Examples of low energy littoral rock:

As the shore becomes increasing sheltered form waves, deposition of sediment increases with sediment often found amongst the rock.   

Seaweeds are able to grow long fronds and come to dominate the shore and characterise the different low energy habitats.


Barnacles become increasingly scarce with increased competition for space and a reduced food supply from the less frequent waves. Instead scavengers and detritovores whose food supply and shelter stems from the seaweeds and the organisms they support increase in number. 

Below are images of low energy littoral rock habitats and characteristic organisms:

LR.LLR.F (Fucoids on sheltered marine shores)

LR.LLR.F (Fucoids on sheltered marine shores)

LR.LLR.F (Fucoids on sheltered marine shores)

Examples of moderate energy littoral habitats:

As wave exposure decreases, the threat of becoming dislodged reduces and the organisms that were confined to the crevices can extend across the shore. Seaweed fronds are less likely to become ripped, so forms are no longer stunted. A patch work of barnacles and seaweeds appear with gastropods grazing on juvenile larvae of both; helping to maintain a balance in the competition for space. Mussels sometimes come to dominate and form beds amongst the barnacles. Organisms that are less robust also begin to appear but are once again often confined to the more sheltered crevices.

Below are images of the two habitat complexes within moderate energy littoral rock habitats:

Moderate energy littoral rock; barnacle and fucoid seaweeds for a patch work like distribution across the shore.
Habitat Classification: LR.MLR.BF (Barnacles and fucoids on moderately exposed shores)

 

Habitat Classification: LR.MLR.BF (Barnacles and fucoids on moderately exposed shores)

Large  Mussels (Mytilus edulis) can sometimes form beds on moderately exposed shores. Habitat Classification: LR.MLR.MusF (Mussels and fucoids on moderately exposed shores)

Examples of high energy littoral rock habitats:

In high energy littoral rock habitats organisms experience the continual pounding of waves and/or strong currents that could dislodge them at any time. Only those that are adapted to with stand the waves and resist dislodgment by strong ‘anchors’ be it large muscular feet of periwinkles or, strong holdfasts and stunted growth in seaweeds can survive. Barnacles with their own special like cement securing them to the rocks thrive and cover the available hard substrate. These barnacles are the characteristic species of high energy environments. Other organisms such as periwinkles, limpets, small mussels and the odd robust seaweed are confined to crevices or, if large enough the old test of a barnacle which provides shelter from the wave exposure.

Below are images of high energy littoral rock habitats and characteristic organisms:

High energy littoral rock can become dominated by barnacles.

 Organisms such as these limpets, periwinkles, small mussels and robust seaweeds are confined to crevices that provide shelter from the dislodging power of waves.

Limpets and mussels seek refuge within a crevice.

Small and rough periwinkles seek refuge within a crevice.

Small periwinkles seek refuge within a crevice.

Examples of littoral rock habitats:

Habitat classifications use the associations between reoccurring groups of organisms, substrate type and wave exposure to describe variations in the communities found on the shore.

In the posts that follow are images of habitats based on the JNCC habitat classification hierarchy with a brief description of each, with emphasis on rocky shores.

One of the major subdivisions of the habitat classification hierarchy the characterization of rocky habitats based on the level of wave exposure experienced by the rock, which ranges from high to low energy. 

The images below show examples of high energy littoral rock, moderate energy littoral rock and low energy littoral rock:

High energy littoral rock (LR.HLR)

Moderate energy littoral rock (LR.MLR)

Low energy littoral rock (LR.LLR)

There is an additional divide to capture specific physical or temporal features within rocky communities that can occur across wave exposures. These habitats come under the habitat Features of littoral rock (LR.FLR). Such features include rockpools, caves and ephemeral seaweeds.

Rockpool habitats would come under the broad habitat features of littoral rock (LR.FLR)

An introduction to common habitats: Littoral rock

Habitat classifications use the associations between reoccurring groups of organisms, substrate type and wave exposure to describe variations in the communities found on the shore.

In the posts that follow are images of habitats based on the JNCC habitat classification hierarchy with a brief description of each, with emphasis on rocky shores.

One of the major subdivisions of the habitat classification hierarchy is littoral rock, which is characterized further by the level of wave exposure experienced by the rock.

Some examples of littoral rock (and hard substrate) include bedrock, artificial hard substrate and boulders. 

Boulders

Bedrock

Artificial hard substrate

Examples of littoral sediment habitats:

Habitat classifications use the associations between reoccurring groups of organisms, substrate type and wave exposure to describe variations in the communities found on the shore.

In the posts that follow are images of habitats based on the JNCC habitat classification hierarchy with a brief description of each, with emphasis on rocky shores.

One of the major subdivisions of the habitat classification hierarchy are littoral sediments:

Littoral sediments include coarse sediments, mixed sediments, sand and mud.

Littoral coarse sediments (LS.LCS) are mobile sediments made up of pebbles, cobbles and gravel.

Littoral mixed sediments (LS.LMx) contain varying amounts of mud, gravel, pebbles and cobbles that are poorly sorted.

