A PRELIMINARY COMPARATIVE STUDY OF THE PRODUCTIVITY OF THREE ECONOMIC SEAWEEDS

The rates of photosynthesis and respiration of Porphyra, Laminaria and Undaria were determined with an oxygenmeter at different temperatures in an enclosed continuous-flow system. The temperature coefficients of respiration and the net primary productivities for the three species were calculated. The spectacular rates of primary production were found to be as high as 270 g C m-2 for P. yezoensis, 2200 g Cm-2 for L. japonica and 160g C m-2 for U. pinnatifida annually. The low respiratory rates of these three species as well as low light compensation points especially at low temperatures are considered as a reason to save heat energy, resulting in a high productivity, especially in case of Laminaria.