The Microzooplankton Recording System consists of a black and white video camera outfitted with a macro-lens, a microscope ring illuminator, and an SVHS video recorder. The camera, light-ring, and sample flask sit on a gimbaled platform inside a mini-refrigerator. The lamp, video recorder and monitor are mounted outside the unit. Samples are taken at priority stations, filmed, and preserved in Lugol's preservative for later identification. The objective of this study is to observe, record, and analyze motility patterns and size spectra of microzooplankton prey organisms from three locations in the water column (near bottom, pycnocline, and surface) at all broadscale stations from January to June.
PROCEDURE:
The following illustrates an ideal situation taking typical samples. We will cover contingencies and trouble-shooting later and the entire sampling protocol will be demonstrated to you before disembarking.
Upon arrival at a Priority 1 station, take the plastic beaker with cord and dip out a surface sample (be sure to wear a vest outside!). Pour the sample into a tissue sample flask which was previously dipped in soapy water to prevent fogging. Place the sample in the holder and turn on the recorder, light, and monitor. Be sure that the video recorder is on channel A1 and that the lens is at an angle perpendicular to the flask.. An image should appear on the monitor. Adjust the f-stop and focus so that focal plane is approximately in the middle of the flask and there is enough light to illuminate microzooplankton, but not too much to shrink the depth of field.
If this is the beginning of a tape, it would be wise to calibrate the system by focusing on the calibration ruler in front of the flask and then placing it behind the flask and adjusting the focus. Record the field of view in millimeters both horizontally and vertically and dictate the position of the ruler (front or back) into the microphone. Remove the ruler, readjust the focus, and film the surface sample. Recording is achieved by simply pressing the record button only. Fill out the data sheet in the notebook noting the f-stop used. Record each sample for about 12 to 15 minutes. Please record the calibration ruler every tape or so.
Once the CTD has been deployed and recovered, find out from the operator which bottles were tripped at each depth. We want samples from the bottom and the pycnocline if present. If the water is well mixed, sample approximately halfway down or at a feature such as a salinity discontinuity; use your own judgment. For example, a typical crest sampling might be 30 and 55 meters. If a surface beaker sample was not taken, simply film a CTD surface sample. Since protozoans are quite fragile, siphon them gently from the GO-FLO bottles. Use a clean tygon tube and either unscrew the teflon vent-cap completely, or open the top cap enough to get your siphon in. Siphon sample directly into a labeled tissue-culture flask ; don't use the bottom spigot please.
Back in the lab, film the samples in their flasks or if you find that there are scratches or sea water droplets which interfere with filming, carefully pour the sample into a reserved "filming flask". All flasks should periodically be dipped in soapy water and air dried to reduce fogging. Samples waiting to be videoed should be kept cool in the refrigerator (5 C).
Please film all samples for about 12 minutes recording the timecode at the beginning and end of each sample, the f-stop and the lighting level used, and all other relevant data in the binder with the data sheets. Generally the f-stop will remain fairly constant and the lamp should be on the 100% level Be sure the depth and CTD information (No. Cast, Lat., Lon., Time of cast, etc.) is correct for each station. If possible obtain a copy of the print-out of the cast. After filming, pour the sample into a preserving bottle and add enough Lugol's Preservative to turn the sample a dark "tea colour". Be sure to label the flask with depth, Station #, and date. Feel free to add comments concerning the number, size, and activity of the microzooplankton present in each sample. Please film the three depth samples for Priority 2 stations, but do not preserve the sample. Feel free to film Priority 3 and 4 samples if time allows, but do not jeopardize Priority 1 and 2 sampling.
To review:
TROUBLESHOOTING AND REMINDERS
Generally when the system is not working, a connection is probably loose or something was inadvertently turned off. If there is no image whatsoever, be sure to check the power cord which would allow the monitor, VCR, and the Horita time code generator to operate. Next, check that the VCR is on channel A1 and that the lamp for the light source is turned on. Since the video signal first goes to the time code generator, be sure that its power supply cord is plugged in. Lastly, be sure that the flask isn't just fogged up or that the camera lens is pointed away from the light source. If nothing works, try turning off all the power and restarting.
At the end of a recording session, you can turn off the monitor and the light source. If the time code generator is turned off or a power outage occurs, reset the time by pressing the "gen" toggle switch to the "set" position until the hours display flashes. Advance to the appropriate hour by pressing the toggle. In a few seconds the minutes display will flash, and the correct time in minutes is obtained by advancing the clock with the toggle again. After a few seconds, press the toggle two or three times and the clock will begin running. To restart the clock in the event of a mistake, hold the toggle in the "set" position again.
If the lamp bulb burns out, you have a spare in the supplies box. Be sure to minimize touching the bulb with your fingers. A spare red gel filter is in the notebook as are copies of the various instrument manuals. If a flask becomes scratched or dirty, adjust the camera stand a bit to focus on a clear section, but make sure the lighting is optimal. Eventually replace the flask with a new one. Save the old flask as a potential preservation bottle.
Be sure to check that the microphone is recording, as this is the back-up for the written notes. Be sure that the SVHS switch on the recorder is on SVHS. Be aware that the recorder will automatically rewind and stop recording when it reaches the end of the recording tape (120 minutes). Be sure not to tape over a previously recorded session. The LED tape counter helps you to avoid this.
If needed, please call Scott Gallager or Phil Alatalo or e'mail us:
Scott 508-289-2783 sgallager@whoi.edu
Phil 508-289-2980 palatalo@whoi.edu
Leave a message on our machines when you arrive back in port, so we know to pick up the system if the ship arrives earlier than expected. Thank you for your valuable contribution to our research effort within the GLOBEC Program.