Particulate matter has been collected by gentle filtration (100mm Hg) of 1.2 liters of seawater on precombusted (450° C for 24 h) Whatman GF/F filters (25 mm in diameter). After filtration, filters were immediately placed in 25 ml Pyrex bottles (Duran Schott) fitted with screwcap equipped with Teflon ring. New bottles were previously washed with 10% HCl and then submitted to a preliminary digestion to completely remove traces of organic matter. Levels of carbon , nitrogen and phosphorus contained in the particulate matter retained in GF/F filters were determined according the procedure described by Raimbault et al. (1999). Filters used for blank determination were previously placed on the filtration system in order to reproduce the same experimental conditions as those for samples. Filter blanks were made in replicate with each batch of samples

Reference

Raimbault P., Diaz F., Boudjellal B., 1999 Simultaneous determination of particulate forms of carbon, nitrogen and phosphorus collected on filters using a semi-automatic wet-oxidation procedure. Mar. Ecol. Progr. Ser., 180: 289-295.