Photosynthesis of Cladophora in Relation to Light and CO2 Limitation CaCO3 Precipitation

Abstract

In productivity studies of Cladophora by the light—and—dark—bottle method, errors may arise from CaCo 3 precipitation, self—shading, pH/Co 2 limitation, or variations in the condidtion of the alga. Precipitation of CaCo 3 and MgCo 3 by Cladophora may equal one—third of production at pH 9.3 to 10.4, resulting in overestimation of photosynthesis by either the 1 4 C or pH method. The calcification is readily removed by acid rinse without loss of fixed carbon. Consideration of such errors in relation to a recent study leads to the refutation of the conclusion the Cladophora shows an unusual ability to utilize low light intensities.