Open AccessMicroprofiles of photosynthesis and oxygen concentration in Microcystis sp. scums
Author(s) -
Ibelings Bas W.,
Mur Luuc R.
Publication year - 1991
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.1991.tb01753.x
Subject(s) - photosynthesis , biology , oxygen , photoinhibition , photic zone , botany , irradiance , limiting oxygen concentration , cyanobacteria , oxygen evolution , environmental chemistry , ecology , photosystem ii , phytoplankton , chemistry , nutrient , physics , genetics , organic chemistry , quantum mechanics , electrode , bacteria , electrochemistry
Summary Oxygen microelectrodes were used to monitor oxygen concentration and rates of gross photosynthetic activity in Microcystis sp. scums which were formed and incubated under laboratory conditions. The depth of the photic layer, rate of photosynthesis, oxygen concentration and the location of the transition to anoxia in the scum depended on irradiance levels and colony size. Gross photosynthetic activity never extended below 2.5 mm depth in the scum. At high irradiance levels oxygen concentration in the upper 1.5 mm of the scum decreased and the oxygen concentration peak shifted to greater depth. Oxygen concentrations in scums composed of small colonies (< 55 μm) were higher than concentrations in large colonies scums (>300 μm) but small colonies showed stronger indications of photoinhibition. In a natural scum small colonies are presumably shielded from inhibitory intensities by larger colonies which will dominate the upper layers. Accumulation of low‐light adapted, smaller colonies in deeper layers likely yielded a second peak in photosynthetic activity. In order to systematically discuss scums and scum formation a distinction is made in three different scum types.