Beach Habitats

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Beach Habitats
Lauren Ryan Jenny Herbig Caitlin Golding
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Habitats

• A habitat is the environment in which organisms
  live and interact.
• Beaches
• Home to many different species of plants and
  animals.
• Provide protection for the interior mainland.

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What exactly is a beach?

• Beaches are made of sand and are created by waves
  and currents.
• Covers the area from the low tide line to the
  dunes.
• Sand comes from the erosion of rocks and coral
  reefs.
• Consists of the backshore, berm, and foreshore.
• Backshore- part of the beach that remains dry
  except for unusually high tides and extreme
  storms.
• Berm- Where backshore meets foreshore the
  highest point on the beach where waves deposit
  sediments during high-tide.
• Foreshore- Where the waves constantly interact
  with the sand. The most dynamic region of the
  beach.

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What are beaches made of?

• Sources of Sand
• Coral Reefs
• Glacial sediment deposits
• Rock sediment
• Organism remains
• Shell fragments
• The color of sand depends of the material it is
  made of.

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Classic Beach Structure

• Backed by either dunes or cliffs.
• Followed to seaward by berm, beach flat, trough
  and bar.
• Seasonal onshore/offshore drift of sand

Summer- gradual consistent slopes and larger
beach face
Winter- steeper beach slopes and offshore bars
due to more erosive wave activity
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Dynamic Beaches

• The shape of beaches is constantly changing due
  to
• Longshore drift
• Effects of climate change
• Effects of rising sea level
• Wind
• Waves
• Storms
• Tides
• Salt sprays

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Longshore Drift

• Longshore Current
• The zigzag movement of water along the shore.
• Longshore Drift
• Also known as longshore transport
• Is the movement of sediment in a zigzag fashion
• Caused by the longshore current
• Amount of longshore drift depends on equilibrium
  between erosional and depositional forces
• Moves millions of tons of sediment along the
  coast every year
• Is disrupted by interferences such as jetties and
  other structures
• Erosional vs. Depositional
• Erosional- beach is primarily eroding
• Marked by cliffs and tectonic uplift (Pacific
  Coast)

• Depositonal- beach is primariy being built
• Marked by sand deposits and offshore barrier
  islands (Here!)

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Effects of Climate Change and Sea Level Rise
As the global climate changes, the sea levels
are rising which means that beaches are
disappearing quickly. On flat beaches, a
one foot rise in sea level could result in 200
feet of lost beaches.
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• Waves
• Sand is deposited by waves when the swash is
  stronger than the backwash.
• Sand is eroded by waves when the backwash is
  stronger that the swash.
• In the longshore drift, sand is deposited when it
  reaches an area of low wave energy.
• Wind
• Can carry the sand to new locations.
• Can build or destroy dunes.
• Can sort the sand based on particle size which
  can affect beach slope.
• Storms
• During times of high wave energy (such as
  storms), sand can be carried over the dunes, away
  from the beaches.
• Produces higher wind and wave energy which
  intensifies their effects.

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Keystones Species
Plants- Beachgrasses and sea oats help protect
the beaches from erosion. Also, salt meadow
cordgrass, bitter panic grass, dropseed grass,
sandspur, beach elder, and prickly pear cactus.
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Birds- Seagulls, Least Terms, Black Skimmers,
Willets, Wilsons Plovers, American
Oystercatchers (On Bald Head Island)
Willet
American Oystercatcher
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Invertebrates- Mole Crabs (Sand fleas), mussels,
clams, whelks, periwinkles
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Sea Turtles (make their nests on the beaches)
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Issues with the beach Coastal Development-
disrupts natural processes of the beach Boating-
causes abnormal wave energy Hard Stabilization-
seawalls, jetties, etc. disrupt the longshore
drift of sediments Soft Stabilization- whether or
not to add dredged sand to beaches These things
cause the flow of water to be altered which
changes the habitats and species that live on the
beaches.