5 Water is a polar molecule One end is positively charged and the other is negatively charged
6 The attraction between the negative end of a water molecule and the positive end of another water molecule give rise to a “weak” attractive force known as hydrogen bonds.
7 The Three States of Water Only substance on Earth to naturally exist in three states!Solid water molecules pack close together & locked in fixed three dimensional patternBecomes more dense until about 4°C (get less dense) & expands
11 Water as a SolventDissolve more things than any other natural substance (universal solvent) especially saltsIn water, strong ion charges attract water molecule, water molecules surround the ions and pull them apart (dissociation)
16 Salt CompositionSalinity is the total mass, expressed in grams, of all inorganic substances dissolved in one kilogram of sea water (with additional stipulations, we’ll ignore)Sodium chloride account for 85% of all solids dissolved
17 Salinity Measurement Often measured in parts per thousand Abbreviated ppt or o/ooAverage salinity of the ocean is about 35 o/oo.
18 Red Sea salinity is about 40 ‰ Baltic Sea salinity is about 6 to 8 ‰ Example:1000g of sea water is evaporated. 35g of salts remain behind. Salinity of the sample would be said to be 35 parts per thousandRed Sea salinity is about 40 ‰Baltic Sea salinity is about 6 to 8 ‰
19 Why is Red Sea salinity so high and the Baltic Sea so low?
20 Salinity, Temperature, and Density Get denser as it gets saltier, colder, or both -2° to 30°Ctemps. below zero possible because saltwater freezes a colder temps.Density controlled more by temperature than salinityThere are exceptions therefore salinity & temp need to be measured to determine density
21 Dissolved Gases O2, CO2 and N2 in atmosphere & sea surface 80% of gasses is carbon dioxideGas exchange happens between the surface & atmosphereDissolved gas concentration higher in cold water, lower in warm water
22 Dissolved GasesAmount of oxygen in water is affected by photosynthesis & respirationMost oxygen is released into the atmosphereMore susceptible to oxygen depletion than atmosphere
23 TransparencySunlight can penetrate, but it’s affected by the material suspended in the waterImportant to the photosynthetic organismsRunoff makes coastal waters less transparent than deep blue waters of open ocean
24 Pressure On land, organisms are under 1 atm at sea level Marine organism have the pressure of the atmosphere & waterWith every 10m increase depth another atm is addedSubmarines & housing must be specially engineered to withstand pressure