Oceans and Coasts

The oceans are the last major part of the global environmental systems for our discussion.  They are the result of plate tectonic processes, the storage for most water for the hydrologic cycle, a buffer for carbon dioxide in the atmosphere, and a sink for weathered material from the continents as they feed the lithosphere at subduction zones.  They are also a giant solar collector and metronome for global weather and climate at scales from waterspouts to glaciations.

Coastal Erosion | Why does Erosion Matter? | Global Sea Level Change

Problems:

1. Consider the problem of coastal erosion.  The USGS Coastal Erosion Home Page is helpful - note long-term, low frequency, and El Nino issues.  The San Mateo, CA El Niño Web page has a selection of detailed maps of the coast of San Mateo county (seaward and south of San Francisco) with abundant information.
   1. What materials are least susceptible to coastal erosion?  What materials are most susceptible? 
   2. What coastline geometries are least susceptible to coastal erosion?   What geometries are most susceptible?  Does that change with time?
   3. What geological activities are important to coastal erosion.   Consider the information from the Coalition to Restore Coastal Louisiana .  Consider Houston, TX and the coast of Alaska as well.
   4. What timescales are important to coastal erosion?  As with river floods, areas of coastal hazard can be identified, but may not be continuously active.   Consider El Niño (above), hurricanes and typhoons , and global change .
2. So why does it matter? 
   1. Consider what might happen if you owned shoreline property on an ocean, a Great Lake, or Flathead Lake.   How might you prepare yourself and your property?  The Natural Hazards Center at the University of Colorado is an international clearinghouse of hazard information.  They have a long Hurricane Damage to Residential Property Report - use the Table of Contents to look for relevant information!
   2. You might build well back from a bluff, but suppose your neighbor, who has inherited a family cabin just up-drift (into the prevailing wind and waves) from you, feels that her house is under attack by the elements and proposes to rip-rap the cliff, build a sand-trapping groinfield, and/or nourish her beach.  What fears might you have, and how might you respond? 
3. Consider the problem of sea level change. Discover Our Earth provides a good simulation of global sea level change. We are going to change the sea level at different increments and determine what effects that change might have on the continents. This program can be a bit slow so be patient!
   1. In an open QUEST (found under the "Tools" --> "Interactive Mapping" menu window, click on the Menu button and set the Map Area to World.
   2. From the Main Menu click on Data Sets and choose Topography from the pull down menu.
   3. Next, select the Show Sea Level Change button and raise sea level by 125 meters using the Change in Sea Level text box.
   4. When you are done be sure to click on both OK buttons in the green Topography window and the tan Data Sets window.
   5. Lastly, click on the Get Map button.
   6. Once your map appears look it carefully. The black lines indicate the new coastline and the grey lines the present day coastline.
   7. Answer the following questions:
      • How does this affect the continents (in general)?
      • Are there any continents (or large islands) that are now joined? Where?
      • Zoom in (anywhere on the map) and re-examine these areas using the Region Selector. What effect could this higher sea level have on communities of organisms living on these continents?
1. Now change your sea level rise to 25 meters. Answer the same questions as above.
   • How does this affect the continents (in general)?
   • Are there continents (or large islands) that are now joined? Where?
   • Zoom in (anywhere on the map) and re-examine these areas using the Region Selector. What effect could this higher sea level have on communities of organisms living on these continents?