Doctor of Philosophy
Department of Biology
Moran, Peter John, The effects of industrial pollution on the larval settlement, development and succession of marine fouling communities in Port Kembla Harbour, Doctor of Philosophy thesis, Department of Biology, University of Wollongong, 1982. http://ro.uow.edu.au/theses/2115
This study was carried out to assess the effects of industrial pollution on fouling conununities in Port Kembla Harbour and to investigate the mechanisms by which these observed effects were brought about.
The experimental design of the study consisted of comparing the successional stages of fouling conununities from sites situated within Port Kembla Harbour with those from a control site in Wollongong Harbour. · The successional stages of the conununities were collected on sandblasted perspex panels submerged for specified periods . of time at each site; After submergence, panels were preserved and the frequency of occurrence of species recorded. This data was subjected to both statistical and multivariate (numerical classification and ordination) analyses.
Several complementary experiments were also carried out, involving; the assessment of species richness of macroalgae in the initial stages of conununity development; measurement of the growth of the serpulid Hydroides elegans; estimation of the abundance of food species in both study areas; determination of the effects of water from Port Kembla Harbour on the larval settlement of 4 fouling species; transference of mature fouling conununities between the two study areas.
In the main study, 53 species of fouling animals occurred in the conmninities in Wollongong Harbour compared to only 40 in those from Port Kembla Harbour. Twenty-eight species, including many bryozoans, occurred only in Wollongong Harbour, wh.ilst 15 species occurred solely in Port Kembla Harbour. There were also 10 species which occurred in both areas but which occurred more abundantly in the experimental area. The species richness of fouling conununities in Port Kembla Harbour decreased along the pollution gradient from the outer harbour (35 species) to the inner harbour (30 species).
The multivariate classification showed that the major difference in the development and succession of the fouling communities was between Port Kembla Harbour and Wollongong Harbour. A secondary division generated by the classification suggested that at all sites, the species composition of the communities in Port Kembla Harbour changed with time, and was independent of the season during which the connnunities were first established.
The results of the ordination provided information concerning the successional processes in each study area. It showed that in both areas there were species which colonised the initial stages of development and stayed on throughout the rest of the development of the community. The species involved in this process were different in each area, and it was more prono.unced in Wollongong Harbour. The ordination also indicated that communities in Port Kembla Harbour contained an assemblage of species which were gradually replaced by a second group of different species. A similar, but less distinct pattern of development took place in communities in Wollongong Harbour. The results of the other experiments showed that; a greater number of macroalgae occurred in the initial stages of development of communities in Wollongong Harbour compared to those in Port Kembla Harbour; the growth of Hydroides elegans under both 'competitive' and 'non-competitive' conditions was significantly more rapid in Port Kembla Harbour; food species (e.g. bacteria and phytoplankton) occurred more abundantly in the experimental area than the control area; the settlement of larvae of the bryozoans, Bugula neritina and Tricellaria sp. was reduced in water from Port Kembla Harbour; fouling communities transferred from Wollongong Harbour to Port Kembla Harbour were more similar to control communities in Port Kembla Harbour than they were to control communities in Wollongong Harbour.
These results were not attributed to the acute, toxic effects of pollution, but were caused by pollution affecting the comrminities in a more subtle and indirect manner.