California Cooperative Oceanic Fisheries Investigations

1. Chl samples are drawn on all rosette bottles tripped from ~200m to surface; sampling on a standard 20-bottle cast usually starts at #7 (sample vol is ~140mls).  For shallow stations, all the bottles may be sampled; noontime prodo casts may have extra bottles to sample; duplicate depths are usually skipped.  Refer to the electronic sample log to verify which bottles to sample or ask the watchleader.

2.  Drawing from the middle valve, add ~20mls, cap loosely, shake then dump; three rinses.  Double-check the sample bottle number matches the rosette bottle number (often).

3.  Chl samples are volumetric so after rinsing, fill it completely, cap loosely, tap the bottle gently against the rosette frame to dislodge any small bubbles then top-off, cap tightly, invert the bottle – if you see a bubble, top-off and check again. Squeezing the sides of the bottle can change the sample volume and create a persistent bubble; cup the bottle in your palm during the final fill to minimize this problem.

4. Once all the chlorophylls have been drawn, draw the LTER water samples such as HPLCs.  The sample volume will vary with chlorophyll concentration so with the LTER watchleader for bottle size and sample depths.

5. Again, all bottles are rinsed three times then fill completely.

6. Once samples are drawn, fill out sample tags or forms, then initial the sample log.

7. When filtering chlorophylls: take the chlorophyll sample form from the clipboard along with the chlorophyll samples to the chl van to filter ASAP.  The prodo experiment filtrations in the evening may delay the filtrations so ask to be notified when the chl van is available.

• Retrieve an empty nutrient rack from the lab fridge if needed and record the color key on the sample log sheet.
• Tubes are inverted when empty and should not be turned over until filled
• Never touch the inside of the cap or tube since residue from your fingers can contaminate the sample – soap contain phosphates.  If unavoidable – rinse several times.
• Nutrients are normally drawn from the middle valve – fill the tube with ~25mls, cap loosely, shake then dump.  Repeat three times.
• Double check the tube number matches the rosette bottle number.
• Fill the tube completely then flick out several mls so the sample reaches the base of the neck/threads.  Cap tightly.
• Draw one sample per rosette bottle (except on the surface bottle).  If tube 24 is not needed, draw a duplicate surface sample.
• Once all the nutrient samples are drawn:
  • Carefully tip the nutrient rack until you can see the sample through the cap of each tube – if a tube is empty and not inverted, double-check the sample log and fill if necessary.
  • fill out a sample label (from the sample log clipboard) with the time, your initials, total number of samples
• Wrap the label around tube #1 and carefully re-insert into rack – be sure to include the extra surface sample to the sample count by listing it as “+1”
  • return the filled rack to the nutrient fridge right away.
  • add your initials to the bottom of the sample log’s nutrient column

Common mistakes are empty tubes that shouldn’t be; missing duplicate surface sample; contaminated samples; and duplicate draws – two sample tubes filled from the same bottle