The global water cycle plays a pivotal role in the transport of sediment and nutrients through the Earth system, as exemplified in this Landsat 7 image of the North Carolina coast. The image was taken on September 23, 1999, one week after Hurricane Floyd hit the continent. Along with soil swept away by the flood waters, the estuaries were filled with human and animal waste, fertilizers, and pesticides. The slow degradation of the deposited organic waste and soil is expected to worsen greatly the eutrophic conditions in the estuaries as oxygen is depleted and as increased nutrient concentrations stimulate algal blooms. The pulse of organic-rich sediments from the flood represents a persistent ecological impact threatening sport and commercial fisheries in this large productive estuary,

Credit: Image:Brian Montgomery, NASA Goddard Space Flight Center. Text: Water Cycle Study Group, A Plan for a New Science Initiative on the Global Water Cycle (2001)