Label 250ml amber plastic bottles with preprinted labels. Add sample date to labels and cover with clear contact paper.
Fill out the pooling information form using the hypsometric tables to calculate % Lake Volume represented by each sample that has been collected. The last depth range always goes to bottom of lake. Check that '% lake volume' column totals 100. We want to create a 250 ml pooled sample, so the % lake volume numbers are multiplied by 2.5 to obtain the subsample volumes needed.
Invert sample bottle several times to mix. Use a graduated cylinder to measure out the required volume from each sample, and put it in the Pooled Sample jar. Rinse the graduated cylinder with RO water before pooling another lake.
Store pooled samples until the end of the year. Discard the remainder of the pre-pooled samples.
Send pooled samples to Phycotech the following spring, once danger of freezing during UPS transport is past. At Phycotech they are made into permanent slide mounts. We archive the slides in the UW Zoology museum. We do not archive any wet phytoplankton samples.