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OUR OCEAN PLANET
OUR OCEAN PLANET
SECTION 4 – COASTS
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REVISION HISTORY
Date
Version
Revised By
Description
Aug 25, 2010
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VL
Original
4. COASTS
4. COASTS
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4. COASTS
PHYSICAL COASTLINE
Coasts are areas along a landmass where land meets the sea.
Major changes and fluctuations in sea levels have expanded and
contracted continental shelves and have helped shape coastlines
over long periods of time. Ocean processes such as winds, waves,
currents and tides have also played an important role in shaping the
coastline and providing sediments for beaches.
These sediments can come from fragments of rock or skeletal
particles or be chemical precipitates from water.
Many of the sedimentary rocks along the coastline were born in the
ocean. Over millions of years, dead marine organisms have left
their skeletons behind which have accumulated and created vast
volumes of siliceous and carbonate sediments.
Sediments along the shoreline can also be transported to the coast
by rivers. For example, the erosion of coastal mountains by wind,
rain and water provides particles to coastlines where they are
redistributed by waves along the continental shelf.
A coast can be one of three types based on its sediment:
1. Rocky
2. Sandy – beaches and sand
3. Muddy – muddy estuaries and marshes
Ocean Literacy Principle 2(a)
Many earth materials and
geochemical cycles originate in the
ocean. Many of the sedimentary
rocks now exposed on land were
formed in the ocean. Ocean life laid
down the vast volume of siliceous
and carbonate rocks.
Ocean Literacy Principle 2(b)
Sea level changes over time have
expanded and contracted
continental shelves, created and
destroyed inland seas, and shaped
the surface of land.
Ocean Literacy Principle 2(c)
Erosion—the wearing away of rock,
soil and other biotic and abiotic
earth materials—occurs in coastal
areas as wind, waves, and currents
in rivers and the ocean move
sediments.
4. COASTS
LIVING ALONG COASTS
The coast is one of the most difficult habitats in which to live. Tides,
waves and predators cause vertical zonation patterns along the
shore, influencing the distribution and diversity of organisms. Some
of the challenges organisms face include:
1. Winds
2. Waves
3. Currents
4. Temperature changes
5. Salinity changes
6. Drying out as the tide recedes
Different life inhabits rocky coasts, sandy coasts and estuaries, with
estuaries providing important and productive nursery areas for many
marine and aquatic species. Each type of coast presents a different
set of challenges to the animals and plants that lives there.
REFERENCES & FURTHER READING
http://walrus.wr.usgs.gov/pubinfo/jump.html - erosion
http://facstaff.gpc.edu/~pgore/Earth&Space/erosion.html
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Ocean Literacy Principle 2(e)
Tectonic activity, sea level changes,
and force of waves influence the
physical structure and landforms of
the coast.
4.1 ROCKY COASTS
4.1 ROCKY COASTS
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4.1 ROCKY COASTS
4.1 ROCKY COASTS
4.1.1 Sea Cliffs
SEA CLIFFS
In the North Atlantic, steep rocky cliffs form an abrupt transition
between land and sea. Their steep sides make them highly
inaccessible but birds, such as puffins, gannets, guillemots and
razorbills may live there. A variety of small salt-tolerant plants, such
as sea campion and thrift, may also cling to the cliff.
The area where spray from breaking waves is thrown above the high
tide level is an area called the “splash zone”. Animals that live here
have special adaptations to help them stay attached to the rocks.
Marine invertebrates such as mussels hold on with a “beard” of
strong protein fibers produced by a special gland in their feet while
barnacles secrete a type of glue, which is stronger than most
commercial products, to help them adhere to the rock.
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4.1 ROCKY COASTS
ROCKY COASTLINES
Creatures exposed on rocky shores can potentially dry out at low
tide. To prevent this, many tidal animals have developed a
protective shell. For example, mussels and barnacles have two
shells that they can close tightly to hold in moisture. Animals with a
single shell, such as limpets, clamp themselves down onto a rock to
get a watertight seal. Some invertebrates, such as crabs, will hide
under damp rocks or in tide pools until the tide comes in again.
Other animals and plants are highly tolerant of desiccation (drying
out) and can be re-hydrated when the tide returns. For example,
molluscs, such as chitons (pronounced “ki-tons”), can lose 75% of
the water in their body tissues while certain seaweeds can lose up to
90% and still survive.
