Microelectrode studies of the photosynthesis and O/sub 2/, H/sub 2/S, and pH profiles of a microbial mat
The profiles of O/sub 2/, H/sub 2/S, and pH within a microbial mat of the hypersaline pond Solar Lake, Sinai, were measured by 2-200-..mu..m-thick microelectrodes during diurnal and artificial light cycles. The oxygen concentration in the photic layer varied from a maximum of 1,400 ..mu..M during the day to 0 during the night. The pH in the same layer varied between 9.6 in the early afternoon and 7.7 in the early morning. Sulfide was not present in the photic zone during the day, but built up to about 50 ..mu..M during the night. The diffusion gradients of sulfide and oxygen were very steep and the two compounds coexisted in a layer only 0.25 mm thick during the day. Diffusion flux calculations showed that the average turnover time of sulfide within this layer was 21 s. The rapid turnover indicated that the oxidation of sulfide must be biologically mediated. Oxygenic photosynthesis was measured by a new oxygen microprofeil method which accurately determines the vertical distribution of photosynthetic activity. There was no difference in the efficiency of photosynthesis between morning and afternoon.
- Research Organization:
- Univ. of Aarhus, Denmark
- OSTI ID:
- 6784182
- Journal Information:
- Limnol. Oceanogr.; (United States), Vol. 28:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
HYDROGEN SULFIDES
DAILY VARIATIONS
OXIDATION
OXYGEN
PH VALUE
ELECTRODES
LAKES
PHOTOSYNTHESIS
PHYTOPLANKTON
SALTS
AQUATIC ORGANISMS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
HYDROGEN COMPOUNDS
NONMETALS
PHOTOCHEMICAL REACTIONS
PLANKTON
SULFIDES
SULFUR COMPOUNDS
SURFACE WATERS
SYNTHESIS
VARIATIONS
520100* - Environment
Aquatic- Basic Studies- (-1989)
550700 - Microbiology