Ponds and LakesPonds and Lakes

What is the difference between What is the difference between them?them?

LAKESLAKES

• A lake is usually defined as a body of water large enough to have at least one wind-swept beach.

• A lake is too deep for rooted plants to grow except near the shore. The deepest lake is Lake Superior, one of the five Great Lakes in the northeastern part of the United States.

• Lakes are generally composed of fresh water; although one exception is Salt Lake in Salt Lake City, Utah.

• Great Salt Lake is endorheic (has no outlet besides evaporation) and has very high salinity, far saltier than sea water. The Jordan, Weber, and Bear rivers deposit around 1.1 million tons of minerals in the lake each year.

• Often lakes are attached to each other in a chain-like pattern and flow in and out of each other like the Chain-O-Lakes in Wisconsin.

• Many times, lakes are the source for some rivers.

PONDSPONDS

• Ponds usually are not large enough for winds to blow across the water and create waves to wash away the plants that may be trying to take root.

• See Lynxfield Pond in Chichester, NH in the next frame.

• Roots can grow throughout the pond because it is 12-15 feet deep near the center.

• The sun can warm up the pond top to bottom, so roots and plants can grow.

• Light reaches the bottom of the pond.

What is a Reservoir?What is a Reservoir?

• A reservoir is a lake-like area where water is kept until it is needed. 

• Building a man-made reservoir is a big job.  It takes from 5-8 years to plan, three years to build, and costs lots of money, too.

• Reservoirs are owned by a water company or government authority.

• See Hoops Reservoir in the next frame.

What is Lake or Pond What is Lake or Pond TurnoverTurnover??

• Turnover is the gentle, natural mixing of pond and lake waters. It is caused by changing temperatures in surface waters.

• During fall turnover and spring turnover, winds mix lake water from surface to bottom, causing a uniform temperature and an even distribution of nutrients throughout the various depths.

What is Eutrophication?What is Eutrophication?

• means an increase in chemical nutrients -- typically compounds containing nitrogen or phosphorus -- in an ecosystem.

• excessive plant growth and decay further impacts causing lack of oxygen and severe reductions in water quality and in reduced fish and other animal populations.

• See the next frame showing euthrophication in the Gulf of Mexico off the coast of Florida.

Video ClipsVideo Clips

• http://www.youtube.com/watch?v=e9agsHEAI2s

• http://www.youtube.com/watch?v=YNumiEa-VNo

• http://www.youtube.com/watch?v=VXNnqTimBOQ

The EndThe End