The material in this slide show is provided free for educational use only. All other forms of storage or reproduction are subject to copyright- please contact the National Marine Aquarium The slide show was designed and produced for the NMA by STEP, the Science Training & Education Partnership T raining & S cience E ducation P artnership

Oceans, atmosphere and carbon

Atmosphere and climate The carbon cycle Summary Ocean biology and carbon

Atmosphere and climate The carbon cycle Summary Ocean biology and carbon

Our planet’s atmosphere is very important in controlling our climate

The average surface temperature on Earth is 30° warmer than the surface of the Moon This is because the Earth has an atmosphere, while the Moon does not

The atmosphere traps heat radiation - the ‘greenhouse effect’

The atmosphere is transparent to incoming solar radiation The atmosphere absorbs some heat energy re- radiated from the surface STEP

The greenhouse effect occurs because the atmosphere is transparent to some infra-red wavelengths, but absorbs others

This graph plots absorbance against wavelength The atmosphere is transparent to visible light In the infra-red region of the spectrum, there are several transparent ‘windows’ Incoming solar radiation passes through the windows Heat is re-radiated from the Earth’s surface at longer wavelengths, and some is absorbed

The absorbance peaks are caused by different gases in the atmosphere

These gases are the so-called ‘greenhouse gases’ Carbon dioxide Methane Nitrous oxide Water vapour Some man-made, such as CFCs

Data from polar ice-cores show that natural climate variability has been accompanied by changes in greenhouse gas concentrations in the atmosphere

Over the last 250 years, human activities have increased concentrations of several greenhouse gases, and introduced new ones

Increase in carbon dioxide is due to burning fossil fuels, to deforestation, and to industrial and land-use practices

Carbon dioxide concentrations remained constant for several centuries Industrialization has resulted in rapid increase in atmospheric carbon dioxide since 1800 Estimates of future concentrations vary Source: Intergovernmental Panel on Climate Change Recent interglacial maximum Recent glacial minimum

Atmosphere and climate The carbon cycle Summary Ocean biology and carbon

To understand the present and future effects of changes in atmospheric carbon dioxide, we need to know how and where carbon-containing material is stored on the planet

Oceans billion tonnes carbon Atmosphere 750 billion tonnes carbon Terrestrial biota and soil 1750 billion tonnes carbon

Carbon dioxide exchanges between these stores through a variety of processes

Carbon cycle 1. Carbon dioxide in atmosphere 2. Emissions from land biosphere 4. Land photosynthesis 5. Land C-storage 6. Air-sea exchange 7. Ocean C-storage 3. Other emissions from land STEP

WATER OXYGEN CARBOHYDRATE CARBON DIOXIDE Photosynthesis by green plants removes carbon dioxide from the atmosphere and from water STEP

Photosynthesis removes a significant amount of carbon dioxide

about 100 billion tonnes carbon per year equivalent to 13% atmospheric pool per year Annual global primary production

Incorporation of carbon dioxide into plant biomass on land and in the ocean is one of the ‘sinks’ in the global carbon cycle

Photosynthesis removes carbon dioxide from the water Carbon dioxide is replaced from the atmosphere Sinking of algal biomass represents a long-term removal of carbon

Land ecosystems ‘store’ much more carbon in plant biomass than marine ecosystems

30% of the planet’s surface 70% of the planet’s surface 99% of all living material Less than 1% of all living material 54% of the annual growth of new living material 46% of the annual growth of new living material Very big plants Very small plants LAND OCEAN

Plant growth is a major carbon sink There are also non-biological processes that remove carbon dioxide from the atmosphere

Cold water in polar waters sinks to the deep ocean, carrying dissolved carbon dioxide

Atmosphere and climate The carbon cycle Summary Ocean biology and carbon

We believe that carbon dioxide levels in the atmosphere were more or less stable for the period prior to industrialization

So, if photosynthesis was taking place at the same rates in the past, other processes must have been returning carbon dioxide to the atmosphere

WATER OXYGEN CARBOHYDRATE CARBON DIOXIDE Respiration breaks down organic material, and releases carbon dioxide STEP

Photosynthesis removes carbon dioxide from the water Carbon dioxide is replaced from the atmosphere Sinking of algal biomass represents a long-term removal of carbon Grazing removes algal biomass Respiration produces carbon dioxide Excess carbon dioxide is lost to the atmosphere

WATER OXYGEN CARBOHYDRATE CARBON DIOXIDE WATER OXYGEN CARBOHYDRATE CARBON DIOXIDE Respiration counteracts photosynthesis STEP

Only 1-3% of primary production enters long-term storage in the deep ocean Most primary production passes through the food chain, and most of that is respired

Photosynthetic growth in the oceans and on land represents a sink for carbon However, breakdown of plant material by respiration means that this sink is much smaller than you would expect from the measured value of primary production

Dave Peake Several different types of marine plants and animals also incorporate carbon dioxide as calcium carbonate

Surprisingly, this does not represent an additional carbon sink This is because calcium carbonate deposition reduces the amount of carbon dioxide that can dissolve in the water

Atmosphere and climate The carbon cycle Summary Ocean biology and carbon

The ‘greenhouse effect’ keeps the Earth warm Concentrations of ‘greenhouse gases’ are rising You have seen that -

The global carbon cycle involves living and non-living processes The oceans are the largest reservoir of carbon You have seen that -

Photosynthesis removes >10% of atmospheric carbon dioxide annually Much of this material is recycled, and the carbon dioxide returned to the atmosphere You have seen that -

NOTES for USERS The material in this slide show is designed to support the teaching of science at Key Stage 1 A full description of the slide show, and linked activities for students, can be found on the National Marine Aquarium (NMA) web-site: Teachers are free to amend the slide show in whatever way they feel fit, or to use slides in other contexts. However, please note that neither the NMA nor the designers will accept responsibility for modifications, and original material remains copyright of the NMA Individual images used in the slides are copyright of NMA or STEP, except where acknowledged separately The slides have been set up to display as A4 landscape format. If they are incorporated into other slide sequences with different display settings, change in aspect ratio and text location will occur The slide sequence contains the minimum of effects and transitions. However, there are some automated animations, and teachers will wish to make sure that they are familiar with the sequence before use in class Use the PowerPoint notes viewer to obtain additional information for some slides