Life in the Tidal ZoneLife in the Tidal Zone

Survival!Survival!

What is an Estuary?What is an Estuary?An estuary is a semi-enclosed body of water

where freshwater meeting and mixes with saltwater.

An estuary is a semi-enclosed body of water

where freshwater meeting and mixes with saltwater.

Tidal Zone AdaptationTidal Zone AdaptationTidal habitats change daily with the tides, so organisms adapt, or adjust to changing

environmental conditions with special features to:

Tidal habitats change daily with the tides, so organisms adapt, or adjust to changing

environmental conditions with special features to:

Avoid drying out

Protect themselves from predators

Anchor themselves to resist waves

Limpets shape their shells to fit a specific rock: effective seal against

water loss

Tube feet of sea star used for

locomotion and suction/anchorage

Hermit crab hiding in it’s

scavenged shell

Pipefish well camouflaged in eelgrass bed

Types of Tidal HabitatsTypes of Tidal Habitats

Sandy Beaches and Mud Flats Rocky Shores

Different tidal habitats require different adaptations

• Substrate offers lots of nutrients, but little structure for attachment

• Animals bury themselves in mud

• Can also attach to plants

• Little protection from strong waves: animals must anchor

• Complex tide pools possible

• Seaweeds offer protection from drying

Tidal ZonesTidal Zones

Splash Zone

High Tide Zone

Middle Tide Zone

Low Tide Zone

Zones affected daily by changing tidesAdaptations are required to avoid drying out, wave action and predators

Intertidal ZoneHigh, Mid and Low

Tidal habitats are divided into zones based on relative beach location and how often they are covered by water

High on beach Out of water most of the timeSpecies must tolerate salt, heat, cold, and extended dry periods Adaptation example: Amphipods bury themselves to stay moist when the tide is out.

Splash ZoneSplash Zone

Splash Zone Life

Splash Zone Life

Amphipods

Periwinkles

IsopodsBlue-Green

Algae

Lichen

Increased wave action Tide pools provide some protection Adaptations include ability to survive exposure to air without drying out and to survive wave action.Adaptation example: Anemones survive wave action by attaching themselves to the sheltered side of large rocks

High Tide ZoneHigh Tide Zone

High Tide Zone LifeHigh Tide Zone Life

Barnacles

Limpets

Shore Crab

Rockweed

Anemones

Most active region Covered and uncovered twice a day Life must tolerate BOTH submersion in

water and exposure to air Animals move in and out of adjacent zones

to feed Adaptation example: The tube feet of a star

fish allow it to suction on to surfaces

Most active region Covered and uncovered twice a day Life must tolerate BOTH submersion in

water and exposure to air Animals move in and out of adjacent zones

to feed Adaptation example: The tube feet of a star

fish allow it to suction on to surfaces

Middle Tide ZoneMiddle Tide Zone

Middle Tide Zone Life

Middle Tide Zone Life

Wrinkled Whelks Pisaster Sea Stars

Batillaria snailJapanese Eelgrass

Anemones

Most food and shelter Less exposure to air and heat –

under water for a lot of the time Animals unable to exist in other

zones because they will dry out Adaptation example: Tube worms build

hard tubes around their soft bodies for protection

Most food and shelter Less exposure to air and heat –

under water for a lot of the time Animals unable to exist in other

zones because they will dry out Adaptation example: Tube worms build

hard tubes around their soft bodies for protection

Low Tide ZoneLow Tide Zone

Low Tide Zone Life

Low Tide Zone Life

Native Eelgrass

Opalescent Nudibranch(sea slug)

Orange Sea Cucumber

Black Katy Chiton

Tube Worm

Summary Summary Exposure to Water

Most time

Each zone requires unique adaptations for survival

Splash Zone

High Tide Zone

Middle Tide Zone

Low Tide Zone