Looking for Light

Every spring, groups of people gather for a ritual — they wade into tributaries around the Bay, walk until they can no longer see their feet, then measure and record the water clarity. This spring, many wade-ins found the waters amazingly clear. Yet by summer, the waters had grown darker, even darker than the previous year. What is causing this steady decline? Scientists Larry Sanford and Chuck Gallegos suspect that studying sediment may help answer this question.