Rocky

1
Rocky Boulder Shores
MR2505 Lecture 2
2
Rocky Shores

• Rocky shores - areas of bedrock revealed between
  high and low tide levels on the seashore
• Ecosystem present is complex
• Why? interaction between terrestrial and aquatic
  systems
• Plants and animals are distributed on the shore
  in horizontal zones that relate to the tolerance
  of the species to either their exposure to air or
  submergence in water during the tidal cycle.
• Zonation (see later) is often clear and very
  abrupt
• Tide pools often have rich communities of
  organisms normally associated with the lower
  shore or sub-tidal habitats
• The plants are typically algae (seaweeds) and
  lichens
• In sheltered muddy locations e.g. cord grass and
  Eel-grass may occur
• Animals include marine benthic fauna tolerant to
  various periods of exposure to the air at low
  tide, and vagrant terrestrial species including
  insect larvae.

http//www.npwrc.usgs.gov/resource/1998/classwet/r
ocky.htm
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Rocky Shores

• Rocky shores are found all over the world.
• Rocky shores are not all the same. For example,
  in the USA on the Pacific Northwest coast you
  will find steep, rocky cliffs. In Maine, you will
  find rocky coasts, too, but they slope gently
  into the sea.
• Marine plants and animals that live along these
  rocky shores have adapted to a habitat that
  changes every day. In the intertidal zone, water
  levels along rocky shore may drop 12 feet or more
  between high and low tide. That means that
  organisms living on the rocks may be exposed to
  the air for 10 hours or more between high tides.
  And when the tides roll in, these same organisms
  must be able to withstand the waves which often
  hit with incredible force.

Five Islands Provincial Park Rising majestically
from the shores of the Bay of Fundy, Five Islands
Provincial Park is one of Nova Scotia's premiere
outdoor destinations. The park features 90 metre
(300 ft.) sea cliffs overlooking the world's
highest tides
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Rocky Shores

• Factors modifying the tidal environment
• Exposure to wave action and "fetch"
• Shore topography
• Slope
• Cracks and crevices
• Pools
• Aspect
• Microhabitats
• Climatic factors (sun, wind, rain and frost)
• Biotic factors

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Rocky Shores

• The seashore is a boundary between the land and
  the sea and due to this transition creates a very
  diverse habitat.  
• There are two high and two low tides in
  approximately 24 hours around the British coast.
  The times and levels vary due to the
  gravitational pull of the moon.
• Life on a rocky shore is harsh due to many
  factors including high and low tides, temperature
  changes, salinity levels and the vagaries of the
  weather. The flora and fauna which live there
  have adapted to these changes in various ways to
  enable them to survive.
• Rocky shores are abundant in wildlife due to the
  variety of habitats it encompasses. Within a
  rocky shore there are rock pools, damp crevices,
  bare rock and sand all which offer homes to many
  species.

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Rocky Shores

• PHYSICAL ASPECTS
• Rocky shores form as a result of marine
  weathering and erosion of the overburden and the
  bedrock, due to a combination of rising sea level
  and wave action, in areas where there is a low
  sediment supply.
• l. Bedrock resistant bedrock, such as granite,
• slate and quartzite, erodes slowly and produces
• steep gradients. Less-resistant sedimentary
  bedrock is commonly eroded into a wave-cut
  platform with gentle slopes. Differential erosion
  of soft and hard rocks
• 2. Wave action exposure to wave action, related
• to dominant wind direction, storms and ocean
  swell shapes the environment. Conditions will
  control e.g. plant and animal attachment
• 3. Tidal regime tidal range determines the area
  of shore exposed to the air. There is
  considerable
• regional variation
• 4. Climatic conditions weather conditions
  include summer and winter temperature extremes,
• humidity, precipitation and wind exposure.

http//museum.gov.ns.ca/mnh/nature/nhns/h2/h2-1.pd
f
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Rocky Shores

• Rocky shores
• Where the shore is composed of rock outcrops, the
  characteristic species are
• Silene maritima           
• Scilla verna
• Artemisia maritima
• Crithmum maritimum
• Carex distans (in rock crevices)
• Carex extensa (in rock crevices)
• Armeria maritima
• Blysmus rufus (in wet rock crevices)
• Limonium binervosum (at one site only, in Co
  Down)
• Cochlearia danica
• Cochlearia officinalis
• Spergularia rupicola

http//www.habitas.org.uk/flora/habitats/rockyshor
es.htm
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Rocky Shores

