1. Oceans a very large expanse of water
71% of the Earth's surface is covered by the oceans
97% of Earth's water is in the oceans
80% of life on Earth is found in the ocean

2. Estuary
a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea
Most ocean life starts out in the estuaries ("sea's nursey")

3. Brackish water
Water that is a mix of salt and fresh water
This is the water found in estuaries.
Organisms in this water must be able to adapt to extreme conditions.

4. Marine ecosystem
Aquatic ecosystems in saltwater
Ex: salt marshes, intertidal zones (beaches), estuaries, lagoons, mangrove forest, coral reefs, the deep sea, and the sea floor

5. biodiversity
the variety of life in the world or in a particular habitat or ecosystem.

6. upwelling
a process in which deep, cold water rises toward the surface bringing nutrients from the bottom
Upwelling attracts many lifeforms to the surface of the ocean
Upwelling is caused by wind and ocean currents

7. ocean currents
a continuous, directed movement of seawater generated by forces acting upon it

8. photosynthesis
a process used by plants and other organisms to convert light energy, normally from the Sun, into chemical energy
How plants make their own food

9. chemosynthesis
A process used by some organisms to convert chemical energy into food
Many sea floor organisms use this method to make their food.
Different from photosynthesis because the organisms use chemicals instead of sunlight

10. Hydrothermal vent
a fissure/crack in the ocean's floor from which geothermally heated water is released
Many worms and bacteria live near these vents and use chemicals from the vents to make their food through chemosynthesis

11. salinity
the measure of all the salts dissolved in water
1 kg of ocean water = 35 g of salt
All marine ecosystems have a high salinity

12. plankton
a diverse group of organisms that live in the ocean and that cannot swim against a current.
Main source of food for many ocean animals
Bottom of marine food web
2 kinds: phytoplankton (like plant) and zooplankton (like animals)