A method for the measurement of particulate C and P on the same filtered sample
Lampman, G.G.; Caraco, N.F.; Cole, J.J. (2001). A method for the measurement of particulate C and P on the same filtered sample. Mar. Ecol. Prog. Ser. 217: 59-65. http://dx.doi.org/10.3354/meps217059
In: Marine Ecology Progress Series. Inter-Research: Oldendorf/Luhe. ISSN 0171-8630; e-ISSN 1616-1599, more
|   |
| Authors | | Top |
- Lampman, G.G.
- Caraco, N.F.
- Cole, J.J.
|
|
|
| Abstract |
There is substantial interest in measuring C:P ratios in aquatic systems because these particulate ratios may influence food quality of phytoplankton to zooplankton grazers. In most analyses C is measured by dry combustion using a CN analyzer requiring that P be measured on a separate sample. We show for marine and freshwater phytoplankton cultures and naturally occurring seston that C can be measured by a variation of the same wet-persulfate digestion method frequently used for P analysis, allowing C and P to be measured on the same filter. Over a large range of C values (1 to 40 µmol C filter -1), the persulfate method for measuring C gave the same C value for lake seston, estuarine seston, and marine and freshwater phytoplankton cultures as high temperature dry combustion on a Carlo-Erba CN analyzer. For C, the wet digestion method is much less expensive than the dry combustion method in terms of both equipment and per-sample materials costs. Further, the persulfate method is more precise (CV = 3%) than the dry combustion method (CV = 12%) for the measurement of C. This greater precision of C measurement, and the fact that C and P are measured on the same sample, means that small differences in C:P ratios can more readily be detected. |
|
