New Zealand Journal of Marine and Freshwater Research abstracts

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Photosynthesis of Anabaena in Lake Rotongaio: short-term responses to a changing light environment

RICHARD D. ROBARTS¹

CLIVE HOWARD-WILLIAMS²

¹National Institute for Water Research Council for Scientific and Industrial Research P. O. Box 395, Pretoria 0001, South Africa

²Taupo Research Laboratory Department of Scientific and Industrial Research P. O. Box 415, Taupo, New Zealand

Abstract In situ photosynthesis versus irradiance characteristics of the Anabaena sp. populations in Lake Rotongaio were measured by ¹⁴C-photosynthetic assays at different times of day. Simultaneously, changes in the incorporation of ¹⁴C into the major end products of photosynthesis (proteins, polysac-charides, lipids, and low molecular weight compounds) were measured in populations from high (subsurface) and low (10%) light conditions. These populations were incubated in situ or displaced to the opposite light condition. Photosynthetic capacity (PC), measured by DCMU enhanced fluorescence, and photosynthetic pigments (chlorophyll a, C-phycocyanin) of the Anabaena at depths spanning the euphotic zone, were measured over diel cycles. Detailed studies of PC combined with ^l4C-fixation measurements were made over short-time periods in 2- or 20-litre incubation vessels in the lake.

New Zealand Journal of Marine and Freshwater Research, 1987, Vol 21- 531 0028-8330/87/2103-0531$2.50/0 © Crown copyright 1987 Received 13 March 1987; accepted 29 May 1987

PDF file of entire paper: medium quality (88K); (scanned from paper original: notes about this process)

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