Assuming a 50% cell occupancy of the lorica overestimates tintinnine ciliate biomass

To estimate biomass and production, the cell volume of tintinnine ciliates has been assumed to be 50% of lorica volume. This assumption was tested using a high-precision digitizing system which measured individuals of 17 tintinnine species in samples taken in two annual studies of biomass and production in both tropical (Kingston, Jamaica in 1986) and temperate (Passamaquoddy Bay, Canada in 1983–1984) regions. Using this assumption, percent occupancies and hence, biovolume estimates, were overestimated by as much as 317% for tropical species and 178% for temperate species. Daily production estimates of the tropical tintinnine assemblage were overestimated by as much as 147%. In studies attempting to estimate biomass and production accurately, it is concluded that cell volume of tintinnines should be measured directly rather than assumed to be 50% of lorica volume.This research was financed by an NSERC Canada operating grant awarded to Dr D. H. Lynn