Distribution of Bacillariophyceae in the Avon-Heathcote Estuary, Christchurch, New Zealand and their use as palaeoenvironmental indicators [article]

Sean Thomas Freeman, University Of Canterbury
The Avon-Heathcote Estuary/Ihutai (AHE) is located on the east coast of New Zealand's South Island, just north of Banks Peninsula. Over the last ~150 years the AHE has undergone change caused by the rapid settlement of European immigrants, extensive land use changes and the industrialisation of society. Estuaries are one of the most important ecological areas and also one of the area's most built around areas by humans. For this reason it is important that the impacts which anthropogenic
more » ... nthropogenic activities can have on the environment, and in particular primary producing biota are understood. This knowledge will assist with developing effective remediation processes for already damaged areas and assist in producing future communities that are environmentally friendly. While there is a moderate pool of knowledge on the current situation with pollutants in the AHE the existing knowledge of Bacillariophyceae (diatoms) is extremely limited, and prior to this study, no data existed on diatom communities pre-dating European arrival or during the industrial development of Christchurch. Modern diatom communities and environmental factors were studied in a spatial sense. Sediments collected along multiple transects around the AHE allowed a modern database to be developed containing information on trace metal concentrations, organic carbon concentration, variations in sediment size, salinity, pH and elevation changes for sample sites, as well as the structure of the AHE diatom community. Statistical analyses indicate that the modern diatom communities are relatively homogenous across the Estuary, as are the selected environmental factors. Very few correlations could be made between what little variance was recorded in diatom communities and the above environmental factors. Canonical correspondence analysis was also undertaken to determine how much of the variance seen in diatom species could be attributed to the selected environmental factors (traces metals, organic carbon, grain size, elevation). The results indicated that the abo [...]
doi:10.26021/9122 fatcat:dc32nw46kzconhvzquw6a5y6s4