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Changing Shorelines & Erosion

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Waves, currents, sand grain sizes, sandbar configurations, water table levels beneath the beach, and other phenomena combine in complex ways to cause very different patterns along the same beach. (Photo by Steve Elgar, Woods Hole Oceanographiuc Institution)

Spend just a few minutes on almost any beach, and the ocean will soon demonstrate a few of the many ways it can transform the narrow strip of shallow water and adjacent land that makes up the shoreline. With every wave, sediments are deposited and withdrawn in complex ways. On a much larger scale, waves, currents, wind, and tides form complex interactions over time to cause erosion along some stretches of shoreline and accretion (growth) in others.

This is just the beginning, however. Add storms, coastal development, and sea level rise to the mix and the fact of our constantly changing shoreline becomes a far more complex and serious issue.

In the U.S. alone, billions of dollars are spent each year in housing, businesses, and recreation, national security, and infrastructure along our dynamic coasts. While beach erosion threatens property near the shoreline, it also profoundly influences natural systems that regulate the exchanges of water, nutrients and organisms with the open ocean. As a result, billions more are used to protect wetlands, maintain beaches and waterways, and rebuild damaged or aging infrastructure.

Salt marshes, estuaries, and mangroves, for example, are a critical component of our coastal ecosystem and are particularly vulnerable to human activity and accelerated sea-level rise. Tidal marshes, the dominant estuarine habitat along the East Coast of the U.S., are ecologically and economically important as they filter and absorb terrestrial nutrients and pollutants, buffer coastlines from waves and storm surges, and provide nurseries for fish and other marine animals.

Linking diverse coastal processes and the impacts of natural and human-induced change requires a systems-oriented, multidisciplinary approach to tackling basic science questions that can have real and lasting impacts. Scientists are working to identify areas subject to both long- and short-term coastline change, and understand the many factors influencing these changes, in order to help individuals and governments make better decisions regarding management of important coastal resources.