NEBRASKAland Magazine is dedicated to outstanding photography and informative writing with an engaging mix of articles and photos highlighting Nebraska’s outdoor activities, parklands, wildlife, history and people.
Issue link: https://mag.outdoornebraska.gov/i/377644
54 NEBRASKAland • OCTOBER 2014 could easily track development of the fragile eggs as they were kept suspended off the gravel substrate in a mesh hatching basket. Mason Barron, a fourth-grader at Disney, thought that the coolest part of having a trout tank was "when they were hatching and wiggling around in their eggs trying to get out." Disney student Chloe Jewell agreed that her favorite part of the experience was "seeing them get out of their shells and swimming with their egg sacs on them." Schmit said, "I cannot believe the interest everyone in the building has in these little critters. People stop in all the time to look at our trout!" Student responsibilities included checking trout daily for any mortalities, testing and keeping records of water quality and maintaining a healthy habitat for their growing fish. Dead eggs or alevin were promptly removed from the aquarium, waste was vacuumed from the gravel bed of the tank and regular water changes were a priority. Jewell's favorite responsibility was using a water siphon to vacuum muck from the gravel, although Barron claimed that was the hardest part because "the water was so cold and I didn't like putting my hands in it." During monitoring, students learned that trout are active fish and require high levels of dissolved oxygen. They also learned that cold water contains more oxygen than warm, making the water chiller a necessary piece of equipment. They learned that in nature, water becomes oxygenated as it churns over rocks and as aquatic plants photosynthesize. In the classroom, an air stone in the tank and the flow of water through the chilling and filtration systems provided sufficient dissolved oxygen. Students also learned about the importance of pH, a measure of water acidity or alkalinity. Values of pH range from 1 to 14, and a neutral pH (7) is ideal for most aquatic animals. pH can drop too low (less than 6) when fish respire, taking up oxygen through their gills and releasing carbon dioxide into the water, a process that produces carbonic acid in a chemical reaction. Too much carbonic acid can lower the pH of the water. Too many trout in a confined space can cause this pH imbalance. Among other complications, acidic water (low pH) damages gills and reduces their ability to extract oxygen from water. High pH can cause problems, too. Alkaline water can strip a fish of its protective slime coat and can also increase the toxicity of other substances. For example, the toxicity of ammonia at a pH of 8 is ten times its toxicity at a pH of 7. Ammonia is continually released into aquarium water as trout process food and create waste. Uneaten food also releases ammonia as it decomposes. McKeone's classroom learned this lesson as they struggled to lower the pH of alkaline tap water used to fill their tank. Even with the addition of pH balancing chemicals, they lost fish as ammonia built up in their system. "Keeping the pH low enough was a challenge, but it also provided a great learning experience for my students. We learned a lot about asking questions, trying out possible solutions and evaluating outcomes," said McKeone. In the aquariums, beneficial bacteria in the filtration system transformed ammonia into nitrite and finally nitrate, an end product that won't harm fish. When too much waste accumulated in the water, students learned that bacteria could be overwhelmed and fall behind in processing the nitrites into nitrates. High nitrite levels can cause a lethal "brown blood disease" in fish, making their blood unable to transport oxygen. Some classrooms learned the nitrite lesson the hard way after losing fish due to overfeeding. In addition to learning a lot about chemistry, sharpening observational skills and keeping meticulous records, students also made important connections between classroom trout habitats and natural habitats. They took interest in the things that affect the water quality of those habitats. Activities such as "What's in the Water," adapted from Aquatic WILD, and "Sum of the Parts," adapted from Project WET, helped students identify sources of aquatic pollution and how pollutants get into a watershed, affecting the water and ultimately the organisms living in those ecosystems. Guided by the Trout in the Classroom curriculum, students also studied rainbow trout life cycles in nature and in hatcheries, aquatic food webs, fish anatomy and Nebraska Rainbow trout fingerlings, averaging about one inch, swim in an aquarium at Patriot Elementary School in Papillion. A student identifies an aquatic sow bug in a water sample collected from the canyon ponds at Schramm Park State Recreation Area in Gretna. PHOTOS BY JEFF KURRUS