These natural wrack lines furnished the organic material to newly formed (or newly migrated) barrier islands that was necessary to nourish the start of growth of vegetation on islands. Both the driftwood and the saltmarsh straw came from the sound behind the island, carried out to sea, through the inlets by tides and winds. The major constituents were driftwood, seaweed and especially salt marsh (Spartina) straw. In this age of souvenir caps the logos reveal cap origins not unlike the way heavy minerals in beach sands reveal their source rocks.īefore human beings began contributing substantially to the content of wrack lines, the debris consisted primarily of organic material. On some islands baseball caps, blown off the heads of passengers in speeding skiffs, are surprisingly abundant. Each beach seems to have a different type of trash depending on whether the main villains are commercial fishing vessels, naval vessels, smaller recreational fishing boats or the mighty freighters that ply the Gulf Stream and beyond. Containers of alcoholic drinks seem to prevail followed in abundance by paint, soap and various chemical containers. The human-made flotsam and jetsam in drift lines is in significant part derived from offshore. A walk into the dunes, into the center of the island, far from the shoreline, may reveal old lines left from significant flooding as long ago as 10 or 20 years. The next line, a foot or two higher, is from the last Spring or full-moon tide, and the highest wrack line is from the last big storm. The lowest line of debris marks the normal high-tide line. On some beaches, especially the undisturbed ones, as many as three separate wrack lines can sometimes be seen. The positions of the drift lines are a good indicator of the high tide or storm wave limit. Much of the extraneous material on beaches is found in drift lines (wrack lines) which are the linear piles of natural and man-made objects that are left behind at the uppermost limit of the wave swash (Figure 5.2). A wrack of Spartina (salt marsh) straw adn wood from destryed decks and dune walkovers in South Nags Head during a nor’ easter in 1998 The Comfort Inn at Whalebone Junction is in the background.
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