Researching how plants and ecosystems function Charlie Warren School of Biological Sciences The Univ

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Researching how plants and ecosystems
functionCharlie WarrenSchool of Biological
SciencesThe University of Sydney
The tall poppy is a metaphor for excellence and
symbolises Australias pride in its outstanding
achievers in all fields.

With support from
www.tallpoppies.net.au
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• How did I get here?
• Ecosystem function and Earth-Systems Science
• Examples of my research?
• Global and ecosystem carbon cycle
• Ecosystem cycles of nutrients

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How did I get here?
Sydney
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• Research interests
• Ecosystem cycles of N
• Photosynthesis at leaf gtgt ecosystem scales
• Exploring past climates with treerings
• Climate change

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Ecosystem function

• Ecosystems affect and are largely responsible for
• Water cycle
• Nutrient cycles
• Carbon cycle
• Energy (radiation) balance
• We are totally dependent on these ecosystem
  functions for clean water, clean air, food,
  timber, paper etc.
• Enormous economic and environmental value
• Knowledge of ecosystem function was cornerstone
  of 1960s search for extra terrestrial life, led
  to field of Earth-Systems Science

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Effect of life on Earths atmosphere
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Atmospheric evidence of large carbon exchanges by
the biosphere.
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Earth-Systems Science

• Search for ET led to realisation that our Earth
  isnt in physical or chemical equilibrium due to
  action of the biosphere
• Earth-Systems Science recognises biotic and
  abiotic controls over Earths function (e.g.
  climate, geology, atmosphere)
• Biotic controls are various ecosystem functions
  referred to earlier, e.g. C cycle, nutrient cycles

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Ecosystem function and management

• Ecosystems and their management, generally
  thought about in terms of biodiversity, not
  ecosystem function.
• Why is this a problem?
• Intrinsic value of biodiversity impossible to
  quantify (e.g. cancer cure fallacy)
• Misses the point that biodiversity is unrelated
  to what ecosystems do and the various services
  they provide us
• Misses the point that biodiversity is not
  essential for survival of ecosystems or our
  economic environmental survival, whereas
  ecosystem function is essential for ecosystems
  and humanity
• Management based on pre-1960s science cannot be
  good!
• Ecosystem management should consider effects on
  ecosystem function

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Ecosystem C cycle
Plants take CO2 from atmosphere via
photosynthesis Plants add CO2 to atmosphere via
respiration Soils contain carbon, they add CO2
to atmosphere via respiration (of decomposers)
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Photosynthesis at the leaf level
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Photosynthesis at the ecosystem level
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Photosynthesis at the ecosystem level
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Respiration of soil
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Where do we do it?Forests of south-east Australia
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Where do we do it?Snowy Mountains
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Tasmania
Canada
New Zealand
Germany
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Nutrient cycling
Nutrient inputs
Internal cycling
Ecosystem
Nutrient losses
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why does nutrient cycling matter?
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cycling of N within ecosystems
Soil
Dissolved organic N
Which forms of N do plants take up?
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cycling of N within ecosystems plants have
broader palate than we used to think
Plant uptake
Soil
Dissolved organic N
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Plant and ecosystem function

• How to get involved
• For more info
• Websites of different universities
• http//www.bio.usyd.edu.au/
• http//www.bio.usyd.edu.au/c_warren/