Nitrogen fixation (acetylene reduction) in nonheterocystous cyanobacterial mats from the Dampier Archipelago, Western Australia
Australian Journal of Marine and Freshwater Research
40(2) 147 - 153
Published: 1989
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.
https://doi.org/10.1071/MF9890147
© CSIRO 1989