New Zealand Journal of Marine and Freshwater Research abstracts

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LIMNOLOGY OF MORTON DAM AND UPPER KARORI RESERVOIR, WELLINGTON, NEW ZEALAND

I. L. Vidal
G. W. Frieda Maris-McArthur

Laboratory, City Engineer's Department, Wellington City Corporation, P.O. Box 2199, Wellington, New Zealand

Abstract Chemical and biological data were collected between 1947 and 1967 from Morton Dam and Upper Karori Reservoir, two artificial lakes which are part of the water supply of Wellington City, New Zealand.

Chemical analyses included the major ions, nutrients, and physical and chemical properties of engineering importance. The emphasis in biological analyses was on the dominant phytoplankters. Bacteriological results are presented as tables of plate counts and "most probable numbers" of confirmed faecal coli-forms; iron-fixing bacteria were identified.

Primary productivity has accelerated since 1940-42: annual maxima have increased 30-fold at Morton Dam, and 10-fold in Upper Karori Reservoir. In 1942, Morton Dam was believed to be oligotrophic, but the type and quantity of phytoplankton at present indicate a rapid progression to eutrophy.

Despite the extent of biological changes, no dramatic changes in the physical and chemical characteristics of either reservoir can be detected.

N.Z. Journal of Marine and Freshwater Research 7 (4) : 265-300
(Received for publication 12 November 1968; revision received 9 May 1973)

PDF file of entire paper: medium quality (1854K); (scanned from paper original: notes about this process)

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