Chlorophyll A Concentration Of Fresh Water Phytoplankton Analysed By Algorithmic Based Spectroscopy
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Date
2016-02
Authors
Johan, Fairooz
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Phytoplankton are microscopic single-celled plants that play an important
role in the ecosystem as a major primary producers through photosynthesis. The
main objective of this study was to investigate properties through reflection and
chlorophyll a concentrations of phytoplankton in freshwater. In this study, reflection
phytoplankton were taken using spectroradiometer to observe the relationship
between the reflectance and the wavelengths of phytoplankton in freshwater. The
lake selected for this study is known as Tasik Harapan located in Universiti Sains
Malaysia. In this study, 20 litres water samples undergone the filtering using
phytoplankton net. The water samples collected were analyzed in the laboratory to
determine the reflectance and chlorophyll a concentration of phytoplankton. Two
spectrometers were used in this study, firstly, spectroradiometer which was used to
measure the reflectance of phytoplankton and secondly, spectrophotometer which
was used to measure the concentration of chlorophyll a. The water samples taken
were prior to culture in the medium known as Bold's Basal Medium before the
reflections were taken so that accurate reflection measurements on phytoplankton
can be acquired. The algorithms that related between chlorophyll a concentration and
reflectance of phytoplankton were used. The good results are obtained in this study which are evidenced by the good correlation in the analysis results using the
developed algorithm. Three regions were focused which were the red, green and blue.
These bands have been identified to be appropriated in analyzing phytoplankton.
Reflectance of each band specified referred to the concentration of chlorophyll a for
calibration algorithm. The wavelength range was tested and the R2 were compared.
Finally, three wavelengths of 438 nm, 550 nm and 675 nm were selected. The
selection of these three wavelengths were found to be strongly correlated to
phytoplankton and chlorophyll a. The value of R2 obtained also in accordance with
the developed algorithm in this study. The water sampling for validation was also
taken from the same lake but not on the same date and was analysed using the same
algorithm. The validation results showed very good results with a high R2 value was
obtained. The results from this lake proved that the algorithm developed was
successful in measuring the concentration of chlorophyll a in phytoplankton. In
addition, some suggestions are given to repair this study in the future.
Description
Keywords
Phytoplankton