PART 1: COLLECTING THE WATER
Ideal sampling strategies will vary among habitats and monitoring contexts. We recommend that you speak to a member of our team to plan your survey. We also recommend the inclusion of field negative controls (blanks) to detect possible contamination introduced during sampling. NatureMetrics provide a free kit to be used as a field blank if 20 or more Standard Aquatic eDNA Kits are purchased.
Download and log into the NatureMetrics app before arriving in the field. Avoid introducing DNA (from yourself, soil or other waterbodies) into the water and prevent spread of disease or invasive species by wearing the provided gloves and minimising contact with the water.
PART 2: FILTERING THE WATER AND PRESERVING THE DNA
1. Draw up 100 mL of water from the sampling bag into the large syringe. If there is a high sediment load, then leave the sample for a minute to allow the sediment to settle before drawing water up into the syringe. This should increase the amount of water that you can filter.
2. Attach the syringe to the filter inlet (narrow end). The syringe should easily twist onto the inlet side of the filter. Press the plunger to push the water through the filter.
3. Repeat steps 1 and 2 (holding the filter in one hand while it is not attached to the syringe) until all water has been filtered or the filter clogs. Keep track of the number of times the syringe is refilled. Make a note on the sampling datasheet of the total volume processed.
4. Detach the syringe from the filter, hold the filter in one hand, and pull back the plunger to fill the syringe with air. Reattach the filter and push the air through to expel any water trapped inside the filter. Repeat several times to remove as much water as possible. It helps to gently shake the filter as you do this.
PART 3: PRESERVING THE DNA
1. Uncap the small syringe (already filled with preservative solution) and twist it on to the filter inlet. Do not discard the Luer Lock cap – hold the cap in one hand as it will be needed in step 2. The solution is non-hazardous to aquatic life but release into the environment should be avoided. We advise performing this step away from the water’s edge and avoiding spills.
2. Hold the filter so that the outlet (wide end) points upwards. We advise you to do this step away from anyone’s eyes. Carefully and slowly press the plunger to push the preservative solution into the filter. This must be done slowly to allow the preservative solution to spread out over the filter surface. Stop when the first drop can be seen emerging from the filter outlet, but do not remove the small syringe with preservative solution. Cap the filter outlet using the Luer Lock cap that was on the small syringe in step 1.
3. Invert the filter so that the filter outlet points down, and slowly press the plunger to expel the rest of the preservative solution. The entire volume of preservative solution should be added to the filter and the small syringe should be empty. Detach the small syringe whilst keeping the plunger depressed and cap the filter inlet with the separate Luer Lock cap. The preservative solution contains a detergent – don’t be alarmed if it foams a little!
4. Place the filter inside the specimen bag and seal. If storing samples at ambient temperatures, samples should be received by
the lab within 2 weeks of sampling. If this is not possible, we recommend that samples are frozen as soon as possible after sampling to enhance DNA preservation until samples are sent back to us. Cold shipping is not necessary for frozen samples. It should be noted that although freezing is recommended as best practice for optimal storage, we understand that it is not always feasible. Storing at ambient temperatures is a tried and tested method that yields excellent data. The addition of freezing is to further safeguard the samples against potential DNA degradation, which can affect species detection when samples are stored at high temperatures for long periods. Please contact NatureMetrics if return within 2 weeks or long-term freezing is not possible.
You can view a video demonstration of filtration with the Standard Aquatic eDNA Kit here.
PART 4: RETURNING YOUR SAMPLES
Once you have collected and filtered your sample, follow our guidelines below to safely transport your sample to the NatureMetrics laboratory.
1. Complete the sampling datasheet and use the NatureMetrics app to scan the barcode on the sampling datasheet to complete your online submission. Please record your sampling data on paper and through the app so there is a physical and electronic copy of your data.
2. Place the bagged filters and sampling datasheet inside the bag that the kit contents arrived in.
3. For UK sample returns, simply use the standard postal service with recorded delivery. Follow the packaging notes and send to: Nature Metrics, 1 Occam Court, Surrey Research Park, Guildford, GU2 7HJ, United Kingdom.
3. For international sample returns, contact your NatureMetrics Business Development Manager or our Logistics team (firstname.lastname@example.org) for further information. NatureMetrics is fully compliant with current legislation on the transport of biological material and our operations team are on hand to ensure that all return shipments meet the required specification. We are only able to analyse samples that are returned using the correct NatureMetrics logistics procedure.