SEA WATER COMPOSITION I. Salinity: The amount of solid material dissolved in water A. 1. Seawater is composed of Cl, Na, Ca, Mg, S, K. These elements make up 99% of the dissolved materials in the ocean. B. Sources: 1. Add-weathering of rock, volcanoes, melting ice, and runoff 2. Remove- evaporation and formation of ice

Why is the ocean salty? Clip on: why tell me why? explaining-saltwater-video.htm

Areas of Diverse Salinity C. Variations: 1. Open ocean is between 33-38parts per thousand 2. Brackish water has been diluted with fresh water (estuaries and bays) 3. Hyper saline water is typical of inland bodies of water where evaporation is high and circulation low. (Great Salt Lake 28.0%, Dead Sea 33.0%)

Salty lakes hid deep in the Mediterranean Geoscientists have discovered three lakes of extremely salty brine lying in pockets on the floor of the Mediterranean Sea, south west of the island of Crete. Such Lakes could help explain why the Mediterranean is saltier than typical ocean water. The three brine lakes situated more than 3300 meters below the sea surface were discovered in 1993 and 1994 by a team of European scientists conducting the Mediterranean Ridge Fluid Flow project. MEDRIFF Researchers found the lakes using echo sonar which sends down pulses of sound to probe the seafloor. The boundary between the dense brine fluids and normal seawater above creates a flat lake surface that stands out amid rougher surrounding seafloor. The density contrast prevents the brine from mixing easily with the seawater.

Salty lakes hid deep in the Mediterranean The scientists focused attention on a horseshoe-shpaed lake, called Urania which had an average depth of 80 meters. The chloride content in the Urania brine measured about 5X’s that of Mediterranean seawater. The lakes formed when seawater dissolved deposits of salt-rich rocks along the seafloor. These lakes may explain the Mediterranean’s high salinity. Current theories explain the high salinity to high evaporation rates.

How does salinity affect the density of water Complete the Inquiry Activity from pg. 421 Answer the Analyze and Conclude questions in your notebook Homework: pg 427 #1-5 and writing in science

Effects of Salinity D. Effects of Salinity 1. Salinity increases density But is not a significant factor in determining density at depth (temperature is more important)

2. Average ocean water has a salinity of 35g/1000ml. The Range is ppt 3. Salinity increases temperature at which water boils 4. Temperature is inversely proportional to density Decrease in temp=increase in density Increase in temp=decrease in density

5. Buoyancy changes with changes in salinity (higher=more buoyant, lower=less buoyant) due to density

Salinity and Humans Lack of salt in a diet can produce goiters and associated health issues

Salinity Notes Freshwater coming in from rivers and precipitation make lower salinity Salinity is higher in polar regions because salt is left behind when water freezes Density of salt water is greater than fresh water. Fresh water floats on salt water

Temperature Temperature differences are caused by solar radiation at different latitudes As you get closer to the poles the angle of radiation from the sun decreases and radiation is spread over a larger surface area Deep ocean water is the same temperature as the polar region surface waters There are rapid temperature changes in the first kilometer of depth

Density Dependent on salinity and temperature Salinity increases, density increases Temperature increases, density decrease Less dense water remains at the surface In the open ocean, temperature is more important in determining density—Near shore the salinity is more important in density determination Thermocline-Rapid change in decreased temperature Pycnocline-rapid change in density Halocline-rapid change in salinity

Water Molecule Atoms are made up of: Protons, Neutrons, Electrons Molecule: a combination of atoms which are bound together. Three important bond types: Ionic bonds: complete transfer of electrons (for example salts like NaCl) Covalent bonds: sharing of electrons (for example water H 2 O) Metallic bonds (for example Fe)

Water Molecule: Covalent Bonds In water, each hydrogen nucleus is bound to the central oxygen atom by a pair of electrons that are shared between them; chemists call this shared electron pair a covalent chemical bond.

Water Molecule: The Sharing is Not Equal! Each electron from hydrogen atoms is pulled slightly toward the positively charged protons in the nucleus of the oxygen atom, creating a slight positive charge on the exposed “hydrogen end” of the water molecule, and a slight negative charge on the “oxygen end” of the water molecule

Water Molecule: Water is special This property makes each water molecule like a tiny, weak magnet. Magnets have positive and negative “poles,” so water molecules are called “polar.”

Water Molecule: Water is special The fact that water molecules are polar gives rise to some interesting properties: The attractive forces between water molecules allows water to be a liquid rather than a gas at room temperature Water makes a great “solvent.”: Solvent: a solid, liquid or gas that dissolves another solid, liquid or gas, creating a solution. When materials, especially salts, are added to water the molecules are surrounded by water molecules and then easily dissolved Surface tension

Making a water molecule Follow the instruction on the water molecule worksheet Please return the information sheet to me.

