A LIGHT-LIMITED CONTINUOUS-CULTURE STUDY OF EMILIANIA-HUXLEYI - DETERMINATION OF COCCOLITH DETACHMENT AND ITS RELEVANCE TO CELL SINKING

The coccolithophore Emiliania huxleyi (Lohm.) Hay and Mohler is one of the most abundant calcite producing organisms on earth, producing cal cium carbonate plates known as coccoliths. Consequently, these coccoli ths represent a major carbon sink in the world ocean. This study addre sses the rate of detachment of coccoliths from coccolithophores under controlled growth conditions using light-limited continuous cultures. Cells were grown at six different growth rates between 0.24 day(-1) an d 1.00 day(-1). Other cell properties including chlorophyll, particula te inorganic carbon, and total particulate carbon, were also investiga ted with regard to growth rate of the cells. The coccolith detachment rate increased linearly with cellular growth rate at a ratio not signi ficantly different from 1.00. This change in detachment with growth co uld affect several processes such as sinking rates of cells and the ap pearance of blooms in remotely-sensed imagery. The importance of sinki ng to coccolithophores is discussed.