these gases over time.
Suggest the possible impact that an increase in global temperatures would have on the polar regions, as well as the global consequences of this impact.
