Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.635679
Title: Effects of oil pollution on the ecology, behaviour and physiology of the sand lizard (Acanthodactylus scutellatus) in Kuwait
Author: Al-Hashem, Mona Abdulla Sayed Yousef
Awarding Body: University of Wales, Swansea
Current Institution: Swansea University
Date of Award: 2006
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Abstract:
The effects of oil pollution on a sand lizard {Acanthodactylus scutellatus) were studied throughout 2002 and 2003 at Greater Al-Burgan oil fields in Kuwait. This study examined the effects on this species because large land-based oil spills (such as in Kuwait in 1991) present a new environmental concem. The most unexpected outcome of the study was that assumptions made about the degrees of contamination based on physical evidence (such as soot and tar) were not supported. All the classes of contaminated sites appeared to be equally contaminated. Population studies of the lizards and their ant prey seem to have many interpretational problems. The population sizes of A. scutellatus did not vary markedly among the study sites using the pitfall trap and transect methods which could be due to the fact that all the sites were equally polluted with oil. Initially, the daily behaviour of A. scutellatus was observed. Field observations included the timing of morning emergence as well as basking and foraging behaviours. These behaviours seemed influenced by oil pollution with lizards on the highly polluted sites emerging earlier than the other sites. The presumably highly polluted sites exhibited the highest substrate temperatures, influencing basking of A. scutellatus. Basking duration decreased as the degree of pollution increased. Foraging behaviour did not differ between the study sites because the lizards continued as a 'Sit and wait' predators at all the locations and did not have to increase their foraging. Lizards were examined in the laboratory for their substrate preference. They were monitored using a digital video camera and the times spent on polluted and/or nonpolluted substrates were recorded. Lizards collected from the tar mat sites preferred to remain on the dark substrate whereas those collected from the control sites chose the light substrate. The strength of this response suggests that the behaviour is highly adaptive because possessing this cryptic colouration is essential to avoid predators. Lizard body size and weight were measured and adult lizards were larger on the tar mat and soot sites than on the clear and control sites. Food appeared to be available in greater quantities on the tar mat and soot sites and consuming prey with high levels of fat resulted in lizards accumulating adipose tissue in their bodies. Crude oil contains heavy metals with nickel and vanadium generally being the predominant elements. An attempt was also made to determine if heavy metals in the environment influenced sand lizards. Concentrations of these elements were determined in soil and whole body tissues of lizard using ICP/AES analysis. There was a significant variation in nickel concentration in soil between the control and the soot and tar mat sites. Nickel concentration differed in lizard samples from the control and the tar mat sites. Vanadium concentration in soil differed between the control and the tar mat sites but did not show any difference in lizard tissues between the different study sites. Sixteen PAHs (EPA priority pollutants) were studied using GC/MS in lizard and ant whole body tissues to investigate their presence and concentration. Of the 16, phenanthrene, fluoranthene and benzo[a]anthracene were present in the polluted sites but undetectable in the control sites for both lizards and ants. Although 12 years have passed since the Kuwait oil spill catastrophe, all sites are still contaminated with PAHs (there was no distinction between tar mat, soot and clear sites). The effects of PAHs and heavy metals on the histopathology of A. scutellatus vital organs such as liver were also investigated. Hepatocytes showed remarkable responses to PAHs and heavy metals. Swollen hepatocytes, ballooning degeneration of cytoplasm and dead cells were the most common cytopathological signs observed. This research confirms that A. scutellatus is a suitable bioindicator species for ecotoxicological studies on the effect of PAH compounds. The importance of lizards was emphasized in hope that they be included in ecological risk assessments as well as studies on environmental contamination in desert locations such as Kuwait. This is because lizards are an important component of biodiversity, and many such species are listed as threatened or endangered.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.635679  DOI: Not available
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