Cell identification and sizing using digital image analysis for estimation of cell biomass in High Rate Algal Ponds

A.J. Gray, D. Young, N.J. Martin, C.A. Glasbey

Research output: Contribution to journalArticle

12 Citations (Scopus)


Current environmental concerns make estimation of microbial biomass apriority for monitoring purposes and to advance scientific understanding. Thispaper considers problems associated with algal cell imaging and measurement forcell biomass estimation in samples from high rate algal ponds. In a complexsystem, the only way of measuring microbial activity is to measure theindividual cells and estimate biovolumes. Accurate biomass determinationsdemanddirect microscopic counting and measurement of the sizes of individualmicrobialcells taken from known volumes of water. The system used for routinemeasurementat the laboratory where the images were generated, based on standard microscopeequipment, is only suitable for treatment of well dispersed specimens.Differential interference contrast (DIC) microscopy, on the other hand, offersthe best solution for optical enhancement of cell contrast, and produces animage with well defined edges, yet presents a great challenge to routine cellidentification by digital image analysis, owing to the bas-relief type imageproduced. The paper outlines several image analysis methods developedspecifically for this purpose, and presents illustrative results.
Original languageEnglish
Pages (from-to)193-204
Number of pages12
JournalJournal of Applied Phycology
Issue number3
Publication statusPublished - 1 Jun 2002


  • algae
  • biomass estimation
  • cells
  • differential interference contrast (DIC)
  • image analysis
  • statistics
  • biometrics

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