DOES FREEZING OF NUTRIENT SAMPLES CAUSE ANALYTICAL ERRORS
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As it is not always possible to analyse nutrient samples on board ship during research cruises, it is necessary to preserve them for analysis ashore, and freezing is by far the simplest and seemingly the most accurate means of preservation. To verify this statement, a series of experiments on samples analysed both at sea and later ashore (after freezing) was conducted. Freezing is apparently a viable method for preserving samples destined for analysis of nitrate and low silicate (<3040 mmolm3), but phosphate samples are seemingly not well preserved when frozen. In the latter case, the deficits between analysis of fresh samples aboard ship and frozen duplicates ashore vary randomly. To determine normal trends in nutrient distribution it seems feasible to store samples in the frozen state, but for highly accurate work, as would be necessary for WOCE studies, it is advisable to analyse samples at sea immediately after collection. 1990 Taylor and Francis Group, LLC.