Collection Instructions
The Collection kits contain all needed material to collect samples and mail to Tennessee Tech University
Collection kits can be obtained from Jeff Wright at Trout Unlimited (Jeff.Wright@tu.org) or Justin Murdock at Tennessee Tech (jnmurdock@tntech.edu).
What is Didymo?
Didymosphenia geminata, commonly referred to as Didymo or Rock Snot, is a single cellular alga called a diatom. Under the right conditions, Didymo can produce thick stalks that resemble tuffs of wool growing on the stream bottom. Didymo can produce enough stalks to completely cover the stream bottom in some rivers in what are referred to as mats. While mats are easily identifiable, Didymo cells can exist in streams even when they do not form mats. What causes mats to form is unclear. We need your help to collect algae samples from various rivers to determine where Didymo is present. We will look at the samples you send back with a microscope to determine if they contain Didymo cells. By identifying which rivers contain Didymo, we can learn more about what causes mat formation in some rivers and not in others. The samples you send us will help improve Didymo management strategies and protect coldwater streams.
Be Mindful of:
a) Latitude and longitude data are critical to the success of this project. If possible, record latitude and longitude coordinates of sampling sites. Most cell phones can provide this information using apps such as Google Maps. You may also use a physical map or other app to record the coordinates.
b) Sample wherever you happen to be. We need a variety of rivers, streams, and small waterways. It is important to have data from sites where Didymo is present and not present. These differences will allow us to determine what conditions allow Didymo to survive.
c) Algae should be collected from 3 fist-sized rocks or 5 golf ball-sized rocks at each location. This allows us to standardize our effort among sites so we may compare them.
d) Collect a variety of algae, not just algae that looks like Didymo. There may be Didymo cells that you can’t see attached to a rock.
Sampling Instructions
IMPORTANT: The sample vial contains Lugols iodine and will stain clothing (DO NOT DUMP OUT)
1. Select 3 fist-sized or 5 golf ball-sized rocks from the stream. Collect rocks evenly across the width of stream if possible.
2. Use the cone with a hole at the bottom as a funnel to help get the sample into the vial.
3. Use the toothbrush to scrub the top surface of the rock (we want the slime) in a circular motion to dislodge any attached algae.
4. Collect stream water in the cone without a hole. You will use this to rinse the rock.
5. Hold the rock above the funnel leading into the sample vial, and slowly pour the stream water over the scrubbed surface of the rock, ensuring all the water runs off into the funnel and vial.
*** Use as little water as possible when rinsing or the vial will overflow ***
6. Repeat steps 3 – 5 for each rock collected.
* If you fill up the vial before scrubbing rocks 2 or 3, wait 5 minutes for the slurry to settle and then pour the excess water out. Take care not to pour out the settled algae!!
7. Remove the funnel, close and tighten the lid on the vial, and wrap the red electrical tape around the edge of the vial cap to prevent leaking.
8. Take photos of the area you sampled if possible.
9. Fill out the information on the data sheet (don’t forget the latitude and longitude!!)
10. Use the prepaid, self-addressed envelope to return your sample AND data sheet to Tennessee Tech.
Notes: We included a second vial if needed. Rocks can be split up between the 2. It is OK if you do not get all the rock scraping into the vial. Try to get the most you can fit. Write down any notes on the data sheet about the sampling or site you feel relevant. Thank you for your help!