1. Flow of Energy Ecosystems across the world are linked in networks of energy and nutrient exchange between biotic and abiotic factors. We often take for granted the services that ecosystems provide to our society Air and water purification Renewal of soil fertility Decomposition of wastes Pest control Regulation of climate Pollination of vegetation

2. The components of any ecosystem can be summarised as: inputs → production and/or processing → outputs In a self sustaining system, outputs become inputs. All ecosystems require the input of energy. This energy comes from the sun, but needs to be converted from radiant to chemical energy.

3. Energy Converters Living things that convert solar energy to chemical energy are: Plants Algae Cyanobacteria These organisms (known as autotrophs) supply all the organic matter that other organisms depend on. Solar energy is used to synthesise organic material (outputs) from inorganic material (inputs).

4. Energy Converters continued Chemotrophs use inorganic compounds (Iron or Sulphur) as their energy source. Found in harsh conditions such as volcanoes, salt flats and hot springs. Chlorophyll in autotrophs is only able to absorb red and blue wavelengths of light, the rest is reflected giving a plant its green colour. Some green light is absorbed by other pigments in the foliage making the appear brown, red, yellow. Heterotrophs can’t produce their own energy, so consume autotrophs for their energy needs, hence the term consumers.

5. Photosynthesis, Producers and Productivity Photosynthesis is represented by this equation: 6CO 2 + 12H 2 O C 6 H 12 O 6 + 6H 2 O Dependent on: Light intensity Availability of H 2 O and CO 2 Minerals to make chlorophyll Light Chlorophyll

6. Photosynthesis, Producers and Productivity continued… Photosynthetic efficiency refers to how well a producer converts light energy to chemical energy. Dependent on availability of inputs of energy, temperature and nutrients. Reactions are faster with increasing temperature. Ocean ecosystems trap large amounts of light and produces lots of organic material, but production is not very efficient due to the lack of nutrients.

7. Photosynthesis, Producers and Productivity continued… Gross Primary Productivity (GPP) refers to the total amount of organic material produced by producers. Not all of this is available to consumers as the producers also require some energy to survive. The organic matter that is available to consumers is referred to as the Net Primary Productivity (NPP). NPP is measured as: Mass – g/m 2 /year Energy – kJ/m 2 /year