• ECOSYSTEM
• Energy supply is obtained through primary
  production by seaweeds and phytoplankton and
  through organic detritus derived from adjacent
  land and other intertidal habitats (e.g., tidal
  marshes). This energy is directly utilized by a
  variety of herbivorous and detritus- feeding
  animals on the shore, which are, in their turn,
  preyed upon by several levels of carnivore on the
  shore, by fish entering the habitat at high tide
  and by terrestrial animals, particularly birds,
  entering at low tide.
• PLANTS
• The plants are typically algae and lichens. In
  sheltered or muddy locations where there is some
  sediment accumulation amongst the rocks and in
  tide pools, Cord Grass and Eelgrass may also be
  found.
• The seaweeds and lichens are distributed on the
  shore in horizontal zones that relate to
  tolerance of the species to either exposure to
  air (seaweeds) or submergence in water (lichens)
  during the tidal cycle

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Rocky Shores

• Zonation
• Few features of the shores are more obvious than
  zonation.
• All shores, no matter how large or small the
  tidal range (max. 17m Bay of Fundy) have at least
  some degree of zonation or vertical banding of
  the organisms living on them.
• Types of Zonation
• Horizontal
• Local (small scale differences)
• Geographical (climate / currents)
• Vertical
• Tides
• Degree of wave action
• Just as plant communities occupy definite bands
  or zones on mountains corresponding to tolerances
  to decreasing temperature with increasing
  elevation, so intertidal communities occupy
  definite zones on the shore. Compared to the
  mountains though, the shorelines are much
  compressed vertically.
• Generally where the range of tides is small or
  where the slope of the beach is steep, the zones
  are generally narrow. Where the slope of the
  beach is flat and the range of tides is great,
  then the zones are wide. Heavy wave action widens
  the zones, both above and below the calm water
  limits and the upper and lower borders of the
  zones are less distinct.

• Horizontal Zonation (Distribution)
• Geographical Scale
• Sea temperature
• Air temperature
• Water currents (larval distribution)
• Local Scale
• Substrate
• Salinity
• Wave
• Exposure
• Topography

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Rocky Shores
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Rocky Shores

• The Tidal Environment
• Shore Zonation - the problems
• Physical pounding by waves
• Being dislodged to unsuitable level
• Desiccation evaporative / physiological
• Temperature variation
• Reproduction
• Planktonic dilutions
• Settlement in suitable benthic regions

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Rocky Shores

• Factors determining zonation
• Rule of limiting factors (applies to adults and
  juveniles / larval stages)
• Tides and their characteristics
• Types and frequency of tides
• Tidal levels for semi-diurnal tides
• Immersion / emersion frequency

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Rocky Shores

• Degree of shore exposure
• Physical effects emersion, light regime,
  dessication, temperature
• Biological interactions larval settlement,
  competition, predation, grazing, behaviour
• Relative influences of physical and biological
  factors

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Rocky Shores

• Conspicuous plants inhabit different zones
• Splash Zone Above the extreme-high-water mark but
  reached by storm waves, the splash zone is
  generally bare of vegetation. There may be
  grasses growing in cracks of rocks and some
  patches of lichens (e.g., Xanthoria parietina).
• Upper Shore Rocks bare at the top but, below
  the level of high water of spring tides, the
  upper shore supports algae (e.g., Codiolum spp.,
  Calothrix crustacea) and lichens (Verrucaria
  spp.)
• Middle Shore - The middle shore supports dense
  growth of brown rockweeds Ascophyllum nodosum and
  Fucus spp. The red seaweed Porphyra and Fucus
  serratus and green seaweeds, such as Cladophora
  spp., are common in some places. The epiphytic
  Polysiphonia lanosa can be found growing on the
  Ascophyllum.
• Lower Shore - Below the dense rockweeds on the
  lower shore, there is a conspicuous zone of Irish
  Moss and calcareous algae (Lithothamnium spp. and
  Corallina officinalis). Below this, kelps
  (Laminaria spp.) are present but only visible at
  low water of spring tides. This zone continues
  into the sub-littoral benthic habitat
• The seaweed growth is usually well developed on
  all rocky shores but is best in exposed,
  clearwater conditions.
• In certain parts of the world ice action and
  turbidity limit seaweed growth.

