![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
The stable isotopic analyses of molecular oxygen dissolved in water (δ18O(DO)) and dissolved inorganic carbon (δ13C(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 Sulejów Lake (central Poland), during the summer cyanobacterial bloom. All data obtained, isotopic, hydrochemical, and biological, show a high mutual consistency. Namely, the lowest δ18O(DO) values, obtained at 10:00 and 14:00 (16.0 and 15.5‰, respectively), correspond to the highest amount of cyanobacterial cells observed (66 and 63 mg dm−3, respectively), whereas the minimum δ13C(DIC) (−10.6‰) obtained at 22:00 corresponds to the maximum content of organic matter (110 mg dm−3). This evidence suggests that isotopic assays of δ18O(DO) and δ13C(DIC) are a reliable tool for the quantitative study of biochemical processes in freshwater systems.
† Revised version of a paper presented at the 9th. Symposium of the European Society for Isotope Research (ESIR), 23 to 28 June 2007, Cluj-Napoca, Romania.
Acknowledgements
We would like to acknowledge Sebastian Ratajski, Maciej Górka, Wojciech Drzewicki, and Roksana Knapik for their substantial help in the field work. This manuscript has benefited a lot from the comments of two anonymous reviewers. The project was supported by the Polish Ministry of Education and Science, grant No. 2PO4G04528 and ‘S’ and ‘W’ grants of University of Wroclaw.
Notes
† Revised version of a paper presented at the 9th. Symposium of the European Society for Isotope Research (ESIR), 23 to 28 June 2007, Cluj-Napoca, Romania.