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4.1 ROCKY COASTS
Marine mammals, such as seals and walruses, are also found on
North and South Atlantic rocky beaches. The beaches are breeding
areas for these mammals. For example, the North Atlantic grey
seal, which breeds on isolated beaches on the British coast, has
only recently turned to breeding on land. This is known because the
pups are white – which is perfect camouflage if you are born on ice
but less effective on dark coloured rock. The move from ice to land
is probably the grey seal’s attempt to extend its range further south.
REFERENCES & FURTHER READING
Byatt, Andrew, Fothergill, Alastair and Holmes, Martha, The Blue
Planet: Seas of Life, Chapter 2, DK Publishing Inc., (2001), ISBN 07894-8265-7
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4.1 ROCKY COASTS
4.1.2 Tidal Pools
INTERTIDAL ZONE
Along rocky shores, the tide rises and falls creating a strip of land
between high and low tide called the “intertidal zone”. This zone is
covered by water during high tide and exposed to the air when the
tide is low. As the tide recedes, shallow pools of water called “tide
pools” are left behind in the cracks and crevices of the rocky shore.
TIDE POOLS
Tides pools often contain a variety of plant and animal life including
seaweeds such as sea lettuce, rockweed, and Irish moss. Most of
the animals found in a tide pool are invertebrates (animals without
backbones) although fish can also be found. Typical invertebrates
found in tide pools include:
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4.1 ROCKY COASTS
Cnidarians
• Sea anemones
• True jellyfish
Crustaceans
• Shrimps
• Crabs
• Lobsters
• Barnacles
Molluscs
• Clams
• Periwinkles
• Limpets
• Mussels
• Scallops
• Octopus
Echinoderms
• Sea stars (or starfish)
• Sea urchins
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Interesting!
Scientists are trying to get away
from using the word “starfish” and
using “sea star” instead. This is
because the animal is not a fish but
an Echinoderm and an invertebrate.
4.1 ROCKY COASTS
Plants and animals living in tide pools are well-adapted to the harsh
conditions of this environment since they must be able to withstand
the drying effects of low tide, re-hydration when the tide
subsequently comes back in, crashing waves and rapid changes in
temperature and salinity.
Animals and plants live in different areas of the rocky shore
according to their needs. Animals that must always be wet, like sea
anemones and sea urchins, live below the low tide mark. Others,
like periwinkles and mussels, hold water in their shells and can live
in areas uncovered at low tide. Crabs and sea stars move to follow
the tide or hide among seaweeds and under rocks to stay wet.
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Interesting!
“Shellfish” is a general term for
aquatic organisms with a shell. It
refers to crustaceans (crabs,
shrimp, lobsters, etc) and molluscs
(clams, oysters, mussels, etc).
Scientists are trying to get away
from the term but it is still commonly
used. For example, people say that
they are allergic to shellfish
generally meaning they get sick if
they eat clams or oysters.
4.1 ROCKY COASTS
4.1.3 Rocky Coast Life
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4.1 ROCKY COASTS
PUFFIN
The Atlantic or common puffin (Fratercula arctica) is a seabird
species in the auk family. It is the only puffin species found in the
Atlantic Ocean and is a pelagic (open ocean) bird that primarily
feeds on fish but will also eat other animals such as crustaceans and
squid. Its most obvious characteristic is its brightly coloured beak
which is seen during the breeding seasons.
The curious
appearance of the bird, with its large, colourful bill and its striking
piebald plumage, has given rise to nicknames such as “sea parrot”
and "clown of the ocean".
WALRUS
Walruses (Odobenus rosmarus) are large marine mammals that are
found in the north Atlantic & Pacific Oceans. Walruses are
immediately recognizable by their prominent tusks, whiskers and
great bulk. Adult Pacific males can weigh 2,000 kg (4,400 lbs) and
are exceeded in size only by elephant seals among pinnipeds
(marine mammals with flippers such as true seals, eared seals and
walruses). Walruses reside near shallow oceanic shelves and
spend a significant proportion of their lives on sea ice in pursuit of
their preferred diet of benthic bivalve molluscs. They are relatively
long-lived, social animals and are considered a keystone species in
Arctic marine ecosystems.
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4.1 ROCKY COASTS
SEA ANEMONE
Sea anemones are simple animals (cnidarians) that are often
attached to the sea bottom. Sea anemones have cylindrical bodies
that are surrounded by upward-facing tentacles. The tentacles have
stinging cells on them which kill prey and move the food into a sea
anemone’s mouth. The mouth leads into the body cavity which
digests the food. A continuous current of water through the mouth
circulates through the body cavity and removes waste.
Sea
anemones are found in cold and warm waters. Many are colourful,
and large species can be 1 m (3 ft) in diameter.
SEA STAR
Sea stars (or starfish) are soft-bodied marine animals with five arms.
