New Zealand Journal of Marine and Freshwater Research abstracts

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Limnology of nine Westland beech forest lakes

H. W. Paerl*

G. W. Payne

A. L. Mackenzie

P- E. Kellar

M. T. Downes

Ecology Division, Freshwater Section, Department of Scientific and Industrial Research, P.O. Box 415, Taupo, New Zealand

Abstract Lakes in the beech (Nothofagus sp.) forest foothills between Greymouth and Hokitika, Westland, are characterised by amber-coloured waters. Microbiological, biochemical, and chemical analyses of samples from nine such lakes during March 1976 indicate that they are unproductive. Microbial biomass was intensively investigated in heavily stained Lakes Haupiri and Lady and in least-stained Lake Brunner. A combination of adenosine triphosphate assays, Utermohl phytoplankton counts, and autoradiographic biomass determinations revealed a greater bacterial than algal biomass in heavily stained lakes, a highly unusual phenomenon which suggests that most of the production of organic matter was allochthonous. Autochthonous productivity was low, probably because biologically available phosphorus was very scarce and because discoloration reduced the transparency of the water. Hypqlimnetic oxygen depletion was slight during this period of maximum thermal stratification; decomposition of organic matter was apparently incomplete. Reactive phosphorus did not increase appreciably in partially deoxygenated hypolimnia. Much of the allochthonous organic matter originating from beech forests and their soils may be partially resistant to biodegradation.

New Zealand Journal of Marine & Freshwater Reaearcn, 1979, 13(1): 47-57.
Received 13 July 1977; revision received 12 September 1978

PDF file of entire paper: medium quality (791K); (scanned from paper original: notes about this process)

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