meth_1.10 Coastal Seawater Sampling for Downstream DIC and TA Analyses for Marine Microbes Coastal Project

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AM Project ID: Legacy

  1. Use (250 mL)- borosilicate glass bottles with stopper or with screw cap to collect samples. All bottles should be acid washed and well rinsed with seawater.
  2. Collect at depth of 2 m. Either fill bottles underwater and seal underwater to avoid excess gas exchange. Alternatively, lower bottle in bucket (see above) and then close under water. If sampling using a Niskin bottles, then attach tubing (make sure there are no gas bubbles in tubing) to tap of Niskin bottle, insert the tubing into the bottom of the sample bottle and begin water flow. Allow the bottle to fill completely and to overflow 3 full volumes.
  3. Collect n=3 per site. Labelled bottles according to the instruction given in the spreadsheet “sampling_schedule”.
  4. Leave 1-2cm head-space in sample bottles.
  5. Add 100 µL for 250 mL bottle (adjust for volume of container) of HgCl2 using a pipette. Make sure to use a pipette dedicated for toxics. Do not submerge pipette tip into sample.
  6. Note: Prepare a saturated solution of mercuric chloride: 1:10 ratio for a saturated HgCl2 solution; e.g., 10 g mercuric chloride salt per 100 mL DIW. Standard volumes used for saturated HgCl2 solutions are 0.02-0.05% of the total sample volume.
  7. Invert the sample several times to mix the mercuric chloride thoroughly.
  8. Seal the sample bottle with silicon grease around the stopper and a rubber band. If using screw cap seal with parafilm.
  9. Store bottles at cold/ambient temperature in the dark.