Field assessment of effects of timing and frequency of copper pulses on settlement of sessile marine invertebrates |
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Authors: | E L Johnston M J Keough |
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Institution: | (1) Department of Zoology, University of Melbourne, Melbourne, Victoria 3010, Australia Fax: 0061 3 8344 7909 e-mail: johnstone@zoology.unimelb.edu.au, AU |
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Abstract: | CuSO4-treated plaster blocks were used to create localised concentrations of copper significantly above ambient levels. Between
October 1996 and March 1997 we used this system to manipulate the timing and frequency of transient copper-pollution events
close to settlement plates. We assessed the impacts on the development of assemblages of sessile marine invertebrates that
occur on hard substrates at Breakwater Pier in Williamstown, Victoria, Australia. Barnacle densities were reduced by up to
one-third, while serpulid polychaetes were insensitive. Assemblages at different stages of development were differentially
sensitive to short-term pulses. Reductions in sponge and scyphozoan polyp densities were greatest (50%) when pulse-pollution
events occurred at times of high settlement. If a pulse copper-pollution event occurred in the first week of substrate becoming
available for colonisation, then it had few observable impacts on recruitment for all invertebrates examined. When the first
pulse occurred in the first week of the experiment there was no difference between the impacts of single or double-pulse exposures
to the toxicant.
Received: 4 January 2000 / Accepted: 1 August 2000 |
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Keywords: | |
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