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Rocky Shores
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Rocky Shores
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Rocky Shores
http//www.mesa.edu.au/friends/seashores/zonation.
html
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Rocky Shores
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Rocky Shores

• For Example
• The barnacle zone is the first clearly demarcated
  zone at the top of the shore and this zone occurs
  on almost every shore in the world.
• This is followed by a zone of mixed barnacles and
  seaweeds, the mid tide region is marked by
  mussels and goose barnacles and beneath this zone
  is another of barnacles and algae and several
  whelks and limpets.
• Below this zone and marking the beginning of the
  lower intertidal zone is the clearly marked zone
  of brown algae (kelp) interspersed with chitons,
  starfish, and surf grass.
• The zones are by no means constant in
  composition, number, width and these factors vary
  from season to season, year to year, shore to
  shore, and even rock to rock.

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Rocky Shores

• ANIMALS
• The animals include marine benthic epifauna
  tolerant to various periods of exposure to the
  air at low tide, and vagrant terrestrial species.
  A system of horizontal zonation of the aquatic
  fauna is apparent.
• Upper Shore - On the bare rock surfaces, there
  are very few animals present, except the Rough
  Periwinkle.
• Middle Shore - At the top, there is a conspicuous
  zone of barnacles, which is limited at its lowest
  extent by the growth of rockweed. There is a
  variety of herbivorous animals, including Rough
  Periwinkles, Smooth Periwinkles, Common
  Periwinkles and amphipod crustaceans. Sessile
  species include Hydroids (Sertularia spp.) and
  Blue Mussels. The Green Sea Urchin is found at
  lower levels. Carnivores which feed mainly on the
  molluscs include Dog Whelks and Purple Starfish.

• Lower Shore - Lower down the shore, the
  diversity of animals increases as more species
  are tolerant to the shorter period of exposure at
  low tide. This is particularly true where animals
  can find shelter under rocks or seaweeds.
  Herbivores include Common Periwinkles, Limpets,
  Green Sea Urchins, isopods and amphipods. The
  sessile particulate feeders include sponges,
  hydroids, tube worms (Spirorbis spp. On
  seaweeds), Horse Mussels, brittle starfish and
  tunicates. The carnivores include Sea Anemones,
  Scale Worms, Purple Starfish, Rock Crabs and Sea
  Slugs.
• Vagrant terrestrial species, insects, birds and
  mammals enter the rocky-shore habitat at low tide
  to feed. Several shore-bird species feeding on
  rocky shores include Ruddy Turnstones Herring
  Gulls are also typical.

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Rocky Shores
Upper Shore
Channelled Wrack (Pelvetia canaliculata)  
Spiral Wrack (Fucus spiralis)
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Rocky Shores
Middle Shore
Beadlet Anemone (Actinia equina)
Edible Periwinkle (L. littorea)    
Shore Crab (Carcinus maenas)
Common Limpet (Patella vulgata)
Bladder Wrack, (Fucus vesiculosus)
Mussels (Mytilis edulis)
http//www.marlin.ac.uk/learningzone/Seashore_life
/species_list_seashore.asp
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Rocky Shores
Lower Shore
Serrated Wrack (Fucus serratus) 
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Rocky Shores
Tortoiseshell limpets can grow up to 3cm across
-noticeably smaller than most other limpets which
you see around Shetland. The background colour of
the shell can range from white to grey to pale
green, and its surface is very smooth  compared
with other limpets. The feature that gives this
limpet its name and makes it stand out from all
the others, is the dark brown stripes which run
from the tip right down to the edge of the shell.
They can be found on boulders or small smooth
stones, particularly those with pink crusts
growing on them. Pearly Topshell (Margarites
helicinus)                     Topshells are a
group of small marine snails. The shell of the
pearly topshell is only about 3mm tall  -
 smaller than a pea! Its colour varies  from an
orange-red to cream-brown, patterned with green
or purple. Topshells are found under stones or
attached to seaweed on the lower shore, as well
as in rock pools. Star Barnacles (Chthamalus
stellatus)
http//www.nature.shetland.co.uk/brc/rocky.htm
25
Rocky Shores

• SPECIAL FEATURES
• The local modification of plant and animal
• zonation relates to the tide range, exposure, ice
  action and other environmental factors.
  Considerable regional variation is seen.
• Tide Pools Where water is retained in
  depressions or cracks in the bedrock during the
  lowtide period, the plants and animals are not
  subjected to dessication. As a result, these
  pools often exhibit rich growths of organisms
  normally associated with the lower shore and
  subtidal habitats. Large pools are not strongly
  influenced by air temperatures, but smaller
  pools, particularly if located at high levels on
  the shore where they may not be flushed out by
  neap tides, experience wide ranges of temperature
  and salinity. In these conditions, only hardy
  algal species, such as Enteromorpha intestinalis,
  can occur.

