Your Federal Quarterly Tax Payments are due April 15th Get Help Now >>

6. The Rocky Shore - Conservation Education - YPTE by dandanhuanghuang


                                                 SUMMER TERM 2003                                                           ISSUE SIX

Published by the
Young People’s Trust for the Environment
8 Leapale Road, Guildford, Surrey, GU1 4JX
Tel: 01483 539600
                                                 Peter Littlewood writes…
Web site:
ISSN 0262-2203                                   The Rocky Shore – the coastline of Britain is
Founder: Cyril Littlewood MVO, MBE, OGA
Director: Peter Littlewood
                                                 approximately 10,000 miles in length, and highly
Sponsored by
                                                 varied in nature, with sandy beaches, rocky
                                                 shores, cliffs, shingle and estuaries are just some
                                                 of the habitats one can find along its length.
                                                 Each kind of shore has its own beauties      quickly and release them again safely
                                                 to reveal, but perhaps the most              into the same pool they were found in.

                                                 fascinating treasure houses of all are       Wherever possible, it is kinder to
                                                 the rockpools found along many               observe the creatures in situ, both by
                                                 stretches of our coastline.                         watching a rockpool and
                                                 Rockpools come in all shapes                             perhaps by gently lifting
       Rocky Shore:                              and sizes, each one a
                                                 fragile ecosystem that
                                                 is covered by tides
                                                                                                             weed and stones to see
                                                                                                               what they conceal.
                                                                                                                 Always replace them

                                                 twice a day.                                                     again with as little
      2                                          Rockpools make                                                     disturbance as
                                                 fantastic areas for                                                 possible.
                                                 outdoor study,                                                       Rockpools are
      3      food web                            aided by the fact
                                                 that many of the
                                                 animals that live in
                                                                                                                      wonderful places,
                                                                                                                      but remember
                                                                                                                     safety is
      4       seaweed                            them are fairly easy
                                                 to catch. There are
                                                 few practical
                                                                                                                    important. Make
                                                                                                                   sure the students are
                                                                                                                appropriately dressed

                                                 environmental sessions                                       and that you have the
                                                 which create more
      5                                          excitement and interest than
                                                                                                          correct equipment. Know the
                                                                                                tide times, and visit the rockpools at
                                                 rockpool study, simply because the           low tide if possible, as this is when you
      6        Life in a Rock                    students can engage directly with their      will see the most. Always ensure the
                                          Pool   subject. However, many rockpool-
                                                 dwelling creatures are also easy to
                                                                                              safety of any animals you catch.

               Protecting                        harm, so every care must be taken when       Mostly though, take the opportunity to
      7                                          handling them.                               enjoy studying a wonderful and

               the Seashore
                                                                                              accessible environment – the rocky shore.
                                                 Making sure that your catches have a
                                                 safe environment while they are being
                                                 studied is of great importance. Shallow
      8      Pollution Proble                    plastic sample trays filled with water are
                              ms                 ideal for observation, but need a few

                                                 rocks and some seaweed under the
                                                 shade of which creatures can take
               Pick a Project                    shelter. Prolonged exposure to heat and
                                                 sunlight can be quite harmful to your
          Useful Websites                        catches, so make your observations
                                                 A Rocky Shore Ecosystem
                                           Rocky coastlines are found all over
                                          the world but they are not all
                                         the same. Some are made up of
                                        steep, rocky cliffs whilst others
                                      slope gently into the sea.                                                                                 Phytoplankton
                                                                                                                                                 & Zooplankton                             Acorn Barnacle                            Dog Whelk                      Herring Gull

                             These craggy        and dry for ten hours or more between        A high tide brings food and nutrients to    When a herbivore eats a plant… and            not normally eaten by anything. In a rocky     that we can think of every organism as
                         seashores have been     high tides. When the tide rolls in, these    the organisms living further up the shore   then the carnivore eats the herbivore…        shore ecosystem there may be hundreds          part of a complicated food web rather
                  formed by the force of the     organisms must be able to withstand          and when it goes out waste products are     the sequence of events is called a food       of food chains. Above is an example:-          than as a link in a straight chain.
    sea pounding against hard cliff faces,       the waves that often hit with incredible     taken with it and washed away.              chain. Each organism is a link in a chain.
                                                                                                                                                                                        The dog whelk and the herring gull will
    gradually breaking them up and                     force – and they have to cope with     Animals in an ecosystem obtain the          The animal at the top of a food chain is      eat other animals too. There are so
    wearing them away. This                                  being submerged in salty         energy they need by eating plants, or       often called a ‘top predator’ because it is   many connections between food chains
    continuous action is                                        water for several hours.      other animals that have eaten plants.
    called erosion. The                                                                       The plants themselves get their energy

