A method of quick determination of unicellular algae counting——using Photoshop software to analyze microscopic image contour model

Cell counting is an important step in algae culture, red tide investigation and water environment monitoring.A quick counting method of single cell algae was proposed and tested:the image of fixed volume sample was captured by the stereomicroscope and imaging instrument.And then Photoshop software was used to analyze the contour model of microscopic image.In this study, 5 representative microalgae species with different cell sizes were selected and the cell densities were measured by our new method and conventional microscope counting method, respectively.The results indicated that the counted numbers of cell density by our new method were apparently lower than those by microscope measurement for Platymonas subcordiformis.However, for other four algae species(Prorocentrum donghaiense, Karenia mikimotoi, Alexandrium tamarense, Akashiwo sanguinea), the counting results of the two methods were quite close, presenting a significant linear correlation between them(R²≥0.981 1).Thus, for unicellular alga with sizes larger than 15 μm, the new method could determine the biomass of pure and mixed cultivation effectively.Compared with the microscope counting method, the new method simplifies the measure procedures and reduces the artificial errors.Therefore, it has a certain application value in counting of single-cell or particles.