Low Energy Beaches

Johnny Spears

Schofield Middle School

    Low energy beaches form when sediments carried by tidal creeks are deposited when current energy drops.  These beaches tend to form in an area where there is an inlet.  The area where tidal creeks empty into an inlet area is where these unique features are found. Tidal forces help create the low energy beach.  The sediments carried in the creek water are usually very fine sands and clays, with particles smaller than typical beach sand.  When tidal creek water flow meets water flow from the rising tide in an inlet, the creeks’ water flow is slowed and these fine sediments are deposited. Typically, one end of the beach will be sand, while the other end will be soft mud or clay.  During flood tides, the beach may be somewhat covered with very shallow water, similar to a sandbar.  During the ebb tide, or low tide, the beach is completely exposed.

    As mentioned, the low energy beach is typically barren.  No plants are found except for some uni-cellular algae and the occasional sea lettuce. Spartina grass can be found on the border of the salt marsh and the low energy beach.  Other than that, no vegetation will be seen.

While plant life is virtually non-existent, diversity is the name of the game when it comes to other organisms.  While the "touristy" beaches may have approximately thirty species, a low energy beach may have around three hundred different species.  Many of these creatures have used burrowing as a method of staying alive on a low energy beach.  They do so for a few reasons.  First, burrowing under the sand allows them to stay in one place.  Because they are under ground, water currents do not move them.  Also, burrowing acts as a buffer for extremes of temperature and salinity.  Another important aspect of burrowing is that it protects from predators.

 So, what different types of organisms live under ground?  Right.  There are numerous types of worms on a low energy beach.  But there are also crabs, such as the horseshoe crab that burrow.  How do they eat?  Several ways.  Some, such as several worms and some crabs, are filter feeders.  This means they take in water and filter the nutrients.  Others are direct feeders, which means they can use their mouths to eat the source of nutrition.  Also, there are indirect feeders, which use tentacles to bring food to the mouth.

 Symbiosis is another term used to describing a low energy beach, because there are many creatures living together on a low energy beach.  There are three types of symbiotic relationships.  Commensalism, where two organisms live together and one benefits while the other is not hurt, but does not get a benefit.  One example of commensalism is the commensal crabs that live in the tube of the Parchment Tube worm.   Mutualism, where both parties benefit, and parasitism, where one benefits and the other is harmed.

 Organisms that can be found on a low energy beach and in the shallow waters that border it include: Parchment Tube worms, Spaghetti Worms, Bloodworms, flukes, flatworms, sea squirts, hermit crabs, sea cucumbers, sea spiders, acorn worms, Moon Snail, Sea Slug, Sand Dollar, sea lettuce, Lady Crabs, and Blue Crabs.


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http://rpsec.usca.sc.edu/Classwork/731sp2001/Lesson/Spears/Lowenergy2.html (January 2001)