Rockpooling destination: Seapalling, Norfolk October 2013

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 previous visits, in March and April, certain features of the shore have changed, including changed in sand deposition, decreased ephemeral algae and increased barnacle biomass. Many of the species ‘washed in’ by the storm in March still persist within the tidal pools beneath the sea defences.

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)	Rkp (Rockpools)	Eph.FLR.Eph (Ephemeral green or red seaweed communities	LS.LSa.sh (Shingle and gravel shores)	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. Habitat classification: LR.HLR (High energy littoral rock) and LS.LSa (Littoral sand).

Sand masons (Lanice conchilega) occur on the lower shore of one of the multiple bays. Habitat description: LS.LSa (Littoral sand).

Two spherical eyes protruding from the sand give away the position of a shrimp (Crangonidae) buried in a tidal pool of the sheltered bay. 

A goby is equally camouflaged in a tidal pool of the sheltered bay

The sea defences comprise large rectangular boulders that have relatively shear faces. Habitat classification: LR.HLR (High energy littoral rock).

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).

The barnacles show a patchy distribution across the rock, often only covering certain faces of the rock; possibly as a result of variation in settlement success.

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

Rough periwinkles (Littorina sp) and a small common mussel (Mytilus edulis) seek shelter within the ‘hollowed’ remains of barnacles. 

Small and Rough periwinkles  (Melarhaphe neritoides and Littorina sp) seek shelter within the ‘hollowed’ remains of barnacles.

Limpets (Patella vulgata) within the barnacle community.

Mastocarpus stellatus and ephemeral green seaweeds on barnacles

Seaweeds have colonised a small rockpool. Habitat classification: LR.FLR.Rkp (Rockpools).

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. 

Beadlet anemone (Actinia equina).

A dog whelk (Nucella lapillus).

A limpet

 The tidal pools beneath the sea defences host a number of species that were possibly washed in by the winter storms. Many of the subtidal species observed washed up on the beach  during March are now found within these pools.

Since the storm in March Common starfish (Asterias rubens) are frequently encountered beneath the break water

Common whelks (Buccinum undatum), usually a subtidal species occur beneath the breakwater.  It is possible that these individuals have come up from the mussel community observed at extreme low tide at this site.

Common whelk (Buccinum undatum)

Common whelk (Buccinum undatum) smells food out with its siphon.

An anemone (Urticina spp). 

Many Urticina were washed up during the winter storms (Photo from winter 2013).

 Seasonal Comparisons: since April the deposition of sand behind the sea defence has changed with sand eroded from the base of the sea defences at some locations to reveal more boulders and elsewhere deposited.  Ephemeral algae has decreased in abundance and barnacle biomass has increased on many boulders.

 Since April the spiral wrack (Fucus spiralis) has come out of its reproductive phase with receptacles absent or burst and the ephemeral green algae has died back. Habitat classification: LR.HLR.MusB (Mussels and/or barnacles in high energy littoral rock).

April

July- the spiral wrack is in its reproductive phase and ephemeral green algae is present.

October - the spiral wrack is not in its reproductive phase and ephemeral green algae has died back.

 In this example below, barnacle biomass has increased and  all but two limpets maintain the same position on the boulder face, except for two who are absent in the photo from the October survey.

April

October

 Two photographs, the first in April and the second October, reveal changes in sediment deposition at one location on the shore.

April

October, sediment has been removed from this location, revealing the rocks beneath.

Rockpooling destination: Land's End Peninsular, September 2013

Revisit of Land’s End Peninsular

The bay experiences a dynamic regime, alternating between periods of erosion and deposition. The underlying substrate is boulders, however, variable amounts of sand may be deposited on top, sourced from the sand bar situated offshore. The communities encountered reflect the alternation between these regimes.

At the time of visitation the beach was mainly sand with boulders exposed in the region of the river and amongst out cropping bedrock in the mid to lower shore.

