Instructions for sampling of chlorophyll
DIC: Draw carefully and airbubble free water with a „special“ tube directly from the CTD into a syringe. Let the water run until the syringe overflows. Press very carefully and air bubble free the plunger into the syringe. Filter slowly and carefully the water sample through the 0,2 µm syringe filter into a small brown glass bottle until a „mountain“ has formed. Throw away the first milliliters. Lock the bottle airbubble free.
Draw some water from the tap of the CTD into the 1 l sampling bottle using the tubes for rinsing the sampling bottle.
For sampling nutrients and alcalinity fill nearly half a sampling bottle (500 ml) at the CTD without a silicon pipe and split the sample in the lab.
Filter the nutrients using a 30 ml syringe through a 0,45 µm syringe filter into a small PE bottle (50 ml). Use the first milliliter for rinsing the sampling bottle. Store the sample dark and cold.
Alcalinity: Filter approx. 300 ml of the sample water through a GF/C-filter using -200 mbar into a 250 ml brown glass bottle (fill the entire bottle). Store it dark and cold. Rinse the filtration with Milli-Q, remove the water from the suction bottle as good as possible. Filter some water of the next sample to rinse the filtration and throw this water away.
Draw 1 liter of the sampled water for the chlorophyll measurement.
For the outward journey:
Filter this water through a nylon filter using -200 mbar. After the water has run through, rinse once with filtered sea water. Fold the filters carefully with tweezers and put them into a labelled tube. Put 2 ml of aceton on the filters, freeze them.
As a rule the filters stay in the -80 freezer for 2 days.
As the filters will not disintegrate using this method, the samples will be homogenized manually with a teflon stick and will be put into an ultrasonic bath for 90 minutes.
The supernatant liquid will be taken off and put into the HPLC.
The amount of filtered water should be dependent on the density of the plancton. In case of a dense bloom 1 liter would probably cause difficulties. In that case fewer volumes can be filtered, as long as the filtered volumes are recorded.
For the return journey:
Filter this water through a cellulose-nitrate filter using -200 mbar. After the water has run through, rinse once with filtered sea water. Fold the filters carefully with tweezers and put them into a labelled tube. Put 10 ml of aceton (90%) on the filters, freeze them. After 12 hours at the least shake the tube carefully. The filter should have disintegrated completely.
Then put the content into a quartz glass cuvette for measuring in the fluorometer. Put 2 drops of hydrochloric acid (1M) into the cuvette, swivel carefully, measure.
Rinse all with Milli-Q for the next sampling.
All bottles must be labelled carefully.
The sampling bottles must only indicate the depth. They are used continuously.
The bottles for the various purposes must be labelled legibly as follows:
Purpose (nutrients, DIC, alcalinity, chlorophyll)
Name of cruise
Labelling is done by an edding on tape to enable later identification of the samples without problems!
All equipment has to be cleaned thoroughly with Deion, dryed and packed safely into the boxes. Glass must always be wrapped in plastic foil.