Carbon to volume relationships for dinoflagellates, diatoms, and other protist plankton
Limnol. Oceanogr., 45(3), 2000, 569-579 | DOI: 10.4319/lo.2000.45.3.0569
ABSTRACT: Cellular carbon and nitrogen content and cell volume of nutritionally and morphologically diverse dinoflagellate species were measured to determine carbon to volume (C : vol) and nitrogen to volume (N : vol) relationships. Cellular C and N content ranged from 48 to 3.0 x 104 pgC cell-1 and 11 to 2,656 pgN cell-1 for cells ranging in volume from 180 to 2.8 x 105 µm3. C and N density in dinoflagellates decreased significantly with increasing cell volume. C:N ratios ranged from 3.44 to 6.45. C: vol and N: vol in dinoflagellates are significantly related as expressed by the equations pgC cell-1 = 0.760 x volume0.819 and pgN cell-1 = 0.118 x volume0.849. Previously published data were combined to compare C: vol relationships in different phylogenetic protist groups, including chlorophytes, chrysophytes, prasinophytes, and prymnesiophytes. Our analysis indicated differences between the C: vol relationships available for ciliates. A new C: vol relationship for diatoms was established (pgC cell-1 = 0.288 x volume0.811). Dinoflagellates are significantly more C dense than diatoms. Except for diatoms, we found few significant differences between C: vol relationships of different phylogenetic groups. Consequently, one C: vol relationship for taxonomically diverse protist plankton excluding diatoms was determined (pgC cell-1 = 0.216 x volume0.939). In the combined data set, carbon density was not constant but decreased significantly with increasing cell volume. Using constant C: vol conversion factors for plankton over large size ranges will cause systematic errors in biomass estimates.