Punshon, StephenMoore, Robert M.2013-06-192013-06-192008-11Punshon, Stephen, and Robert M. Moore. 2008. "Aerobic hydrogen production and dinitrogen fixation in the marine cyanobacterium Trichodesmium erythraeum IMS101." Limnology and Oceanography 53(6): 2749-2753. DOI:10.4319/lo.2008.53.6.27490024-3590http://dx.doi.org/10.4319/lo.2008.53.6.2749http://hdl.handle.net/10222/27159Rates of hydrogen production and acetylene reduction were measured in aerobic cultures of the marine cyanobacterium Trichodesmium erythraeum IMS101 grown in a supplemented seawater medium low in combined inorganic nitrogen. Both hydrogen production and acetylene reduction conformed to a circadian pattern with maximum activity in the afternoon. Normalized hydrogen production rates ranged from 0.06 to 0.71 nmol H-2 mu g chlorophyll a (Chl a)(-1) h(-1), while nitrogen fixation rates, calculated using an assumed ratio of 4 mol acetylene to 1 mol dinitrogen, ranged from 0.12 to 4.71 nmol N-2 Chl a(-1) h(-1). Yields of hydrogen from nitrogen fixation were in the range 0.15-0.48 mol H-2 evolved per mol N2 reduced. A comparatively low net rate of H2 uptake was observed in one culture during the dark period (-0.01 nmol H-2 mu g Chl a(-1) h(-1)). These measurements suggest that T. erythraeum is potentially a net source of hydrogen to the low-latitude surface ocean.article5362749