Stop 3: Beach Erosion
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eroding cliff Even with the protection of the barrier sand spit (see Coatue across the harbor), the bluff or marine scarp you are standing on is subject to erosion by pounding waves and wind.

The sandy soils move easily. Waves throw cobblestones into the base of the cliff during intense storms. Look for larger stones at the bottom of the bluff.

The onshore prevailing winds shape the trees.

 
tree shaped by wind

Notice how the onshore prevailing winds shape the trees. Wind and water are powerful weathering and erosional agents. When the station's field house was first built, it was much farther from the edge of the cliff than it is today. As the cliff erodes from below, the edge can no longer support its own weight, and the wind-ravaged or water-soaked soils collapse from the near vertical face. The slumped material accumulates at the base of the scarp and temporarily stabilizes the cliff until this loose material is removed by the next storm.

In 1991, the combination of a late season hurricane and a major low pressure system created what is known as the “Perfect Storm”. Waves and wind punched a hole in Coatue that sent 8 foot waves rolling across the harbor and salt marsh, stripping away 4 feet of this bank and flooding the beach house by the salt marsh.

Eroding beach cliff showing bare sandNear the bottom of the bluff, patches of bare sand have been recently exposed by chunks of the cliff that fell away. The unstable habitat is frequently colonized by a variety of plant species including Beach Grass (Ammophila breviligulata) and Seaside Goldenrod (Solidago sempervirens). Beach grass attempts to maintain and expand its position at the bottom of the cliff by growing underground stems that spread across the dune, and by sprouting new clonal shoots at regular intervals.

 
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Back to the start of the trail Harbor and Barrier Spit Stop 3: Beach Erosion The Ospreys Mowing and Succession Stop 6: How Plants Reproduce The Tangled Web of Vines Plants by the Pond Hidden Treasures at the Pond Wrack Lines at the Beach Folger's Salt Marsh

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