Figure 6.15 Ponds and lakes. Ponds and lakes are characterized by nonflowing fresh water with areas of water that are too deep for emergent vegetation. (a) Red Rock Lake, Colorado. (b) Lakes contain a variety of zones. The littoral zone exists around the edge of the lake and contains rooted, emergent plants. The limnetic zone consists of the open water in the middle of the lake where the dominant photosynthetic organisms are floating algae. Below the limnetic zone is the profundal zone, which is too deep for sunlight to penetrate enough to permit photosynthesis. The layer of sediments at the bottom of the lake is the benthic zone.

Photo by Lee Wilcox.