Gaia

Gaia, as defined by James E. Lovelock, F.R.S. is 'a complex entity involving the Earth's biosphere, atmosphere, oceans and soil; the totality constituting a feedback or cybernetic system which seeks an optimal physical and chemical environment for life on this planet'. The maintenance of relatively constant conditions by active control may be conveniently described by the term 'homeostasis'. 'Gaia has remained a hypothesis, but, like other useful hypotheses, she has already proved her theoretical value, if not her existence, by giving rise to experimental questions and answers which were profitable exercises in themselves... ' (p. 11). The word Gaia, from which our common terms 'geo(ology)', 'geo(desy)', 'geo(graphy)' and 'Geos' are all derived, means Mother Earth in ancient Greek. The concept defined above is the subject of this small trade book designed for the lay audience interested in the wide sweep of scientific exploration. Lovelock says: ' If Gain does exist, then we may find ourselves and all other living things to be parts and partners of a vast being who in her entirety has the power to maintain our planet as a fit and comfortable habitat for life'. An unusually broad and philosophical statement for a scientist perhaps, but Lovelock prefers to think of himself as an inventor a man who holds more than 100 patents. (See 'The Independent Practise of Science' by J. E. Lovelock CoEvolution Quarterly, Spring 1980, p. 22-30). The book, subtitled ~ new look at life on Earth', proceeds to view the microbes from the vantage point of space. Most biology books begin with organisms our size, plants and animals, and examine the working of their parts. Gaia is entirely different in that it takes as its province the sum of all life on Earth and asks: What has been the effect o f the phenomenon of life on the planet Earth? Its conclusion is that the surface of the planet has been markedly altered by the action of animals, plants and microbes and that the nature of these alterations simply can not be due to chance: they are too favorable for the support o f those same animals, plants and microbes. Although this conclusion may not strike ecologists and natural historians, as well as poets, as being astounding, it certainly raises questions for geochemists, atmospheric chemists, and others who in their training tend to learn that a planet's characteristics can be understood on the basis of physics and chemistry alone. One clear effect of Gaia, the book, is that it points such scientists toward the imperative of biology. If there is a grain of truth to Lovelock's thesis at all, those concerned with the surface sediments, waters and the atmosphere, are going to have to factor biology in to their equations in a serious and quantitative way. However potentially serious and quantitative Lovelock's subject is, the book, as the author claims, is written for pleasure and amusement. It is not (what one would call) a scholarly treatise, for many details are unreliable. But, when taken as an overview, it is most profound and important. It is written in a personal and friendly style, individual people are important as are the various voyages and pieces of equipment that comprise Lovelock's experience. Gaia is organized into eight chapters and an epilogue. After the introduction to his point of view, Lovelock describes the conditions of the early Earth in Chapter 2. The next chapters deal with the recognition of Gaia as manifested in a planetary surface that differs too greatly from that of its neighbors, Mars and Venus. Cybernetics, the study of self-regulating systems of communication in men and machines, is then applied to Gaia, in atmospheric compositional control, for example. The cybernetic view leads one to ask: how is that compositional control maintained? What mechanisms exist for the regulation of the oxygen content of the atmosphere, or of the nitrous oxide? How would one expect such mechanisms to work on a planetary scale? Chapter 6 deals with a particularly thony question: why is the salinity of the ocean just less than that required to kill all eukaryotic Iife on Earth? Unlike the other facets of the book, this has not been properly addressed in the primary scientific literature. Rather epiphanous in nature, it is full of concepts begging for careful scientific investigation. Is the hand of Gala here too? Chapters 7 (Gaia and Man: the problem of pollution), and 8 (Living with Gaia) make an attempt, at this stage of our knowledge, to assess the effects on man's activities on the functioning of the system. Lovelock