                                                                                                                                          Rocky Shore Food Web
    shore may consist of                                            Spring tides (from the
                                                                     Old English word         from the sun.
    rocky ledges with
    cracks and hollows                                                ‘springen’, to rise)    Animals that feed mainly on plants are
    that form pools as                                                 occur every two        called herbivores and most seashore
    they fill with salty                                               weeks at times of      herbivores, like the limpet, feed on
    water. The sea                                                     the full and new       young seaweeds. Others, for example
                                                                      moon. The best time        zooplankton (microscopic animal          How many food chains can you find in this web?
    breaks part of the
    rocky cliffs into                                                to study the                     life), feed on phytoplankton
    boulders and pebbles                                            shore is                              (microscopic plant life).
    that are finally ground                                       during these
                                                                                                           Animals that feed mainly
    into grains of sand.                                       tides as they
                                                                                                           on other animals are called
                                                           rise further up
    Living in this seaside habitat is a                                                                     carnivores. They are often
                                                  and drop lower down the
    community of hardy plants and animals,                                                                  called ‘predators’ and the
                                                 shore than neap tides,
    and each species is specially adapted                                                                  animals they feed on are
                                                 which happen between
    for coping with the harsh environment                                                                 called their ‘prey’.
                                                 spring tides.
    around it. The plants and animals                                                                  Animals that feed on both
    interact with each other and with their      Seashore life occurs in zones on                   plant and animal material are
    non-living surroundings (the habitat) to     the shore, according to how well the         called omnivores. On the seashore
    form the rocky shore ecosystem.              different species can tolerate exposure      many types of animals are omnivores
                                                 to air and sunlight. Above the level of      because they feed by filtering both
    Depending on its situation, a rocky
                                                    the highest tides is the splash zone,     phytoplankton and zooplankton from
    shore may be in an exposed or
                                                          strongly affected by salt spray.    the seawater.
    sheltered area. Of all the
                                                             The upper shore is not covered
    seashore habitats, the
                                                              by every high tide, usually
    sheltered rocky shore
                                                               only those of spring tides.
    has the greatest number
                                                               Very few species can
    of species and therefore
                                                               tolerate the relatively dry
    is probably the best type
                                                               conditions of the upper
    to study.
                                                              shore. Most seashore
    Life is difficult on the                                plants and animals live in
    seashore because this type of                        the middle shore, the main
    habitat changes every day. The                 area that is covered and
    organisms (the plants and animals) on        uncovered by every tide. The lower
    the rocks in the intertidal zone (the area   shore is only exposed during the low
    exposed between high and low tides)          tides of spring tides and the plants
    have to survive the continual cycle of       and animals that live here are more
    changing tides that may leave them high      like those that live deeper in the sea.

