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Towards Deep-Sea Toxicology: Experimental Approaches With Echinoderms

Towards Deep-Sea Toxicology: Experimental Approaches With Echinoderms
Towards Deep-Sea Toxicology: Experimental Approaches With Echinoderms
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.
Hughes, Sarah Jane Murty
48c21280-ddc9-4518-a8c6-fdd5bcb955e4
Hughes, Sarah Jane Murty
48c21280-ddc9-4518-a8c6-fdd5bcb955e4

Hughes, Sarah Jane Murty (2010) Towards Deep-Sea Toxicology: Experimental Approaches With Echinoderms. University of Southampton, School of Ocean and Earth Science, Doctoral Thesis, 297pp.

Record type: Thesis (Doctoral)

Abstract

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.

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Published date: September 2010
Organisations: University of Southampton

Identifiers

Local EPrints ID: 168893
URI: http://eprints.soton.ac.uk/id/eprint/168893
PURE UUID: b7f8e3ed-59de-49c4-827c-4f6d62f19ff8

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Date deposited: 06 Dec 2010 14:42
Last modified: 10 Dec 2021 18:38

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Author: Sarah Jane Murty Hughes

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