Nitrogen fixation (acetylene reduction) in nonheterocystous cyanobacterial mats from the Dampier Archipelago, Western Australia

Paling, E.I., McComb, A.J. and Pate, J.S. (1989) Nitrogen fixation (acetylene reduction) in nonheterocystous cyanobacterial mats from the Dampier Archipelago, Western Australia. Marine and Freshwater Research, 40 (2). pp. 147-153.

Abstract

Discs punched from non-heterocystous cyanobacterial mats, one containing Microcoleus chthonoplastes, Oscillatoria sp. and Phormidium sp., the other Phorrnidium sp. and Aphanocapsa sp., were incubated for 23 days in artificial sea-water of salinity 0 to 140 g L-1. The chlorophyll a content of both mats increased over this salinity range, with lower increases above 100 g L-1. There was little change in the species composition of mats at salinities 240 g L-1; ≥ 40 g L-1, mats produced essentially monospecific thalli containing small quantities of the other species.

Acetylene reduction ranged from zero at the highest salinity to a maximum of 1100-1500 pmol C2H2 reduced m-2 h-1 at 20-60 g L-1. Maximum fixation rates were two orders of magnitude higher than in situ measurements (8-60, mean 16 pmol C2H2 reduced m-2 h-1). The salinity range observed in the field was 40-60 g L-1, but maximum fixation rates in the field (60 Fmol C2H2 reduced m-2 h-1) were much lower than those observed in the laboratory.

Item Type:	Journal Article
Publisher:	CSIRO Publishing
Copyright:	© CSIRO 1989
URI:	http://researchrepository.murdoch.edu.au/id/eprint/17361

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