IX. Oceans

A. Water salinity 1. In the tropics, because of evaporation, salinity is higher 2. Cold water, glaciers lower salinity a. Water is also more dense

B. Oceanic Zone 1. Oceanic zone is the open ocean 2. Largest and makes up 90% of ocean 3. The currents are caused by wind

4. Photic zone is a max of 100 m deep a. Only producers are phytoplankton b. Produce 1.6 billion tons of carbon per year

c. Base of the food web and support the smallest and largest animals in the world 4. Aphotic zone is comparable to desert in terms of biomass a. Light is the limiting factor b. Dead matter, detritus, feeds these organisms

C. Neritic zone 1. Continents do not just drop off a. Areas of sloping off into ocean called the continental shelf 2. Region between the surface and the shelf is the neritic zone 3. Usually all is in the photic zone so plant life exists on the bottom

4. Only 8% of the ocean but is the most productive 5. Two types: reefs and estuaries 6. Reefs a. Natural structures built by coral b. Kelp reefs are in colder environments c. Breeding ground for animals d. Protect shore from erosion e. Only top layer of reef is alive f. Feed on algae so only in photic g. Chemicals and sediment kill

7. Estuaries a. Areas where salt and freshwater meet b. Salinity depends on time of year c. Very productive

8. Productivity is high because gets a lot of sun a. A lot of minerals because of runoff b. Barrier reefs form because larger reefs remove all the oxygen from water and kill the things closer to land