Brent Cornell

    
A climograph is a graphical representation of basic climatic parameters at a given geographical location

• It is a diagram which shows a combination of monthly average temperature and precipitation (rainfall) at a certain location

Climographs provide a quick view of the climate of a region and can be used to identify seasonal patterns and changes

Examples of Climographs (Northern Hemisphere Biomes)

In 1975, ecologist Robert Whittaker developed a holistic climograph that allowed for the classifying of 9 distinct biomes

• These biomes were distinguished according to their average yearly temperatures and rainfall (precipitation)
  • Deserts typically have high average temperatures but low precipitation (hot and dry)
  • Rainforests typically have both high average temperatures and high precipitation (warm and wet)
  • Taigas typically have low average temperatures and reasonably low precipitation (cold and icy)

Whittaker’s Climograph

    
Pyramids of energy show the flow of energy between trophic levels and are measured in units of energy per area per time

• The standard units for a pyramid of energy are kJ m^–2 y^–1
• Pyramids of energy are always triangular and never inverted as ~90% of energy is lost between trophic levels

Pyramids of energy will differ between ecosystems due to the effect of climate on primary productivity

• Warmer temperatures will speed up enzyme reactions required for photosynthesis (i.e. light independent reactions)
• High precipitation will also increase photosynthesis as the photolysis of water is essential for non-cyclic photophosphorylation

Consequently, tropical rainforests have a high net primary productivity (NPP), whereas deserts have a low NPP

• Ecosystems with higher productivity will be able to supply more energy to consumers and hence support more trophic levels
• Therefore a pyramid of energy for a tropical rainforest will display a wider base and more levels than a desert

The types of species within a particular biome may also affect how efficiently energy is transferred between trophic levels

• For instance, homeotherms will use more energy maintaining a stable body temperature compared to poikilotherms

Pyramids of Energy Comparison

    
Gersmehl diagrams show the differences in nutrient flow and storage between different types of ecosystems

Nutrients are stored in one of three nutrient sinks – either as biomass, litter or soil

• Biomass is the total mass of living organisms (mainly plant tissue) in a given area
• Litter is any organic matter in and on the soil – it includes humus and leaf litter (defoliation)
• Soil is the top layer of the earth that is composed of disintegrated rock particles

Nutrients can be transferred between nutrient sinks and may also be cycled via environmental inputs and outputs

• Nutrients can be transferred from biomass to litter (fallout), litter to soil (decay) or soil to biomass (uptake)
• Litter can additionally gain nutrients via precipitation (rainfall) and lose nutrients in surface runoff
• Soil can gain nutrients from the erosion of rocks via weathering, but will lose nutrients via leaching

Standard Gersmehl Diagram

Comparing Gersmehl Diagrams

The inter-relationships between nutrient stores and flows will be affected by climatic factors (e.g. temperature and rainfall)

• Hence Gersmehl diagrams will differ between biomes (e.g. tropical rainforest, taiga and desert)

Tropical Rainforest

• Most nutrients are stored as biomass (litter is rapidly decomposed and vast roots quickly draw nutrients from soil)
• There is a fast rate of transfer between stores (hot and wet conditions promote precipitation, runoff, weathering and leaching)

Taiga

• Most nutrients are stored as litter (low temperatures slow decomposition which delays nutrient transfer to soil and biomass)
• There is little nutrient gain from precipitation or weathering due to low levels of rainfall (cold temperatures produce snow)
• There is little nutrient loss via leaching (due to low rainfall) but surface runoff may be high at certain times (if the snow melts)

Desert

• Most nutrients are stored in the soil (few plants exist to store nutrients as biomass or produce litter)
• There is little nutrient gain from precipitation and little nutrient loss via runoff due to very low levels of rainfall
• The amount of weathering and leaching is negligible

Comparison of Gersmehl Diagrams