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GEOPHYSIOLOGY: FROM PASTEUR AND HUTTON VIA VERNADSKY, REDFIELD TO LOVELOCK. 2) THE BIOSPHERE, CLIMATE STABILISATION, LOVELOCK AND DAISYWORLD
A) HISTORY OF THE DEVELOPMENT OF THE CONCEPT OF GLOBAL PHYSIOLOGY
1600 - Giordano Bruno – suggested extraterrestrial life Brought to the Campo de' Fiori, a central Roman market square, his tongue in a gag, hung upside-down naked and burned at the stake, on February 17, 1600. At his trial, he said: "Perhaps you, my judges, pronounce this sentence against me with greater fear than I receive it.
1785 – James Hutton saw the earth as a self-regulating system. An abstract of Hutton's Theory was first read at meetings of the Royal Society of Edinburgh on 7 March 1785 and 4 April 1785. It was then published in Volume I of the Transactions of the Royal Society of Edinburgh, 1788.
1899 Swiss geologists Eduard Seuss introduces term Biosphere (Ger. Biosphäre)
1926 - Biosphere - Vladimir Ivanovich Vernadsky (1863-1945) develops the concept: The biosphere is a stable, complex, adaptive, evolving life system with the potential of operating in the right conditions as the major geological force transforming a planet's crust and as the source of sufficient free energy to power the start-up of a technosphere
Noosphere - Literally defined as "Sphere of Intelligence." Vernadsky defined "a new state of the biosphere termed noosphere in which mankind as a whole would become a new and a powerful geological entity able to transform the planet." The outcome is has not been as optimistic as Varnadsky’s idealistic prescriptions.
1934 – Redfield’s first paper addressing on the control of N and P in the oceans 1945 - Vernadsky’s article in American Scientist vol. 33; pp. 1-12 : The Biosphere and the Noosphere 1946 - George Bush born in New Haven, Connecticut 1958 – Redfield’s paper on the homeostatic control of N and P and the link to oxygen in the oceans 1972 – Gaia: the word invented by Lovelock, following a suggestion by William Golding, his neighbour and author of Lord of the Flies. Gaia Theory - a theory originated by James Hutton but popularised by Lovelock - views the Earth as a Agouron_PW_Lecture_2 2/9 physiological system that is, in a sense, alive, at least to the extent that the climate and chemical composition of the surface are self-regulated at a state favourable for life. 1974 - Formal statement of the Gaia Hypothesis and the control of the Atmosphere by Lovelock and Margulis 1983 - Daisyworld published by Watson and Lovelock 1998 - Vernadsky’s “Biosphere” translated into English B) INTERACTIONS BETWEEN THE BIOSPHERE/LITHOSPHERE/NOOSPHERE
C l i Biosphere Lithosphere m a t e
Noosphere or Technosphere
C l i m a t e
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C) WARMING PLANET PUZZLE
Temperature timecourses due to a warning Sun
40 40
20 20 Warming sun - greenhouse effect - end 0 0 15C Warming sun - greenhouse effect -start -20 -20 0C Life temperature
Theperature (C) Theperature -40 -40 Warming sun - no -60 -60 greenhouse effect -4 -3 -2 -1 0 Time (109 years)
30 300
Warming sun - greenhouse 20 200 effect -start 0C Life temperature
Carbon dioxide 10 100
0 0 -4 -3 -2 -1 0
30 300
UV y 20 200 Carbon dioxide
Oxygen
Ozone 10 100 Relative quantit
0 0 -4 -3 -2 -1 0 Time (109 years)
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D) MECHANISMS FOR CO2 DRAWDOWN
1) Weathering
2+ - e.g. CaAl2Si2O8+ CO2 +3H2O = Ca + 2HCO3 + Al2Si2O5(OH)4
2) Photosynthesis CO2 + H2O = CH2O + O2
Both probably occur but the chemical reaction is far slower than the biological. Chemical weathering essentially transfers CO2 from the atmosphere to the oceans. The biological reaction puts O2 into the atmosphere which will generate ozone, which will cut down the UV reaching the surface. The combined effect of the photosynthetic reaction will be a cooling of the surface of the planet and a reduction in UV – both contributing to the improvement of the terrestrial system for colonisation. The deposition of organic C in the sediments give rise to oil (and later coal) deposits – which gave the basis for the industrial revolution in the mid-1700s
CO2 O2
CO2 + H2OO2 + [CH2O] CO2 + H2O O2 + [CH2O]
Microbial foodweb Microbial & metazoan [CH2O] foodweb Oil & Coal
However, the biological system only works if there is accumulation of organic material – that is large faecal and similar particles are produced – i.e. the evolution of the metazoa.
