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Solar Energy and Productivity. TREN 1F90: Sustainability, Environment and Tourism. Solar Energy and Productivity. Average annual solar energy input to the surface of the earth is about 1.5 x 10 6 kcal / m 2 / year - PowerPoint PPT Presentation
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Solar Energy and Productivity
TREN 1F90:Sustainability, Environment and Tourism
Solar Energy and Productivity
• Average annual solar energy input to the surface of the earth is about
1.5 x 106 kcal / m2 / year• Primary producers convert solar energy
into potential energy of chemical bonds in their tissues through photosynthesis
Arctic ice diatoms: Melosira arctica
Young oak seedling Quercus sp. on forest floor
Reindeer “moss”: the lichenCladonia rangiferina
Solar Energy and Productivity
• The overall rate of this conversion is calledGross Primary Productivity (GPP)
• Subtracting the amount of energy required for cellular maintenance and respiration of the primary producer yields
Net Primary Productivity (NPP)
GPP – (respiration and maintenance) = NPP
Productivity in different ecosystems
• Productivity and biomass production vary widely in different biomes
• Most productive environments per unit area: wetlands and estuaries
• Least productive environments per unit area: deserts and open ocean
Energy and Trophic Levels
Energy and Trophic Levels
AUTOTROPHS:• photosynthetic• chemosyntheti
c
Plants, algae,cyanobacteria
FirstTrophicLevel
SecondTrophic
level
ThirdTrophicLevel
FourthTrophicLevel
HETEROTROPHS
Feed on other animals
(2° and up)
Feed on plants (1° consumers)
Animalbio-
mass
Plant biomass
5 - 20% of biomass
passesbetween
levels
5 - 20%
5 - 20%
Energy for growth and metabolism
Energy and nutrient flow in an ecosystem
Energy and nutrient flow in an ecosystem
Food webs
• Complex and difficult to diagram
• A given organism may function at one trophic level
or multiple trophic levels at the same time
Simplified elements of a food web in Lake Erie
Biogeochemical cycles
Prominent
• Hydrologic (water) cycle• Geologic (rock) cycle
• Carbon cycle• Nitrogen cycle• Phosphorus cycle
include
Hydrologic cycle
and land
Groundwater
Geologic (rock) cycle
Major elements of a nutrient cycle for a defined ecosystem
Source: Modified from Likens et al. (1977)
Elements of the global carbon cycle
Units: billions of tonnes of carbon (109 t)Fluxes between compartments are in 109 t/y.
Sources: Blasing (1985), Solomon et al. (1985), and Freedman (1995)
Global carbon cycle - simplified
Nitrogen cycle
Phosphorus cycle
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