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Coastal and Ocean Habitats

Animals of the Benthos

98% of marine species are benthic

Rocky shore

Sandy shore

Coral reefs

Hydrothermal vents

Rocky Shores

spray zone

high tide zone

middle tide zone

low tide zone

The Rocky Shore

Spray Zone:
periwinkle snails mark boundary between spray & intertidal
rock louse & sea roaches scavenge organic debris

High Tide Zone:
filter-feed seawater / larvae are planktonic
limpets, buckshot barnacles

Middle Tide Zone:
more variety, competition for space
goose barnacles, mussel, sea stars

Low Tide Zone:
dominated more by plants than by animals
surf grass, sea urchins, sea anemones

Shore Crabs roam entire intertidal range
Scavengers feeding on dead animals, seaweed

Animals of the Rocky Shores

spray zone

high tide zone

middle tide zone

low tide zone

Sandy Shores

no fixed surface to attach to

different adaptations protect animals from fluctuations in:

clams, worms, sand stars, amphipods


Worms, Amphipods, Sand Stars

Feeders on Sandy Shores




Sand stars


Coral Reefs: Tops in Marine Biodiversity

Coral Reef Zone Tour

major factors for coral reef growth are: intensity of currents, wave surge, sunlight, and water depth

1 - Beach Zone:
sands derived from erosion of reef limestone

Boxer crab doesn't eat anemones but use them instead as weapons!

2 - Reef Flat:

  • RIGOROUS environment
  • wave action, intense UV radiation, high salinities, warm temps
  • corals are hermatypic (depend on zooxanthellae algae that live in coral poly tissues)

    2 - Reef Flat:
    Sharks & mantas frequent visitors

    3 - Algal Ridge:

    4 - Submarine Terrace

    Increasing coral cover attract fishes that prefer rich coral growth
    Basslett fish (haremic, capable of sex reversal)

    5 - Terrace

    6 - Slope

    7 - Drop Off:
    Soft corals are non-reef building (i.e., no zooxanthellae) and no limestone skeletons
    Secrete toxins to discourage competitors

    The Story of the "Tubeworm Barbecue"

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