Because of its geographical location, the Arctic environment is considered as pristine.
However, expanding industrial activities in the Arctic require assessment of the toxicity
of chemicals at low temperature. Biomarkers defined as "biological responses to a
chemical or chemicals that give a measure of exposure or toxic effect" were shown to
be relevant to measure in situ impact of oil discharges. Most biomarker studies have
been performed with temperate organisms. The Arctic is characterised by low stable
temperature, strong seasonality in light, resulting in a short primary production in
Spring. Therefore, indigenous organisms have developed specific adaptations to live
with a hmited food supply in water near freezing point. Conversely, physical properties
of petroleum hydrocarbons are affected by low temperature (i.e. reduced solubility).
Consequently, the biological adaptation of cold-water organisms together with the
altered oil behaviour, may affect typical biomarker responses. Because oil compounds
are strongly prooxidant, the research strategy of this work was based on oxidative stress.
The antioxidant defences were investigated by measuring the total oxyradical
scavenging capacity (TOSC). The impact of reactive oxygen species was investigated
by measuring the stability of the cell membranes. Finally, the physiology of the
organisms was considered by looking at heart and respiration rates. Invertebrates were
selected for study owing to their abundance in the polar ecosystem. They were sampled
using dredges and Scuba diving from the research vessel Jan Mayen (University of
Tromso) in May and August 1999, and during May and September 2000 in the l^ords of
Svalbard and in Antarctica as well in January 2000. In the Arctic, two bivalves, Mya
tnincata and Chlamys islandicus, and two crustaceans, Hyas araneus and
Sclerocrangon boreas were selected. In this work, the ecophysiology of Arctic and
Antarctic marine invertebrates was investigated and compared to temperate organisms. Polar marine invertebrates are characterised by low respiration and heart rates and a
high TOSC. The elevated level of antioxidant defences is thought to reflect the
oxidative pressure of the polar marine ecosystem; however, it suggested that a high
TOSC may help to protect biomolecules from oxidative damage as repair mechanisms
are limited due to the lack of food for 9 months. Organisms were exposed to poly
aromatic hydrocarbons either dissolved, dispersed injected or via sediment. TOSC, cell
membrane stabiHty and heart rate were valid biomarkers to monitor the impact of poly
aromatic hydrocarbons in Arctic marine organisms. The biomarker responses obtained
in this study provide essential background information for monitoring the potential
impact of oil and gas activities in the Arctic.
Date of Award | 2001 |
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Original language | English |
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Awarding Institution | |
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BIOMARKERS RELEVANT TO OIL AND GAS INDUSTRIAL ACTIVITIES IN LOW TEMPERATURE MARINE ECOSYSTEMS
CAMUS, L. A. Y. (Author). 2001
Student thesis: PhD