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Title: Towards deep-sea toxicology : experimental approaches with echinoderms
Author: Hughes, Sarah Jane Murty
ISNI:       0000 0004 2697 1972
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 2010
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As anthropogenic activities expand into the deep sea, it is only recently that the importance of deep-sea ecosystems and processes to global biogeochemical systems has become clear. If the potential impact of human activity upon deep-sea organisms and ecosystems is to be understood and predicted, experimental studies are required to improve our knowledge of their sensitivity to contamination and disturbance. Echinoderms are integral components of deep-sea benthic communities and, by virtue of their abundance, they contribute significantly to deep-sea biogeochemical processes. As such, echinoderms can be considered relevant target organisms for deep-sea experimental studies. Three approaches to the investigation of deep-sea anthropogenic impact upon echinoderms were undertaken in this study. The first was based on contaminant exposure experiments with two species of shallow-water echinoid, the eurytopic Psammechinus miliaris and the stenotopic Brissopsis lyrifera. A range of biomarkers was used to assess the responses of the echinoids to contaminant exposure. Compared with the significant cytological and molecular (assess via qPCR) responses in P. miliaris, a reduced capacity to respond to contaminant exposure was found in B. lyrifera at these levels of biological organisation. Stenotopic species are hence recommended for future experimental studies as proxies for deep-sea echinoderms which, due to their adaptation to the stable environment of the deep sea, are also considered to have a reduced capacity for homeostasis in the face of environmental perturbation. The second experimental approach involved sediment burial experiments, simulating anthropogenic drilling disturbance, with the deep-water echinoderm species Echinus acutus. ROV technology was used to perform the burial experiments in situ at 114 m depth. The application of quantitative PCR molecular biomarker methodology revealed a significant increase in the expression of a stress-70 protein in response to sediment burial. These results demonstrate the sensitivity of the qPCR technique to assess an organism’s stress-response, and its relevance to deep-sea experimental studies. Finally, the development and successful deployment of an in situ respirometer, the benthic incubation chamber system (BICS) 2, made possible the acquisition of physiological measurements from deep-sea echinoderms at the abyssal sea floor at 3500 m. The results revealed similarities between the oxygen consumption rates of shallow-water and deep-sea echinoderms. The future performance of in situ deep-sea experimentation is dependent on the development of experimental equipment that confers the ability to perform experiments in situ with ROV technology and to obtain results without interference from recovery-related side effects.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: GC Oceanography