Effects of Abiotic Factors on Acetylene Reduction by Cyanobacteria Epiphytic on Moss at a Subantarctic Island

• Main Author: Smith, Valdon R.
• Format: Text
• Language: English
• Published: 1984
• Subjects: General Microbial Ecology; Marion Island
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC241572; http://www.ncbi.nlm.nih.gov/pubmed/16346626

Acetylene reduction (AR) rates by cyanobacteria epiphytic on a moss at Marion Island (46°54′ S, 37°45′ E) increased from −5°C to a maximum at 25 to 27°C. Q10 values between 0 and 25°C were between 2.3 and 2.9, depending on photosynthetic photon flux density. AR rates declined sharply at temperatures above the optimum and were lower at 35°C than at 0°C. Photosynthetic photon flux density at low levels markedly influenced AR, and half of the maximum rate occurred at 84 μmol m−2 s−1, saturation occurring at ca. 1,000 μmol m−2 s−1. Higher photosynthetic photon flux density levels decreased AR rates. AR increased up to the highest sample moisture content investigated (3,405%), and the pH optimum was between 5.9 and 6.2. The addition of P, Co, and Mo, individually or together, depressed AR.