Lakes

Nicholas Viano Martin Lopez

Locations of Lakes

Great Lakes

Lake of the Woods

Great Salt Lake

Lake Okeechobee

Lakes are found all over the world. It is estimated that there is over 360 million lakes on Earth. Here is a map of some of the largest lakes in the US.

Physical Characteristics

Lakes do not have a true definition, but a good description would be a depression in the ground of fair size filled with water. Almost all of the physical characteristics, such as the salinity, depth, temperature, and size of lakes vary greatly in each individual body of water. Most are freshwater, although some do have a very high salt content, such as the extremely salty Dead Sea (really a lake). The depth also ranges from thousands to ten feet. However, they all have the same temperature structure. An upper layer of warmer water, called the epilimnion, is placed on top of a colder layer called the hypolimnion. In between the two is the thermocline, a rapid change of temperature. These layers become less evident during winter.

Zones of Lakes

Other than the temperature layers stated above, lakes are also divided into zones. The first zone, called the littoral zone, is the area of the lake where the floor is just a few inches or feet below the surface. It is where most photosynthesis happens. Next is the limnetic zone. This zone is mainly open water, only as deep as light hits. At the bottom is the bethnic zone, which is basically the lake floor. If a lake is large enough it has a profundal zone, where there is water, but no sunlight. Very little photosynthesis happens there. The profundal zone usually has small amounts of oxygen due to bacteria using it for their means.

Animals and other OrganismsWhat animals live in a lake depends on the lake’s characteristics (which vary from lake to lake), such as salinity & temperature. However, here is a basic list of general animals. Surface: The surface of a lake is its major access point to its surrounding ecosystem. From here, a lake can be a food and water source for thousands of animals, such as ducks, bears, moose, etc. Littoral zone: The littoral zone customarily holds the greatest variety of life. Some examples of forms of organisms that live in this area are fish, amphibians, turtles, snails, & insects. Aquatic plants (hydrophytes) also grow in this area. Limnetic zone: This zone of the lake is mostly controlled by the microbes, such as phytoplankton, algae , and zooplankton. Many other fish also live in this area.Profundal & bethnic zone: Small amount of animals can grow in these areas, due to the lack of producers and the large amount of oxygen-depleting bacteria.

Lake Trout

Phytoplankton

Food Web

Press space for example of a lake food web from Lake Eire, one of the five Great Lakes.

Producers: Algae, First level consumers: Cyclopoids, 2nd level consumer: Yellow perch, tertiary consumers: rainbow trout.

Fun facts• Due to there being no official term for a

lake, there are three candidates for largest ocean: the Caspian Sea, Lake Michigan-Huron, and Lake Superior

• There are lakes on every continent, even subglacial ones on Antarctica, such as Vostok

• The oldest lake in the world is Baikal, located in Siberia; its around 25 million years old. Lake Baikal is also the deepest lake in the world, going down 5,712 feet deep, a little over a mile.

• There are 41 million acres of lakes in the U.S.

• Lake Titicaca is the highest lake in the world, located 12,500 ft above sea level.

Caspian Sea

Lake Baikal

Works cited• “Environmental Science for AP” by Freidland and Relyea • http://library.thinkquest.org/04oct/01590/intro/freshwater.html • http://marine.usgs.gov/fact-sheets/baikal/ • http://nationalatlas.gov/printable/reference.html • http://oceanservice.noaa.gov/education/yos/resource/JetStream/ocean/l

ayers_ocean.htm

• http://rst.gsfc.nasa.gov/Sect17/Sect17_5.html • http://www.glerl.noaa.gov/pubs/brochures/foodweb/LEfoodweb.pdf • http://www.glerl.noaa.gov/pubs/photogallery/Fish/pages/0145.html • http://www.lakescientist.com/learn-about-lakes/how-lakes-differ/where-

are-lakes-2.html

• http://www.lei-extras.com/tips/sonartut/thermoclines.asp • http://www.photolib.noaa.gov/htmls/corp2365.htm • http://www.school.eb.com/eb/article-14220 • http://www.strange-facts.info/interesting-lake-facts • http://www.thewildclassroom.com/biomes/lake.html • http://www.ucmp.berkeley.edu/exhibits/biomes/aquatic.php • http://www.coastwatch.msu.edu/ • http://www.newyorkfishinglakes.com/NY%20Adirondack%20Lakes.jpg