Nitrogen fixation in Clear Lake, California. 4. Diel studies on Aphanizomenon and Anabaena blooms

Journal Article · Mon Jan 01 04:00:00 EST 1979 · Limnol. Oceanogr.; (United States)

DOI:https://doi.org/10.4319/lo.1979.24.2.0329· OSTI ID:5475027

Horne, A J

Day and night measurements of N/sub 2/ fixation (as acetylene reduction) were made during spring blooms of Aphanizomenon flos-aquae and two autumn blooms of Anabaena spp. From 9 to 23% of the 24-h fixation occurred between 1100 and 1300 hours. Nitrogen fixation in spring showed complex, physically shallow but optically deep and mobile subsurface peaks of nitrogenase activity, which were totally unrelated to Aphanizomenon biomass but may have been due to diel changes in light penetrating the relatively clear water. Nocturnal fixation was uniformly distributed with depth and accounted for 1/5 to 1/3 of daylight fixation. In more turbid autumn waters, the pattern of N/sub 2/ fixation for Anabaena blooms was simpler, with a surface (or near-surface) peak decreasing with depth. Nocturnal fixation was more uniformly distributed with depth. The difference in fixation patterns between the two species is attributable to the interactions of oxygen with the nitrogenase enzyme system. The diel changes in nitrogenase activity suggest a need to establish whether the precursors of nitrogenase accumulate in an oxygen-stable form.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 5475027
• Journal Information: Limnol. Oceanogr.; (United States), Journal Name: Limnol. Oceanogr.; (United States) Vol. 24:2; ISSN LIOCA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550700 -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
ALGAE
BIOCHEMICAL REACTION KINETICS
CATALYSIS
CHEMISTRY
CRYOGENIC FLUIDS
ELEMENTS
ENZYMES
FLUIDS
KINETICS
LAKES
METABOLISM
NITROGEN CYCLE
NITROGEN FIXATION
NONMETALS
OXYGEN
PHOTOCHEMISTRY
PLANTS
REACTION KINETICS
SEASONAL VARIATIONS
SURFACE WATERS
TIME DEPENDENCE
VARIATIONS