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dc.identifier.citationSacco, M. (1975). Effects of oil dispersants on the brine shrimp Artemia salina L. (Master's dissertation).en_GB
dc.description.abstractThe work consists of a study on the toxicity of oil dispersants tot he brine-shrimp, Artemia salina L. The first part comprises a review of past work in the field of oil pollution, particularly studies of the effects of oil dispersants. The development of dispersants, their chemistry, mode of action and toxicity to various farms of marine life is discussed. Observations on the effects of oil dispersants in the field, are compared with the results of laboratory investigations. Standardized techniques developed for the toxicity-testing of oil dispersants are also reviewed. The heavy metals, copper and mercury, are discussed in their roles of pollutants of the marine environment. Their toxicity when combined with oil dispersants, is later tested. The influence of the environmental factors, temperature and salinity, on marine invertebrates is reviewed, with particular reference to the brine shrimp. The effects of oil dispersants on the different stages in the life-cycle of Artemia salina L. are investigated. On exposure of the eggs to the oil dispersants, hatching is generally stimulated. This is explained as resulting from an increased rate of water absorption into the eggs, following changes in the permeability of the membranes. Toxicity tests are carried out on the 3-day old larvae and 20-day old adults of Artemia salina L., the larvae being found to be much more susceptible to the toxic effects of the oil dispersants than the adults. This is interpreted as reflecting the instability of the larval stage, as a result of the stresses of growth and development. The influence of temperature on the toxicity of the dispersants to larvae is investigated. It is observed that the higher temperature alone produce greater mortalities among the larvae, and therefore at these temperatures the weakened larvae succumb more readily to the toxic effects of the dispersants. In some cases, however, increased evaporation of the volatile components of the dispersants at the higher temperatures, reduces the toxicity of the test-solutions to the larvae. The toxicity of the oil dispersants to the larvae is also found to be affected by changes in salinity, in general, mortalities are greater in the lower salinities tested. This is interpreted as resulting from a greater vulnerability of the larvae in conditions in which they may osmotically stressed. Artemia salina is found to tolerate oil dispersants in the higher salinities, resembling those found in its natural habitat, better than in the lower salinities. In the final experiments the combined toxicity of oil dispersants and heavy metal salts to larvae of Artemia salina L. is investigated. A variety of effects are recorded, ranging from antagonism to synergism. These are determined by the nature of the dispersant and the heavy metal salt, as well as their proportions in the mixture. Suggestions are also made for further experiments with oil dispersants and with mixtures of heavy metals and dispersants, that could be carried out as a sequel to this study.en_GB
dc.subjectMarine pollutionen_GB
dc.subjectLarvae -- Effect of temperature onen_GB
dc.titleEffects of oil dispersants on the brine shrimp Artemia salina L.en_GB
dc.rights.holderThe copyright of this work belongs to the author(s)/publisher. The rights of this work are as defined by the appropriate Copyright Legislation or as modified by any successive legislation. Users may access this work and can make use of the information contained in accordance with the Copyright Legislation provided that the author must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the prior permission of the copyright holder.en_GB
dc.publisher.institutionUniversity of Maltaen_GB
dc.publisher.departmentFaculty of Science. Department of Biologyen_GB
dc.contributor.creatorSacco, Marguerite-
Appears in Collections:Dissertations - FacSci - 1965-2014
Dissertations - FacSciBio - 1966-2014

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