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A precise potentiometric method for determination of algal activity in an open CO 2 system
Author(s) -
HOFSLAGARE OLOF,
SAMUELSSON GORAN,
SJÖBERG STAFFAN,
INGRI NILS
Publication year - 1983
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/1365-3040.ep11587621
Subject(s) - alkalinity , saturation (graph theory) , potentiometric titration , analytical chemistry (journal) , carbon dioxide , chemistry , glass electrode , suspension (topology) , electrode , chromatography , electrochemistry , mathematics , organic chemistry , combinatorics , working electrode , homotopy , pure mathematics
. The activity of the green alga Scenedesmus obliquus was studied in simplified nutrient solutions (20 mol m −3 NaNO 3 , 20 mol m −3 NH 4 C1, 20 mol m −3 NH 4 NO 3 , and 20 mol m −3 NaCl, respectively) at 25 °C. The experiments were performed under welldefined incident photon density fluxes ranging from 10 to 200 μmol m 2 s −1 , Light‐dependent changes in pH and alkalinity (A) were followed by means of a potentiometric method using a glass electrode. In the experiments, carbon dioxide with known partial pressure was bubbled through the algal suspension, and during dark periods ul intervals of 1 h, the solution was allowed to equilibrate with the gas phase. This technique was applied to calculate equilibrium values of pH and alkalinity at regular intervals during a 12‐h period. Results obtained in NaNO 3 , solution show a linear increase in A with time, at each level of illumination studied. After an initial drop, A also increases in NH 4 NO 3 , solution in a similar way to that in NaNO 3 solution. The change in A with time was also found to increase linearly with the photon density flux studied and no saturation level could be defined. In experiments in NaCl solution, no changes in A were registered while measurements in NH 4 Cl solution showed a decrease in A with time.