Seawater Sampling and Collection

Hi, I'm Elena Kova from the Laboratory of Stephen Hallam in the Department of Microbiology and Immunology at the University of British Columbia. Today we'll show you a procedure for collecting sea water for physical, chemical and biological analysis. We use this procedure in our laboratory to study ocean graphic parameters of marine waters.

So let's get started. First, the number of casts and depths in each cast are assigned, then depths to be sampled, and the total volume to be collected for the current cast are determined. Ensure that the go flow and kin water sampling devices are in the open position and that all valves and spigots are closed.

Attach the CTD to the base of the line and lower it into the water for the deepest depth in the profile. Bring a sampling device onto the line immediately following the CTD. Make sure that the line is properly fitted into the device bracket and the screws are tightened.

Attach a weighted messenger to each device except for the deepest sampling depth before lowering it into the water. Lower the line and the distance between the first specified depth and the next, then rig another sampling device. Note that for depth intervals where large volume water samples are collected, a total of two x 12 liter bottles are loaded consecutively approximately 0.75 meters apart.

After all the devices are on the line, lower the line to the deepest depth and allow two minutes to pass. Send a messenger down, tripping each device into the close position. Allow a few minutes to pass before recovering the line.

To ensure that all devices are closed, reel the line in and unload each device onto the deck as it emerges from the water. For depths that require large sample volumes for protein DNA or RNA purification, employ two sampling devices in tandem. Collect RNA immediately from one bottle and filter it on ship.

After sampling chemicals and nutrients in the other bottle, drain the remaining water into the car to yield a 20 liter final volume. For low volume samples, set aside one liter of water for filtration in sterile Nalgene bottles. Typically low volume samples from 16 depth intervals are collected as 16 x one liter samples and six x 20 liter samples are collected as high volume samples.

When collecting gas samples, always take oxygen and trace gas samples. First, attach a thin piece of tubing to the spigot of the water sampling device. Place the other end of the tubing into the glos serum bottles.

Rinse the serum bottle three times, but sample water and fill it to overflowing such that no air bubbles are present. Add 50 microliter mercuric chloride to the serum bottle. Be careful not to introduce air bubbles into the sample.

Seal the serum bottle with a rubber stopper C crimp with an aluminum cap and then store it on ice to collect samples for nutrient measurements including nitrate, phosphate and silicate. First rinse a 60 cc syringe with sample water. Then attach a 0.2 micrometer acro disc filter in line.

Push approximately two ml water through the syringe. To purge the filter. Rinse a polyethylene bottle with approximately 10 ml of filtered water three times.

Shake the bottle when rinsing, then add filtered sample water to the bottles about three quarters full. Store the sample on ice. Empty collection tubes of distal water to collect samples for ammonia measurements.

First rinse collection tubes, but sample water completely. Fill a 10 ml graduated cylinder with sample water pipe at five ml of sample water out of the graduated cylinder and empty the remainder from the cylinder. Then add the five ml back to the empty cylinder.

Once samples from all depths have been collected at 7.5 ml of ammonium working reagent to each tube. To collect samples for cell counts, fill a pre-labeled 50 ML Falcon tube containing 5.4 ml, 37%formality height to the 50 ml mark for a final concentration of 4%Take care not to overflow the tube. Store the sample on ice to collect samples.

For hydrogen sulfide measurements. Fill a pre-labeled 50 ML Falcon tube containing three ml, 20%zinc acetate to the top. Take care not to overflow the tube.

Store the sample on ice to collect small volumes. For biomass concentration. Fill one liter Nalgene bottles to the top to collect large volumes for biomass concentration.

Fill 20 liter carboys to the top. The final outcome of seawater sampling results in approximately 32 to 48. Gas samples, 32 ammonium samples.

16 hydrogen sulfide samples. 16 samples for cell counts. Six 20 liter car, 16 one liter bottles, and four sterex.

Point two two micrometer filters containing microbial biomass are preserved for later. RNA isolation. We've just demonstrated how to collect different kinds of water samples for biochemical analysis.

This requires a great deal of preparation and planning. So budget two days before the trip to get things in order and one day afterwards for cleanup, do not let salt water come into contact with a peralt pump or into the aluminum zago box used to transport the field equipment. Treat the equipment with respect and it will serve well for a long time to come.

So that's it. Thanks for watching and good luck with your experiments.