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- After
completion of the net tow, concentrate the plankton sample into the cod
end by washing down the net with the deck seawater hose (DO
NOT use fresh water). Be sure to spray the net from
the outside to minimize damage of the delicate plankton in the sample.
- Once the sample is
concentrated into the cod end, use a screwdriver to loosen the hose
clamp. Give the cod end a tug to detach it from the PVC
coupler. If the sample will overflow the cod-end when
removing it from the coupler, grab a bucket and remove the sample over
the bucket. Make sure to wash down any sample remaining in the
net into the bucket as all our plankton tows are quantitative (no
sample can be lost).
- Take the cod end into the preservation sink
area. Remove the appropriate jar from the sample box (pint
jar for Pairovet and Manta, quart jar for Bongo; all boxes are labeled
accordingly) and set it into the sink rack. Be sure the
begin-tow time is written on both inside & outside labels,
using pencil for inside and Sharpie for outside. Peel off the
outside label backing and stick to jar lid. Put the inside
label into jar.
- Using the filtered seawater hose, concentrate the
plankton into the bottom of the cod end. It is ok to gently
spray the inside of the cod end at this point but not so hard you will
damage the organisms. Once the plankton are sufficiently
concentrated towards the bottom, invert the cod end into the draining
sock (a wooden dowel helps). There are 2 different mesh sizes
of draining sock, always make sure you use the
appropriate size mesh for the sample you are preserving (.150 for
Pairovet samples, .333 for Manta or Bongo). The draining sock
is helpful because it allows you to use as much seawater as necessary
to thoroughly rinse the cod end. Gently spray the cod end with enough
seawater to remove all the plankton clinging to it. It is
very important not to lose any part of the sample or it will no longer
be quantitative. Large pieces of kelp or grass or anything
obviously not plankton can be rinsed off thoroughly and discarded at
this point. Using a spoon, transfer the plankton into the
jar. Rinse the spoon into the draining sock and then invert
the draining sock into the jar. Wash down any of the
remaining plankton into the jar with the rest of the sample, filling
the jar with seawater to just below the shoulder.
- Wear eye protection.
Add a squirt of supersaturated sodium borate to the sample for
buffering purposes. Formalin is slightly acidic so the borate
raises the pH of the sample to neutral. Add 10 cc. to pint
jars, 20 cc. to quart jars. The syringe is usually marked
with a “P” for Pint and a “Q”
for Quart.
- To add full strength formalin, unclip the plastic
binder attached to the tygon tubing of the formalin rig to allow for
flow. Hold the 60 cc. syringe firmly and pull out the stopper
to the desired amount (25 cc. for Pint and 50 cc. for Quart).
Re-clip the plastic binder and dispense
the formalin into the jar. Be careful not to spill any or
push so hard the formalin squirts out the back of the
syringe. Formalin is very caustic and extra care should be
taken when dispensing it. If you have any allergies to
formalin then you should not help with this step of the preservation
process.
- After the formalin is added, secure the lid tightly
and invert the jar a few times to ensure proper mixing of sample
& chemicals. Return the sample jar back to the
correctly labeled box.
- Rinse the cod end with the deck seawater hose and
invert it back to the original position. Reattach the cod end
to the coupler and tighten the hose clamp securely.
Thank you for all your help, it’s greatly
appreciated !!
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