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Rocky Shores
This diagram shows four different rock pools. No
2 is a shallow high tidal pool in Leigh, where
very few species survive slimy green algae and
tiny Stiliger sea slugs. Pool 3 is an upper mid
littoral splash pool in which the neptune's
necklace seaweed survives. Pools 4 and 5 are deep
lower mid littoral pools from Ocean Beach, near
Whangarei Heads. They are rich pools with many
surviving plant species and sensitive species
such as Cystophora torulosa and Pterocladia
capillacea.
Temperature, Salinity, Oxygen, Sediment, Light,
People
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Rocky Shores

• 1. Supralittoral zone ..near sea but above the
  high tide mark with some marine influence (spray)
  
• 2. Supralittoral fringe...upper limit of
  barnacles (in quantity) to nearest higher
  convenient landmark (upper limit of Littorina or
  lower limit of land lichens. Spring tides invade
  part of this zone. 3. Midlittoral zone the
  entire intertidal areas, from the upper limit of
  barnacles to upper limits of large brown algae at
  the lower part of the shore. The barnacle
  demarcation is an important reference point in
  the universal scheme.
• 4. Infralittoral fringe the lower fringe of the
  intertidal ..an area extending from the upper
  limit of whatever organism sets the lower limit
  of the midlittoral zone, to the ELWS (extreme low
  water spring) tide mark, or in areas of waves, to
  the lowest level visible between waves. Organisms
  living here cannot tolerate complete emersion but
  can live in an area of broken emergence through
  wave action. 5. Infralittoral zone the area
  between ELWS tidal level and corresponding more
  or less to the more commonly used "sublittoral"
  term.

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Rocky Shores

• 1. Spray - This is the uppermost zone that
  extends from the highest reach of spray and storm
  waves to about the mean of all high tides. This
  zone is infrequently wetted. Other authors give
  the following names to this zone Supra-littoral
  or Littorina zone Organisms living in this zone
  are very hardy and semiterrestrial.
• 2. High - This zone extends from the mean high
  water to about the mean flood of the higher of
  the two daily lows which is slightly below mean
  sea level. This is the zone just above the
  mussel beds. Other authors call this the
  mid-littoral or Balanoid zone.
• 3. Mid - This zone extends from the mean
  higher-low water to the mean lower low water
  which is the zero of the tide tables. This zone
  is typically covered and uncovered twice each
  day. Also called lower mid-littoral or lower
  Balanoid zone.
• 4. Low - This zone typically is uncovered only
  by minus tides. This zone can only be examined
  for a few hours each month. Organisms of this
  zone can tolerate only minimum exposure.
  Alsocalled the infra-littoral fringe or Laminaria
  zone.

http//is2.dal.ca/theriaud/ztheriault/xmar/theria
ultst.html
29
Rocky Shores
30
Boulder/Cobble Shores

• Boulder/cobble shore habitats are exposed between
  the extreme high tide and extreme low tide marks.
  They form where there is erosion of glacial till
  on headlands and islands, and are found along the
  whole Nova Scotia coastline. Boulder/cobble
  shores are best developed along the Atlantic
  coast, where there are shoreline drumlins and
  other glacial till deposits.
• In high energy situations (waves, swell, storms),
  the cobbles may form a storm beach at and above
  the high tide mark. Little life will be found
  here because the boulders and cobbles are always
  moving. In intermediate and low-energy
  situations, the boulders rest on a wave-cut
  platform. There can be horizontal zonation in
  plant (seaweed) colonization related to the
  period of exposure at low tide. Various animals
  (barnacles, isopods, amphipods, periwinkles,
  Green Crabs, Dog Whelks, Blue Mussels and Purple
  Starfish) are often present except where
  colonization is limited by the movement of
  boulders and cobbles. Tend to be more
  ecologically barren