Steep cliffs surround the bay, craggy edges of which are covered by lichens. Below, large swathes of sand cover the shore through which a fresh water river has eroded a channel to the sea. Steep sloping bedrock and cliff bases of the mid and lower shore are covered by barnacles, limpets, periwinkles and whelks. Boulders and bedrock of the mid and lower shore host a similar barnacle community plus a variety of seaweeds, including where sand scour is event, ephemeral seaweeds. Throughout the mid and lower shore rockpools occur.

The shore is comprised of bed rock and boulders over which sand has been deposited. A river brings fresh water onto the shore and erodes the sand to reveal the boulders beneath and a succession of strandlines mark the recession of the lowering tide. Habitat classification: LR.HLR (High energy littoral rock), LR. MLR (Moderate energy littoral rock), LS.Sa (Littoral sand) and LS.Sa.st (Strandline).

Habitats classification:

Substrate	LR (Littoral rock)									LS (Littoral sediment)
Habitat	LR.HLR (High energy littoral rock)	LR.MLR (Moderate energy littoral rock)			LR.FLR (Features of ilttoral rock)					LS.LSa (Littoral sand)
Biotope complex	LR. HLR.MusB (Mussels and/or barnacles on high energy littoral rock)	LR.MLR.BF (Barnacles and fucoids on moderately exposed shores)			LR.FLR.Rkp (Rockpools)		LR.FLR.Eph (Ephemeral green or red seaweed communities	LR.FLR.CvoV (Littoral caves and overhangs).	LR.FLR.Lic (Lichens on supralittoral rock)	LS.LSa.St (Strandline)
Biotope		LR.MLR.BF .FspiB (Fucus spiralis on full salinity exposed to moderately exposed upper eulittoral rock)	LR.MLR.BF .Fser (Fucus serratus on moderately exposed eulittoral rock)	LR.MLR.BF .Rho (Rhodothamniella floridula on sand scoured lower eulittoral rock)	LR.FLR.Rkp .Cor (Corallina officinalis, coralline crusts and brown seaweeds in shallow eulittoral rockpools)	LR.FLR.Rkp .SwSed (Seaweeds in sediment- floored eulittoral rockpools).	LR.FLR.Eph.EntPor (Porphyra purpurea and Entomorpha spp. on sand scoured mid to  lower eulittoral rock)
Sub Biotope			LR.MLR.BF.Fser.R (Fucus serratus and red seaweeds on moderately exposed lower eulittoral rock)		LR.FLR.Rkp.Cor.Cor (Corallina officinalis and coralline crusts in shallow eulittoral rockpools)

The communities found were similar to those of the previous visit.

Below are photographs of some of the organisms encountered whilst rock pooling in this habitat.

Fresh water influx cuts a channel through the uppershore to reveal the cobbles below the sand.

Spiral wrack (Fucus spiralis) and ephemeral green seaweed occur on the more sheltered bedrock of the upper shore. Habitat classification: LR.MLR.BF.FspiB (Fucus spiralis on full salinity exposed to moderately exposed upper eulittoral rock).

Small periwinkles (Melarhaphe neritoides) seek refuge within a crevice of the steep faced bedrock which supports an upper shore community akin to littoral fringe biotopes. 

Small periwinkle (Melarhaphe neritoides). 

Representatives of the species complex ‘Rough periwinkle’ Littorina saxatilis agg also inhabit the bed rock. 

Representatives of the species complex ‘Rough periwinkle’ Littorina saxatilis agg. 

Representatives of the species complex ‘Rough periwinkle’ Littorina spp. 

In the cervices of the steep sided cliffs in the mid and lower shore barnacles, common mussels (Mytilus edulis) and Limpets occur. The barnacles and mussels characterise the biotope complex LR.HLR.MusB (Mussel and/or barnacle communities).

Within the barnacle community small rock pools are colonised by the coralline algae, Corallina officinalis  and Corallinaceae crusts, which, characterise the biotope LR.FLR.Cor.Cor (Corallina officinalis and coralline crusts in shallow eulittoral rockpools).

Where these pools drain into damp crevices coralline algae grow as ‘turfs’. Habitat classification: LR.HLR.MusB (Mussel and/or barnacle communities).

