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AQUAFACT INTERNATIONAL SERVICES LTD 12 KILKERRIN PARK

TUAM ROAD GALWAY CITY

www.aquafact.ie

info@aquafact.ie

tel +353 (0) 91 756812 fax +353 (0) 91 756888

Table of Contents

1. Executive Summary................................................................................. 1

2. Introduction .............................................................................................. 1

3. Materials & Methods ................................................................................ 2

3.1. Sampling Procedure ............................................................................... 2 3.2. Sample Processing ................................................................................. 4

3.3. Data Analysis .......................................................................................... 6

4. Results ...................................................................................................... 9

4.1. Fauna ..................................................................................................... 9 4.1.1. Univariate Analysis ....................................................................................... 9 4.1.2. Multivariate Analysis ................................................................................... 10 4.2. Sediment .............................................................................................. 15 4.3. Station Summary .................................................................................. 18

5. Discussion/Conclusion ......................................................................... 19

6. References ............................................................................................. 20

List of Figures

Figure 2.1: Location of the Ocean Energy Test Site ............................................................................. 2

Figure 3.1: Location of all stations sampled on the 30th

August 2012. ................................................ 3

Figure 4.1: Dendrogram produced from Cluster analysis. ................................................................. 12

Figure 4.2: MDS plot. ....................................................................................................................... 13

List of Tables

Table 3.1: Station coordinates and depths. ........................................................................................ 3

Table 3.2: The classification of sediment particle size ranges into size classes (adapted from

Buchanan, 1984) ........................................................................................................................ 5

Table 4.1: Univariate measures of community structure. ................................................................... 9

Table 4.2: SIMPER Results ................................................................................................................ 14

Table 4.3: Organic carbon results from the 5 grab stations sampled. ............................................... 15

Table 4.4: Sediment type and Folk (1954) classification. .................................................................. 17

Table 4.5: Station summary data ..................................................................................................... 18

List of Appendices

Appendix 1 Photographic Log Appendix 3 Sediment Analysis Methodologies Appendix 3 Faunal Abundances

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1. Executive Summary

AQUAFACT sampled Inner Galway Bay on the 30th August 2012 from the R.V. Celtic Voyager. Five

grab stations were surveyed. All stations were sampled for fauna (which were sieved on a 1mm

mesh sieve), granulometry and organic carbon.

The sediment type along the cable route varied from muddy fine sand to gravelly muddy sand. The

muddy fine sand stations were located west of the Ocean Energy Test Site outside the 20m contour

line and the coarser more gravelly substrate was encountered inside the 20m contour line closer to

the Spiddle coastline. Organic content was considered average at all stations except GB 04 where

levels were considered high. Group a conformed to the JNCC habitat SS.SMU.ISaMu.MelMagThy

Melinna palmata with Magelona spp. and Thyasira spp. in infralittoral sandy mud (EUNIS Code:

A5.334) and Group b contained elements of the latter habitat and SS.SSA.CMuSa.AalbNuc Abra alba

and Nucula nitidosa in circalittoral muddy sand or slightly mixed sediment (EUNIS Code: A5.261)

All of the species present are typical of the area. No rare, sensitive or unusual species were recorded

during this survey.

2. Introduction

AQUAFACT International Services Ltd. was commissioned by the Marine Institute to carry out a

subtidal benthic survey along a proposed cable route in Inner Galway Bay. The cable route is located

between the Ocean Energy Test Site (located approximately 2.7km southeast of Spiddle) and the

shoreline at Spiddle. Figure 2.1 shows the location of the Ocean Energy Test Site in relation to the

coastline.

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Figure 2.1: Location of the Ocean Energy Test Site

3. Materials & Methods

3.1. Sampling Procedure

To carry out the subtidal benthic assessment, AQUAFACT sampled a total of 5 stations. Sampling

took place on the 30th August 2012 from the RV Celtic Voyager. The weather on the day was calm

with 2/8 cloud cover and a moderate northwesterly breeze. All stations sampled can be seen in

Figure 3.1 and Table 3.1 shows the station coordinates and depths.

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Figure 3.1: Location of all stations sampled on the 30th

August 2012.

Table 3.1: Station coordinates and depths.

Station Longitude Latitude Easting (ITM)

Northing (ITM)

Easting (ING)

Northing (ING)

Depth (m)

GB 01 -9.2714 53.22728 515108 720407.9 115101 220405.2 26.2

GB 02 -9.28955 53.22636 513894.2 720327.9 113887.1 220325.2 26.6

GB 03 -9.30703 53.22689 512728.2 720408.1 112721 220405.4 27.2

GB 04 -9.30937 53.23346 512585.1 721141.1 112577.9 221138.5 24.5

GB 05 -9.2922 53.2296 513723.9 720691.4 113716.8 220688.7 25.2

AQUAFACT has in-house standard operational procedures for benthic sampling and these were

followed for this project. Additionally, the recently published MESH report on “Recommended

Standard methods and procedures” was adhered to.