Sea stars are echinoderms, a large group of invertebrates which
include sea urchins, sand dollars, sea cucumbers and brittle stars.
Sea stars typically live in the middle of a tidal range and can survive
short periods of exposure to air as the tide retreats.
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4.1 ROCKY COASTS
SEA URCHIN
Sea urchins are echinoderms.
They are round, spiny and
herbivorous invertebrates that graze on algae and detritus from
grass beds and rocky areas. Many sea urchins have long, sharp
spines on their backs, which protect them from predators such as
fish, crabs, moray eels and sea otters. However, their underside is
often spineless and they are vulnerable to attack from that side if the
predator can turn the sea urchin over.
LIMPET
Limpets are marine molluscs with flattened, cone-shaped shells.
They live throughout the intertidal zone on the rocky coasts of most
oceans. A hard shell protects limpets from drying out and against
predators. At high tide, limpets search for seaweed on rocks. After
feeding, limpets always return to the same spot.
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4.1 ROCKY COASTS
PERIWINKLE
The common periwinkle is a species of small edible sea snail and is
a type of marine mollusc.
QUAHOG
The quahog or hard clam (Mercenaria mercenaria) is a bivalve
mollusc. It is native to the eastern shores of North America from
Prince Edward Island to the Yucatan Peninsula and is one of many
unrelated bivalves generically referred to as “clams”.
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4.1 ROCKY COASTS
SCALLOP
A scallop is a bivalve mollusc related to clams and oysters. The
edges of their shells are serrated, which gives rise to the general
term “scalloped edges”. Scallops are found in all of the world's
oceans. Many scallops are highly prized as a food source. Some
scallops are valued for their brightly coloured shells.
SEA LETTUCE
Sea Lettuce (Ulva lactuca) is a green alga, usually with a broad, thin,
almost transparent single frond from a small holdfast (outgrowths at
the base of an alga which hold it to the substrate). The thalus (leaf)
may be divided to form ruffled branches. The frond may grow to 15
cm (6 in) long and 10 cm (4 in) across. It common name, sea
lettuce, describes it well.
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4.1 ROCKY COASTS
BARNACLES
A barnacle is a crustacean and is distantly related to crabs and
lobsters. When an appropriate place is found, the barnacle larva
cements itself headfirst to the surface and then undergoes
metamorphosis into a juvenile barnacle. Typical barnacles develop
six hard armoured plates to surround and protect their bodies. For
the rest of their lives they are cemented to the substrate, using their
feathery legs (called “cirri”) to capture plankton and gametes when
spawning. Barnacles are usually found in the intertidal zone.
CRAB
Crabs are crustaceans with ten legs (decapods), eyes on short
stalks, pincers and a broad flattened carapace with a small abdomen
folded under the thorax. True crabs have five pairs of legs, the first
of which are modified into a pair of feeding claws and are not used
for locomotion. Crabs are omnivores. Some feed primarily on algae
while others will eat many types of food, including molluscs, worms,
other crustaceans, fungi, bacteria and detritus. For many crabs, a
mixed diet of plant and animal matter results in the fastest growth.
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4.1 ROCKY COASTS
SHRIMP
True shrimp are decapod (ten legged) crustaceans with semitransparent bodies that are flattened from side to side. They have a
flexible abdomen which ends in a fan-shaped tail, and swim
backwards by flexing their abdomen and tail. Together with prawns,
they are widely caught and farmed for human consumption. Shrimp
occur in all oceans, both in shallow and deep water, as well as in
freshwater lakes and streams.
LOBSTER
Lobsters are crustaceans that live in salt and fresh water. Lobsters
live on the Atlantic and Pacific coasts. A lobster has a hard shell
that can be blue or even yellow but turns bright red when cooked.
Lobsters are actually a large crayfish. Two common types of lobster
are the American (Maine) lobster (Homarus americanus) which has
two big meat-filled claws and the spiny lobster (Panulirus argus) with
two ordinary front legs where the claws would be. Instead of claws,
the spiny lobster has two long, thorny antennae which it uses as
whips for fighting and defence.
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4.2 SANDY COASTS
4.2 SANDY COASTS
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4.2 SANDY COASTS
4.2 SANDY COASTS
4.2.1 Beaches
A beach is composed of small loose rock (sand) that gathers by the
shore of a body of water. The sand comes from the skeletal remains
of organisms or from the erosion of larger rocks both far away from
and near the water. A beach's shape depends on how the waves
move – some waves move material up the beach while others move
material down the beach. On sandy beaches, waves move sand
away from the beach, making gentle slopes. When the waves are
not strong enough to move the sand away, the beach is steeper.