31
Boulder/Cobble Shores

• FORMATION
• Boulder/cobble shores form where there is erosion
  of glacial till on headlands and islands. In high
  energy situations, the cobbles may form a storm
  beach at and above the high-tide mark. In
  intermediate- and low-energy situations, the
  boulders rest on a wave-cut platform.
• PHYSICAL ASPECTS
• l. Substrate boulders provide a relatively
  stable hard substrate. Cobbles and pebbles are
  usually mobile.
• 2. Wave action in high-energy situations,
  exposure to wave action, related to dominant wind
  direction, storms and ocean-swell conditions, the
  boulders and cobbles are mobile, limiting
  colonization by intertidal organisms.
• 3. Tidal regime tide range determines the area
  of shore that is exposed to the air.
• 4. Waterland interaction water conditions
  include summer and winter temperature extremes,
  formation and movement of ice, and variations in
  turbidity and salinity.
• 5. Climatic conditions air conditions include
  summer
• and winter temperature extremes, humidity,
• precipitation and wind exposure.

32
Boulder/Cobble Shores

• Wave action, the cobbles are more stable and
  become colonized by encrusting lichens and
  flowering plants, such as Sea-lungwort and Beach
  Pea. Animal life is limited to various species of
  amphipods and fly larvae, which feed on decaying
  seaweed cast up by storms. Spiders and birds prey
  upon these animals.
• ECOSYSTEM
• Primary production within the habitat is limited
  to the seaweed growth, which is very limited or
  absent in exposed situations. Energy also enters
  the system through primary production in the
  plankton, and through suspended organic detritus
  derived
• from the land and adjacent intertidal habitats.
  There are herbivores and detritus-feeders in the
  epifauna, but populations are often small. These
  animals are preyed upon by carnivores, including
  birds.
• In more sheltered locations the boulder spaces
  form a particularly good environment for a wide
  range of animals to hide. Reef Crabs (Ozius
  truncatus), and Variegated Rock Crabs
  (Leptograpsus variegatus), are common.

33
Boulder/Cobble Shores

• PLANTS
• Mainly algae (seaweeds) colonize the surfaces of
  boulders. In intermediate- and low-energy
  situations, there is horizontal zonation related
  to the period of exposure at low tide.
• Upper Shore - On the upper shore, where the
  cobbles are easily moved by wave action, there is
  no seaweed growth, but some lichens and flowering
  plants occur above the high-tide mark.
• Middle Shore - On the middle shore, in sheltered
  conditions, there is a narrow black band of algae
  and lichens below which brown seaweeds, Fucus
  spp. and Ascophyllum nodosum, are conspicuous.
  Various filamentous algae are present in the
  spring. Cord Grass may be found growing in mud
  and gravel between the boulders at lower levels.
  In more exposed situations, the seaweed growth is
  limited by the movement of the boulders and
  cobbles. Where seaweeds do occur, there is
  usually a sparse growth of the brown seaweeds,
  with Irish Moss and the calcareous species
  Corallina officinalis and Lithothamnium spp.
  growing in the lower zone.

34
Boulder/Cobble Shores

• ANIMALS
• The movement of boulders and cobbles in
  high-energy situations severely limits
  colonization by animals.
• In low and intermediate energy situations,
  barnacles, isopods, amphipods, periwinkles, Green
  Crabs, Dog Whelks, Blue Mussels and Purple
  Starfish are often present.
• SPECIAL FEATURES
• On exposed, high-energy shores, the cobbles are
  often washed up to form a storm beach or berm.

35
Rocky Shores

• http//museum.gov.ns.ca/mnh/nature/nhns/h2/h2-1.ht
  m

• http//www.field-studies-council.org/outdoorclassr
  oom/16plussearch/courseinfo.asp?no168

• http//www.lanecc.edu/science/Zonation/marine1.htm

• http//museum.gov.ns.ca/infos/rocky/

• http//www.nature.shetland.co.uk/brc/rocky.htm

• http//www.biol.sc.edu/coral/photo-archive/mollusk
  pics/Molluskpicsindex.html

• http//ecology.hku.hk/jupas/rocky.htm

• http//fieldtrip.britishecologicalsociety.org/rock
  y20tour201/rocky20shore20tour20web/sheltered
  /sheltered.html

• http//www.pbs.org/americanfieldguide/teachers/oce
  ans/Tour_files/frame.htm