A 0.1m2 Day grab was used to sample the proposed cable route. On arrival at each sampling station,

the vessel location was recorded using DGPS (Lat/Long and Easting & Northing). Additional

information such as date, time, site name, sample code, depth, sampler, anchorage, weather, sea

state and exposure were recorded in a data sheet.

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One grab sample was taken at each station. The grab deployment and recovery rates did not exceed

1 metre/sec and were <0.5 m/sec for the last 5 metres for water depths up to 30m and for the last

10m for depths greater than 30m. Upon retrieval of the grab, penetration depth was measured and

recorded in the sample data sheet. Only grab samples that contained a depth of >7cm for sand and

>10cm for mud were retained. All additional relevant data (sediment type, texture, grain size, colour,

odour, layering, volume, presence of fauna, algae, surface features) were recorded in the sample

data sheets.

A digital image of each sample (including sample label) was taken and its reference number entered

in the sample data sheet. These images can be seen in Appendix 1. The grab sampler was cleaned

between stations to prevent cross contamination.

A sediment sample was retrieved from the grab and split into two, one sample for granulometric

analysis and one sample for organic carbon. Both samples were placed in plastic sampling bags and

labelled internally and externally. These samples were frozen (<-18ºC) as soon as possible after

acquisition.

The remainder of the grab sample was carefully and gently sieved on a 1mm mesh sieve as a

sediment water suspension for the retention of fauna. Great care was taken during the sieving

process in order to minimise damage to taxa such as spionids, scale worms, phyllodocids and

amphipods. Very stiff clay was fragmented very carefully by hand. The sample residue was carefully

flushed into a pre-labelled (internally and externally) container from below. Each label contained the

sample code and date. The samples were stained immediately with Eosin-briebrich scarlet and fixed

immediately in with 4% w/v buffered formaldehyde solution (10% w/v buffered formaldehyde

solution for very organic mud). These samples were ultimately preserved in 70% alcohol upon return

to the laboratory.

3.2. Sample Processing

All faunal samples were placed in an illuminated shallow white tray and sorted first by eye to remove

large specimens and then sorted under a stereo microscope (x 10 magnification). Following the

removal of larger specimens, the samples were placed into Petri dishes, approximately one half

teaspoon at a time and sorted using a binocular microscope at x25 magnification.

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The fauna was sorted into four main groups: Polychaeta, Mollusca, Crustacea and others. The

‘others’ group consisted of echinoderms, nematodes, nemerteans, cnidarians and other lesser phyla.

The fauna were maintained in stabilised 70% industrial methylated spirit (IMS) following retrieval

and identified to species level where practical using a binocular microscope, a compound

microscope and all relevant taxonomic keys. After identification and enumeration, specimens were

separated and stored to species level.

The sediment granulometric analysis was carried out by AQUAFACT using the traditional

granulometric approach. Traditional analysis involved the dry sieving of approximately 100g of

sediment using a series of Wentworth graded sieves. The process involved the separation of the

sediment fractions by passing them through a series of sieves. Each sieve retained a fraction of the

sediment, which were later weighed and a percentage of the total was calculated. Table 3.2 shows

the classification of sediment particle size ranges into size classes. Sieves, which corresponded to the

range of particle sizes (Table 3.2), were used in the analysis. Refer to Appendix 2 for a detailed

methodology of this procedure.

Table 3.2: The classification of sediment particle size ranges into size classes (adapted from Buchanan, 1984)

Range of Particle Size Classification Phi Unit

<63µm Silt/Clay >4 Ø

63-125 µm Very Fine Sand 4 Ø, 3.5 Ø

125-250 µm Fine Sand 3 Ø, 2.5 Ø

250-500 µm Medium Sand 2 Ø, 1.5 Ø

500-1000 µm Coarse Sand 1 Ø, 1.5 Ø

1000-2000 µm (1 – 2mm) Very Coarse Sand 0 Ø, -0.5 Ø

2000 – 4000 µm (2 – 4mm) Very Fine Gravel -1 Ø, -1.5 Ø

4000 -8000 µm (4 – 8mm) Fine Gravel -2 Ø, -2.5 Ø

8 -64 mm Medium, Coarse & Very Coarse Gravel -3 Ø to -5.5 Ø

64 – 256 mm Cobble -6 Ø to -7.5 Ø

>256 mm Boulder < -8 Ø

Organic carbon analysis was carried out by the OMAC Laboratories using the Loss on Ignition

technique outlined in Appendix 2.

