Stream Explorers 2017: dissolved oxygen and habitats

Today we had two more students show up, bringing up the class size to 13! We met at the Touber building again.

Today’s session started with an experiment to determine how water temperature is related to dissolved oxygen. All students got a mason jar with room temperature water (purified) into which we put a goldfish. After 5 or so minutes, to let the fish settle down, each student counted the number of gillbeats in 30 seconds. Then the water was warmed up (some 140F water added) or cooled (3-4 ice cubes), and the counting repeated. We discussed water temperature as a factor in habitat, and then plotted the combined temperature vs. gill beats results. We made the connection between “more breaths means less oxygen in water”.

Next, we went down to the river to build fish habitats. Each students got a 2 liter bottle to fill with sticks, stones, moss, and river water. Into each bottle we then placed a goldfish, and discussed what needs to be done to keep the fish well and alive. Some students added food (mayfly and caddis and stonefly nymphs), other extra rocks, etc. Each student drew and described their habitat, and they will bring them back next week.

The students also made neck pendants by filling little sample caps with river water and some aquatic insect nymphs.

Next week we’ll discuss the fish habitats, take the fish to a better home (aquarium with filters and aerator), and start tying flies!