GEOG1710 1st Edition Lecture 21 Outline of Previous Lecture I Glacial Landscapes II Glaciers Move III Glacier Formation IV Glacial Flow V Glacial Erosion Outline of Current Lecture I II III Glaciers Oceans and Coastal Processes Components of Seawater that Matter for Life in the Ocean Current Lecture Glaciers Masses of Ice Flow Pulled by Gravity Primary cause of glacial interglacial cycles o Climate changes Milankovitch cycles Glaciers now o Mass balance accumulation ablation o Over time glaciers have become thinner Retreating Glaciers o Impacts climate sea level freshwater biodiversity o Sea level rises as more glaciers melt o Glacier melt problems mudslides hydroelectric power and social conflict Biodiversity o Invasive species are coming in and increasing productivity Oceans and Coastal Processes o 40 of global population lives 100 km from the coast o Coastal ecosystem are some of the most productive in the world o Coastal populations live better than most but with hazards o Coastal health destroyed degraded These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Where did oceans come from o Asteroids o Mantle rock Components of seawater that matter for life in the ocean o Salinity Concentration of dissolved salts Water universal solvent Average salinity of seawater 35 o parts per thousand Ocean chemistry fairly uniform I Constant reaction and circulation mixing Chloride and sodium are the most abundant in salinity Affected by precipitation and evaporation precipitation evaporation salinity down precipitation evaporation salinity up River discharge upwelling salinity down amazon can decrease salinity in ocean for up to a mile Glacier melt salinity decreases o Temperature Varies horizontally and vertically Vertically I Mixing zone all one temperature II Thermocline temperature decreases rapidly III Deep cold zone all one temperature o Dissolved gases Diffusion Net movement of molecule from an area of greater to an area of lesser concentration Dissolved O2 decreases because oxygen is used by microbes to breakdown organic debris Dissolved CO2 increases because breakdown releases CO2 o Dissolved nutrients Iron and silica limiting nutrients in the ocean Diatoms a type of phytoplankton need silica for their cell walls Phytoplankton need Iron to grow Iron comes from atmosphere dust upwelling island sediments
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