Ocean Composition Mrs. Streetman
Looking at this salinity map, where do you think the higher salinity areas are? PSU = Practical Salinity Unit
Top 3 Minerals found in oceans: Salinity Salinity – a measure of the amount of dissolved solids in a given amount of liquid. Top 3 Minerals found in oceans: Sodium Chloride (sodium & chlorine) Magnesium Sulfur
Where does all that salt come from? Runoff to Rivers to Oceans Acid rain breaks down rocks dissolved salts and minerals are carried away (runoff) to moving rivers rain and dissolved salts and minerals are deposited from moving rivers to the ocean
Underwater Volcanoes Hydrothermal Vents Result of seawater filtering down in the ocean crust where it meets the magma Minerals in the crust begin to dissolve, adding to the salt content of the ocean Underwater Volcanoes Similar to the process with hydrothermal vents, during an underwater eruption, seawater reacts with hot rock and some minerals are dissolved into the ocean water
What affects salinity? Climate. Salinity Increases Salinity Decreases Coastal or tropical areas and places with hotter, drier climates have a higher salinity Coastal water in cooler, more humid places has a lower salinity. Heat INCREASES the evaporation rate. Evaporation removes water but leaves salts and other dissolved solids behind. More fresh water from streams and rivers run into the ocean in these areas Glaciers melting add freshwater to the oceans Ice forming in the ocean.
What affects salinity? Water Movement Slower moving areas of water develop higher salinity Example: bays, gulfs, seas, open ocean without currents running through them Dead Sea = Very Salty – 337 PPT (33.7%) Baltic Sea = Not Very Salty – 10 PPT (1%)
Salinity, Density, and Temperature Salt makes seawater more dense than freshwater Oceans with a higher salinity are going to have a higher density due to the extra salts Warmer water = lower density Colder water = higher density *Water that is cold and high in salt will sink to the bottom of the ocean floor due to its density*