This work assesses the effectiveness of sample preservation techniques for measurements of pH_T (total scale), total dissolved inorganic carbon (C_T), and total alkalinity (A_T) in organic-rich estuarine waters as well as the internal consistency of measurements and calculations (e.g., A_T, pH_T, and C_T) in these waters. Using mercuric chloride (HgCl₂)-treated and untreated water samples, measurements of these carbonate system parameters were examined over a period of 3 months. Respiration of dissolved organic matter in untreated samples created large discrepancies in C_T concentrations (~37 μmol kg⁻¹ increase, p < 0.0001), while C_T was effectively constant in treated samples (3095.0 ± 1.14 μmol kg⁻¹). A_T changes were observed for both treated and untreated samples, with HgCl₂-treated samples showing the greatest variation (~ 26 μmol kg⁻¹ decrease, p < 0.001). In response to changing A_T/C_T ratios, pH_T changes occurred in both treated and untreated samples but were relatively small in treated samples. Results in organic-rich estuarine waters that reflect the in situ carbonate system characteristics of the samples at the time of collection can be improved when samples obtained for C_T and A_T analysis are collected and stored separately. Accurate analyses of C_T can be obtained by filtration and preservation with HgCl₂. Accuracy of A_T analyses can be improved by filtration and storage without adding HgCl₂. The quality of pH_T measurements can be improved by prompt analysis in the field and, if this cannot be accomplished, then samples can be preserved with HgCl₂ and measured in the laboratory within 1 week.

中文翻译：

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HgII 在富含有机物的河口水域中保护碳酸盐系统参数的评估

这项工作评估了样品保存技术在富含有机物的河口水域中测量 pH _T（总规模）、总溶解无机碳 (C _T ) 和总碱度 (A _T ) 的有效性，以及测量和测量的内部一致性。这些水域中的计算（例如，A _T、pH _T和C _T）。使用氯化汞 (HgCl ₂ ) 处理和未处理的水样，在 3 个月的时间内检查这些碳酸盐系统参数的测量结果。未处理样品中溶解有机物的呼吸导致 C _T浓度存在较大差异（增加约 37  μ mol kg ^-1，p  < 0.0001），而处理样品中的 C _T实际上保持恒定（3095.0 ± 1.14  μ mol kg ^-1）。对于处理和未处理的样品均观察到 T 变化，其中 HgCl 2_处理的样品显示出最大的变化（约 26  μ _mol kg ^-1减少，p  < 0.001）。为了响应 A _T /C _T比率的变化，处理过的和未处理过的样品中都发生了 pH _T变化，但处理过的样品中的 pH T 变化相对较小。_{当单独收集和储存用于 C T}和 A _T分析的样品时，可以改善富含有机物的河口水域的结果，这些结果反映了样品在收集时的原位碳酸盐系统特征。_{通过过滤和用HgCl 2}保存可以得到准确的_CT分析。_{通过过滤和储存无需添加 HgCl 2}即可提高_AT分析的准确性。通过现场快速分析可以提高pH _T测量的质量，如果无法做到这一点，则可以用 HgCl ₂保存样品并在 1 周内在实验室进行测量。