The "SAMPLING INFORMATION" section is for recording the sampling start and end times, the sampling reach identifier (A, B, or C), the mesh size associated with the sample type (210 µm for QMH samples), sample-identification numbers, the proportion of the sample (subsample) retained for analysis, and the methods used for sample elutriation and splitting. The beginning and ending times of the qualitative sampling effort are recorded to provide a chronology of sampling activities in the sampling reach. Inf ormation related to sample processing methods includes the mesh size used (preprinted on the data sheet), the elutriation method used (circle "Bucket" if bucket elutriation is used or specify the appropriate technique next to the "Other" category), and th e sample-splitting method used (circle "Sieve diameter" if the sieve diameter method is used or specify the appropriate technique next to the "Other" category). If sample elutriation or sample-splitting procedures are not used in the processing of the co mposite sample, then "NA" (not applicable) is entered in the appropriate space. Also, enter "NA" in the cells of the matrix associated with sample components that were not generated during processing. For example, if the main-body sample component was 0.75 L or less, then a split-sample component is not generated, and "NA" is entered in the spaces related to the split-sample component and the sample-splitting technique. The general objective in completing field data sheets is to enter information into all data fields, thereby avoiding ambiguities presented by blank data fields.
A unique identification number ("Sample ID number") is entered in the "SAMPLING INFORMATION" section for each sample container produced. This identification number is the 16-character sample-identification code. All containers produced from the processi ng of a single composite sample have identical sample-identification code numbers with the exceptions of the eleventh character, which identifies the sample component type (L, M, S, or E), and the last character, which is unique for each sample container (fig. 11). If multiple jars are used to contain a sample component (typically, the large-rare component only), then the first 15 characters are entered, followed by the appropriate sample container letter codes assigned to each jar, separated by commas. For example, the entry LSUS0992IRL0005A,B,C indicates that the large-rare sample component (L) is contained in three jars: A, B, and C. Any modifications to standard sample-collection, processing, and labeling procedures are recorded in the "SAMPLE AND PHOTOGRAPH NOTES" section.
The "SAMPLING INFORMATION" section also contains an entry space labeled "Subsample." If the sample component (elutriate or main-body) is split, this space is used to record the proportion of the total composite sample retained for processing. The proportion entered here is used to calculate the relative abundances of organisms in the composite sample and to determine the efficacy of sample elutriation and splitting. Consequently, it is extremely important that the information entered here be accurate. The subsample entry for the large-rare sample component (1/1) is preprinted on the data sheet to indicate that this component is never a subsample. Proportions are entered in the same manner as used for the large-rare sample component: 1/1, no sample splitting; 1/2, one-half of the sample is retained for processing; and 1/4, one-fourth of the sample is retained for processing.