Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences

Effects of seasonal water level changes on the chemical and biological limnology of Lake Murray, Papua New Guinea

PL Osborne, JH Kyle and MS Abramski

Australian Journal of Marine and Freshwater Research 38(3) 397 - 408
Published: 1987


Lake Murray, with a surface area of 647 km2 and a high-water convoluted shoreline 2038 km long, is the largest lake in Papua New Guinea and exhibits marked seasonal fluctuations in water level. The fall in water level of 4 m between April and December 1982 was accompanied by a marked rise in pH (from 5.3 to 9.6), conductivity (from 12 to 100 µS cm-1), total hardness (from 80 to 400µM) and filterable residue (from 11 to 45 mg l-1). In November 1982, maximum production of phyto-planktonic oxygen was 1120 mg O2 m-3 h-1 at the surface but declined sharply with depth because of light attenuation by suspended solids. It was much higher than that recorded in April 1982 (250 mg O2 m-3 h-1). The long shoreline and the shallowness of the lake result in a very large littoral zone. Diurnal variation in oxygen concentrations during periods of high water level indicated that the littoral zone is a very productive area of the lake. However, when the water level is low, the lake is surrounded by a wide expanse of barren mud.

© CSIRO 1987

Export Citation