Sea Level Change - over the past 2 million years sea levels have varied from 20 feet higher to 400 feet lower than present.

Causes of Sea Level Change

• Major Factor: Role of Ice
  - formation and melting of ice sheets is the largest factor in sea level change - this is controlled by climatic variation
• Minor Factors include: tectonic alteration of ocean basins, changes in volcanism
• Milankovitch Cycles- Changes in the earth's orbit, major cause of ice ages

Future Coast Lines - sea level is currently rising because of global warming - low lying areas will be increasingly flooded

Human Intervention designed to prevent or slow shoreline erosion:

i) Groins - walls perpendicular to the shore - trap sand on the updrift side
ii) Sea Walls- parallel to the shore - often cause increased erosion
iii) Beach Replenishment- best beach preservation strategy - import sand of the same size as the beach

Barrier Islands - large migrating sand bars - often inhabited

Coastal Cells - connection of rivers, longshore drift and canyons

Rip Currents - powerful local currents of water returning to surf zone

Estuaries - salt wedge estuary, well mixed estuary, partially mixed estuary, fjord estuary, reverse estuary

Ocean Engineering Developments

• ROV - Remotely Operated Vehicles
• AUV - Autonomous Underwater Vehicles