Modelling microalgal productivity in a High Rate Algal Pond based on wavelength dependent optical properties

Bernd M.A. Kroon, Henk A.M. Ketelaars, Howard J. Fallowfield, Luuc R. Mur

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


A model is presented to predict algal biomass concentration and productivity in a High Rate Algal Pond (HRAP) at all possible combinations of incident photon flux density (PFD), pond depth and hydraulic retention time (HRT). The total extinction coefficient k t and the absorption coefficient ka of algal biomass were measured at 1 nm intervals. The k t values were used to calculate the underwater light climate, which included the spectral narrowing of the photon flux density with increasing depth. The number of quanta absorbed (QA) from the photosynthetic available radiation (PAR) was calculated using the k a /k t ratio and incident PFD at 1 nm intervals. Algal oxygen production is related to QA by the quantum requirement (QR), which was determined from k a,and the slope of the photosynthesis versus irradiance curve (α). Based on this calculation we propose a new concept: the compensating absorption rate (CAR), which represents the rate of photon absorption necessary to balance oxygen consuming processes. The model calculated productivities using literature data on HRT, pond depth and incident PFD, that compared well with the actual measured productivities. To achieve optimal HRAP productivities under fluctuating climatological conditions, we propose a pond management strategy based on model simulations.

Original languageEnglish
Pages (from-to)247-256
Number of pages10
JournalJournal of Applied Phycology
Issue number3
Publication statusPublished - 1 Nov 1989
Externally publishedYes


  • attenuation
  • High Rate Algal Pond
  • light absorption
  • mathematical model
  • productivity
  • quantum requirement


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