1. LAKE BIOME
Presented By:
Jason Palonis

2. What is a Lake?
Lakes are enclosed basins which can trap standing water
Another definition is a body of fresh or salt water of considerable size that is surrounded by land.
On Earth a body of water is considered a lake when it is inland, not part of the ocean, and is larger and deeper than a pond.

3. Where are Lakes Found? Lakes are located through out the world
The majority of lakes on Earth are fresh water, and most lie in the Northern Hemisphere at higher latitudes.
More than 60 percent of the world's lakes are in Canada.

4. Most Notable Lakes
The largest lake by surface area: 117,350 km² is Lake Michigan-Huron.
The deepest lake is Lake Baikal in Siberia, with a bottom at 1,637 m (approx 1 mile).
The longest lake is Lake Tanganyika, with a length of about 660 km (410 miles).
The world's oldest lake is Lake Baikal (25 million years old) , followed by Lake Tanganyika (Tanzania).
The world's highest lake is the crater lake of Ojos del Salado, at 6,390 meters (20,965 ft).
The world's lowest lake is the Dead Sea, bordering Israel and Jordan at 418 m (1,371 ft) below sea level. It is also one of the lakes with highest salt concentration.

5. Structure & Stratification
Epilimnion-
Water is warmer and typically has a higher pH and dissolved oxygen concentration than the hypolimnion.
Freezes in winter.
Metalimnion- (thermo cline)
Temperature & oxygen changes rapidly with depth
Hypolimnion.
Typically the coldest layer of a lake in summer, and the warmest layer during winter.
4 °C throughout the year

6. Zonation
The Littoral zone is the near shore area where sunlight penetrates all the way to the sediment and allows aquatic plants (macrophytes) to grow. In most lakes, the sunlit zone is called the photic zone and occurs within the epilimnion.
The Limnetic zone is the open water area where light does not generally penetrate all the way to the bottom.
The bottom sediment, known as the Benthic zone, has a surface layer abundant with organisms.

7. Types of Lake Organisms
Note which zone each is found in
Macrophytes: large leafy plants
Plankton: Suspended small organisms controlled by currents
Benthos: Bottom dwellers
Nekton: Larger, mobile organisms

8. Typical Macrophytes Littoral Zone
submersed
Floating leaved
Emergent

9. Typical Zooplankton Limnetic Zonemm
Rotifer:grazer on phytoplankton
Copepod: grazer on phytoplankton
Water flea: grazer on phytoplankton

10. Typical Benthos Benthic Zone
Midge larvae
bivalves
Dragonfly nymph

11. Typical Nekton Go where they please..
Bass: a piscivore (fish eater)
Bluegill: a planktivore and benthivore
Catfish: a detritivore (scavenger)

12. Human Influences Usually a negative influence on lake ecology.
Introduction of nutrients and toxic chemicals.
Industry
Farming
Introduction of non native flora and fauna to lake ecosystems.
Central American Water Hyacinth
Eurasian Zebra Mussel

13. The End