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Animals of the Benthos

98% of marine species are benthic

Rocky shore

Sandy shore

Coral reefs

Hydrothermal vents

Rocky Shores

• mostly dry, covered by water only during storms

high tide zone

• fairly dry, covered only by the highest high tide

middle tide zone

• equally exposed & covered during all high & low tides

low tide zone

• mostly wet

The Rocky Shore

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

• mostly dry, covered by water only during storms
• periwinkle snail
• rock louse

high tide zone

• fairly dry, covered only by the highest high tide
• buckshot barnacles
• limpets

middle tide zone

• equally exposed & covered during all high & low tides
• more variety, competition for space
• goose barnacle, mussel, sea star
• sea anemone, hermit crabs, sea urchins (tidal pools)

low tide zone

• mostly wet
• surf grass, algae, seaweeds
• sea urchins, sea anemones

Sandy Shores

different adaptations protect animals from fluctuations in:

• temperature
• salinity
• water levels (so as not to dry out)

clams, worms, sand stars, amphipods

Clams

Worms, Amphipods, Sand Stars

Feeders on Sandy Shores

• suspension feeding

Worms

• deposit feeding by ingestion

Amphipods

• deposit feeding on surface

Sand stars

• carnivorous feeding on unlucky neighbors

ADDITIONAL MATERIAL

Coral Reefs: Tops in Marine Biodiversity

Coral Reef Zone Tour

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:

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"
(dusk.geo.orst.edu/oceans/tubeworm_bbq.html)

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http://dusk.geo.orst.edu/oceans/intertidal.html