2                                                                                                                                                                                                                                                                                  3
    Seaweeds of                                                                                                                                              Animals of
    the Rocky Shore                                                                                                                                          the Rocky Shore
                                                                                                                                                             As we have seen, the seaweeds of a rocky
    Seaweeds belong to a group of primitive plants known as algae.                                                                                           shore grow in different areas – zones –
    They do not have leaves, stems, roots and flowers but have fronds                                                                                        depending on their ability to survive out of the
    that are anchored to rocks and other solid objects by a holdfast.                                                                                        water. The animals show a similar zonation, but
                                                                                                                                                             because they can move around it is not so obvious.
    Like land plants, they contain the green       pools. Brown seaweeds are found on                 because it can only survive in the air for
    substance called chlorophyll so they           the middle shore to lower shore, and red           a few hours. The bladder wrack also                    Like the plants, the animals are greatly                tide goes out, each limpet returns to its               this is the work of the dog whelk. The
    are able to make their own food by the         seaweeds are mainly on the lower                   lives on the middle shore and the                      influenced by the tide. Some species                    own ‘home’.                                             dog whelk itself may be attacked by
    process known as photosynthesis.               shore. The reds need very little light and         serrated or toothed wrack is found                     live almost as land animals around the                                                                          crabs and herring gulls.
                                                   often grow in deeper rock pools or                 nearest the sea as it can only live for a              high water-mark of spring tides, and                  Crusty Barnacles and Dangerous Dogs –
    Several types of seaweeds grow in the          attached to brown seaweeds out at sea.             very short time exposed to the air.                    others are only briefly exposed to the                The rocks of the upper shore are often                    More Molluscs – As well as the limpets
    intertidal zone and they are specially         A few red weeds, such as coral weed,                                                                      open air at the low water-mark of                                                    covered in barnacles,      and the dog whelks, several other
    adapted to be able to live for lengthy         can survive in rock pools higher up                The biggest brown seaweeds are the                     spring tides.                                                                          particularly the         molluscs live in the intertidal zone.
    periods out of the water. They produce a       the shore and withstand                                    kelps, such as oarweed and sea                                                                                                          acorn barnacle.        Molluscs of the rocky shore are mostly
    slimy substance that coats their fronds                                                                       belt, and these mark the                   All the animals are adapted to                                                           These crustaceans
                                                   periods of drying out.                                                                                                                                                                                                    gastropods which are the snails with
    and helps to prevent them from drying                                                                            bottom of the intertidal                feed and breed during                                                                    start life as tiny
                                                   The brown seaweeds,                                                                                                                                                                                                       one shell, whilst those on the sandy
    out. The position on the shore where a                                                                             zone, growing anchored                the few hours                                                                          larvae floating in the
                                                   usually called wracks,                                                                                    when they are                                                                                                   shore are mostly bivalves, the molluscs
    species lives depends on the length of                                                                               to rocks below the                                                                                                         sea with the
                                                   dominate the shore.                                                                                       covered by the                                                                                                  with two shells, such as cockles. The
    time the shore is exposed to the air.                                                                                  surface of the sea.                                                                                                     plankton, and most
                                                   The channelled                                                          They quickly die if               tide. When the                                                                                                  bivalves can burrow down into the sand
    Some seaweeds are able to live almost                                                                                                                                                                                                        come to rest in the
    totally in the air, while others can survive   wrack lives on rocks                                                     exposed to dry air               tide is out, birds                                                                                              for safety, but the gastropods, being
                                                   on the upper shore                                                                                        such as gulls and                                                                   intertidal area of a        unable to burrow into rock, have strong
    for only a very brief period out of the sea.                                                                            and are only briefly                                                        The top of the edible crab’s shell,

