People can seem a little fishy- and we are, in a biological sense. Even though we can’t live in each other’s worlds, people and fish have common needs to sustain life: clean water and oxygen.
On a crisp November day, senior students from Federal Way High School visited King County’s South Treatment Plant in Renton. They learned about what they have in common with fish, and how to test water quality at the nearby Black River.
As members of their school’s Environmental Club, these students have signed up to become stewards of our natural world in the future. They are currently enrolled in the “Water Crisis” unit, studying challenges to a sustainable clean water future for people across the world. These students are learning how people fit into the global water cycle. 
The students sampled water from the Black River and tested the samples for variables that are important to the health of fish- and people. We know oxygen in air is important for people. In water, dissolved oxygen is critical for fish to remain healthy. Water without enough oxygen kills fish.
The students tested for other factors that affect dissolved oxygen levels. Temperature is important: the cooler the water, the more dissolved oxygen it will have. When rivers and streams run low and have no shade, the water gets warm and oxygen levels go down.
Phosphate in water makes algae thrive, which reduces oxygen. Phosphate can come from natural sources like weathering rocks, but high concentrations of phosphate can get into waterways from lawn fertilizers, agriculture, untreated or partially treated sewage.
The pH of water matters to fish and other water dwellers. Low pH, or acidity, is found in common items like vinegar and lemon juice. If water has a pH as low as vinegar, fish will die. Waterways around the world have lower pH levels caused by acid rain, killing fish and undersea coral reefs in marine waters that sustain our fisheries.
Another impact to dissolved oxygen is called turbidity- the amount of particles in water. If water is cloudy, less light filters through the water. Cloudy water has less dissolved oxygen.
These 12th grade students not only learned how to test for water quality, they learned why water quality matters to fish- as much as air quality matters to people.
These seniors will return to South Plant’s CitySoil farm in the spring where they will learn about the nutrient cycle and how recycling water and organic solids fit into that cycle. Their experience and studies can help these young stewards create a sustainable, balanced future for all of us- people and our fishy counterparts, too.