Optical properties of Nannochloropsis sp and their application to remote estimation of cell mass

• Published in: Biotechnology and bioengineering Vol. 69; no. 5; pp. 516 - 525
• Main Authors: Gitelson, Anatoly A., Grits, Yury A., Etzion, Dror, Ning, Zou, Richmond, Amos
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 05-09-2000; Wiley
• Subjects: Absorption; Algal culture (microalgae); Algorithms; Aquaculture - methods; Biological and medical sciences; Bioreactors; Biotechnology; Chlorophyll; Chlorophyll - chemistry; Composition effects; Electromagnetic wave attenuation; Error analysis; Eukaryota - chemistry; Fundamental and applied biological sciences. Psychology; Light absorption; Light reflection; Light scattering; Methods. Procedures. Technologies; Nannochloropsis; Optical properties; Optics and Photonics; pigment concentration; Plant cell culture; reflectance; Remote sensing; scattering; Scattering, Radiation; Water - chemistry; Algae; Biomass; Concentration; Absorptance; Remote sensing; Cell density; Heterokontophyta; Eustigmatophyceae; Optical properties; Pigments; Diffusion coefficient; Monitoring; Thallophyta; Algal culture; Reflectance
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/1097-0290(20000905)69:5<516::AID-BIT6>3.0.CO;2-I

The absorption and scattering coefficients and reflectance spectra of ultra‐high density Nannochloropsis occulata cultures were investigated in detail to identify the optical properties of the cultures and devise algorithms for remote estimation of dry cell mass in ultra‐high cell density cultures. High‐spectral resolution measurements of apparent absorption and attenuation as well as reflectance from 400 to 900 nm were carried out in relation to the dry weight, cell count, and pigment concentration in outdoor cultures. Indices calculated as (RNIR − Rred)/(RNIR + Rred) and RNIR/Rred, in which RNIR is reflectance in the range from 750 to 800 nm and Rred is reflectance in the range 670–680 nm, were used for remote assessment of dry cell mass. Remote estimation in the range 1 to 8 g/L was accomplished with an error of less than 0.66 g/L. A different index, i.e., (RNIR − Rred) was employed for estimation of cell‐chlorophyll concentration. This is the first report of in vivo specific absorption coefficient of chlorophyll‐a and specific scattering coefficient per dry algal weight of Nannochloropsis sp., providing a basis for remote monitoring of dense phytoplankton masses. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 69: 516–525, 2000.