Homework 15.1 Answer questions 6-8 on pg 427 Next time: Salinity of Sound water and making a hydrometer lab

Agenda 1. Quiz 2. Complete Hydrometer Lab—turn in 3. Check on salinity of sound lab-complete if evaporated, make sure to compare the information from the salinity lab to the hydrometer reading for colvos passage and Sinclair Inlet 4. Notes on Water special Properties 5. Salinity Worksheet 6. Composition of water Complete worksheets for homework

Water Video clip cycle-fresh-water-vs-salt-water-video.htm biology-of-water-the-hydrologic-cycle-video.htm

Water’s Special Abilities II. Water’s Special Properties A. Heat Transfer 1. Conduction: Transmission of heat from a region of higher temperature to a region of lower temperature. 2. Heat is conducted away from a body 10X faster in water than in air.

B. Water & Light 1. Light Penetration: Only about 20% of sunlight reaches 30 feet in clear water. a. Photosynthesis occurs at depths up to 300 feet in clear water. b. Turbidity: suspended particles affect light penetration. c. Color dissipates at different depths due to the different wavelengths. Color is lost in the order of Red, Orange, Yellow, Violet, Green, and Blue. (florescent colors emit color when stimulated any light of shorter wavelength)

d. Magnification-objects appear 25% larger underwater and often closer due to refraction e. Sound-water is a good conductor of sound due to the density. Sound in seawater travels 4X faster, allowing sound to reach the ears at the same time.

Agenda 1. Quiz 2. Notes on ocean zones and organisms 3. Worksheet: Physical properties of Ocean zones Homework: Section 15.2 #1-5

Layers of the Ocean III. Three Major Zones: Shallow Mixed (Surface), Transition Zone, Deep Zone

A. Shallow Mixed: Surface H2O has a uniform temp and usually extends to 300m. B. Transition Zone: Temperature falls abruptly creating a thermocline, accounts for 18% of all the sea C. Deep Zone: Temperature is a few degrees above freezing and initiates deep ocean currents.

Marine Organisms IV. Types of Organisms: A. Plankton: These organisms are drifters and include phytoplankton and zooplankton. 1. Phytoplankton: Consist mostly of unicellular algae that are photosynthetic. a. Also includes Diatoms (main primary producers) and Dinoflagellates (cause red tide and bioluminescence) 2. Zooplankton: Consist of herbivores grazing on phytoplankton or carnivores eating other zooplankton.

B. Nekton: Includes all animals that are capable of moving independently. 1. Includes all fish, marine mammals & reptiles, squid and shrimp are only inverts. C. Benthos: Organisms that inhabit the bottom of the ocean. 1. Includes all organisms that live on the bottom both in shallow and deep water.

Life Zone Areas V. Three Factors that Affect Distribution of Life: Light Penetration, Distance from Shore and Depth A. Light Penetration: Photic Zone is affected by sediments, plankton, and decaying organic particles. Divided into 2 individual sub-zones 1. Euphotic: Where photosynthesis occurs up to a max depth of 300ft 2. Aphotic: There is not enough light for photosynthesis, but marine animals use this area to avoid predators.

Agenda Quiz Look at Grades Finish notes Study Guide Test next time

Water population videos biology-of-water-population-and-demand-video.htm biology-of-water-tillamook-bay-video.htm

B. Distance from Shore: Subdivided into 3 areas 1. Intertidal-zone affected by tidal change 2. Neritic-part of the continental shelf, accounts for 90% of the World’s fisheries 3. Oceanic- open ocean with fewer organism

C. H2O Depth: Divided into Three major areas 1. Pelagic-open ocean 2. Benthic-bottom areas, both shallow and deep 3. Abyssal-deep ocean with high pressure, cold temperature and little food D. Hydrothermal Vents: Areas of extreme high temperatures, volatile gases, dissolved nutrients, large amounts of mineral precipitants.

Primary Production VI. Primary Productivity: Production of organic compounds from inorganic compounds via photosynthesis or chemosynthesis A. Polar Regions: Solar radiation limits nutrients B. Temperate Regions: Limited by sunlight and nutrient supply cycles C. Tropical Oceans ( a biological desert): is limited because of lack of nutrients because surface waters don’t mix with the nutrient rich deeper waters

Feeding Relationships Trophic Levels: Energy transfer within the food chain. 1. Transfer of energy between levels is very inefficient only about 2% 2. Trophic levels are the feeding stages (algae, zooplankton and herbivores, carnivores, larger carnivores 3. Food chain is a sequence of organisms through which organisms are transferred. 4. Food web is a complex series of feeding relationships with many organisms relying on multiple sources of food.