1 / 18

Ecosystem ecology

Understand the intricacies of ecosystems and the dynamics of primary and secondary production. Learn about the factors influencing productivity, from trophic levels to trophic efficiencies. Dive into nutrient addition experiments and global variations in primary production across different habitats.

marcelv
Download Presentation

Ecosystem ecology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ecosystem ecology • Definition: an ecosystem consists of all organisms living in a community as well as all abiotic factors with which they interact

  2. Ecosystem framework • Ecosystems are organized into trophic levels: • Primary producers, primary consumers, secondary consumers, detritivores • Laws of physics and chemistry apply to ecosystems • Law of conservation of energy, second law of thermodynamics, conservation of Elements

  3. An overview of ecosystem dynamics

  4. Primary production • Amount of light energy converted to chemical energy (organic compounds) by autotrophs in an ecosystem during a given time period • It is the result of photosynthetic production • Sets the limits for the ecosystem’s energy budget

  5. Components of primaryproduction

  6. Gross and Net primary production • Gross primary production (GPP): total primary production • Net primary production(NPP): gross primary production minus energy used by primary producers for respiration • NPP=GPP-R

  7. Factors limiting primary productivity • Marine/aquatic systems • Light • Nutrients • Terrestrial systems • Temperature • Water (moisture) • Nutrients

  8. Nutrient addition experiments in a Hudson Bay salt marsh

  9. Regional annual net primary production for Earth

  10. Variation in primary production across ecosystems • Most productive per unit area: tropical forests, coral reefs, estuaries • Least productive per unit area: open ocean, tundra, deserts • Highest contribution because of size: open ocean, tropical rain forest

  11. Secondary production • Amount of chemical energy in consumer’s food that is converted to their own new biomass in a given time period • Much of primary production is not used by consumers

  12. Components of secondary production

  13. Production efficiency Production efficiency = net productivity of species n/assimilation of species n Production efficiency is the fraction of food energy that is not used for respiration Production efficiencies: birds and mammals (1-3%), fishes (10%), insects (10-40%). No differences across habitats

  14. Trophic efficiency • Trophic efficiency = net production at trophic level i + 1/ net production at trophic level i • Measures the efficiency of energy transfer across trophic levels • Trophic efficiencies usually range between 5-20% • A consequence of low ecological efficiencies: variation in abundance or biomass across trophic levels

  15. An idealized pyramid of net production

  16. A pyramid of numbers

  17. What limits secondary production? • Primary production • Second law of thermodynamics • Water • Nutrients • Predation • Competition

  18. Food energy available to the human population at different trophic levels

More Related