LAKES AND PONDS ECOSYSTEM

1. LAKES AND PONDS ECOSYSTEM

2. Ponds and Lakes • Range in size from just a few square meters to thousands of square kilometers. • Ponds may be seasonal, lasting just a couple of months (such as sessile pools). • Lakes may exist for hundreds of years or more.

3. Ponds and Lakes • May have limited species diversity • they are often isolated from one another and from other water sources like rivers and oceans. • Most ponds and lakes have outlet streams and both are generally temporary features on the landscape

4. Formation of Lakes and Ponds: • Some of the oldest lakes and ponds (more than three hundred thousand years old) were formed by tectonic activity related to movement of Earth's crust. • EXAMPLE: Lake Baikal in Siberia formed from the movement of tectonic plates and is the largest freshwater lake by volume in the world.

5. Formation of Lakes and Ponds: • Lakes and ponds are formed through a variety of events, including glacial, tectonic, and volcanic activity. • Most lakes and ponds form as a result of glacial processes. • As a glacier retreats, it may leave behind an uneven surface containing hollows that fill with water.

6. Formation of Lakes and Ponds: • Volcanic activity can also lead to lake and pond formation. • EXAMPLE: the collapse of a volcanic cone of Mount Mazama in Oregon led to the formation of Crater Lake, the seventh deepest lake in the world.

7. Lake Baikal Crater Lake , Oregon

8. Ponds and Lakes • Temperature varies seasonally. • During summer the temp. is from 4°C near the bottom to 22°C at the top. • During winter the temp. is from 4° C while the top is 0° C (ice). • during the spring and fall seasons is a mixing of the top and bottom layers resulting in a uniform water temperature of around 4° C.

10. Ponds and Lakes • divided into four different “zones” determined by depth and distance from the shoreline • littoral zone • limnetic zone • profundal zone • Photic zone • Benthic zone

11. Littoral Zone Limnetic Zone Photic Zone Profundal (aphotic) zone Benthic Zone

12. Littoral Zone • warmest since it is shallow and can absorb more of the Sun’s heat • sustains a fairly diverse community • several species of algae (like diatoms) • rooted and floating aquatic plants • grazing snails • Clams • Insects • Crustaceans • Fishes • amphibians

13. Littoral Zone • the egg and larvae stages of some insects are found in this zone • vegetation and animals living in the littoral zone are food for other creatures such as turtles, snakes, and ducks

14. Limnetic Zone • near-surface open water surrounded by the littoral zone • well-lighted (like the littoral zone) and is dominated by plankton, both phytoplankton and zooplankton • plankton are small organisms that play a crucial role in the food chain – most life would not be possible without them • variety of freshwater fish also occupy this zone

15. Profundal Zone • much colder and denser • little light penetrates all the way through the limnetic zone into the profundal zone • Plankton have short life spans—when they die, they fall into the deep-water part of the lake/pond • Animals found are decomposers

16. Photic zone • Primary production in the photic zone is influenced by three major factors • Nutrients • Light- For photosynthesis • Grazing pressure-the rate at which the plants are eaten by herbivores. 

17. Photic zone • Nutrients, especially phosphate and nitrate, are often scarce in the photic zone because they are used up quickly by plants during photosynthesis. • External inputs of nutrients are received through: • Rainfall • Riverflow • Weathering of rocks and soil  • Human activities- sewage dumping.

18. Benthic Zone The area of the bottom.  Many groups and varieties of animals live here, a few are worms, crustaceans, and protozoa.   The life in this zone is mostly made up of bottom dwellers which get most of their food from dead and decaying organisms.   most of the organisms in the benthic zone are scavengers because they depend on dead flesh as their main food source.

19. LAKES ECOSYSTEM

20. Clasification of Lake • Oligotrophic lakes- deep, nutrient-poor lakes in which the phytoplankton is not very productive. • The water is usually clear • Eutrophic lakes-shallow, nutrient-rich lakes with very productive phytoplankton. • The waters are usually murky due to large phytoplankton populations • the large amounts of matter being decomposed may result in oxygen depletion.