Crabs and birds feed on material left on the sand by the waves while
other animals may dig into the sand to get food. Birds use beaches
to nest and sea turtles lay and bury their eggs in the sand. Plants
also grow in certain parts of the beach and dunes.
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4.2 SANDY COASTS
PARTS OF A BEACH
A beach covers the area from the low tide water level to the dunes.
The backshore is the area of dry sediments that is only covered by
water during the highest tides or most severe storms. A berm
separates the backshore from the foreshore. The area just below
the low tide line is sometimes included as a part of the beach
because this is the area where most sand moves.
Berms form where the foreshore and backshore meet, when waves
deposit sediments at high tides. They mark the highest point on the
beach waves generally reach. Berms are easy to see because they
have a higher elevation and have flat tops like terraces. Sometimes
more than one berm is formed on a beach. Severe storms cause
berms to form closer to the dunes because the waves have more
energy to reach a higher part of the beach. Berms formed by one
storm often remain undisturbed until another storm’s waves can
reach the upper beach again.
The beach face is the area between the low and high tide levels.
This area is also called the intertidal zone. The slope of a beach is
determined by the size of the sediment particles and the amount of
wave energy. Although not truly part of the beach, sandbars form
just offshore and are an important supplier of sand and sediments to
the beach.
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4.2 SANDY COASTS
REFERENCES & FURTHER READING
http://www.epa.gov/beaches/kids/what-beaches.html - what is a beach?
http://omp.gso.uri.edu/ompweb/doce2.htm - coastal environments (rocky, sandy) and virtual tours
http://oceanworld.tamu.edu/resources/oceanography-book/typesofcoasts.htm - Types of coast
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4.2 SANDY COASTS
4.2.2 Sand
Sand consists of tiny bits of animals, plants, rocks and minerals.
Most beach sand is eroded from land sources and carried to the
coast by rivers, but sand is also eroded from coastal sources by surf.
Sand is redistributed by waves and coastal currents seasonally.
Sand can be many colors depending on its composition.
following are some examples of different sand colors:
The
1. Black Sand
Black sand beaches come from volcanic ground lava. They are
mostly found on the southeast part of the big island of Hawaii which
is the most volcanically active part of the island. Black sand
beaches are also found in Costa Rica and St. Lucia.
2. White Sand
White sand beaches consist of crushed shells and limestone from
coral skeletons. Coral reefs are a major source of white sand
beaches. White sand beaches are found on the north end of the big
island of Hawaii and also on many Caribbean islands such as the
Cayman Islands.
Ocean Literacy Principle 2(d)
Sand consists of tiny bits of
animals, plants, rocks and minerals.
Most beach sand is eroded from
land sources and carried to the
coast by rivers, but sand is also
eroded from coastal sources by
surf. Sand is redistributed by waves
and coastal currents seasonally.
4.2 SANDY COASTS
3. Green Sand
Green sand beaches are made from olivine crystals. Green sand
beaches are quite rare but can be found in Guam and at the
southernmost tip of the big island of Hawaii.
4. Pink Sand
Pink sand is mostly coral, broken shells and calcium carbonate
(limestone) skeletons from marine invertebrates. The pink color
comes from marine invertebrates called foraminiferans which have
bright pink or red shells. For example, pinks sands are found on
Harbour Island and Eleuthera in the Bahamas and in Bermuda.
REFERENCES & FURTHER READING
http://wrgis.wr.usgs.gov/parks/coast/sand/blacksand.html - Black sand
http://wrgis.wr.usgs.gov/parks/coast/sand/greensand.html - Green sand
http://www.harbourislandguide.com/pink-sands.htm - Pink sand
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4.2 SANDY COASTS
4.2.3 Sandy Coast Life
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4.2 SANDY COASTS
SEA TURTLE
Sea turtles are large air-breathing reptiles with paddle-shaped foreflippers and a number of other adaptations that make them perfectly
at home in the ocean. Today, only seven species remain worldwide
– green, loggerhead, hawksbill, flatback, Kemp’s ridley, olive ridley,
and leatherback turtle. Although they may live their entire life at sea,
sea turtles must return to the land to nest. Under cover of darkness,
a female will drag her body across a sandy beach where she will dig
a nest and deposit about 100 eggs in the warm sand. After about 60
days of incubation, the eggs will hatch and the hatchlings will make
their way back to the sea.
