Determination of nitrogen-fixing phylotypes in Lyngbya sp. and Microcoleus chthonoplastes cyanobacterial mats from Guerrero Negro, Baja California, Mexico.

ABSTRACT: In many environments, biological nitrogen fixation can alleviate nitrogen limitation. The high rates of N(2) fixation often observed in cyanobacterial mats suggest that N(2) fixation may be an important source of N. In this study, organisms expressing nifH were identified in a Lyngbya sp.- and two Microcoleus chthonoplastes-dominated cyanobacterial mats. The pattern of nitrogenase activity was determined for the Lyngbya sp. mat and a Microcoleus chthonoplastes mat sampled directly in Guerrero Negro, Mexico. Their maximum rates were 23 and 15 micro mol of C(2)H(4) m(-2) h(-1), respectively. The second Microcoleus mat, which was maintained in a greenhouse facility, had a maximum rate of 40 micro mol of C(2)H(4) m(-2) h(-1). The overall diel pattern of nitrogenase activity in the three mats w

SUBMITTER: Omoregie EO 

PROVIDER: S-EPMC383108 | biostudies-literature | 2004 Apr

REPOSITORIES: biostudies-literature