%0 Conference Proceedings %9 ACTI : Communications avec actes dans un congrès international %A Le Bouteiller, Aubert %T Comparison of in-bottle measurements using 15N and 14C %S Measurement of primary production from the molecular to the global scale : proceedings %C Copenhague %D 1993 %L fdi:39883 %G ENG %I ICES %K PHYTOPLANCTON ; PRODUCTION PRIMAIRE ; MESURE ; METHODE ; C 14 %K TRACEUR RADIOACTIF ; C/N %K PACIFIQUE EQUATORIAL %P 121-131 %U https://www.documentation.ird.fr/hor/fdi:39883 %> https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_6/b_fdi_35-36/39883.pdf %V 197 %W Horizon (IRD) %X Field date reported in the literature are used for making a direct comparison between primary production estimated by the 14C method and nitrogen uptake measured by the 15N method (nitrate, ammonium and at times, urea). C/N uptake ratio values vary widely, from less than 1 to more than 20 (at/at), without any evident relationship with environmental properties or experimental procedure. The mean uptake ratio calculated on the whole data set is found to be equal to 6.7 ( n = 99). The question arises whether such as C/N ratio may be considered as the assimilation ratio. For comparison purposes, the constituent ratio of phytoplankton assessed by the slopes of the regression lines relating carbon and nitrogen in particles has also been studied from the literature. This C/N ratio ranges between 5 and 7.5 (at/at) in the ocean, whatever the region, the season, or the phytoplankton present, suggesting that in the field the phytoplankton constituent ratio is probably never very different from the mean ratio found in phytoplankton by Redfield. Different possible sources of uncertainty are discussed to explain discrepancies between C/N uptake values and composition ratios. (D'après résumé d'auteur) %B International Symposium Measurement of Primary Production from the Molecular to the Global Scale %8 1932/05/21-24 %$ 036MILMAR01