Littoral sand (LS.LSa) can vary from coarse to fine and sometimes muddy sands.

Littoral mud (LS.LMu)

An introduction to common habitats

Habitat classifications use the associations between reoccurring groups of organisms, substrate type and wave exposure to describe variations in the communities found on the shore.

The initial step in habitat classification is to determine the dominant substrate type. Be it littoral rock or, littoral sediments:

Littoral rock (LR)

Littoral sediments (LS)

An introduction to common habitats........

Whilst rock pooling you may encounter a range of organism living on a variety of substrates.

Some organisms are only found where you have hard substrate because they need a hard surface on which to attach and grow; whilst, others need to be able to burrow and are therefore confined to sediments.

Often a reoccurring group of organism will be found on a particular type of substrate at a particular position on the shore. This is because the substrate type and its location on the shore correlate with many other environmental variables that all interact to determine the distribution of organisms on the shore.

One of the man influencing environmental variables is the degree to which organisms are sheltered from waves and tidal currents, as this in turn affects the deposition of sediments and determines the characteristic substrate type, which in turn will determine which organisms can survive in that particular area. Waves also have a direct impact on organisms, as large waves can dislodge organisms. Consequently only those organisms that have adaptations to reduce their chances of becoming dislodged are found in these environments.

 Habitat classifications use the associations between reoccurring groups of organisms, substrate type and wave exposure to describe variations in the communities found on the shore.

In the posts that follow are images of habitats based on the JNCC habitat classification hierarchy with a brief description of each, with emphasis on rocky shores.

Rockpooling destination: Seapalling, February 2014

The shore at Seapalling is influenced by a series of artificial sea defences that have changed the dynamics of the shore to produce multiple bays comprised of mobile sands with shingle berms in between.

The hard substrate is characterised by a barnacle community with periwinkles, limpets, dog whelks and beadlet anemones. The lower edges of the breakwater harbour occasional seaweeds, whilst beneath the sea defences are a network of tidal pools.

Since October, the deposition of sediments has changed again and a strand line has formed, whilst there has been further die back of seaweeds.

Habitat classifications:

Substrate	LR (Littoral rock)		LS (Littoral substrate)
Habitat	HLR (High energy littoral rock)	FLR (Features of littoral rock)	LS.LSa (Littoral sand)
Biotope complex	LR.HLR. MusB (Mussel and/or barnacle communities)	Eph.FLR.Eph (Ephemeral green or red seaweed communities	LS.LSa.sh (Shingle and gravel shores)	LS.LSa.St (Strandline)	LS.LSa.MoSa.BarSa (Barren littoral coarse sand)
Biotope		LR.FLR.Eph.EntPor (Porphyra purpurea and Entomorpha spp. on sand scoured lower eulittoral rock)

Below are images of some of the organisms you may encounter whilst rock pooling in these habitats:

The sea defences provide an artificial hard substrate amongst the littoral sediments of the shore. During the winter months strandlines of washed up hornwrack (Flustra foliacea) form. Habitat classification: LR.HLR (High energy littoral rock), LS.LSa (Littoral sand) and LS.LSa.St (Strandline).

The sea defences comprise large rectangular boulders that have relatively shear faces. Habitat classification: LR.HLR (High energy littoral rock). The littoral sediments surrounding the sea defences continually experience the dynamic forces of erosion and deposition.  At this time sand has been deposited against the sea defences, while review of this location in October (image below)  shows a lower sediment level that is comprised of sand and shingle.

The same location as above but a few months previous shows how the sediment distributions have changed, from sand and shingle to increased deposition of sand.

Rocky shore communities have formed on the artificial sea defences; barnacles, limpets and periwinkles occur throughout and characterise the biotope complex LR.HLR.MusB (Mussels and/or barnacles in high energy littoral rock).

Spiral wrack (Fucus spiralis) has experienced further die back since October (see image below).

Spiral wrack (Fucus spiralis) in October.

Periwinkles (Littorina sp) amongst barnacles. 

A juvenile dog whelk (Nucella lapillus) amongst barnacles. 

The barnacles covering the rock are of variable sizes indicating a mixed aged community. The dead barnacles provide shelter for a variety of including  periwinkles (Littorina sp)

Limpets within the barnacle community.

Mastocarpus stellatus on a barnacle covered boulder.

The deposition of sand has covered barnacle clad boulders.

Limpets and barnacles ‘emerge’ from the sand, an indication of the relatively recent deposition. 

Nearer to the low water mark, Serrated wrack (Fucus serratus) occurs on a boulder and on the boulders edges ‘emerges’ from the sand.

Beneath the boulder overhangs it is cooler, damp and shaded with interconnecting tidal pools. Barnacles, beadlet anemones (Actinia equina) and dog whelks (Nucella lapillus) occur across these shaded rock faces. 

Sand deposition has filled many of the tidal pools.  Here beadlet anemones (Actinia equina) and common starfish (Asterias rubens) occur where once there was a pool.

Anemones (Urticina spp) washed up last year now inhabit a a pool that has been subject to sand deposition

Anemones (Urticina spp)