Just a few decades ago, the Hudson River was so badly polluted that readings taken during the summer often showed no oxygen in the water. Without oxygen, a river's ecology literally suffocates, and indeed, the Hudson was just barely capable of supporting life.
Fortunately, the Hudson has greatly recovered from those days, to which the healthy dissolved oxygen levels we've found on our Voyages of Discovery can attest.
Students perform titration tests to measure dissolved oxygen levels. A titration test is a complex and delicate chemical procedure that uses changes in color to indicate the level of oxygen present in a given water sample.
