Nutrients in porewater of sediment profile 13370-004

Total carbonate (Ct) concentrations were determined on-board ship during Discovery 222 (leg A) nd 226 cruises, using colourmetric methods (Johnsson et al., 1987) with a precision of 0.2% RSD (n=10) using a sample loop of 4ml. During Discovery 231, 236 and Meteor 42/2 cruises a newly developed system (based on infrared detection of (CO2) were used for determination of total carbonate (Goyet and Snover, 1993; OSullivan and Millero, 1998). The precision of this method was also 0.2% RSD (n=10) using a sample loop of 4ml. Samples were filtrated through disposable sterile cellulose acetate filters (0.45µm) and stored refrigerated in polyethylene vials (rinsed in MQ-water) until analysis on-board.

在发现222（A航次）及226航次期间，于船舶上通过比色法（Johnsson等，1987年）测定了总碳酸盐（Ct）浓度，该方法的精度为0.2% RSD（n=10），采用4ml的样品回路。在发现231、236及气象42/2航次中，采用了基于红外检测二氧化碳（CO2）的新开发系统（Goyet和Snover，1993年；OSullivan和Millero，1998年）来测定总碳酸盐。此方法的精度同样为0.2% RSD（n=10），并使用4ml的样品回路。样品通过可弃无菌的醋酸纤维素滤膜（0.45µm）进行过滤，并储存在经高纯水冲洗的聚乙烯试管中，直至船上分析。