Kathryn H. Taffs

A comparison of diatom community structure on natural and artificial substrata

Artificial substrata have been used in diatom studies for almost 100 years. However, concern still exists over whether diatom communities developing on artificial substrata accurately represent communities developing on natural substrata. This study compares the diatom communities colonising glass slides and clay tiles in two coastal dune lakes, and compares these communities to the naturally occurring communities in the epipelon, epilithon, and epiphyton. Both glass microslides and clay tiles, incubated for three separate periods ranging from 29 to 68 days, resulted in replicate substratum samples supporting similar diatom community compositions at each site. The degree of variation between artificial substrata communities at different sites, and between the two artificial substrata types, was generally no more than the degree of variation between communities on different types of natural substrata. Additionally, the composition of the diatom communities on the artificial substrata was representative of the community composition on the natural substrata. The effects of incubation period and siting are discussed.

Palaeoecology: a tool to improve the management of Australian estuaries

Addressing environmental problems in estuaries is a worldwide problem. Establishing benchmarks and targets for management is critical, whether the aim is conservation, restoration or sustainable use. Palaeoecological techniques have rapidly improved during the past decade, particularly with advances in methods that allow high resolution quantitative assessments of environmental change. Palaeoecology is a useful tool in environmental management as it allows pre-impact conditions, the rate, extent, direction and cause of change, and range of natural variability to be determined. Australian estuarine ecosystems are qualitatively different from the often more well-studied estuaries in North America and Europe, which means site-specific studies of Australian estuaries are needed to inform management. While a potentially useful and valuable tool, palaeoecological techniques have not yet been widely adopted and practically implemented as part of estuarine management strategies and policy frameworks in Australia. We discuss the role palaeoecological techniques have to play in estuarine management by providing two case studies undertaken in Australia that have provided management information. We aim to encourage communication and dialogue between scientists and environmental managers about the potential for widespread practical adoption and implementation of palaeoecological techniques into Australian estuarine science, management and policy frameworks.

The Distribution and Abundance of Beach Debris on Isolated Beaches of Northern New South Wales, Australia

Beach debris items were collected and categorised during surveys of five isolated beaches on the northern New South Wales coastline in September 2003. The selected beaches covered more than 21 km of contiguous coastline. Litter density and distribution per 500 m segment was calculated. The highest density of litter was found on the most isolated beaches with little public access but no protection by headlands from the ocean swells. Litter density was highest at the northern extent of each beach, transported in that direction by longshore drift. The litter was predominantly composed of plastic (72–86 per cent), followed by glass (1–4 per cent) and cigarette butts (1–11 per cent). Plastic litter primarily consisted of soft drink and water bottle lids and seal caps. Glass materials were highest at beaches open to the ocean swells, where transportation of heavier materials is more likely. Cigarette butt density was highest at the beaches with high public usage. Beach debris was presumably of terrestrial origi...

Relationship between diatoms and water quality (TN, TP) in sub-tropical east Australian estuaries

Nutrient over-enrichment of estuarine environments is increasing globally. However, it is difficult to determine the eutrophication trend in estuaries over long periods of time because long-term monitoring records are scarce and do not permit the identification of baseline environmental conditions. In this study, preliminary diatom based transfer functions for the inference of total phosphorus (TP) and total nitrogen (TN) in east-Australian sub-tropical estuaries were developed to address the deficiency in knowledge relating to historical estuary water quality trends. The transfer functions were created from a calibration set consisting of water quality and associated surface sediment diatom assemblage data from fifty-two sub-tropical estuaries in New South Wales and Queensland, Australia. Following data screening processes, Canonical Correspondence Analysis confirmed that TP and TN both explained significant, independent variation in the diatom assemblages. Variance partitioning, however, indicated that the TP was confounded with and may receive some strength from TN. WA and WA-PLS 2 component models for TP that included all calibration set sites yielded statistically weak results based on the jack-knifed r2 scores

Diatom community response to climate variability over the past 37,000 years in the sub-tropics of the Southern Hemisphere.

\left( {r_{\text{jack}}^{{^{ 2} }} \, = 0.22\;{\text{and}}\;0. 2 2 {\text{ respectively}}} \right)

Increasing the understanding and use of natural archives of ecosystem services, resilience and thresholds to improve policy, science and practice

. Removal from the calibration set of 12 sites that had all PO4, NH4, NO2, and NOx concentrations below detection limit resulted in a substantial improvement in WA-PLS 2 component TP model scores

Applying paleolimnological techniques in estuaries: a cautionary case study from Moreton Bay, Australia

\left( {r_{\text{jack}}^{{^{ 2} }} \; = \;\,0.69} \right)