The distribution of fauna in the mid and lower shore is influenced by wave exposure, sand scour, fresh water runoff and desiccation. The result is a patchwork of biotopes that are not distributed evenly down the shore. Here mid shore boulders tops are colonised by barnacles and gastropods, whilst below fucoids occur. Habitat classification: LR.MLR. BF (Barnacles and fucoids on moderately exposed shores).

Barnacles, Dog whelks (Nucella lapillus) and limpets cover the boulder, whilst fucoid seaweeds colonise rock below that occurs at a lower altitude and is thus exposed to desiccation for a lower period of time. Habitat classification: LR.MLR. BF (Barnacles and fucoids on moderately exposed shores).

Barnacles.

Limpets have a low shell profile to deflect the wave’s energy as an adaptation to the wave exposure. 

Where sand is deposited on the boulders fauna are forced to aggregate on the remaining available substrate. 

The tops of fucoids are an indication of the relatively recent sand deposition. 

Fucoids ‘emerge’ from the sand, which has been deposited relatively recent. 

The shore exhibits a mosaic of boulders and sand with the hard substrate colonised by barnacles, fucoids and ephemeral green algae. Habitat classification: LR.MLR. BF (Barnacles and fucoids on moderately exposed shores) LR.FLR.Eph (Ephermeral green or red seaweeds (Fresh water or sand influenced), LS.Sa (Sand).

Between the hard substrate are sandy pools within which seaweed species have colonised available hard substratum. Habitat classification: LR.FLR.Rckp.SwSed (Seaweeds in sediment- floored eulittoral rockpools).

LR.FLR.Rckp.SwSed (Seaweeds in sediment- floored eulittoral rockpools).

LR.FLR.Rckp.SwSed (Seaweeds in sediment- floored eulittoral rockpools).

Serrated wrack (Fucus serratus) covers less exposed boulders of the lower shore and characterises the biotope LR.MLR.BF .Fser (Fucus serratus on moderately exposed eulittoral rock).

Lomentaria articulata and cladophora rupestris form part of the Fucus serratus understory community.

Mastocarpus stellatus forms a mosaic distribution with Fucus serratus. The distribution of Fucus serratus and red seaweeds in this manner is characteristic of the biotope LR.MLR.BF.Fser.R (Fucus serratus and red seaweeds on moderately exposed lower eulittoral rock).

Mastocarpus stellatus forms a mosaic distribution with Fucus serratus. 

In areas of the lower shore where the influence of sand scour is increased sand binder (Rhodothamniella floridula) occurs. Habitat classification: LR.MLR.BF.Rho (Rhodothamniella floridula on sand scoured lower eulittoral rock)

Sand binder (Rhodothamniella floridula). 

Entomorpha sp and Porphyra sp covers boulders in an area of sand scour and fresh water runoff. Habitat classification: LR.FLR.Eph.EntPor (Porphyra purpurea and Entomorpha spp. on sand scoured mid to lower eulittoral rock)  

Sections of the lower and mid shore experiencing sand scour have a community characterised by ephemeral and sand tolerant seaweeds. In this patch the green ephemeral Entomorpha sp covers boulders. Habitat classification: LR.FLR.Eph.EntPor (Porphyra purpurea and Entomorpha spp. on sand scoured mid to lower eulittoral rock)

Porphyra covers sand scoured boulders. 

The ephemeral green seaweed Cladophora rupestris and a flat periwinkle (Littorina sp). 

The ephemeral green seaweed Cladophora rupestris.

Caves in the cliff provide shelter from desiccation and the surrounding biotopes often penetrate into the cave entrance. Habitat classification: LR.FLR.CvoV (Littoral caves and overhangs).

The shaded entrance to the cave supports the red seaweeds Osmundea sp, Lomentaria articulata and Corallinaceae crusts, the green seaweed Cladophora rupestris, beadlet anemones (Actinia equina) and common limpets (Patella vulgata). Many of these species have come from the surrounding Barnacles and fucoids biotope where they occur in the shaded understory, conditions similar to the entrance of the cave.

The shaded entrance to the cave supports Osmondea sp. 

Sand scoured gully on shore