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How to collect a plankton sample

Due to Covid we are not at sea, the demonstration shown here shows a sample of water being taken from a river.  A similar procedure may be used for taking a sample at sea. You can also take a sample of water from your municipally supplied drinking water or even bottled water.  It is likely you will find micro-plastics and fibres from all of the sources.

It is important not to cause contamination of the water sample, so try and avoid wearing clothes such as a fleece that sheds many plastic particles.  Probably not a good idea wearing a fleece in any case,  because you will be breathing in plastic from your clothes.

Make sure you always follow the washing process, we want to try and avoid any contamination which would lead to false readings.


1. Dismantle the filter and remove the two acrylic plates, each plate has 5 x 5mm holes, and 2 x alignment notches on the outside.  Place the filter paper between the plates and align the notches.  Place the filter element sandwich on the bottom section of the filter.  Use the Ocean paper in clean water with low solids content and the Coastal papers near the coast of if the solids load in the water is high.  If you use the Ocean paper in coastal water, it may not be possible to filter all of the water in the tube.

2. Take the top section of the filter and place on the bottom section, make sure it is central. Push the assembly down on a flat surface, lift up the ring and screw the bottom and top sections together, making sure that it is only the threaded ring that rotates.

3. Once the filter element is in place, put the end cap onto the pipe.  The filter is now ready for the next sample.

Taking a water sample.

1.   The Goes Filter is fitted with a stainless steel hanging chain and 2m of stainless steel wire. Simply lower the filter over-board to take a water sample. Take a water sample making sure the tube is at least 1/4 full of water and then instantly empty sample and repeat the flushing process 3 times.  This will insure that the filter is not contaminated by plastic fibres.  On the last fill, make sure the tube is 100% full of water.  

2. Remove the filter from the water and suspended by the chain, allowing the filter to swing with the motion of your vessel. Avoid it from hitting any objects when it swings

3. Water will begin to pour out of the base of the filter, this will continue form 1 to 4 hours, depending upon the number of plankton and solid particle concentration in the water sample. 

4. If the sample was collected at night, you may leave the sample until; the morning to avoid night vision blindness looking at a PC screen.  Once the water has fully drained from the filter place the filter vertically on a flat surface. Pushing down on the top section, unscrew the ring to release both sections, and carefully remove the plastic plates with the 5 x 5mm holes containing the filter paper and place the entire assembly onto a  90mm Petri plate.  There will be some water on the plastic filter disc, the petri plate is just there to protect the equipment from seawater drips

5. Place the Petri plate on top of the light box under the microscope. Focus in on the centre hole, and then wind down the microscope on top of the plastic plate, and then adjust the focus to bring the contents of the filter into focus. Take a picture, and record the number of plankton and plastic on the filter, as well as the size of the plankton. 

6. Wind up the microscope and move to the second 5mm hole and repeat the process, and then repeat for the remaining 3 holes.  At the end you will have 5 x photos and will have recorded all of the plankton and plastic in the sample.  The whole process should take no longer than 15 minutes.  If you are using the Coastal filter paper in contaminated water, you may just count the centre hole.

7. Once you have finished, remove the filter paper, and place a new filter paper between the plastic plates, to prepare the filter for the next sample.



  A video demonstrating the filter will appear here shortly

Life on earth depends upon healthy Oceans, we have 10 years to stop toxic chemical pollution, or life on earth may become impossible

Dr. Howard Dryden, CSO

Goes Foundation

Roslin Innovation Centre
The University of Edinburgh
Easter Bush Campus
Midlothian EH25 9RG