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Return to the Hilton Head Island Guide > The mighty sea The Atlantic Ocean is the second largest water body on earth, over 39 million square miles covering about 4,800 miles between South Carolina and Africa, the ocean is the dominant environment on Hilton Head Island. Changing sea levels have in the past both flooded the island and left it high and dry, miles from the prehistoric coast. Hurricanes and tropical storms, born in the Atlantic in summer, and winter's north-easters have sculpted the shoreline. Sea breezes cool the island in summer, and warm it in winter. The ocean is three times as salty by volume as human blood. Winds blow sea salt across the island, affecting the soil and limiting the kinds of plants that can grow. Originally deposited in river sediments, elements in the ocean range from common table salt to gold. They are the basic fertilizer that supports the marine food chain. The living beach The beach on Hilton Head Island is actually many beaches. The sandy shoreline extends 19 miles from Dolphin Head to South Beach. On the ocean side, light gray beach sands are comprised of finely crushed shells, rocks and organic matter, made hard-packed by ocean waves. Along Port Royal and Calibogue Sounds and inlets, the sand is mixed with mud. All beaches are battle zones between the land and sea. Ocean waves wear away forests and dunes, and carry the soils away on currents. At high tide, animals, shells and marine plants wash ashore, forming a noticeable wrack line. Ebbing tides expose long pools named runnels that are refuges for many marine creatures. At dead low tide, the soggy sands are decorated with peculiar holes, tubes and remains for sea life. Some minute species spend their entire existence between sand grains on the beach. Dunes: A windswept landscape Hilton Head Island's dunes are vitally important to nature and man. Dunes form when blowing beach sand collects in the wrack line of beach flotsam. Specialized seaside plants grow in this organic mulch, and trap even more sand, causing dunes to grow taller and wider. These sturdy herbs, vines and grasses come equipped to withstand salt in the wind and soil; desert-like conditions; intense winds and sunlight; and wild fluctuations in temperature. The maritime forest The dense woodlands on Hilton Head Island are influenced heavily by the nearby ocean and salt marshes. Described as maritime (meaning "near the sea"), island hardwood and pine forests encounter a host of environmental challenges: the spray of sea salt; wind damage from ocean storms; eroding, sandy soils; flooding by saltwater from time to time; and a scarcity of freshwater. Trees and shrubs have adapted for survival by developing low-spreading crowns, waxy leaves and needles, and deep root systems. Hilton Head Island's forests have historically been cut for naval stores (turpentine and pitch for ships), agriculture, timber, and resort-residential development. Throughout time, they have cooled and quieted the landscape, and provided diverse wildlife habitats. Valuable freshwater wetlands Did you know that more species of animals are found in swamps than anywhere else on Hilton Head Island Luxury Rental Homes and Beach Houses? Or that mosquitoes cannot live in a swamp's standing waters (acids from leaves kill the larvae)? Freshwater wetlands were formed long ago when the sea level was higher, covering portions of the island. They are remnants of rivers and creeks that were isolated when the sea level began falling 20,000 years ago. You may not see standing water in wetlands all the time. The ecosystems are primarily controlled by high groundwater. Water-loving plants thrive in the dark peat soils that form under saturated conditions. The island's most common freshwater wetlands are: swamp forests (water-loving trees); flatwoods (mostly pines); bay-galls (small trees and dense shrubs); marshes (grasses, rushes, and ferns); and pocosins (bogs). Nature's nursery: The salt marshes Salt marshes are panoramic, wet meadows that grow in estuaries...meeting zones along tidal streams. Here, plants are unique because they live in salt water which floods and drains the marshes at each tide. Species such as smooth cordgrass inhabit the silty pluff mud that is transported seaward by rivers on the mainland. The plants provide food, shelter, and breeding grounds for countless kinds of wildlife and stabilize the fluid soil with their roots. In
autumn, vegetation dies and is decomposed by bacteria. The end
product, called detritus, is a nutrient-rich food source for plankton,
young shrimp, crabs, oysters, clams, fish and more. For over 4,000
years man has harvested seafood from the fertile salt marshes.
The wide grasslands also slow the rush of tides, protecting homes
and forests from erosion. Some dead marsh grass, carried by currents,
even ends up on beaches and helps build sand dunes. |
