Presentation on theme: "Ocean Water and Ocean Life"— Presentation transcript:
1 Ocean Water and Ocean Life Chapter 15Ocean Water and Ocean Life
2 The Composition of Seawater Section 15.1The Composition of Seawater
3 The Composition of Seawater Salinity – is the total amount of solid material dissolved in water.Because the proportion of dissolved substances in seawater is such a small number, oceanographers typically express salinity in parts per thousands.Most of the salt in seawater is sodium chloride, common table salt.
4 The Composition of Seawater Sources of Sea SaltChemical weathering of rocks on the continents is one source of elements found in seawater.The second major source of elements found in seawater is from Earth’s interior.Volcanic eruptions emitted water vapor and elements – chlorine, bromine, sulfur and boron.
6 The proportion of dissolved substances in seawater is usually expressed in Parts per hundred.Parts per thousand.Parts per ten thousand.Parts per million.
7 Which of the following is a source of dissolved substances in the ocean? Chemical weathering of rocksEvaporation of water from the seas and oceanExcretions from marine organismsMelting icebergs and sea ice
8 The Composition of Seawater SalinityProcesses Affecting SalinityProcesses that decrease salinity:PrecipitationSea ice meltingIcebergs meltingRunoff from land
9 The Composition of Seawater SalinityProcesses Affecting SalinityProcesses that increase salinity:EvaporationFormation of sea ice
11 Which does NOT decrease salinity? PrecipitationRunoffEvaporationIce melting
12 The Composition of Seawater Ocean Temperature VariationThe ocean’s surface water temperature varies with the amount of solar radiation received, which is primarily a function of latitude.Temperature Variation with DepthThe thermocline is the layer of ocean water between about 300 meters and 1000 meters where there is a rapid change of temperature with depth.The thermocline is a very important structure because it creates a barrier to marine life.
15 The Composition of Seawater Ocean Density VariationDensity is defined as mass per unit volume. It can be thought of as a measure of how heavy something is for its size.Factors Affecting Seawater DensitySeawater density is influenced by two main factors: salinity and temperature.
16 The Composition of Seawater Ocean Density VariationDensity Variation with DepthThe pycnocline is the layer of ocean water between about 300 meters and 1000 meters where there is a rapid change of density with depth.
18 Differing amounts of solar radiation across Earth’s latitude affect the ocean’s Salinity in the thermocline.Density at the surface.Temperature at the surface.Density in the thermocline.
19 Which of the following occurs when the ocean’s salinity increases? Density increasesDensity decreasesTemperature increasesTemperatures decreases
20 Which of the following occurs when temperature decreases? Density decreasesDensity increasesSalinity increasesNothing happens
21 The layer of ocean water between 300 meters and 1000 meters where there is a rapid change in density.ThermoclineTransition zonePycnoclineDeep zone
22 The Composition of Seawater Ocean LayeringOceanographers generally recognize a three-layered structure in most parts of the open ocean: a shallow surface mixed zone, a transition zone, and a deep zone.Does not exist in high latitudes because there is no rapid change in temp or density.Surface ZoneShallow (300 to 450 meters)Zone of mixingSun-warmed zone
23 The Composition of Seawater Ocean Layering2. Transition ZoneBetween surface layer and deep zoneThermocline and pycnocline3. Deep ZoneSunlight never reaches this zone.Temperatures are just a few degrees above freezing.Constant high-density water