Lake Michigan, the world’s fifth largest lake, has undergone many changes through the generations. Its current conditions are heavily influenced by the arrival of nonnative Dreissenid mussels known as zebra and quagga mussels. These filter feeders are altering the amount of phosphorus available for phytoplankton throughout the lake, which has an effect all the way up the food chain. Research aboard the Lake Express Ferry is taking the pulse of the lake and informing management decisions.