BIOL 4120: Principles of Ecology Lecture 20: Ecosystem Ecology

1. BIOL 4120: Principles of Ecology Lecture 20: Ecosystem Ecology Dafeng Hui Room: Harned Hall 320 Phone: 963-5777 Email: dhui@tnstate.edu Two chapters: ecosystem energetics, primary production, secondary production, grazing food chain Decomposition and Nutrient cycling, detrital food chain, how and water factors influence the nutrient cycling Here large scale nutrient cycling: carbon, (water), N, P etc. Two chapters: ecosystem energetics, primary production, secondary production, grazing food chain Decomposition and Nutrient cycling, detrital food chain, how and water factors influence the nutrient cycling Here large scale nutrient cycling: carbon, (water), N, P etc.

2. Outline (Chapter 22)Biogeochemical cycles

3. 22.1 Two major types of biogeochemical cycles All nutrients follow biogeochemical cycles Two types of cycle Gaseous Major reservoirs are atmosphere and oceans Global in nature, important gases Oxygen 21% Nitrogen 78% Carbon of carbon dioxide 0.03% Sedimentary Major reservoirs are soil, rocks and minerals Rock phase and salt solution phase Salt solution is the available form Phosphorus Metals, eg Calcium, Magnesium, etc Some cycles are hybrid Sulfur (S) Major pools in Earth�s crust and atmosphere

4. Two major types of biogeochemical cycles Common features: Involve biological and non-biological processes Driven by the flow of energy through ecosystem Tied to water cycle (water is the important medium; Without water cycle, biogeochemical cycle would cease). Share three basic components: inputs, internal cycling outputs.

5. 22.2 Inputs and outputs Nutrients enter the ecosystem via inputs Gaseous cycle from atmosphere (C,N) Sedimentary from rocks and minerals (P, Ca) Wetfall and dryfall Precipitation -- wetfall Airborne particular and arsenal (rainfall on the forest floor is nutrient rich than on the bare soil) -- dayfall Nutrient in aquatic ecosystem From surround lands in the form of drainage water, detritus, sediment and precipitation.

6. Inputs and outputs There are also outputs to the biogeochemical cycles Carbon to carbon dioxide, release back to atmosphere Nutrient to gaseous form (denitrification) Loss of organic matter from ecosystem by washout (from terrestrial to aquatic) Herbivores between aquatic and terrestrial Moose (feed on aquatic plants, deposit nutrient in terrestrial ecosystem in the form of feces) Hippopotamus (move organic matter from terrestrial to aquatic) Harvesting may be replaced by fertilization Loss of nutrient (e.g.Leaching) may be balanced by inputs (weathering of rocks and minerals)

7. Internal cycling Nutrients are recycled within the ecosystem Internal recycling important within ecosystem Some systems have large amount of short term recycling Lakes Other have most stored as biomass Forests Long term storage in water systems is in the sediment System dependent on primary production and decomposition Without latter, everything will become locked up

8. Figure 22.1 View from a global perspectiveFigure 22.1 View from a global perspective

9. Pools and fluxes If not steady-state, the ecosystem is either expanding or shrink If not steady-state, the ecosystem is either expanding or shrink

10. Figure 22.2 General C cycling in terrestrial ecosystem. Climate factors influencing the internal cycling (tropical forest; cold area, accumulation of carbon) Fresh water and marine ecosystems, Figure 22.2 General C cycling in terrestrial ecosystem. Climate factors influencing the internal cycling (tropical forest; cold area, accumulation of carbon) Fresh water and marine ecosystems,

11. Figure 22.3Figure 22.3

12. Figure 22.5Figure 22.5

13. Missing carbon Atmospheric increase= Emissions from fossil fuels +Net emissions from changes in land use -Oceanic uptake -Missing carbon sink 3.2�(�0.2)=6.3�(�0.4)+2.2�(�0.8)-2.4�(�0.7)-2.9�(�1.1) http://www.whrc.org/carbon/index.htm

14. Figure 22.6Figure 22.6

15. Figure 22.7 N2O(nitrous oxide), NO(nitric oxide), NO2 (nitrogen oxide). Resident time in atmosphere is up to 20 yrsFigure 22.7 N2O(nitrous oxide), NO(nitric oxide), NO2 (nitrogen oxide). Resident time in atmosphere is up to 20 yrs

16. Figure 22.8 Atmosphere is the largest pool, 3.9x 10^21 g N. biomass is 3.5x10^15 g, soil 120 x 10^15 g. Figure 22.8 Atmosphere is the largest pool, 3.9x 10^21 g N. biomass is 3.5x10^15 g, soil 120 x 10^15 g.

17. Figure 22.9 Not much in atmosphere, follow water pathway, from land to sea Less important in plant ecosystem, only internal cycling Three forms in waterFigure 22.9 Not much in atmosphere, follow water pathway, from land to sea Less important in plant ecosystem, only internal cycling Three forms in water

18. No atmospheric reservoir (rock and natural phosphate deposits) Permanent loss of phosphorus to oceans Input limited to weathering of rocks Terrestrial systems can be limited by phosphorus availability Phosphorus is more abundant in marine and freshwater systems Particular Dissolved organic phosphorus Rapidly utilized by zooplankton Secrete inorganic Dissolved inorganic phosphorus Rapidly utilized by phytoplankton Phosphorus can sink as particulate phosphorus and become locked in bottom sediment Depletion of surface layers

19. Figure 22.10Figure 22.10

20. Figure 22.11Figure 22.11

21. Figure 22.12Figure 22.12

22. Figure 22.13Figure 22.13

23. Figure 22.13Figure 22.13

24. End