                                                   as it can withstand                                                                                       oystercatchers
                                                                                                                                                                                                        called a carapace, is shaped just like
                                                                                                                                                                                                                                                 rocky shore,                shells with an operculum (trapdoor
                                                                                                                           uncovered by the                                                             the pastry lid of a pie. The adult crabs
    There are three main groups of seaweed         drying out                                                             lowest spring tides.               search the shore
                                                                                                                                                                                                        can grow to more than 15cm across
                                                                                                                                                                                                        the shell, and they live in deep water.
                                                                                                                                                                                                                                                 cementing themselves        attached to the foot muscle).
    – green, brown and red. Generally              completely. The spiral                                                                                    probing amongst the seaweeds               The baby crabs may be found in rock
                                                                                                                                                                                                        pools, hunting prawns and other
                                                                                                                                                                                                                                                 firmly to the rock.
    speaking, the green seaweeds, such as          wrack, so-called                                                                All the seaweeds          for small animals.                         small animals. They are also             When exposed to the         The gastropods found on the rocky shore
                                                                                                                                                                                                        scavengers, eating the remains of
    sea lettuce, are found on the upper            because it twists into                                                          provide food and                                                     any dead animals they find.              air, the                               are different species of periwinkles
    shore, or growing beneath brown                spirals as it dries out and
                                                                                        The bubbles on the fronds of the
                                                                                        knotted wrack seaweed are air bladders     shelter for many of the   Here are some of the more                                                           barnacle                                                and topshells. Each
    seaweeds on the middle shore, and in           dies, lives in the middle shore
                                                                                        which help the fronds to float up to the
                                                                                        surface of the water. This allows the      seashore animals.         common types of animals you can                       closes its opening with a                                                                  species lives in a
                                                                                        plant to absorb plenty of sunlight so it                             expect to find on the rocky shore:-                                                                                                                particular zone; the
                                                                                        can photosynthesise more easily.                                                                                           hinged trapdoor-like
                                                                                                                                                             Limpet Lifestyle – The limpet is perhaps              operculum – this is made of                                                                  small periwinkle, for
                                                                                                                                                             the most well-adapted of all the marine               two limy plates which join up with                                                          example, lives in the
                                                                                                                                                             snails for a life on the exposed rock                 other plates to protect the body. When                                                     splash zone and is
                                                                                                                                                             surfaces. Each limpet has its own ‘home’ covered by the sea, the operculum                                                                            almost a land
                                                                                                                                                             – an exact spot on the rock                           opens and six pairs of feathery legs                       You can tell what a dog whelk        animal, being able
                                                                                                                                                                                                                                                                              eats by the colour of its shell.
                                                                                                                                                             where it stays when the tide                            called cirri (the equivalent of other                    Pale-coloured dog whelks have        to breathe air.
                                                                                                                                                                                                                                                                              eaten barnacles, and dog-
                                                                                                                                                             is out. On soft rock, the                                     crustaceans’ legs) appear and filter               coloured whelks have eaten           However, the
                                                                                                                                                                                                                                                                              mussels. The one pictured here
                                                                                                                                                             limpet grinds the                                                  out particles of food.                        has a banded shell that may          females have to
                                                                                                                                                                                                                                                                              mean that it has a varied diet.
                                                                                                                                                             surface with its shell to                                                                                                                             release their eggs
                                                                                                                                                                                                                                    The barnacle thrives best in                                                   into the sea at high
                                                                                                                                                             make an exact fit; on
                                                                                                                                                                                                                                    exposed conditions high up on            tides so that the larvae can live amongst
                                                                                                                                                             hard rock, the shell is
                                                                                                                                                                                                                                  the shore, but even here it is not         the plankton.
                                                                                                                                                             ground down to fit the
                                                                                                                                                                                                                  Limpet          safe from predators. It is the
                                                                                                                                                             rock’s shape. This tight fit
                                                                                                                                                                                                                                  favourite prey of a carnivorous            At low tide, other
                                                                                                                                                             allows the limpet to trap a spoonful of
                                                                                                                                                                                                                   mollusc, the dog whelk, which wanders                     periwinkles and
                                                                                                                                                             water inside to prevent it drying out. A
                                                                                                                                                                                                                   up from the middle shore to attack the                    the topshells
                                                                                                                                                             strong foot muscle gets a firm grip on
                                                                                                                                                                                                                   barnacles. The whelk also attacks other                   may be found
                                                                                                                                                             the rock, making it difficult for birds to
                                                                                                                                                                                                                   molluscs, particularly the limpet, by                     stuck to the
                                                                                                                                                             prise off the limpet.
                                                                                                                                                                                                                   either producing a shell-dissolving acid                  rocks by their
                                                                                                                                                             When the tide covers their rock, or in                that makes a hole in the shell, or by                     sucker-like foot, but
                                                                                                                                                             wet, cool weather, the limpets leave                  boring a hole through the shell using its                 when the tide covers
                                                                                                                                                                                                                                                                                                                     Rough Periwinkle
                                                                                                                                                             their base and wander about, grazing on               rough, belt-like tongue. The flesh is                     them, they creep slowly
                                                                                                                                                             young seaweeds which have started                     then sucked out. If you find an empty                     about, grazing on
                                                                                                                                                             growing on the rock surface. Before the               limpet shell with a small, neat hole in it,               young seaweeds.

