What It's All About
There are two main types of aquatic ecosystems. One is freshwater and the other is saltwater. Freshwater systems include rivers, streams, wetlands, ponds, and lakes. Saltwater systems, also know as marine ecosystems, are the large bodies of water surrounding the continents, oceans, and seas. Different types of fish, animals, and plants live in each type of water.
Sweetwater Seas
Fresh water makes up only 3 percent of the Earth's water, but it is home to 41 percent of the world's fish species. It also supplies all human drinking water. The Great Lakes — Superior, Michigan, Huron, Erie, and Ontario — and their connecting channels form the largest surface freshwater system on Earth. They are also known as the Sweetwater Seas; they're so large, they're like seas, only they're not salty. Some interesting facts:
The Great Lakes contain 90 percent of the freshwater supply in the United States, equaling approximately 6 quadrillion gallons of water. They provide drinking water to 30 million people.
If you stood on the moon, you could see the lakes.
If you dumped out the lakes and spread them evenly across the fortyeight contiguous states, the water would be about 9.5 feet deep.
These lakes are big, big, big — but not so big that people cannot affect them. Despite their size, their ecosystem is just as fragile as any other, and all the species that live in this vast underwater world are suffering from pollution, invasive species of fish, and the diversion of water.
While Lake Superior is the largest freshwater lake as far as surface area goes, Lake Baikal in Russia is the deepest freshwater lake. More than 300 streams feed it, and it is home to the world's only freshwater seal, the Baikal seal.
Make your voices heard and let polluters know you want them to protect water. There is nothing like a letter from a kid to sensitize individuals and companies to environmental issues — and a drawing with the letter really helps. Investigate the companies near water areas in your community. Send them letters to ask them what they are doing to help protect the water in your neighborhood. For an easily printable handout for upper-elementary students, go to www.kidsforsavingearth.org and click on “Water.” Check out “Wonderful World of Water.”
A Salty Underwater Home
Covering three-quarters of the Earth's surface, oceans are as diverse as they are large. These saltwater havens are home to the tiniest plankton and the largest creature on Earth, the blue whale. The oceans are full of bizarre and fascinating creatures that have adapted to extreme and unusual conditions, but people still know very little about them.
The Monterey Bay Aquarium makes a memorable field trip if you live in California. For those of you who don't, visiting the website is the next best thing to visiting in person. Visit www.mbayaq.org. There are great activities under the “Teachers” tab, and you can use their webcams to see what's happening at the aquarium.
Create classroom “Fish Stories” books. To understand the importance of the oceans, it a good idea to learn a bit about the fish that call this habitat home. You can create a list of animals of the sea and have the kids draw names from a hat. The list can include pictures of these animals as well. You can go to www.enchantedlearning.com/coloring/oceanlife.shtml to help you find marine life and drawings for your list.
Assign students activities to research and write about. You can show the diversity within one animal family by assigning each student a different type of species. For example, there are more than 375 known species of sharks. Many people think sharks are scary, cranky carnivores, but not all of them are. Sharks come in all sizes, from the massive whale shark to the tiny dwarf shark; they have babies in all different ways; some like deep waters and some like shallow; and some eat fish and some eat plankton.
Have each student draw a variety of different pictures of the fish for their book, maybe showing development from baby to adult. Include the name of the fish, habitat information, food, what pollution dangers the fish faces, and finally one action that can be taken to help protect the fish. Bind the book pages together and pass the book around the class to take turns reading fish stories. Take turns sending it home to read with parents.