JELLYFISH
A jellyfish (or jelly) is a simple invertebrate (cnidarian) which drifts
with the currents to get from place to place. They are abundant in
sounds and estuaries during summer and eat small organisms that
they sting with tentacles. Some jellyfish have extremely potent
stings and can seriously injure humans. Even dead jellyfish that are
sometimes seen washed up on the beach can be hazardous since
their stinging cells can still be active long after the animal itself has
died. Jellyfish are preyed upon by only a few animals most notably
sea turtles.
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4.2 SANDY COASTS
DUNGENESS CRAB
Dungeness crabs are crustaceans that inhabit eelgrass beds and
sea bottoms from the Alaskan Aleutian Islands to California. They
can measure 25 cm (10 in) but typically are under 20 cm (8 in).
They are a popular delicacy, and are the most commercially
important crab in the Pacific Northwest and the western United
States generally. Dungeness crabs have a wide, hard shell which
they must split in order to grow. They have five pairs of legs, the
foremost pair of which ends in claws which the crab uses as defence
and to tear apart large food. They eat clams, other crustaceans and
small fish but are also effective scavengers. Dungeness crabs can
also bury themselves completely in the sand when threatened.
HERMIT CRAB
Hermit crabs are decapod crustaceans. Most hermit crabs have
long soft abdomens which they protect by living inside the empty
seashells of sea snails (marine gastropod molluscs). The tip of the
hermit crab's abdomen is adapted to clasp strongly onto the snail
shell. There are about 500 species of hermit crabs in the world
mainly living on shallow coral reefs and shorelines or deep sea
bottoms. In the tropics, however, some species are terrestrial and
can be large, such as the soldier crab (Coenobita clypeatus) and
coconut crab (Birgus latro). The coconut crab is the world’s largest
arthropod weighing up to 4 kg (9 lbs) and with a leg span of 2 m (6
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4.2 SANDY COASTS
SAND DOLLAR
Sand dollars are echinoderms. When living, their shells are covered
with a suit of moveable spines. Like its close relative the sea urchin,
the sand dollar has five sets of pores arranged in a petal pattern.
The pores are used to move sea water into its internal watervascular system, which allows the creature to move. Sand dollars
live beneath the surface of sandy or muddy areas. The spines on
the underside of the animal allow it to burrow or to creep through the
sand. Its food consists of plankton and organic particles on the
sandy bottom. When a sand dollar dies, it usually loses its velvety
covering of minute spines and has a flat bleached look that
resembles a large coin.
RAZOR CLAM
Razor clams are long, narrow bivalves that bury themselves in the
sand. At high tide, their feeding tubes poke above the sand to suck
in plankton carried in by the water. Razor clams get their name from
their resemblance to a straight-edge razor although the edges of
their shells are also “razor-sharp” and can cause serious cuts if you
run your finger along the edge.
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4.2 SANDY COASTS
COCKLE
A cockle is the common name for a family of bivalve molluscs.
Shells of various species of cockles are found on many beaches
throughout the world. The distinctive rounded shells of cockles are
symmetrical, “heart-shaped” and most are ribbed. Cockles typically
burrow using their foot and feed by siphoning water in and out and
filtering plankton from it. A cockle is capable of 'jumping' by bending
and straightening its foot. Unlike most bivalves, cockles are
hermaphrodites and reproduce quickly.
WHELK
A whelk is a saltwater mollusc, which lives in sounds and intertidal
areas. They are carnivores and eat bivalves. Whelks are eaten by
crabs and octopuses. They move just under the surface of the
sandy or muddy substrate.
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4.2 SANDY COASTS
SAND PIPER
A sandpiper is a small wading bird with a slender bill and piping call.
Sandpipers are closely related to the plovers. The majority of
species eat small invertebrates picked out of the mud or soil.
Different bill lengths enable different sand piper species to feed in
the same coastal habitat without directly competing with one another
for food.
SEA GULL
Sea gulls are resourceful and highly-intelligent birds. They are
usually grey or white in colour and often have black markings on the
head or wings. They have stout, longish bills, and webbed feet.
Gull species range in size from the Little Gull, at 120 g (4 oz) and 29
cm (11.5 in) in length to the Great Black-backed Gull, at 1.75 kg (4
lbs) and 76 cm (30 in) in length. Most gulls are ground nesting
carnivores and will feed on live food or scavenge opportunistically.
Live food includes crabs and small fish. Apart from the kittiwakes,
gulls are typically coastal or inland species and rarely venture far out
to sea. Large species may take up to four years to attain full adult
plumage but two years is typical for small gulls.
