Free ammonia inhibition of algal photosynthesis in intensive cultures

Journal Article · Thu Apr 01 04:00:00 EST 1982 · Appl. Environ. Microbiol.; (United States)

OSTI ID:6747870

Azov, Y; Ciddman, J C

The effect of free NH/sub 3/ inhibition on short-term photosynthesis was investigated in three microalgal species: the freshwater chlorophyte Scenedesmus obliquus, the marine diatom, Phaeodactylum tricoruntum and the marine chlorophyte Dunaliella tertiolecta. By performing a series of assays at various concentrations of added NH/sub 4/C1 and culture pH, the the authors demonstrated that the inhibitory compound was free NH/sub 3/, and that pH played no role in determining the magnitude of inhibition, other than in establishing the degree of dissociation of nontoxic NH/sub 4/+ to toxic NH/sub 3/. When corrections were made for pH, all three species displayed the same sigmoidal response curve to free NH/sub 3/ concentration; 1.2 mM NH/sub 3/ led to 50% reduction in photoassimilation of /sup 14/C. Based on literature values, some marine phytoplankton appear to be significantly more sensitive to free NH/sub 3/ than were the test species, which are noted for their excellent growth characteristics. However, the combination of low algal biomass and strong pH buffering commonly found in most marine and many freshwater environments probably limits the possibilities for NH/sub 3/ toxicity to low alkalinity freshwater and intensive algal cultures in which NH/sub 4/+ is the maine source of N. Such conditions occur commonly in algal wastewater treatment systems. (Refs. 18).

• Research Organization: Woods Hole Oceanographic Inst, Woods Hole, MA 02543
• OSTI ID: 6747870
• Journal Information: Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 43:4; ISSN AEMID
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
140504* -- Solar Energy Conversion-- Biomass Production & Conversion-- (-1989)
550700 -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
ALGAE
AMMONIA
BIOLOGICAL EFFECTS
CHEMICAL REACTIONS
HYDRIDES
HYDROGEN COMPOUNDS
INHIBITION
MICROORGANISMS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
SCENEDESMUS
SYNTHESIS
UNICELLULAR ALGAE