Nutrient Cycle Nutrient – a substance (element or

compound) that promotes growth and health in living things

Plants and animals absorb nutrients from gas or soluble salts

Oxygen, carbon, hydrogen and nitrogen are needed in large quantities – these are known as macronutrients

Trace elements such as magnesium, sulphur and phosphorous are called micronutrients

E.g. Carbon Cycle

Nutrient Cycle

BIOMASS

SOILLITTER

Uptake Pathway

Gain from weathering

Loss by leaching

Loss by runoff

Gain from precipitation

Decay Pathway

Fallout Pathway

Biomass

BIOMASS

SOILLITTER

Uptake Pathway

Loss by leaching

Loss by runoff

Decay Pathway

Fallout Pathway

Gain from weathering

Gain from precipitation

Soil

BIOMASS

SOILLITTER

Uptake Pathway

Loss by leaching

Loss by runoff

Decay Pathway

Fallout Pathway

Gain from precipitation

Litter

BIOMASS

SOILLITTER

Uptake Pathway

Loss by leaching

Loss by runoff

Decay Pathway

Fallout Pathway

Gain from weathering

Gain from precipitation

Uptake Pathway: Absorption and take-up of elements from soil by plant roots

BIOMASS

SOILLITTER

Uptake Pathway

Loss by leaching

Loss by runoff

Gain from precipitation

Decay Pathway

Fallout Pathway

Fallout Pathway:Death of plants and animals and the addition of nutrients to the litter store

BIOMASS

SOILLITTER

Uptake Pathway

Loss by leaching

Loss by runoff

Gain from precipitation

Decay Pathway

Fallout Pathway

Gain from weathering

Decay Pathway:Decomposition of litter to humus and return of nutrients to soil

BIOMASS

SOILLITTER

Uptake Pathway

Loss by leaching

Loss by runoff

Gain from precipitation

Decay Pathway

Fallout Pathway

Gain from weathering

Gain from Weathering:Chemical elements added to soil by weathering of rocks

BIOMASS

SOILLITTER

Uptake Pathway

Loss by leaching

Loss by runoff

Gain from precipitation

Decay Pathway

Fallout Pathway

Gain from weathering

Gain from Precipitation:Additional nutrients from precipitation, lightning or wind-blown dust etc.

BIOMASS

SOILLITTER

Uptake Pathway

Loss by leaching

Loss by runoff

Decay Pathway

Fallout Pathway

Gain from precipitation

Gain from weathering

Loss by Runoff and Leaching:Nutrient removal through the erosive movement and chemical action of water.

BIOMASS

SOILLITTER

Uptake Pathway

Loss by leaching

Loss by runoff

Decay Pathway

Fallout Pathway

Gain from precipitation

Gain from weathering

Positive Human Impacts

Organic fertilizers Inorganic fertilizers Planting trees and other plants

Negative Human Impacts

Deforestation Unsustainable farming practices Using crop stalks and manure for fuel Irrigation Harvesting

Nutrient Cycles – Biomes Compared

Tem

pera

te d

eci

duou

s fo

rest

•balance between stores

•moderate transfers between stores

Bore

al fo

rest

(ta

iga)

•litter is main store (needles)

•little transfer between stores

Tro

pic

al ra

in f

ore

st

•biomass is main store

•rapid transfer between stores and environment

 

 

Nutrient Cycling models for BIOMES

(Gersmehl)

Questions to consider…

Biomass- What types and sizes of plants are there? How many layers?

Litter- How quickly will it decompose? What kind of litter will fall?

Soil- How quickly will the litter decompose? What is the climate like? How much precipitation is there?