Evaluation of a portable chlorophyll optical meter to estimate chlorophyll concentration in the green seaweed Ulva ohnoi

In situ measurement of chlorophyll concentration, with an optical meter, in the green seaweed Ulva ohnoi is presented to estimate the absolute chlorophyll content. The MC-100 optical meter (Apogee Instruments) was used during the study; the optical meter gives chlorophyll content in relative units as Chlorophyll Content Index units (CCI). Absolute chlorophyll content, in µmol m-2, was determined by extraction with dimethylformamide, and the chlorophyll concentration was measured with a spectrophotometer. Equations to convert CCI from optical meter to absolute chlorophyll content were presented for total chlorophyll, chlorophyll a, and chlorophyll b. Highly linear relationships (r2 above 0.9, n = 130) were found for total chlorophyll, chlorophyll a, and chlorophyll b. In situ non-destructive estimation of U. ohnoi chlorophyll content using the MC-100 portable chlorophyll optical meter was considered convenient, fast, and accurate.This work was funded by Spanish Ministerio de Ciencia,Innovación y Universidades (RTI2018-095062-A-C22)Postprint (author's final draft