Kelsey asked if I wanted to be her water-testing buddy today for Lake Pend Oreille Waterkeeper, and I said sure. So we took a boat out to Bottle Bay, where she tested the murkiness of the water and took samples from the depth at which her line disappeared (6.4 meters today, averaged out over multiple dips for maximum accuracy). She took enough to test nitrogen, phosphorus, oxygen, and more, and refrigerated the samples until they could be sent to the lab. During the summer, she and volunteers do this each month from multiple sites around the lake. This way, they can collect data and track water quality levels over time, and alert the authorities if something goes wrong. Like if city beach gets polluted with chemical waste or something.