4                                                                                                                                                                                                                                                                                                                                         5
               Life in a Rock Pool
              A rock pool is like an attractive sea aquarium, an
                                                                                                                                                 Protecting the
              oasis at low tide for many animals and seaweeds.
              The life within them is always submerged whatever
              the tide is like but there are problems for the
             residents of a rock pool,
            particularly a shallow one.
                                                                                                                                                 Seashore Conservation Code – When
                                                                                                                                                 investigating a seashore it is important to
                                                                                                                                                 remember that the welfare of the plants and
    On a hot day, the sun will evaporate the surface                                 The anemones
    water, making the water saltier than usual.                                      stick themselves                                            animals must come first.
    When it rains the water in the pool will become                                     to rocks with a slimy disc.                              Treat them with care! If seaweeds are       normally firmly stuck to rocks
    diluted. So a shallow pool on the upper                                                They can move around a little but usually             attached to rocks do not try to pull them   and any attempt to remove
    shore will have less life than a                                                        just stay put, waving their tentacles to             off, just examine them where they are       them may result in their death.
    deeper one on the middle or                                                              attract small fish or crustaceans. When             growing. Handle animals with care and       Replace any large stones that are
    lower shore.                                                                             a small animal is seized and enfolded               return them to the place where they         moved – animals that live on the
                                                                                                  in the tentacles, stinging cells               were found. Anemones and limpets are        underside soon die if left exposed.
    The best rock pools
                                                                                                    paralyse the prey and it is swept
    for wildlife are
                                                                                                     into the mouth to be digested
    those low down on
                                                                                                    by special juices.
    the shore, large and
    deep enough to                                                                                             The crustaceans you are
                                                                     The shore crab does not easily
    prevent drastic changes                                          dry out so it can live under              most likely to come across in
                                                                     stones and in cracks well up
    in temperature on cold or                                        the shore, as well as in pools.           a rock pool are the shore
    hot days, ideally with                                           Adult crabs are green, but the
                                                                     young can be red or yellow with
                                                                                                               crab, hermit crab and
    overhanging areas and dark crannies.                             white patches. The crabs feed
                                                                     on small animals, dead or alive.
                                                                                                               common prawn.
    Such a pool will probably be full of life,
                                                                                                               Unlike the familiar cooked
    although not all of it will be easily visible. A
                                                                                                        prawn, a live prawn is not pink!
    smaller pool is easier to
                                                                                                          The common prawn is a
    investigate. If you watch
                                                                                                          transparent greyish colour with
    quietly by the side of a
                                                                                                         coloured dots and lines visible
    shallow pool, the first
                                                                                                              inside. It has very long
    obvious signs of life will be
                                                                                                                 antennae and lives in rock
    the seaweeds, some
                                                                                                              pools on the lower shore,
    pink ones encrusting
                                                                                                                    scavenging for bits of
    the rocks, others
                                                                                                                 seaweed and dead
    attached to the rocks,
                                                                                                             creatures, as well as
    swaying in the water. Wait
                                                                                                           capturing small live prey.
    patiently and you may see
    fish, prawns, crabs and other                                                                                       The only vertebrate
                                                                 The common hermit crab is well known for its
    creatures acting out their lives in                          habit of living in empty mollusc shells. The           animals you are likely
                                                                 smaller crabs live in the rock pools on the lower
    front of your eyes.                                          shore and the larger ones are found further out in     to come across living
                                                                 deeper water. Unlike other crabs, the hermit crab
                                                                                                                        in a rock pool are a
    The beautiful sea anemones are seen                          does not have a carapace but has a soft,
                                                                 unprotected abdomen which it hides away in an
                                                                                                                        few species of fish.
    at their best in the deeper pools.                           empty periwinkle or whelk shell. As it grows, the
                                                                 crab has to pop out of its shell and moult its hard    Rock pool fish may be
    Anemones are related to jellyfish and                        outer skin, and then quickly find a bigger shell to
                                                                 move into before a predator spots it! The crab         permanent residents
    corals – all simple, aquatic                                 walks slowly around the bottom of a pool
                                                                 scavenging for any dead plant or animal remains.       or just visitors
    animals belonging to
                                                                                                                        stranded by the tide.
    a group known as
    Cnidaria, a                                                                          The fish you are most likely to come
    word which                                                                        across from the upper shore downwards
    comes from                                                                           is the common blenny or shanny. It
    the ancient                                                                  has no scales but its body is protected by a
    Greek                                                                               thick layer of soft slime which helps it
    meaning                                                                              to slide amongst sharp rocks, and also
    “nettle”.                                                                                 helps to stop it drying out if
    Cnidarians have                                                                            stranded between tides on a drying
                                      The beadlet anemone is the most common
    tentacles around their            anemone. It is usually a deep red colour with            beach. Tough little teeth allow the
                                      purple blotches marking the positions of the
    mouths that can sting like        stinging cells. It may be found on the upper             shanny to crack open barnacles
    the leaves of a nettle.           shore, left high and dry at low tide, looking
                                      like a blob of red jelly, its mouth cavity firmly        and even limpets.
                                                 closed, with the tentacles tucked inside.
                                                 This helps it to retain moisture while waiting
                                                 for the next high tide.

