2.2. Measurement of biogenic opal, POC and lithogenic matter fluxes
Biogenic opal was determined by applying a modified version of the method described by Mortlock and Froelich (1989), includ- ing sequential treatment of the samples with 2 N HCl and H2O2 (2%) to remove carbonate and organic matter, and leaching of the residual material with 7% Na2CO3 at 85 1C for 5 h. Subsequently, the concentration of dissolved silica in the supernatant was measured photometrically, and the mean standard deviation of the triplicate analyses was 7 1%. Total particulate organic carbon (POC) was measured on a Carlo Erba NA 1500 Elemental Analyzer after removal of carbonate carbon by acidification of the sample with 1 N HCl. The precision of this method was 7 1%. An empirical factor of 1.8 was used to convert organic carbon to total organic matter (TOM) (Müller et al., 1986).
2.2. Measurement of biogenic opal, POC and lithogenic matter fluxesBiogenic opal was determined by applying a modified version of the method described by Mortlock and Froelich (1989), includ- ing sequential treatment of the samples with 2 N HCl and H2O2 (2%) to remove carbonate and organic matter, and leaching of the residual material with 7% Na2CO3 at 85 1C for 5 h. Subsequently, the concentration of dissolved silica in the supernatant was measured photometrically, and the mean standard deviation of the triplicate analyses was 7 1%. Total particulate organic carbon (POC) was measured on a Carlo Erba NA 1500 Elemental Analyzer after removal of carbonate carbon by acidification of the sample with 1 N HCl. The precision of this method was 7 1%. An empirical factor of 1.8 was used to convert organic carbon to total organic matter (TOM) (Müller et al., 1986).
การแปล กรุณารอสักครู่..