21. Lakes Ecosystem A lake is bigger than a pond, and is too deep to support rooted plants except near the shore. Some lakes are big enough for waves to be produced. Lakes may exist for hundreds of years or more. Lakes are often classified as oligotrophic or eutrophic, depending on the amount of organic matter produced.

22. Oligotrophic lake Eutrophic Lake

23. Examples of lakes Taal volcano lake Mitchigan lake Silver lake Lake lamonia Grasmere lake

24. Layers of lake separated by density gradient.

25. 1. Epilimnion  the top-most layer in a thermally stratified lake. It is warmer and typically has a higher pH and dissolved oxygen concentration than the hypolimnion. It typically mixed as a result of surface wind-mixing. Free to exchange dissolved gases (ie O2 and CO2) with the atmosphere. It contains the most phytoplankton.

26. 2. Thermocline (sometimes metalimnion) is a thin but distinct layer in a large body of fluid (e.g. water, such as an ocean or lake, or air, such as an atmosphere). Temperature changes more rapidly with depth than it does in the layers above or below. Thermoclines may be a semi-permanent feature of the body of water in which they occur, or they may form temporarily in response to phenomena such as the radiative heating/cooling of surface water during the day/night. Factors that affect the depth and thickness of a thermocline include seasonal weather variations, latitude, and local environmental conditions, such as tides and currents.

27. 3. Hypolimnion The hypolimnion is the dense, bottom layer of water in a thermally-stratified lake. It is the layer that lies below the thermocline. Typically the hypolimnion is the coldest layer of a lake in summer, and the warmest layer during winter. Being at depth, it is isolated from surface wind-mixing during summer, and usually receives insufficient irradiance (light) for photosynthesis to occur. In deep, temperate lakes, the bottom-most waters of the hypolimnion are typically close to 4°C throughout the year. The hypolimnion may be much warmer in lakes at warmer latitudes.

28. BLUE LAKE

29. Mono Lake Dal Lake Okanagan Lake Lake Titicaca

32. Lac Pavin in France is a meromictic crater lake

33. Lake Hoare

34. Freshwater: biological communities of lakes

35. PONDS ECOSYSTEM

36. Ponds Ecosystem A pond is a small, shallow body of fresh, standing water in which relatively calmwater and extensive plant growth. The amount of dissolved oxygen may vary greatly during a day. In really cold places, the entire pond can freeze solid. Water temperature is fairly even from top to bottom and changes with air temperature.

37. Types of ponds Cypress Ponds Bog Ponds Meadow-Stream Ponds Mountain Ponds Farm Ponds

38. 1. Cypress Ponds Commonly found in the central or lower Mississippi Basin Waters are described as being brownish in color Many dry out during parts of the year. Willows, bay trees mixed with cypress trees, grow along the shore and are often found out in the waters.

39. Cypress Pond on the Conecuh River near River Falls, Alabama

40. 2. Bog Ponds Bog Ponds are often found in the moist temperature regions of North America. Water is highly acidic and often muddy. Alders and cedar trees dominate Floating-leaf plants usually cover the surface.

42. 3. Meadow-Stream Ponds Where streams widen and the speeds of its currents slow down tremendously. The shallow part of the pond usually has an abundance of pondweeds, cattails, stoneworts and other plants. Floating leafy plants on the surface of the water, such as lilies and water shields.

44. 4. Mountain Ponds Formed by glaciers Bottoms range from being rocky, graveled or muddy. Most of the time Mountain Ponds have ice in them and they usually dry up at some point during the summer. Sedges grow along its margins. In spite of the pond’s short summer season, a variety of animals and plants live in these icy waters.

46. 5. Farm Ponds Man-made ponds built to help keep the farmlands fertile. It should also have a spillway to control the water level. Farm ponds usually become abundant in fish, and are usually good waters for swimming and boating. They should also fill from seepage, not from another stream which would fill the basin of the pond with silt and eventually kill the pond.

48. Examples of ponds

49. VEGETATION IN LAKES AND PONDS ECOSYSTEM

50. Animals in Lakes and Ponds Bitterling Green and Gold Bell Frog Bullfrog Common Carp Largemouth Bass  Great Crested Grebe Great White Pelican Zambesi Softshell Platypus Lake Trout