Guide 34 Ecosystem Ecology: Energy Flow and Nutrient Cycles p://www.mordantorange.com/blog/archives/comics_by_mike_bannon/mordant_singles/0511/
Overview: Ecosystems, Energy, and Matter An ecosystem consists of all the organisms living in a community As well as all the abiotic factors with which they interact
Regardless of an ecosystem s size Its dynamics involve two main processes: Energy Flow and Chemical Cycling Energy flows through ecosystems While matter cycles within them
Energy flows through an ecosystem Entering as light and exiting as heat Tertiary consumers Microorganisms and other detritivores Secondary consumers Detritus Primary consumers Primary producers Key Heat Chemical cycling Energy flow Sun
Environmental Material Cycling Involves TRANSFORMATION In the water cycle it is Transformation of State gas liquid solid In chemical cycles (C, N, P, S) it is Transformation in Redox State
http://www.wou.edu/las/physci/gs361/energy_from_fossil_fuels.htm
The major Chemical Transformations in the Environment are carried out by microorganisms and on a global scale, very large amounts are transformed every year. Recent increases in anthropogenic N fixation in relation to natural N fixation. Modified from Vitousek, P. M. and P. A. Matson (1993) 1 Tg = 1 X 10 9 kg
Microorganisms can make a living off of the energy available in the Electron Tower
A General Model of Chemical Cycling All elements Cycle between organic and inorganic reservoirs Gaseous forms of carbon, oxygen, sulfur, and nitrogen Occur in the atmosphere and cycle globally Less mobile elements, including phosphorous, potassium, and calcium Cycle on a more local level
The carbon cycle Reflects the reciprocal processes of photosynthesis and cellular respiration
Decomposition and Nutrient Cycling Rates Decomposers (detritivores) play a key role In the general pattern of chemical cycling Consumers Producers Nutrients available to producers Decomposers Abiotic reservoir Geologic processes
GtC Giga Tons Carbon - One Billion Tons of Carbon
In considering material flow through an environment Two Factors need to be considered: Pool Size (Compartment Size) BOXES Flux gain or loss to the pool over some period of time ARROWS N in plants Kg/ha Gm N per day
Net primary production (NPP) Is equal to Gross primary Production (GPP) minus the energy used by the primary producers for respiration Only NPP Is available to consumers http://sciencebitz.com/?page_id=204
Different ecosystems vary considerably in their net primary production And in their contribution to the total NPP on Earth Open ocean Continental shelf Estuary Algal beds and reefs Upwelling zones Extreme desert, rock, sand, ice Desert and semidesert scrub Tropical rain forest Savanna Cultivated land Boreal forest (taiga) Temperate grassland Woodland and shrubland Tundra Tropical seasonal forest Temperate deciduous forest Temperate evergreen forest Swamp and marsh Lake and stream 5.2 0.3 0.1 0.1 4.7 3.5 3.3 2.9 2.7 2.4 1.8 1.7 1.6 1.5 1.3 1.0 0.4 0.4 65.0 125 24.4 360 5.6 1,500 1.2 3.0 90 140 500 600 600 250 800 700 900 1,200 1,300 1,600 2,500 2,200 2,000 0.1 0.9 0.04 0.9 0.6 0.3 3.5 3.8 2.3 5.4 4.9 7.9 7.1 9.1 9.6 22 Key Marine Terrestrial Freshwater (on continents) 0 10 20 30 40 50 60 0 500 1,000 1,500 2,000 2,500 0 5 10 15 20 25 (a) Percentage of Earth s surface area (b) Average net primary production (g/m 2 /yr) (c) Percentage of Earth s net primary production
Overall, terrestrial ecosystems Contribute about two-thirds of global NPP and marine ecosystems about one-third North Pole 60 N 30 N Equator 30 S 60 S South Pole 180 120 W 60 W 0 60 E 120 E 180
Trophic Relationships Energy and nutrients pass from primary producers (autotrophs) To primary consumers (herbivores) and then to secondary consumers (carnivores)
Trophic Efficiency Is the percentage of production transferred from one trophic level to the next Usually ranges from 5% to 20% http://www.esf.edu/efb/schulz/fattyacid.html
Pyramids of Production This loss of energy with each transfer in a food chain Can be represented by a pyramid of net production Tertiary consumers 10 J Secondary consumers 100 J Primary consumers 1,000 J Primary producers 10,000 J 1,000,000 J of sunlight
The dynamics of energy flow through ecosystems Have important implications for the human population Eating meat Is a relatively inefficient way of tapping photosynthetic production
Worldwide agriculture could successfully feed many more people If humans all fed more efficiently, eating only plant material Trophic level Secondary consumers Primary consumers Primary producers
Food webs: complexes of feeding relationships A food web refers to all the trophic (feeding) connections among species within a community.
http://www.sltec.com.au/sltec/products_liqfert_sustain_n_gro.html
Biogeochemical Cycles THE WATER CYCLE THE CARBON CYCLE Solar energy Net movement of water vapor by wind Transport over land CO 2 in atmosphere Cellular respiration Photosynthesis Precipitation over ocean Evaporation from ocean Evapotranspiration from land Precipitation over land Burning of fossil fuels and wood Higher-level Primary consumers consumers Runoff and groundwater Percolation through soil Carbon compounds in water Detritus Decomposition
Water moves in a global cycle Driven by solar energy
Water Movement is a major force in Geological Change
Wadi Zin
The nitrogen cycle and the phosphorous cycle THE NITROGEN CYCLE THE PHOSPHORUS CYCLE N 2 in atmosphere Rain Assimilation Geologic uplift Weathering of rocks Runoff Plants Nitrogen-fixing bacteria in root nodules of legumes Ammonification Decomposers Nitrification NO 3 Denitrifying bacteria Nitrifying bacteria Sedimentation Leaching Soil Plant uptake of PO 4 3 Consumption NH 3 NH 4 + NO 2 Nitrogen-fixing soil bacteria Nitrifying bacteria Decomposition
http://www.mpi-bremen.de/binaries/binary135/figone.jpg
Nitrogen Cycle http://www.physicalgeography.net/fundamentals/images/nitrogencycle.jpg
The sulfur cycle http://www.scienceclarified.com/oi-ph/oxygen-family.html
http://www.fos.su.se/~magnuss/sinnature.png
The End