Communities physical processes interconnect to form ecosystems

1

• Communities physical processes interconnect to
  form ecosystems
• Ecosystems are connected by
• 1. energy flow between trophic levels energy
  also released as heat energy into environment
• Autotrophs 10 producers
• Primary productivity amount of C fixed in an
  ecosystem by CO2 H20 light --gt (C6H1206)
  O2
• Heterotrophs
• Consumers herbivores, omnivores, carnivores
• Decomposers
• 2. Nutrient and water cycling (Biogeochemical
  cycling)
• 1. water, 2. carbon, 3. nitrogen, 4.
  phosphorus
• Humans have impacts on ecosystems

2
Energy flow (also refer to Fig. 20.3 20.7)

• Only 10 transfers between levels.
• Loss due to Metabolism and waste

3

• BioGeoChemical cycles Nutrients cycle btwn
  biotic abiotic forms
• Definitions of Reservoirs and fluxes,
  mineralization, fixation/assimilation
• Flux rate dependent on ?
• Major Biogeochemical cycles Atmospheric cycles
  carbon and nitrogen Sedimentary phosphorus
  Hydrologic

9
4
Carbon

• Reservoirs ?
• Transformations?

5
Nitrogen - why is N impt?- what is symbiotic N
fixation?- cause and results of excess N?
Nitrogen fixation
Rhizobium
Denitrification
Anaerobic bacteria
Industrial inputs Fertilizer, atmospheric
deposition
6
Phosphorus
Pools? Transformations? Cause and consequences
of excess P in aquatic systems
7

• PO4- is difficult to acquire
• 80 of plants have mycorrhizal symbionts to help
  (fungi) other benefits (H20) offset cost

8

• Biotic factors increase nutrient retention how?
• Excessive disturbance decreases retention why?

9
Human Impact 1

• Reduced biodiversity, habitat loss, habitat
  fragmentation

10
Human Impact 2

• Pollution air, water, land
• Reduction in ozone layer

11
Human Impact 3 - Excess N P
12
Human Impact 4 - Accelerated release of CO2
13
(No Transcript)