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
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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
Description
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