Seawater Sampling and Collection

Summary

This video documents methods for collecting coastal marine water samples and processing them for various downstream applications including biomass concentration, nucleic acid purification, cell abundance, nutrient and trace gas analyses.

Abstract

This video documents methods for collecting coastal marine water samples and processing them for various downstream applications including biomass concentration, nucleic acid purification, cell abundance, nutrient and trace gas analyses. For today’s demonstration samples were collected from the deck of the HMS John Strickland operating in Saanich Inlet. An A-frame derrick, with a multi-purpose winch and cable system, is used in combination with Niskin or Go-Flo water sampling bottles. Conductivity, Temperature, and Depth (CTD) sensors are also used to sample the underlying water mass. To minimize outgassing, trace gas samples are collected first. Then, nutrients, water chemistry, and cell counts are determined. Finally, waters are collected for biomass filtration. The set-up and collection time for a single cast is ~1.5 hours at a maximum depth of 215 meters. Therefore, a total of 6 hours is generally needed to complete the collection series described here.

Protocol

Part 1: Water Collection Depths are assigned to each cast. Depths to be sampled and the total volume to be collected for the current cast are determined. It is ensured that the Go-Flo and Niskin bottles are open, and that their valves and spigots are closed. The CTD is loaded onto bottom of the line and lower into water. A bottle for the deepest depth sampled in cast first is loaded onto the line after the CTD; it is ensured that the line is properly fitted into bra…

Discussion

Overall, there is a great deal of preparation and planning required for this type of sampling, so budget 2 days before the trip to get things in order and one day afterwards for cleaning everything up. In general, do not let salt water come into contact with the peristaltic pump or into the aluminum Zarges box used to transport the field equipment. Treat the equipment with respect and it will perform well for a long time to come.

Materials

Material Name	Type	Company	Catalogue Number	Comment
20L Carboys		Fisher	02-960-15
3/8″ Tygon		Cole Parmer	06429-36
Sterivex filters		Fisher	SVG010RS
Prefilter Housing Unit		AMD	501200
Luer Fitting		Cole Parmer	31507-27
1/4″ Tygon tubing		Cole Parmer	06429-24
1/4″ Tygon tubing		Cole Parmer	06429-24
1/4″ Tygon tubing		Cole Parmer	06429-24
50ml Plastic tubes
Glass Serum Bottles				Glass Sample Collection
Septa and aluminum caps for glass serum bottles
Hand Crimper
20-200ul Pipette and Tips
Glass Tubes				Ammonium Sample Collection
30ml Plastic Bottles				Nutrient Collection
Acrodisc Filters		Millipore
5 ml Tubes				Nitrite Sample Collection
37% Formaldehyde	Reagent			For cell count samples
20% Zinc Acetate	Reagent			For sulfide samples
Mercuric Chloride	Reagent			For gas samples
milliQ water	Reagent
Ammonium Working Reagent	Reagent			Borate buffer, sodium sulfite, orthophaladialdehyde
Sulfanilamide	Reagent			5g into 450ml water and 50ml HCl
N-(1-naphthy)-ethylenediamine dihydrochloride solution	Reagent			0.5g into 500ml water