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Saeid, Fathia (2018) STUDIES RELATING TO THE THEORY OF PANSPERMIA. PhD thesis, University of Sheffield.

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Abstract Panspermia is the theory that life on Earth originated came from space, for example from comets, or other planets. The Theory focuses on microorganisms because large organisms could not achieve the required space travel and impact events. Microorganisms could be protected from lethal factors (such as ultraviolet light, high pressure, low and high temperatures) by being entrapped in cosmic dust and bolides such as meteorites. In order to extend this theory, the following studies were undertaken: 1- Samples of an established meteorite were analysed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDAX). Results under scanning electron microscopy showed a presumptive bacterial biofilm consisting of a number of apparent microbial forms. Fulgurite was also analysed using SEM, EDAX and molecular biology techniques; such samples are, of course, formed on Earth are not directly relevant to investigate to panspermia, but remain of interest, nevertheless. SEM studies of fulgurite showed an unusual distribution of numerous spherules, which could be viewed as being bacterial fossils, although it is concluded that this is unlikely. Bacteria isolated from fulgurite include Bacillus cereus. 2- An attempt was made to verify the theory of neopanspermia that life is continually arriving to Earth from space. If this is the case then it should be possible to find life forms, which are incoming to the high stratosphere, a region which should not be contaminated with biology in excess of 6microns in size. A novel sampling device, carried by a hydrogen–filled weather balloon was used and a variety of so-called “biological entities” (BEs) were obtained from heights of around 30km. The BEs contain only carbon and oxygen, have biological form and were clearly not inorganic, cosmic dust. Confirmation that these BEs were incoming to Earth and not part of the planet’s biota was provided by the fact that a) they exceed the theoretical size-limit for a particle to be carried from Earth to the stratosphere and b) the presence of BEs on the sampling disks was not associated with Earth materials such as grass, pollen and fungal spores. Demonstration of the existence of bacteria in the stratosphere was also made using a sampling Drone. It is concluded that BEs are continually arriving to Earth from space. 3- Bacteria isolated from geological samples (K/Boundary clay, Boulder clay, amber, and an ancient salt crystal and a stromatolite sample from Sharks Bay, Australia). The relevance of finding bacteria within these samples relates to negative panspermia (i.e. the possibility that material leaving the Earth, following and impact event, could have transmitted bacteria and other microbes from Earth into space). 4- Locally sampled iron-rich micrometeorites were analysed using Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy. Bacteria isolated from micrometeorites were found to be predominantly species of Bacillus. It is concluded that the spore forming genera such as Bacillus, would be ideal organisms in relation to panspermia because they are able to survive environmental extremes similar to those found in space. 5-An attempt was made to verify the work of Barber relating to the presence of proteolytic, silver resistant bacteria in rainwater, which Barber concluded related to the panspermia delivery of bacteria from Venus. No evidence of this was obtained in this study, although it is concluded that Barber’s work remains intriguing.

Item Type: Thesis (PhD)
Academic Units: The University of Sheffield > Faculty of Science (Sheffield)
The University of Sheffield > Faculty of Science (Sheffield) > Molecular Biology and Biotechnology (Sheffield)
Identification Number/EthosID: uk.bl.ethos.733633
Depositing User: Mrs Fathia Saeid
Date Deposited: 05 Feb 2018 09:26
Last Modified: 01 Mar 2020 10:53
URI: http://etheses.whiterose.ac.uk/id/eprint/19284

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