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4.2 SANDY COASTS
SEA GRAPES
Sea grapes (Coccoloba uvifera) are remarkable salt-tolerant species
of plant found along many of Florida’s beaches. Plants may appear
as low spreading bushes or tall continuous hedges along the sand
dunes. This plant can be identified by its thick circular leaves about
25 cm (10 in) in diameter and its grape-like clusters of fruit. The fruit
is consumed by a number of birds and mammals while the protective
canopy provides habitat for animals including songbirds, lizards,
gopher tortoise and beach mice. In addition to providing habitat, sea
grapes help stabilize sand dunes and protect upland structures from
storm-induced erosion. In fact, this plant has been deemed
important enough to be protected under Florida Statute.
SEA OATS
Sea oats (Uniola paniculata) are a type of grass that grows along the
east coast of the United States, Mexico, and on islands in the
Caribbean. Sea oats are well suited to saline environments, and are
often used in soil stabilization projects, because their long root
structure firmly holds loose soil. Sea oats are a protected grass in
most states along the east coast of the United States.
REFERENCES & FURTHER READING
http://www.dep.state.fl.us/beaches/publications/pdf/turtle.pdf
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4.3 MUDDY COASTS
4.3 MUDDY COASTS
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4.3 MUDDY COASTS
4.3 MUDDY COASTS
4.3.1 Estuaries
An estuary is a body of water formed where freshwater from rivers
and streams flows into the ocean, mixing with the seawater.
Estuaries and the lands surrounding them are places of transition
from land to sea and from freshwater to saltwater. Although
influenced by the tides estuaries are protected from the full force of
ocean waves, winds, and storms by the reefs, barrier islands or
fingers of land, mud, or sand that surround them.
A wide variety of birds, fish, and other wildlife make estuaries their
home. A healthy estuary fringed by its streams, marshes, and
shores forms a very productive biological system. The marshes
provide nutrients to the estuary which cycles efficiently from plants to
animals to soil and around again through the food web. The
marshes provide undisturbed nursery grounds and the life cycles of
the plants and animals maintain a natural balance.
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4.3 MUDDY COASTS
People also live, fish, swim, and enjoy nature in estuaries and the
lands surrounding them. However, humans change the estuary
environment when they interact with it. Humans catch fish, dredge
for oysters, dig for clams, and trap crabs. In addition, humans can
add undesirable substances to the water such as industrial chemical
wastes, large quantities of nutrients from municipal sewage
discharges, and silt and sediment runoff from construction sites. In
order to keep navigable channels clear, provide sites for dredging
spoils and create more land for construction, marshes are often
drained and filled. Tankers pump out their ballast tanks which can
cause oil slicks. All of these activities disrupt food chains in the
estuary and its surroundings.
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4.3 MUDDY COASTS
4.3.2 Estuary Life
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4.3 MUDDY COASTS
MUSSEL
The common name “mussel” is used for members of several
different families of clams or bivalve molluscs, from both saltwater
and freshwater habitats. "Mussel" is a loose term but it has
historically been used to describe families of clams where the shell
is longer than it is wide, being wedge-shaped or asymmetricallooking, and where the external color of the shell is dark blue or
brown, as opposed to the more globular lighter-colored families of
bivalves. Marine mussel species live in intertidal and subtidal areas
along coastlines worldwide. Freshwater mussel species inhabit
lakes, ponds, rivers, creeks, canals, and similar habitats.
STEAMER CLAM
Steamer clams are soft-shell clams that live buried in tidal mudflats
most famously in New England but their range extends much farther
north to Canada and to the Southern states. They are also found in
the UK. A steamer clam (Mya arenaria) has a calcium carbonate
shell, which is very thin and easily broken, hence the name "softshells" (as opposed to their beach-dwelling neighbors, the thickshelled quahogs). It can be found about 90 cm (35 in) under the
surface of the mud, where it extends a siphon, which is used to draw
in water that is filtered for food and expelled. The holes through
which water is drawn can often be seen at low tide and water may
be visibly ejected when pressure is applied to the surrounding mud.
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4.3 MUDDY COASTS
CRAB
Crabs are crustaceans with ten legs (decapods), eyes on short
stalks, pincers and a broad flattened carapace with a small abdomen
folded under the thorax. True crabs have five pairs of legs, the first
of which are modified into a pair of feeding claws and are not used
for locomotion. Crabs are omnivores. Some feed primarily on algae
while others will eat many types of food, including molluscs, worms,
other crustaceans, fungi, bacteria and detritus. For many crabs, a
mixed diet of plant and animal matter results in the fastest growth.
SHORTNOSE STURGEON
The shortnose sturgeon is a fish with a short snout and short barbels
(“whiskers”) under the snout. It reaches 1 m (40 in) in length. It
lives mostly in river mouths, estuaries and bays but also enters open
sea and is found from New Brunswick to N.E. Florida. It is seriously
depleted.
