Shoreline
The meeting of land and water: wave-washed beaches, rocky edges, fallen wood or a fringe of wetland plants.
From sunlit shorelines to a hidden underwater world
Pause beside a lake and there is far more to notice than open water. Plant beds, rocky shores, drifting plankton and the lake bottom each support a different part of the community.
The meeting of land and water: wave-washed beaches, rocky edges, fallen wood or a fringe of wetland plants.
Where light reaches the bottom, rooted aquatic plants can grow. This littoral zone offers food and shelter.
Drifting plankton and swimming fish occupy the water beyond the plant beds. Light fades with depth.
Sand, stones, wood and soft sediment support bottom-dwelling life. The bottom extends beneath both shallow and deep water.
A shallow lake may have plants across much of its basin. A deep lake can have a dark zone beyond the reach of enough light for plant growth.
Melting blocks of buried glacial ice left depressions that sometimes filled with water. Explore this history in our Kettle Moraine guide.
Extensive plant beds can connect open water with surrounding marsh. Wind may mix the water often.
Warm surface water can sit above cooler deep water in summer, creating different conditions at different depths.
The Great Lakes bring vast open water and exposed shores. Reservoirs are created or enlarged by dams. These are examples, not mutually exclusive categories: a kettle lake can also be deep.
Look at where the leaves grow and whether the plant is attached to the bottom. These simplified diagrams show growth forms, not a fixed sequence of water depths.
Rooted in sediment, with leaves resting on the surface. Example: American White Water-lily.
Most leafy growth stays underwater. Many pondweeds grow this way, although flowers may reach the surface.
Small plants such as duckweed float without rooting in the lake bottom. Wind can gather them along sheltered edges.
Native aquatic plants help hold sediment, shelter young fish and provide food. A healthy lake does not have to be free of vegetation.
Below is a simplified pattern for a deep northern lake that freezes in winter. Temperature changes affect how easily wind can mix its water.
After ice melts, surface and deeper water can become similar in temperature. Wind helps circulate the water. Migrating waterbirds return.
Warm water overlies cooler water, separated by a temperature transition called a thermocline. Plant beds grow and insects emerge.
Cooling surface water makes mixing easier again. Look for migrating birds and changing shoreline vegetation.
Ice covers the surface while liquid water remains below. Activity continues beneath the ice, although many animals slow down.
Shallow lakes, warmer climates and unusual water chemistry can produce different mixing patterns. Cold deep water is not automatically oxygen-rich.
Algae and aquatic plants capture energy from sunlight. Feeding relationships connect that energy to small animals, fish and birds.
Much of a lake food web is too small to see in a landscape view. Phytoplankton are microscopic producers suspended in the water; zooplankton include small drifting animals that feed on them. Other algae grow on rocks and plants. The scene shows the habitat, while the diagram summarizes one feeding pathway.
Native plants and natural shoreline structure provide habitat and help reduce erosion. Fallen wood and plant beds are part of the living lake.
Runoff connects the surrounding watershed to the lake. Excess nutrients can encourage algal blooms. Clean, drain and dry equipment to help prevent moving invasive species between waters.
Choose one shoreline spot and watch quietly. Find a floating leaf, a submerged plant, a basking perch and a patch of open water. Which places have the most activity? Revisit in another season and compare.
Explore each group below. Select a photograph to enlarge it. These field photographs include lakes, ponds, bogs and other wetlands; not every lake supports the same community.
Ducks, diving grebes and shoreline hunters use different parts of a lake.
Look along sheltered edges and sunny basking logs.
Dragonflies and damselflies begin life underwater. Look among shoreline stems for spiders and their webs, too.
Green Frog tadpoles may overwinter in permanent water. Dragonflies also have an aquatic larval stage before emerging as winged adults.
A closer look at water striders, developing frogs, crayfish, and signs of freshwater life. These photos illustrate the subjects; they do not establish which species occur at a particular lake.
Flowers and floating leaves add color and structure to vegetated lake edges.
Look for animals, building materials and feeding signs along quiet shores.
Beaver lodges usually contain substantial sticks and branches packed with mud. Muskrat houses are generally smaller mounds of cattails, grasses and other marsh plants with mud. Both may also use bank dens, and size alone is not reliable.
The lodge photo above is from Crooked Creek Preserve. The gallery also includes a photographer-identified muskrat lodge, plus beavers swimming and resting among shoreline reeds. A lodge provides shelter, while a dam holds back water. Both kinds of home commonly have underwater entrances.
Explore Lake Michigan’s open shoreline and the surrounding landscape.
Compare inland open water, shoreline vegetation and changing seasonal views.
Field photographs: Where’s Wildlife. Diagrams are simplified teaching models.