WITHDRAWN: The dependence of the fluorescence spectrum of phytoplankton on external influences

Abstract

The concentration of phytoplankton is often used to assess the ecological status of water bodies; it is determined by the fluorescence intensity of chlorophyll-a, which is located in microalgae cells. Investigators do not usually take into account the effect of the medium on the fluorescence intensity when determining the concentration of phytoplankton. This article describes the use of a fibre-optic spectrometer developed by the authors to identify the relationship between the fluorescence of the chlorophyll-a in phytoplankton cells and under environmental conditions, such as temperature and illumination. A mathematical model is used to calculate the chlorophyll-a concentration based on fluorescence measurements and takes the temperature and amount of light into account. Using the resulting proportionality coefficient can reduce the error in the chlorophyll-a concentration determined using fluorescence methods by a factor of two. In this article the, authors describe the results of applying the method they developed to performance monitoring in the waters of the Gulf of Peter

Biosensors Based on Micro-algae for Ecological Monitoring of the Aquatic Environment

“…From [43] implies that the coefficient K has various values depending on the type of microalgae present in the water sample. In [15] presented data, confirming the dependence fluorescence intensity and the coefficient K from light intensity and temperature. Assuming their influence independent, then the coefficient K can be represented by the function (11) [15]:…”

“…To determine the fluorescence intensity dependence on illumination and temperature, it was carried out a series of experiments with the culture of micro-algae from the collection of the Institute of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences. The experimental values of fluorescence intensity dependence on intensity of ambient illumination for the culture of micro-algae Tisochrysis lutea are shown in Figure 4 [15]. The obtained data are well approximated by a straight line whose equation is shown in graph field.…”

“…Otherwise, the error may be very large. For example, Figure 3 [15] showed that the intensity of the LIF at a temperature of 17°C for a sample of the culture at a concentration of 106 cells/ml (upper curve in Figure 3) differs little from the LIF intensity at a temperature of 3°C for a sample at a concentration of 2 × 10 5 cells/ml (second curve in Figure 3). In their turn, the intensity of LIF at 17°C for a sample with a concentration about 2 × 10 5 cells/ml differs little from that obtained at a temperature of 3°C for a sample with a concentration of 105 cells/ml.…”

“…The article [15] describes the results of experiments obtained by study of the dependence of chlorophyll fluorescence on the temperature and concentration of algae. The experiment demonstrates that by measuring intensity of chlorophyll-a LIF, the correct determination of the concentration is only possible in cases where the ambient temperature does not change and is equal to the calibration temperature.…”

“…Methods LIF measurements are characterized by high sensitivity, rapidity, and the possibility of analysis of fluorescent signal nonlinear parameters [13,14]. Furthermore, the fluorescent response of micro-algae cells depends not only on the type and concentration of the culture, but also on the conditions in which they were during the measurement: temperature and light, the presence of dissolved organic and inorganic matter [15]. At present, LIF is one of the main methods used in modern techniques and instruments for the study of condition of the phytoplankton and measuring the concentration of micro-algae [16,17].…”