AB 14:283-288 (2012)  -  DOI: https://doi.org/10.3354/ab00403

ABSTRACT: We conducted experiments to assess the importance of heterotrophic activities (i.e. grazing) in primary production incubations with ¹⁴C. Carbon assimilation over 12 and 24 h was measured in whole seawater and in samples that had been diluted with filtered seawater to various concentrations, in surface samples taken from the Gulf of Aqaba (Israel) in April 2008. Carbon assimilation was higher in the diluted samples by about 20%, suggesting that carbon assimilation in undiluted seawater samples is affected by grazing at time scales of 1 d or less. The difference between the diluted and undiluted samples was, however, statistically not significant. Nevertheless, incubations with ¹⁴C lasting 12 to 24 h may at times be affected by grazing loss.

KEY WORDS: Grazing · Assimilation · Incubation · Dilution · Heterotrophy