E) GAIA HYPOTHESIS (Lovelock J. E. and Margulis, L. 1974 Atmospheric homeotatsis by and for the biosphere: the Gaia hypothesis. Tellus 26 1-9)
In “GAIA, A New Look at Life on Earth”, published in 1979, Lovelock defines the Gaia Hypothesis: “This postulates that the physical and chemical condition of the surface of the Earth, of the atmosphere, and of the oceans has been and is actively made fit and comfortable by the presence of life itself. This is in contrast to the conventional wisdom which held that life adapted to the planetary conditions as it and they evolved their separate ways
For some reason Redfield’s then existing work was not taken as an example of Gaia and the first example of a Gaian mechanism was the so called CLAW DMS hypothesis for cloud formation put forward by Charlston et al in 1987 (Nature 1987 326 655-661) Agouron_PW_Lecture_2 5/9
E) DAISYWORLD (Watson, A. J and Lovelock, J E. 1983, Biological homeostasis of the global environment: the parable of Daisyworld. Tellus 35B 284-289)
This came out of a need to put some substance to the Gaia hypothesis.
The model considers the temperature on flat planet heated by a warming sun. The surface of the planet is grey and it’s albedo is 0.5, i.e. it reflects 50% of incident radiation. The heating of the planet is followed over in increase in solar luminosity form 0.6 to 1.8, which results in a temperature rise from -5 to 70ºC
The growth of all three types of daisies have a identical temperature response, that cardinal points are growth begins at 5ºC, ceases at 40ºC, the optimum growth temperature (22.5ºC) is placed symmetrically between the two, see figure
Grey daisies White daisies Black daisies
The Temperature Consequence of the Varying Albedos of the Daisies
It is populated with black and/or white daisies which have albedos of 0.25 and 0.75 respectively. The former, as they absorb more heat, warm the local environment, the latter cool it, relative to the non-occupied areas. The planet has also been populated by grey daisies which have the same albebo and the planet’s surface and although they grow they do not have any effect on the albedo of the course of the temperature rise
The growth of the daisies themselves is affected by temperature (see below)and this provides feeback
Temperature/growth Response of the Daisies
1
0.75
0.5
0.25 Relative growthrate
0 Optimumtemperature = 22.5C 0 1020304050
Temperature
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Barren Planet or Planet Populated by Grey Daisies
40
20
% Covered Planet 0 0.6 0.8 1 1.2 1.4 1.6 Solar Luminosity
70
50
30
10 Local Temperature
-100.6 0.8 1 1.2 1.4 1.6
Solar Luminosity
Planet populated by Black Daisies
40
20
% Covered Planet 0 0.6 0.8 1 1.2 1.4 1.6 Solar Luminosity
70 -ve feedback
50
30
10
Local Temperature
+ve feedback -10 0.6 0.8 1 1.2 1.4 1.6 Solar Luminosity
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White Daisies
40
20
% Covered Planet 0 0.6 0.8 1 1.2 1.4 1.6
Population collapses Solar Luminosity
70
50
-ve feedback 30
10 Local Temperature
-100.6 0.8 1 1.2 1.4 1.6 Solar Luminosity
Mixed Black & White Daisies
40
20
Covered% Planet 0 0.6 0.8 1 1.2 1.4 1.6 Solar Luminosity Population collapses 70 -ve feedback 50
30
10 +v feedback Local Temperature -100.6 0.8 1 1.2 1.4 1.6 Solar Luminosity
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70 60 50 40 30 20 10 0 Local Temperature Local
Local Temperature 0.6 0.8 1 1.2 1.4 1.6 -100.6 0.8 1 1.2 1.4 1.6 Solar Luminosity Solar Luminosity
70 70
50 50
30 30
10 10 Local Temperature Local Temperature -100.6 0.8 1 1.2 1.4 1.6 -100.6 0.8 1 1.2 1.4 1.6 Solar Luminosity Solar Luminosity
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Evolutionary & Gaia Lenton T. M. (1998) Gaia and natural selection. Nature 394 439-447
Lovelock proposed that Gaia behaved as a single organism and had evolved to control the planetary environment to its “comfort”. This was a complete anathema to the Darwinists (particularly the Oxford evolutionist Richard Dawkins, so-called “Darwin’s rottweiler”), whose bedrock philosophy lies in evolution by competition, in their view without competition there can be no evolution. Evolution cannot occur if there is only one organism. This started off a long, and in the Darwinists’ view, uncompleted debate.