REFERENCES & FURTHER READING
http://www.epa.gov/owow/estuaries/kids/index.htm
http://www.estuaries.gov/welcome.html
http://ux.brookdalecc.edu/staff/sandyhook/index2-2.html
http://omp.gso.uri.edu/ompweb/doee/doee.htm - Estuaries
http://omp.gso.uri.edu/ompweb/doce2.htm - Salt marsh
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4.4 ACTIVITIES
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4.4 ACTIVITIES
4.4.1 Beach Log
CORE ACTIVITY
Have each student keep a small logbook of all animals and plants seen on a beach walk. Use a page for
each organism. Look up the organism using a field guide or use the Web, place it into its appropriate
group (animal-plant, vertebrate-invertebrate, etc.) and keep short notes on each organism. Include a
drawing or a photo of the organism or ask the pupils to describe some of the creature’s adaptations or
features that allow it to live in the environment.
4.4 ACTIVITIES
SAMPLE TABLE OF CONTENTS
Animals
Vertebrates
• Fishes
• Birds
• Reptiles (iguanas, alligators, snakes)
• Amphibians
• Mammals
Invertebrates
• Molluscs (clams)
• Echinoderms (sea stars, sea urchins)
• Crustaceans (shrimps, crabs, lobsters)
• Cnidarians (sea anemones, true jellyfish)
Plants
Grasses
•…
•…
•…
Flowering Plants
•…
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4.4.2 Rocky Beach
CORE ACTIVITY
(a) Make a poster of a rocky beach. Initially, assign an animal to each student. Then, have each student
research their animal using books or the Web. Each student should then write a description of the
animal and draw or find a picture of the animal on an index card (e.g. 6 in x 4 in). After all students have
made their index cards, have each student paste their index card onto large poster board. Display the
poster in the classroom or the hallway. Include identification labels for the animals and plants so that
other students can learn the new information too.
Rocky Beach Habitat
• Puffin
• Walrus
• Barnacles
• Sea Stars
• Periwinkle
• Limpet
• Crab
• Sea Urchins
• Sea Anemones
• Lobster
• Shrimp
(b) What is the difference (if any) between a sea star and a starfish?
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ANSWERS
(a) Make a poster of a rocky beach. Initially, assign an animal to each student. Then, have each student
research their animal using books or the Web. Each student should then write a description of the
animal and draw or find a picture of the animal on an index card (e.g. 6 in x 4 in). After all students have
made their index cards, have each student paste their index card onto large poster board. Display the
poster in the classroom or the hallway. Include identification labels for the animals and plants so that
other students can learn the new information too.
Rocky Beach Habitat
• Puffin
• Walrus
• Barnacles
• Sea Stars
• Periwinkle
• Limpet
• Crab
• Sea Urchins
• Sea Anemones
• Lobster
• Shrimp
(b) What is the difference (if any) between a sea star and a starfish?
There is no difference between “sea star” and “starfish”. However, scientists are trying to get away from
using the word “starfish” and using “sea star” instead. This is because the animal is not a fish but an
4.4 ACTIVITIES
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4.4.3 Sandy Beach
CORE ACTIVITY
(a) Make a poster of a sandy beach. Initially, assign an animal to each student. Then, have each
student research their animal using books or the Web. Each student should then write a description of
the animal and draw or find a picture of the animal on an index card (e.g. 6 in x 4 in). After all students
have made their index cards, have each student paste their index card onto large poster board. Display
the poster in the classroom or the hallway. Include identification labels for the animals and plants so that
other students can learn the new information too.
Sandy Beach Habitat
• Sand Piper
• Sea Gull
• Jellyfish
• Hermit Crab
• Sea Turtle
• Razor Clam
• Cockle
• Whelk
• Dungeness Crab
• Sand Dollar
• Sea Oats
• Sea Grapes
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(b) What is the difference (if any) between a jelly and jellyfish?
(c) What colours can beach sand take? What causes the difference in colours? Where can the different
sandy beaches be found?
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ANSWERS
(a) Make a poster of a sandy beach. Initially, assign an animal to each student. Then, have each
student research their animal using books or the Web. Each student should then write a description of
the animal and draw or find a picture of the animal on an index card (e.g. 6 in x 4 in). After all students
have made their index cards, have each student paste their index card onto large poster board. Display
the poster in the classroom or the hallway. Include identification labels for the animals and plants so that
other students can learn the new information too.
