Sam’s Notebook:Total Alkalinity Calculations – Yaamini’s Ocean Chemistry Samples

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I ran a subset of Yaamini’s ocean chemistry samples on our T5 Excellence titrator (Mettler Toledo) at the beginning of April. The subset were samples taken from the beginning, middle, and end of the experiment. The rationale for this was to assess whether or not total alkalinity (TA) varied across the experiment. If there was little variation, then there’d likely be no need to run all of the samples. However, should there be temporal differences, then all samples should be processed.

Data analysis was performed in the following R Project:

The R Project above was initially copied from the R Project for our titrator on GitHub:

Three separate, data-file-specific versions of the TA_calculations.R script were created and run:

Salinity values (PSU) were collected from the following spreadsheet (Google Sheet) and manually entered in each of the R scripts:

Specifically, the TA calculations were performed using the seacarb library, with the at() function.

Results:
sample_names TA_values
H1 A 2/20/17 2390.88423
H2 A 2/20/17 2393.39207
T1 A 2/20/17 2367.78791
T2 A 2/20/17 2319.39360
T3 A 2/20/17 2309.88602
T4 A 2/20/17 2287.72108
T5 A 2/20/17 2336.14773
T6 A 2/20/17 2298.36327
H1 A 3/20/17 2870.73309
H2 A 3/20/17 2760.49972
T1 A 3/20/17 2930.29308
T2 A 3/20/17 2925.95472
T3 A 3/20/17 2896.55123
T4 A 3/20/17 2769.72514
T5 A 3/20/17 2743.33934
T6 A 3/20/17 2727.94064
H1 A 4/4/17 2770.20971
H2 A 4/4/17 2656.27437
T1 A 4/4/17 2801.77913
T2 A 4/4/17 2822.51611
T3 A 4/4/17 2800.87387
T4 A 4/4/17 2584.60933
T5 A 4/4/17 2645.37017
T6 A 4/4/17 2604.22677

Well, it certainly looks like there’s some variation across the experiment. It’s likely that all remaining samples will need to be processed. Will pass along data to Yaamini for her to evaluate.

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