2019-Chromophoric dissolved organic matter influence correction of algal concentration measurements using three-dimensional fluorescence spectra

In view of the adverse effects of CDOM (Chromphoric or Colored Dissolved Organic Matter) on algal pigment concentration measurement in vivo in natural water body, a CDOM influence correction method of algae concentration measurement based on three-dimensional fluorescence spectra was studied in this work. The three-dimensional fluorescence spectra of five common species of algae belonging to five categories, HA (humic acid) and natural water sampled from Dongpu reservoir, Hefei were analyzed, the spectral similarity of endogenous/exogenous CDOM in algae fluorescence spectra region was compared. HA was selected as the representative of the CDOM spectrum group, The CDOM modified algae pigment concentration measurement method was established by three-dimensional fluorescence spectra coupled with non-negative weighted least squares linear regression analysis. The results show that under the presence of CDOM interference factors, the recognition accuracy rate of Pyrrophyta, Bacillariophyta, Cyanophyta and Chlorophyta were increased 100%, 100%, 40% and 40%; the average recovery rate of Cryptomonas, Pyrrophyta, Bacillariophyta and Chlorophyta were increased by 162.7%, 50.3%, 106.4% and 19.1%; the classification accuracy of Pyrrophyta, Bacillariophyta, Cyanophyta, Chlorophyta were increased by 83.9%, 100%, 38.2% and 48% respectively by comparing with that of the algae pigment concentration measurement method without CDOM modified. This method provides an experimental basis for developing accurate classification phytoplankton fluorescence monitoring technology.