GEOPHYSIOLOGY: FROM PASTEUR AND HUTTON VIA VERNADSKY, REDFIELD TO LOVELOCK. 2) THE BIOSPHERE, CLIMATE STABILISATION, LOVELOCK AND DAISYWORLD

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1 Agouron_PW_Lecture_2 1/9 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 16 - 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, 16. At his trial, he said: "Perhaps you, my judges, pronounce this sentence against me with greater fear than I receive it 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 It was then published in Volume I of the Transactions of the Royal Society of Edinburgh, Swiss geologists Eduard Seuss introduces term Biosphere (Ger. Biosphäre) Biosphere - Vladimir Ivanovich Vernadsky ( ) 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 Redfield s first paper addressing on the control of N and P in the oceans Vernadsky s article in American Scientist vol. 33; pp : The Biosphere and the Noosphere 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

2 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 Formal statement of the Gaia Hypothesis and the control of the Atmosphere by Lovelock and Margulis Daisyworld published by Watson and Lovelock Vernadsky s Biosphere translated into English B) INTERACTIONS BETWEEN THE BIOSPHERE/LITHOSPHERE/NOOSPHERE Lithosphere C l i m a t e Biosphere Noosphere or Technosphere C l i m a t e

3 Agouron_PW_Lecture_2 3/9 C) WARMING PLANET PUZZLE Temperature timecourses due to a warning Sun 4 4 Theperature (C) Time (1 9 years) Warming sun - greenhouse effect - end 15C Warming sun - greenhouse effect -start C Life temperature Warming sun - no greenhouse effect Warming sun - greenhouse effect -start C Life temperature 1 1 Carbon dioxide Relative quantity UV Carbon dioxide Oxygen Ozone Time (1 9 years)

4 Agouron_PW_Lecture_2 4/9 D) MECHANISMS FOR CO 2 DRAWDOWN 1) Weathering e.g. CaAl 2 Si 2 O 8 + CO 2 +3H 2 O = Ca HCO Al 2 Si 2 O 5 (OH) 4 2) Photosynthesis CO 2 + H 2 O = CH 2 O + O 2 Both probably occur but the chemical reaction is far slower than the biological. Chemical weathering essentially transfers CO 2 from the atmosphere to the oceans. The biological reaction puts O 2 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-17s CO 2 O 2 CO 2 + H 2 O O 2 + [CH 2 O] CO 2 + H 2 O O 2 + [CH 2 O] Microbial foodweb Microbial & metazoan foodweb [CH 2 O] 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 Atmospheric homeotatsis by and for the biosphere: the Gaia hypothesis. Tellus ) 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 )

5 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 ) 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.5, i.e. it reflects 5% of incident radiation. The heating of the planet is followed over in increase in solar luminosity form.6 to 1.8, which results in a temperature rise from -5 to 7ºC The growth of all three types of daisies have a identical temperature response, that cardinal points are growth begins at 5ºC, ceases at 4ºC, 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.25 and.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 Relative growth rate Optimum temperature = 22.5C Temperature

6 Agouron_PW_Lecture_2 6/9 Barren Planet or Planet Populated by Grey Daisies % Planet Covered Planet populated by Black Daisies -ve feedback +ve feedback % Planet Covered

7 Agouron_PW_Lecture_2 7/9 White Daisies Population collapses -ve feedback % Planet Covered Mixed Black & White Daisies Population collapses -ve feedback +v feedback % Planet Covered

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9 Agouron_PW_Lecture_2 9/9 Evolutionary & Gaia Lenton T. M. (1998) Gaia and natural selection. Nature 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.