6                                                                                                                                                                                                                                  7
Pollution Problems
Seas and seashores
are under continual                                                                                                                           Investigate…
threat from
pollution. Here are a
                                                                                                                                              Pick a
few examples :-                                                                                                                               Project!
                                                                                                                                              Choose one of the mentioned sources of
                                                                                                                                              pollution and find out as much as you
                                                                        Oil spills – either accidental or                                     can about it. What problems are caused
                                                                        deliberate (it is estimated that around                               by the pollutants? Who, if anyone, is
                                                                        72% of oil pollution is deliberate and                                responsible for cleaning up the
                                                                        illegal), have a devastating effect on                                pollution? Can you suggest what can be
                                                                        marine life, especially seabirds. Large                               done to stop the pollution happening in
                                                                        amounts of black tar-like oil washed                                  the first place?
                                                                        up on a rocky shore are likely to
                                                                                                                                              Holidaymakers make a big impact on
                                                                        completely destroy the entire
                                                                                                                                              beaches all over the world. Find out
                                                                        community of living things. Chemicals
                                                                                                                                              how tourism can affect ecosystems.
                                                                        used to disperse oil spills on a shore
                                                                                                                                              Can anything be done to reduce
                                                                        may clean up the oil but they can also
                                                                                                                                              the problems?
                                                                        cleanse the shore of life! The best
                                                                        policy for marine life is to physically
                                                                        remove as much oil as possible and
                                                                        leave the rest to break down
                                                                        naturally. A rocky shore will recover
                                                                        much more quickly if chemicals are
                                                                        not used.
                                                                        Sewage and litter – also upset
                                                                        seashore ecosystems, making them
                                                                        unsightly and perhaps contaminated
                                                                        with chemicals. Some litter can be
                                                                        dangerous to wildlife – and humans!

                                                                                                                                              Useful Web Sites
                                                                        Toxic chemicals and radioactive
                                                                        waste – a cocktail of toxic chemicals
                                                                        have found their way into the sea over
                                                                        the years, affecting both marine and                                  Marine Conservation Society
                                                                        human life. For many years,                                 
                                                                        potentially deadly radioactive waste                                  Charity dedicated to the protection of
                                                                        from nuclear power stations and                                       the marine environment and its wildlife.
                                                                        other sources was disposed of in the                                  Provides educational resources.
                                                                        sea, and beaches have been
                                                                                                                                              Surfers Against Sewage (SAS)
                                                                        contaminated by accidental leakages
                                                                        from nuclear power stations.
                                                                                                                                              Organisation which campaigns for a
                                                                                                                                              clean, safe, pollution-free coastline.
                                                                                                                                              The National Trust
                                                                                                                                              The National Trust’s educational
                                                                                                                                              resources concerning the protection of
                                                                                                                                              Britain’s coastline.
In association with
Young People’s Trust for the Environment
8 Leapale Road, Guildford, Surrey, GU1 4JX
tel: 01483 539600 fax: 01483 301992                                                                           Printed on paper sourced from
                                                                                                               sustainably managed forests

           Barclays Bank PLC. Registered in England No. 1026167. Registered Office: 54 Lombard Street, London EC3P 3AH

To top