Intro to Marine Biology Chapter 1 Salinity • • • • • Salinity - total amount of salt dissolved in water. 3.5% “salt” and 96.5% water by mass. 1000g of water evaporate = 35 g of salt We express salinity in parts per thousand (35 p.p.t.) Salinity follows the rule of constant proportions – the proportions of the ions in sea water remain constant to each other. The reason salinity varies is because of the addition or removal of pure water rather than salt. Sodium Chloride 55% 30% Sulfer 8% Magnesium Calcium Potassium Bicarb . 4% 1% 1% .5% Measuring Salinity • Salinity can be measured using a Niskin bottle. What affects surface salinity? • 1. evaporation 2. thawing • 3. precipitation • 5. freezing 4. freshwater run-off Surface Salinity in the World’s Oceans 90 - freezing – high salinity 90 60 60 – Rain – low salinity 30 30 – deserts –high salinity 0 0 – heavy rain = low salinity 30 60 Salinity Summary Temperature Salinity Density Warm Low Low Cold High High Challenger Information • 3 ½ year voyage around the world to collect • • • • • data. Ship was an old warship modified into a research vessel. Left one cannon on to discourage pirates! Discovered so much information that it took 19 years to publish 50 thick volumes 4,700 new species discovered Chief scientist was Charles Wyville Thomson Major importance of the voyage was that the azoic theory (which states that life could not live in the deep ocean) was proved wrong! Major Ocean Basins • Oceans cover 71% of the planet’s surface • Pacific Atlantic Indian Arctic Southern Ocean Sea vs. Gulf • Sea – a body of salt water smaller than an ocean that is more or less land locked. • Gulf – a smaller body of water that is mostly cut off from the larger ocean by land formations. • One of the most biologically important properties of sea water is that sunlight can penetrate it. This is good because photosynthesis can occur. • The ocean reflects blue light best….…other colors are absorbed more than blue. • Things that appear red at the surface look black at depth because there is no red light to reflect off them. Transparency Pressure • Land organisms are under 1 atmosphere of pressure (14.7 pounds per square inch (p.s.i.) • Marine organisms are under much more due to air pressure and water pressure (water weighs more than air). • Gas filled structures like air bladders and lungs are compressed.