There is growing concern about the fate and biological effects of chemical contaminants in the
marine environment. In the United Kingdom, the present ability to detect the potential long-term
effects of contaminants is limited by the lack of suitable laboratory methods for measuring
chronic toxicity. The harpacticoid copepod Tisbe battagliai was selected as a candidate test
organism and a suite of chronic toxicity test methods was developed for measuring the effect
of chemical contaminants on individual copepods (postembryonic development, reproduction
and life-table analysis) and populations of T. battagliai. The development of chronic test
methods proceeded alongside investigations of the influence of key environmental variables
(temperature and food availability) on the biology of this species. These investigations
provided a valuable insight into the potential importance of these environmental factors for
influencing the development of populations of T. battagliai in the field, and helped to define
the optimum conditions for the culture and chronic toxicity testing of this species in the
laboratory. The methods were further evaluated using pentachlorophenol (PCP) as a reference
toxicant and the aim was to investigate the potential interaction between toxicant (PCP),
environmental factors (temperature and food availability), and their effects on the population
dynamics of T. battagliai.
In summary, results showed that temperature, and food quantity and quality, were important
determinants of population dynamics. There were significant interactions between the chosen
environmental variables (e.g. temperature), PCP, and subsequent biological effects on Tisbe
battagliai, and results highlighted some important differences in toxicity testing approaches
based on the measurement of individuals and populations of copepods. Established laboratory
toxicity test procedures do not take account of the degree of complexity in the natural
environment and this underlines the difficulty in extrapolating from laboratory. results to the
field situation.
In conclusion, the project was successful in its primary objective of developing a suite of
techniques that can be used to measure the potential chronic toxicity of chemical contaminants
in the marine environment. The methods using Tisbe battagliai are relatively simple to
perform, are amenable to standardisation and provide relatively cost-effective measurements of
chronic toxicity. The test methods can be used to provide chronic toxicity data but, more
importantly, they can be used to address some of the current limitations associated with single
species laboratory tests. For example, used in conjunction with key environmental variables,
the methods provide a greater understanding of the potential interaction between contaminants
and abiotic variables, thereby, improving the extrapolation of laboratory results to the field
situation. The ability to carry out measurements on individual and populations of T. battagliai
provides a valuable insight into the predictive links between effects at different levels of
biological organisation.
Date of Award | 1997 |
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Original language | English |
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Awarding Institution | |
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Life-cycle parameters of Tisbe battagliai (Copepoda: harpacticoida) as indicators of chronic toxicity
Williams, T. D. (Author). 1997
Student thesis: PhD