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Lovelock, J. E.

Publications and source records attributed to Lovelock, J. E..

17 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Some thoughts on GAIA and the sulfur cycle

The data hypothesis states that the composition, oxidation reduction state, and temperature of the troposphere are actively regulated by the biota for the biota. One of the early predictions of the Gaia hypothesis was that there should be a sulfur compound made by the biota in the oceans. It would need to be stable enough against oxidation in water to allow its transfer to the air. Either the sulfur compound itself or its atmospheric oxidation product would have to return sulfur from the sea to the land surfaces. The most likely candidate for this role was dimethyl sulfide. Another sulfur compound of interest from a Gaian viewpoint CS2 (carbon disulfide) is discussed. Theories on the production of dimethyl sulfide and carbon disulfide related to the Gaian hypothesis are examined.

Lovelock, J. E.↗
NASA NTRS1983

The atmospheric lifetime experiment. I - Introduction, instrumentation, and overview

The Atmospheric Lifetime Experiment is designed to determine accurately the atmospheric concentrations of the four halocarbons CFCl3, CF2Cl2, CCl4, and CH3CCl3, and also of N2O with emphasis on measurement of their long-term trends in the atmosphere. Comparison of these concentrations and trends for the four halocarbons with estimates of their industrial emission rates then enables calculations of their global circulation rates and globally averaged atmospheric lifetimes. The experiment utilizes automated dual-column electron-capture gas chromatographs which sample the background air about 4 times daily at the following globally distributed sites: Adrigole, Ireland, Cape Meares, Oregon; Ragged Point, Barbados; Point Matatula, American Samoa, and Cape Grim, Tasmania. The climatology of these 'clean air' sites and their ability to describe the global air mass are reviewed. The instrumentation and methods for data acquisition and processing are then described. An overview of the data obtained and the trends derived during the 3-year period from July 1978 through June 1981 for each of the five species being measured is presented.

Prinn, R. G.↗
NASA NTRS1983

The Atmospheric Lifetime Experiment. II - Calibration

The calibration standards used in the Atmospheric Lifetime Experiment (ALE) for CFCl3, CF2Cl2, CH3CCl3, and CCl4 are described. This includes the preparation of the primary standards by static dilution and their propagation and stability for the period 1977-1982. Two independent assessments of the absolute concentrations of the primary standards used to initiate the ALE measurements in 1977-1978 are reported. For consistency in the ALE program the values assigned to the primary standards and subsequent working standards used in the field were not altered during the experiment when results of better estimates of the original concentration values were obtained. Rather, the appropriate factors by which the ALE mixing ratios for a given species should be multiplied to obtain the best estimate of the current concentration of a given species, are provided.

Rasmussen, R. A.↗
NASA NTRS1981

Atmospheres and evolution

Studies concerning the regulation of the earth atmosphere and the relation of atmospheric changes to the evolution of microbial life are reviewed. The improbable nature of the composition of the earth atmosphere in light of the atmospheric compositions of Mars and Venus and equilibrium considerations is pointed out, and evidence for the existence of microbial (procaryotic) life on earth as far back as 3.5 billion years ago is presented. The emergence of eucaryotic life in the Phanerozoic due to evolving symbioses between different procaryotic species is discussed with examples given of present-day symbiotic relationships between bacteria and eucaryotes. The idea that atmospheric gases are kept in balance mainly by the actions of bacterial cells is then considered, and it is argued that species diversity is necessary for the maintenance and origin of life on earth in its present form.

Margulis, L.↗
NASA NTRS1978

The biota as ancient and modern modulator of the earth's atmosphere

The composition of the terrestrial atmosphere is thought to have been markedly modified by surface microbiota and modulated around quantities of gases optimized for growth of these microbiota. Three diagrams illustrating these suppositions are presented. The first shows a probable order of appearance of major metabolic pathways in microbes that interact with sediment and atmosphere. It is based on evolutionary considerations and is devised independently of the fossil record. The second diagram shows the qualitative emissions and removals of atmospheric gases by anaerobic organisms; it approximates those processes thought to have dominated the terrestrial atmosphere in Archean times. The third diagrams gaseous emissions and removals by the major groups of organisms, including oxygen-releasing and -utilizing forms. Biological gas exchange processes thought to have dominated the atmosphere since the Proterozoic are thus represented.

Margulis, L.↗
NASA NTRS1974

Biological modulation of the earth's atmosphere

Review of the evidence that the earth's atmosphere is regulated by life on the surface so that the probability of growth of the entire biosphere is maximized. Acidity, gas composition including oxygen level, and ambient temperature are enormously important determinants for the distribution of life. The earth's atmosphere deviates greatly from that of the other terrestrial planets in particular with respect to acidity, composition, redox potential and temperature history as predicted from solar luminosity. These deviations from predicted steady state conditions have apparently persisted over millions of years. These anomalies may be evidence for a complex planet-wide homeostasis that is the product of natural selection. Possible homeostatic mechanisms that may be further investigated by both theoretical and experimental methods are suggested.

Margulis, L.↗
NASA NTRS1974

Homeostatic tendencies of the earth's atmosphere

The concept is developed that the atmosphere of the earth flows in a closed system controlled by and for the biosphere. The environmental factors delimiting the biosphere are examined. It is found that neither oxygen nor pressure per se limit the distribution of life as a whole. Rather the major physical variables determining the distribution of organisms are solar radiation, temperature, water abundance, and the concentrations of hydrogen and other ions and elements. An attempt is made to model temperature and atmospheric composition of a lifeless earth.

Lovelock, J. E.↗