Source: Even during the winter, there are some wet swampy areas that defy freezing. Sometimes it’s the current; sometimes it’s the heat from decomposition that keeps the water from freezing. Alternatively chopping through ice in a shallow swampy are would also give you access to the bottom detritus. A sample was taken from my backyard pond on Dec 10th.
Sample: When taking a sample, ensure that there is plenty of vegetation. Some will still be green. You may find Duck Weed, or some kind of filamentous algae. A 500 mL sample will provide enough material for several classes. I re-purposed a used blister pack to act as well slides for this activity. When glued to popsicle sticks, my mechanical stage easily gripped this. That allowed me to have 6 samples on the stage at once.
Thanks for the great ideas Dave!!!!!!!!!!!!!!!