1. © SSER Ltd.

2. The Rocky Shore
Rocky shores are diverse and dynamic ecosystems where the inhabiting communities survive between two worlds – the sea and the land
The familiar shoreline or littoral region is that area of shore which lies between the high-water mark and the low-water mark of spring tides
These littoral zones may differ greatly from one another as local geology, wave action and aspect, influence the structure of the shoreline
Living organisms in these intertidal regions face continual fluctuating environmental conditions as they are subjected to cyclic exposure and submergence from tidal activity
The distribution of life on the littoral shore reflects the development of specialised structures and tissues that adapt the different species to the prevailing conditions

3. Differences in exposure to the force of the waves have a modifying effect on the communities inhabiting sheltered and exposed shores

4. Diversity on The Rocky Shore
The sheltered rocky shore provides a variety of habitable environments where the diversity and the composition of species can be related to their positions on the shore
The exposed rock faces, cervices and intertidal pools provide habitats for a range of species that display adaptations to the local prevailing conditions
The sheltered rocky shore described here is located on the east coast of North Yorkshire where encrusting barnacles and mussels and seaweeds dominate the shore
The following discussion describes the findings of a group of students who surveyed the shore and who carried out a number of investigations based upon their observations

5. The Lower Shore Environmental conditions on the lower shore are
less harsh and relatively stable as surface populations are
never uncovered by the tide for more than a few hours at a time
Species diversity is high on the lower shore and competition for food and space is fierce
Fucus serratus (toothed-wrack) is the dominant brown alga of the lower shore and is intolerant of desiccation (cell wall thickness 0.45 mm)
Red algae are intolerant of desiccation and form dense turfs beneath the carpet of Fucus serratus; these algae are tolerant of shade and possess the additional pigment (phycoerythrin) for efficient photosynthesis at low light levels
Sponges, anemones, sea slugs, blenny fish and shrimps occupy this zone alongside many other species of animals and algae

6. The Laminaria Zone The Laminaria Zone is occupied by species that are
rarely uncovered by the tide but are subjected to intense wave action
Environmental conditions in this zone are relatively constant and productivity is high; this is the least harsh area of the rocky shore providing niches for the establishment of a large diversity of organisms where competition is fierce
The kelps (Laminaria species) are the dominant brown algae of this zone where they form underwater ‘forests’ displaying prolific growth
These giant algae are intolerant of desiccation and possess flexible stipes that attach firmly to the ocean bottom with their powerful holdfasts
Numerous, shade-tolerant species of red algae are found growing among the kelps
Starfish, brittle stars, marine worms and sea urchins are found feeding in this zone

7. Zonation and Diversity
The zonation of both plants and animals observed on this sheltered shore reflected adaptations to different environmental conditions, with diversity increasing from the harsh upper shore to the less harsh lower shore
The brown algae displayed a distinctive zonation pattern that related largely to their ability to resist desiccation and to photosynthesise effectively
Brown algae have developed specialised structures and tissues for reducing desiccation, anchoring themselves to the rocks and ocean bottom, and photosynthesising effectively
Brown algae are distinguished by the presence of the accessory pigment, fucoxanthin; this brown pigment enables the algae to absorb blue-green light (the wavelengths that penetrate deep into the water)

8. The holdfast at the base of the stipes of these brown algae anchors them to the rocks

9. subjected to fluctuating environmental conditions
Zonation pattern
of brown seaweeds
on the sheltered
rocky shore
Organisms inhabiting
the upper shore are
subjected to fluctuating
environmental conditions
and the drying effects
of the air during the
tidal cycle

11. A group of students investigated the distribution of brown algae along a sloping sheltered rocky shore
A transect was laid down along the shore by laying a tape, at right angles to the sea, from the splash zone to the low water mark (LWM)
A one metre, square quadrat frame was used to determine the percentage cover of algae at two-metre intervals along the tape
A five-point abundance scale was used to record the percentage cover of algae within each frame
Abundance scale
% Cover 1
< 5% 2 5 –
25% 3
>25
50% 4
>50
75%

12. Transect Results
Species of Brown Algae
Pelvetia
canaliculata
Fucus
spiralis
vesiculosus
serratus
Laminaria
sp.
Splash
zone 18
HWM 16 2 1
Upper
Shore 14 5 12 4 10 3 8 6
Middle
shore
Lower
Distance
from
low
water
mark (m)
LWM
Draw kite diagrams to illustrate the distribution of algae along the shore
Discuss the pattern of distribution displayed by the different species of algae
Suggest reasons for the pattern of distribution observed

13. Kite Diagram for rocky shore transect
Fucus
spiralis
vesiculosus
serratus
Laminaria
sp.
Pelvetia
canaliculata 2 4 6 8 10 12 14 16
Upper shore
Middle shore
Lower shore

14. Brown Algae and Desiccation
Students collected samples of three different species of brown algae in containers of seawater
and returned them to the laboratory for
further investigation
Each group of students collected three samples of Fucus serratus, Fucus spiralis and Fucus vesiculosus
After blotting off the excess seawater, all the samples were weighed and their initial masses recorded
Clamp stands and string were used to construct ‘washing lines’ to which the algae were then attached
The algae were weighed every thirty minutes for the first two hours and then hourly for a further three hours
The percentage fresh mass at each time interval was calculated for each species and the group results were pooled
The mean percentage fresh mass was determined and the results presented graphically

15. Construct a graph of the data obtained
Pooled Results
Construct a graph of the data obtained

16. Mean % Change in Mass against Time
for different species of brown algae
Relate these results to the zonation pattern of the algae