Diurnal variations in the photosynthesis-respiration activity of a cyanobacterial bloom in a freshwater dam reservoir: an isotopic study.
The stable isotopic analyses of molecular oxygen dissolved in water (delta18O(DO)) and dissolved inorganic carbon (delta13C(DIC)), supplemented with basic chemical measurements, have been carried out on a diurnal basis to better understand the dynamics of photosynthesis and respiration in freshwater systems. Our observations have been carried out in a lowland dam reservoir, the Sulejow Lake (central Poland), during the summer cyanobacterial bloom. All data obtained, isotopic, hydrochemical, and biological, show a high mutual consistency. Namely, the lowest delta18O(DO) values, obtained at 10:00 and 14:00 (16.0 and 15.5 per thousand, respectively), correspond to the highest amount of cyanobacterial cells observed (66 and 63 mg dm(-3), respectively), whereas the minimum delta13C(DIC) (-10.6 per thousand) obtained at 22:00 corresponds to the maximum content of organic matter (110 mg dm(-3)). This evidence suggests that isotopic assays of delta18O(DO) and delta13C(DIC) are a reliable tool for the quantitative study of biochemical processes in freshwater systems.
Laboratory of Isotope Geology and Geoecology, Institute of Geological Sciences, Wrocław, Poland.
Adriana
A
Trojanowska
Dominika
D
Lewicka-Szczebak
Mariusz-Orion
MO
Jedrysek
Marta
M
Kurasiewicz
Leonard I
LI
Wassenaar
Katarzyna
K
Izydorczyk
D002247:Carbon Isotopes / Q000032:analysis* / Q000378:metabolism; D002940:Circadian Rhythm; D000458:Cyanobacteria / Q000378:metabolism*; D005618:Fresh Water / Q000737:chemistry / Q000382:microbiology*; D006801:Humans; D010103:Oxygen Isotopes / Q000032:analysis* / Q000378:metabolism; D010788:Photosynthesis; D011044:Poland; D014881:Water Supply / Q000032:analysis*
D002247:Carbon Isotopes; D010103:Oxygen Isotopes