International Conference, Novi Sad, 21-23.9.2006 Energy

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International Conference, Novi Sad, 21-23.9.2006
Energy the Source of Existence

• Biosphere systems development driven by factors
  limiting energy flow
• 
  Kimon Hadjibiros
• National
  Technical University of Athens

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Introductory notes

• Energy is used as a concept of Physics
• Planet Earth is receiving energy from the Sun and
  emitting energy to space
• One way transformation of energy (lightgtheat)
  takes place (according to the second law of
  thermodynamics) and defines a direction for
  energy systems development

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The question

• Is the development of the Biosphere system driven
  by factors related to energy?
• Modeling will be used, based on the ecosystem
  energy flow model and on the logistic growth model

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Necessary definitions-1

• Biosphere the Earths ecosystem
• Energy a common feature of plants, animals and
  microorganisms ecological functions
• Energy flow amount of energy passing through the
  ecosystem and supporting metabolism and biomass
  formation

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Necessary definitions-2

• Input of energy from the environment to the
  ecosystem photosynthesis of plants
• Output of energy from the ecosystem to the
  environment respiration of plants, animals and
  microorganisms
• Transfert of energy (trophic chains)
• plantgtherbivore
• herbivoregtcarnivore
• carnivoregtcarnivore
• plants or animalsgtmicroorganisms

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Ecosystem energy flow model
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Impulse

• All organisms tend to maximize their own biomass,
  consequently there is a maximization of energy
  input to every compartment of the Biosphere

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Constraint

• Different factors can potentially limit the
  energy input to a compartment, but, at every
  moment, the role of only one factor is decisive
• The limiting factor is determined by the current
  conditions

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Energy input

• The driving force for ecosystem development is
  primary production (production of the plant
  department)
• It depends on H (energy input into the plant
  compartment)
• It determines the energy regime of the whole
  ecosystem

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Energy limiting factor

• The factor that limits energy input to the plant
  compartment determines the whole development of
  the Biosphere

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Logistic growth model

• Tendency of a system to increase limiting
  factor gt carrying capacity
• Replacement of the limiting factor gt change of
  carrying capacity successive logistic curves
• A simplistic description that offers a universal
  final argument

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Logistic curve
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The development of the Biosphere system

• A combination of the energy flow model and the
  logistic growth model (with successive limiting
  factors and related carrying capacities) can give
  an interpretation of the development of Biosphere
  during 4.6 billion years

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Pre-History

• From Big Bang to Solar System and planet Earth -
  15 billion years to 4.6 b. y.
• Formation of light nuclei (H-Fe) and of heavy
  nuclei (Co-U)
• Life (?)
• Limiting factors lack of space-time, lack of
  chemical elements, high temperature, intense
  radiation, low probability of life creation

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History (general trend) of the Biosphere

• Formation of planet Earth - 4.6 billion years
• First solid continents - 4.3 b. y.
• End of meteorite rain, stability - 3.9 b. y.
• First methane producing aquatic bacteria - 3.46
  b. y.
• Photosynthetic bacteria (oxygen production) -
  2.7 b. y.
• High level of aerial oxygen (ozone layer) - 542
  m. y.
• Exodus of organisms on land (UV reduction) - 600
  m. y.
• Domination of vegetation, fossil fuels for 500
  m. y.
• Equilibrium of carbon cycle - 100 m. y.
• Industrial era (increased UV and carbon dioxide
  - 200 y.

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Short-term catastrophes

• 5 greatest species extinctions in 500 m. y.
  (about 11 important extinctions)
• Example Big impact (- 65 m. y.), suspended
  solidsgtpermanent winter, large decrease of
  energy flow in the Biosphere, mass extinction of
  species (dinosaurs)
• Latest mass extinction from human action

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Influence of energy limiting factors

• Dominant influence of one (at each phase)
  limiting factor that controls energy flow
• Possible influence of other limiting factors for
  short periods

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Successive dominant energy limiting factors (for
long periods)

• Primitive life in water, chemosynthesis no
  efficient absorption of surrounding energy
• Photosynthesis use of abundant light energy,
  limitation by nutrients in the water and by UV on
  land
• Conquest of land use of light abundant
  nutrients, limitation by water (probably)
• End of growth limitation by carbon dioxide
• Our era increasing carbon dioxide in the air and
  nutrients in the water, decreasing ozone layer
• Future limiting factors nuclear winter,
  suspended solids, desertification, toxicity,
  extinctions, role of technology

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A possible answer to the question

• Energy gives a long term direction to the
  development of Biosphere
• Short term strong perturbations alter the general
  trend

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Is the development of the Biosphere
system a successful one?