The water is relatively clear and the bottom is usually sandy or rocky. Rivers and streams Flow rate is an important characteristic of rivers and streams determined by the gradient, or slope, of the land. Organisms must adapt to strong currents in swift flowing rivers and streams. For this reason, slow moving rivers and streams are richer in nutrients and support a greater diversity of life. Scoring criteria Name Earth's seven oceans.
Estuaries serve as breeding sites and nurseries for thousands of marine animal species.
Study the map of the Gulf Stream currents. Describe the affects that this flow of water has on the Atlantic Ocean. In warm weather, the coolest water in a pond or lake is at the bottom, while in cold weather, the water is coolest at the top.