Deploy and retrieve the racks

updated: 2020-07-07

Before you begin

Have a research question ready before you begin and  consider what is to be investigated? Do you want to study the biodiversity of animal and plant life in a particular place, or do a more complicated survey with comparisons between different environments? Consider how will the experiment be conducted to answer your questions? See suggestions for more topics (Link to VIRTUE discs - what to investigate?)

Deploy the racks

Racks can be deployed in freshwater, brackish water or sea water. They should be easily accessible for the students and should be placed on quays, jettys or similar. Please read the coordinates of the site using GPS on a cell phone, as it is information that you will later report to the database.

Video instruction (1 minute)


A Host family

Is the school a bit away from a suitable lake or coastline? We suggest to find a “host family”. The family (maybe a student's family) living near a seaside or lake can offer to deploy and retrieve the VIRTUE racks.

Consider water levels

Place the rack in a place that is not overly exposed to wind and waves. Also, note that the water level can change a lot at some coasts. Do not allow your rack to fall dry during low tides! Position racks such that they do not interfere with boat traffic.

The rack should be given some kind of weight in the lower part. The top disc should be placed 50 cm below the water surface. Be sure to use a sufficiently long rope if it is attached to a fixed jetty.

Let people in the surroundings know what you are doing. You may consider this at the very first outset - find a collaborate partner.

Please contact the boat owner / fisherman / harbour captain and tell them about the VIRTUE experiments and what is going on in the harbour or docks to avoid any conflicts. Mark the rack with a plastic sign / marker with name and contact information.

Time to retrieve the rack

Video instruction (2 minutes)


If you only want to study what is growing on the discs at different times of the year, all discs can be observed at the same time. Or, if you want to follow the changes in the composition of the species over time, retrieve some discs and let others remain in place.

Certain types of data are good for collecting in situ, such as currents, salinity and temperature. But do not forget to bring water samples back to the classroom so that you can use some for your disc observations and measure water parameters, in order to understand why some species thrive and others do not. (Read more in Sea Water Parameters).

Transport the discs to the classroom

The discs can be transported from the test site to the laboratory in plastic boxes with sealing caps, such as empty ice cream boxes. Fill with water from the test area. Transport in a cooler bag and store in a refrigerator.

If the investigation does not occur immediately, bring water from the test area and replace the water in the boxes with the discs each day or after the weekend. Also, do not forget to open the covers when you get back to the classroom. Also, the discs can be placed into a tank with synthetic seawater that has the same temperature and salinity, if possible. (There are several recipes for artificial seawater on the web).

Alternative transport method

VIRTUE discs can also be transported in sealed, thick plastic bags with moisture-preserving, wet newspaper. or a simple cooler with a tight fitting lid. Suitable bags can be purchased in aquarium stores and hardware stores. The air inside the bags / the cooler will thus have 100% humidity and the animals can do well with this oxygen supply. Close the bags with a cable tie or rubber strap. Keeping the bags cold increases survival time. Use a cool bag for transport. Place spacers between the discs, thus minimizing the risk of squeezing the animals. We have had complete survival for more than a day if the bags are kept cold.