Sandy Beach Habitat
• Sand Piper
• Sea Gull
• Jellyfish
• Hermit Crab
• Sea Turtle
• Razor Clam
• Cockle
• Whelk
• Dungeness Crab
• Sand Dollar
• Sea Oats
• Sea Grapes
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(b) What is the difference (if any) between a jelly and jellyfish?
There is no difference between “jelly” and “jellyfish”. However, scientists are trying to get away from
using the word “jellyfish” and using “jelly” instead. This is because the animal is not a fish but a
Cnidarian and an invertebrate. Nonetheless, jellyfish is still very commonly used.
(c) What colours can beach sand take? What causes the difference in colours? Where can the different
sandy beaches be found?
1. Black sand beaches come from volcanic ground lava. Black sand beaches are found in Hawaii, Costa
Rica and St. Lucia.
2. White sand beaches consist of crushed shells and limestone from coral skeletons. Coral reefs are a
major source of white sand beaches. White sand beaches are found in Hawaii and also on many
Caribbean islands such as the Cayman Islands.
3. Green sand beaches are made from olivine crystals. Green sand beaches can be found in Guam and
at the southernmost tip of the big island of Hawaii.
4. Pink sand beaches are mostly coral, broken shells and calcium carbonate (limestone) skeletons from
marine invertebrates. The pink colour comes from marine invertebrates called foraminiferans which
have bright pink or red shells. Pink sand beaches can be found in the Bahamas and in Bermuda.
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4.4.4 Estuary
CORE ACTIVITY
(a) Make a poster of an estuary. Initially, assign an animal to each student. Then, have each student
research their animal using books or the Web. Each student should then write a description of the
animal and draw or find a picture of the animal on an index card (e.g. 6 in x 4 in). After all students have
made their index cards, have each student paste their index card onto large poster board. Display the
poster in the classroom or the hallway. Include identification labels for the animals and plants so that
other students can learn the new information too.
Estuary Habitat
• Mussel
• Steamer Clam
• Crab
• Sturgeon
(b) What is an estuary? What kind of water is typically found in an estuary?
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ANSWERS
(a) Make a poster of an estuary. Initially, assign an animal to each student. Then, have each student
research their animal using books or the Web. Each student should then write a description of the
animal and draw or find a picture of the animal on an index card (e.g. 6 in x 4 in). After all students have
made their index cards, have each student paste their index card onto large poster board. Display the
poster in the classroom or the hallway. Include identification labels for the animals and plants so that
other students can learn the new information too.
Estuary Habitat
• Mussel
• Steamer Clam
• Crab
• Sturgeon
(b) What is an estuary? What kind of water is typically found in an estuary?
An estuary is a body of water formed where freshwater from rivers and streams flows into the ocean,
mixing with the seawater. Estuaries and the lands surrounding them are places of transition from land to
sea and from freshwater to saltwater. Although influenced by the tides estuaries are protected from the
full force of ocean waves, winds, and storms by the reefs, barrier islands or fingers of land, mud, or sand
that surround them.
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4.4.5 Invertebrates
CORE ACTIVITY
(a) What are some of the features of the echinoderms? Name 3 echinoderms.
(b) What are some of the features of the molluscs? Name 3 molluscs.
(c) What are some of the features of the crustaceans? Name 3 crustaceans.
(d) Draw an arrow between each of the following animals to its group. For example, a lobster is a
crustacean. One of the animals is not an echinoderm, mollusc or crustacean. Circle that animal.
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ANSWERS
(a) What are some of the features of the echinoderms? Name 3 echinoderms.
• Invertebrates – animals without backbones
• Have “spiny” skin
• Five-fold, radially symmetrical marine animals
• Examples include sea stars, sea urchins, sand dollars, sea cucumbers and crinoids
(b) What are some of the features of the molluscs? Name 3 molluscs.
• Invertebrates – animals without backbones
• Have a hard outer shell protecting a soft body
• Many have a muscular foot
• Examples include clams, mussels, oysters, periwinkles and limpets.
• Squid and octopus are also molluscs but they are unusual because they are shell-less
(c) What are some of the features of the crustaceans? Name 3 crustaceans.
• Invertebrates – animals without backbones
• Have multiple pairs of jointed legs (arthropods) and segmented bodies
• Examples include shrimps, lobsters and crabs
(d) Draw an arrow between each of the following animals to its group. For example, a lobster is a
crustacean. One of the animals is not an echinoderm, mollusc or crustacean. Circle that animal.
4.4 ACTIVITIES
The animal that does not belong to any of the three groups is the sea anemone. Sea anemones are
cnidarians and have their own group.
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