e02.   Where is life found in the water?

The ocean is divided into several zones. The coastal zone stretches from the high tide line to the continental shelf.  Usually in between the dunes are wetlands. A wetland is covered, for the greater part of the year, with water.  Wetlands are homes of migratory birds because of the abundance of food there. Also included in the costal zone are estuaries. An estuary is a partially enclosed coastal area at the mouth of a river where fresh and salt water mix.  These can be nurseries for many species of fish and shellfish. The waters are relatively light, warm and nutrient rich. Although it is only 10% of the ocean, the costal zone has 90% of the ocean life. Two hundred-seven nautical miles or 237 statute miles from the shores of a country is an exclusive economic zone.  Other countries cannot fish in this area without permission. Areas beyond this are called the high seas

The ocean zone is divided into three vertical zones. Euphotic zone is the lighted zone and contains the plankton, including phytoplankton that produce oxygen through photosynthesis.  The majority of nekton (free-swimmers) live in this zone. The Bathyal zone contains several varieties of nekton and extends from 207 feet to 1,507 feet.  Light is dimmer and the water is colder.  There are a few bottom dwellers (benthos) at this level. The abyssal zone is shrouded in darkness.  Animals living here make their own light.  They are almost exclusively predators, except for the chemosynthetic organisms that make their own food from the materials given off by the volcanic vents at the bottom of the ocean. (See Figure 2: Ocean Zones)

Whales are considered nekton. Those that bite and chew their food are toothed cetaceans. These include porpoises, sperm whales, and killer whales. Baleen whales are filter feeders. Members of this group are blue whales, gray whales, finback whales and humpback whales.

g07.    How did plate tectonics affect the diversity of ecosystems?

g08.    What are the spheres that make up the earth?

g14.    How can global warming affect sea levels?

g25.    What are the properties of water?

m15.    How are freshwater and marine environments managed?

m34.    How could food production affect the environment?

m41.    How can matter affect the environment?

m49.    Is there legislation regarding water pollution?

m77.    How is water used?

m78.    How do droughts and floods impact populations?

m79.    Where are our water supplies? 

m80.    How can we protect our water supplies?