2. 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 www.national-aquarium.co.uk www.step-up-to-science.com

3. Ecosystems & Food Webs: Biomass and production

4. Introduction and terms Summary Relating production to biomass

5. Introduction and terms Summary Relating production to biomass

6. Plants are the ‘producers’ in ecosystems The amount of food for plant-eating consumers - ‘herbivores’ - is determined by... The amount of plants growing in a habitat - the ‘biomass’ The addition of new plant growth - the ‘production’

7. The amount of production at the top of a food web is determined by: the amount of producer biomass the rate at which it is being produced the efficiency of transfer through the food web

8. For an ecosystem to be stable over time - ‘sustainable’ - the removal of biomass must be balanced by new growth - production

9. Introduction and terms Summary Relating production to biomass

10. In most land ecosystems, plants are large and slow-growing, so that it takes a large biomass of plants to produce enough to sustain the population of herbivores

11. Similarly, it takes a large biomass of large, slow-growing herbivores to support the population of carnivores

13. Producer Secondary consumer - predator Primary consumer - herbivore

14. In the African savannah, plant growth doubles its biomass in a few months to a year In the open ocean, growth of plankton algae doubles its biomass in a few days to a week

15. There is high production of plant material, and efficient conversion to herbivore biomass Small herbivores also grow fast, so that in turn a small herbivore biomass is enough to sustain the predator population

16. Blue whale eats about 3 tonnes of krill per day

17. It takes about 120 tonnes of krill growing at their maximum rate to support one whale This means that the whale needs to hunt over an area of between 5 and 40 square kilometres

18. Algae produce about 20% growth per day, so it takes about 125 tonnes of algae to support the krill needed to support one whale The krill need to eat 25 tonnes of algae per day

19. For a given area of the Southern Ocean, the biomass at each level in the food chain is very similar This is not what you would expect in a land ecosystem

20. 125 tonnes120 tonnes100 tonnes BIOMASS

21. However, the production of new material by each level is very different The algae produce about 20% new material per day, whilst the whale produces 0.02% growth per day

22. 25 tonnes per day3 tonnes per day120 kilogrammes per day PRODUCTION

23. 25 tonnes per day3 tonnes per day120 kilogrammes per day PRODUCTION

24. Introduction and terms Summary Relating production to biomass

25. These two examples show two very different ecosystems The ratio between producer-biomass and -production underpins these differences

26. These differences can be seen in a global comparison between land and ocean ….

27. 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

28. Large amount per unit area Very small amount per unit area Grow slowly - double biomass in months to years Grow very fast - double biomass in days to weeks ‘Classical’ pyramid of biomass Often small biomass of producers and herbivores Very big plants Very small plants LAND OCEAN

29. Biomasses of plants in land and ocean ecosystems differ Production by plants determines the food available for other levels in the food web You have seen that -

30. Production at high levels in the food web is always lower than production at low levels Biomass of producers is not always larger than that of consumers You have seen that -

31. 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 www.justaddh2o.tv www.national-aquarium.co.uk