Myall Lakes – isotope dating of short term environmental changes in a coastal lake system - anthropogenic pressures causing blue- green algae outbreaks in a national park

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Date
2004-10-25
Journal Title
Journal ISSN
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Publisher
International Atomic Energy Agency
Abstract
The Myall Lakes system, 50 km North of Newcastle, Australia, is a barrier lake system covering 10000ha, and is brackish (ranging from Oligohaline to Mesohaline under the Venice System classification). The Myall Lakes system is far less disturbed than similar coastal lakes, and as an important migratory bird habitat, they are protected under the RAMSAR agreement. They are also fully encompassed by the Myall Lakes National Park, declared in 1972, and are important to the local tourism and fisheries industries. Only two small streams provide freshwater input therefore water-retention time is of concern, because any changes to nutrient regimes, or pollution in the catchment affecting the Lakes, may take a long time to be corrected. In recent summers a series of cyanobacteria blooms have occurred which may indicate that human activities such as agriculture and recreational boating and fishing are affecting the Myall Lakes. Four sediment cores, up to 95cm long, were collected and sub-sampled for trace elements, palynological assemblages, sediment grain size and organic/carbonate content. Lead-210 (210Pb) was used to determine sedimentation rates and construct a chronology. Fossilised algal remains, specifically the akinetes of cyanobacteria, were used to estimate previous algal populations in the lake system. This technique has the potential to be an important tool in not only historical environmental reconstruction but also in catchment management. Results indicate that there have been cyclical fluctuations in the populations of aquatic plants and algae throughout recent history
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Keywords
New South Wales, Australia, Lakes, Birds, Habitat, Public lands, Recreational areas, Algae, Cyanobacteria
Citation
Flett, I., Heijnis, H., Harle, K., & Skillbeck, G. (2004). Myall Lakes – isotope dating of short term environmental changes in a coastal lake system - anthropogenic pressures causing blue- green algae outbreaks in a national park. Paper presented to International Conference on Isotopes in Environmental Studies – Aquatic Forum 2004 Monte-Carlo, Monaco 25–29 October 2004. Book of extended synopses. Retrieved from https://inis.iaea.org/collection/NCLCollectionStore/_Public/36/003/36003223.pdf?r=1#page=5&zoom=auto,-15,800