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3.3. Data Analysis

Statistical evaluation of the data was undertaken using PRIMER v.6 (Plymouth Routines in Ecological

Research). Univariate statistics in the form of diversity indices are calculated. Numbers of species

and numbers of individuals per sample will be calculated and the following diversity indices will be

utilised:

1) Margalef’s species richness index (D) (Margalef, 1958),

DS 1

log2 N

where: N is the number of individuals

S is the number of species

2) Pielou’s Evenness index (J) (Pielou, 1977)

J =H' (observed)

Hmax

'

where: H max

'

is the maximum possible diversity, which could be achieved if all

species were equally abundant (= log2S)

3) Shannon-Wiener diversity index (H') (Pielou, 1977)

H'= - p ii=1

S

(log2 pi )

where: pI is the proportion of the total count accounted for by the ith taxa

4) Simpson’s Diversity Index (Simpson, 1949)

1-λ’ = 1-{ΣiNi(Ni-1)} / {N(N-1)}

where N is the number of individuals of species i.

Species richness is a measure of the total number of species present for a given number of

individuals. Evenness is a measure of how evenly the individuals are distributed among different

species. The Shannon-Wiener index incorporates both species richness and the evenness component

of diversity (Shannon & Weaver, 1949) and Simpson’s index is a more explicit measure of the latter,

i.e. the proportional numerical dominance of species in the sample (Simpson, 1949).

The PRIMER programme (Clarke & Warwick, 2001) was used to carry out multivariate analyses on

the station-by-station faunal data. All species/abundance data from the grab surveys was square

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root transformed and used to prepare a Bray-Curtis similarity matrix in PRIMER ®. The square root

transformation was used in order to allow the intermediate abundant species to play a part in the

similarity calculation. All species/abundance data from the samples was used to prepare a Bray-

Curtis similarity matrix. The similarity matrix was then be used in classification/cluster analysis. The

aim of this analysis was to find “natural groupings’ of samples, i.e. samples within a group that are

more similar to each other, than they are similar to samples in different groups (Clarke & Warwick,

loc. cit.). The PRIMER programme CLUSTER carried out this analysis by successively fusing the

samples into groups and the groups into larger clusters, beginning with the highest mutual

similarities then gradually reducing the similarity level at which groups are formed. The result was

represented graphically in a dendrogram, the x-axis representing the full set of samples and the y-

axis representing similarity levels at which two samples/groups are said to have fused. SIMPROF

(Similarity Profile) permutation tests were incorporated into the CLUSTER analysis to identify

statistically significant evidence of genuine clusters in samples which are a priori unstructured.

The Bray-Curtis similarity matrix was also be subjected to a non-metric multi-dimensional scaling

(MDS) algorithm (Kruskal & Wish, 1978), using the PRIMER programme MDS. This programme

produced an ordination, which is a map of the samples in two- or three-dimensions, whereby the

placement of samples reflects the similarity of their biological communities, rather than their simple

geographical location (Clarke & Warwick, 2001). With regard to stress values, they give an indication

of how well the multi-dimensional similarity matrix is represented by the two-dimensional plot. They

are calculated by comparing the interpoint distances in the similarity matrix with the corresponding

interpoint distances on the 2-d plot. Perfect or near perfect matches are rare in field data, especially

in the absence of a single overriding forcing factor such as an organic enrichment gradient. Stress

values increase, not only with the reducing dimensionality (lack of clear forcing structure), but also

with increasing quantity of data (it is a sum of the squares type regression coefficient). Clarke &

Warwick (loc. cit.) have provided a classification of the reliability of MDS plots based on stress

values, having compiled simulation studies of stress value behaviour and archived empirical data.

This classification generally holds well for 2-d ordinations of the type used in this study. Their

classification is given below:

Stress value < 0.05: Excellent representation of the data with no prospect of

misinterpretation.

Stress value < 0.10: Good representation, no real prospect of misinterpretation of overall

structure, but very fine detail may be misleading in compact subgroups.

Stress value < 0.20: This provides a useful 2-d picture, but detail may be misinterpreted

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particularly nearing 0.20.

Stress value 0.20 to 0.30: This should be viewed with scepticism, particularly in the upper

part of the range, and discarded for a small to moderate number of points such as < 50.

Stress values > 0.30: The data points are close to being randomly distributed in the 2-d

ordination and not representative of the underlying similarity matrix.

Each stress value must be interpreted both in terms of its absolute value and the number of data

points. In the case of this study, the moderate number of data points indicates that the stress value

can be interpreted more or less directly. While the above classification is arbitrary, it does provide a

framework that has proved effective in this type of analysis.

The species, which are responsible for the grouping of samples in cluster and ordination analyses,

were identified using the PRIMER programme SIMPER (Clarke & Warwick, 1994). This programme

determined the percentage contribution of each species to the dissimilarity/similarity within and

between each sample group.

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4. Results

4.1. Fauna

The taxonomic identification of the benthic infauna across all 5 stations sampled on Inner Galway

Bay yielded a total count of 122 taxa, consisting of 790 individuals ascribed to 9 phyla. Of the 122

taxa, 87 were identified to species level. The remaining 35 could not be identified to species level for

the following reasons: 18 were juveniles, 14 were partial/damaged and 3 were indeterminate.

Appendix 3 shows the faunal abundances from Inner Galway Bay.

Of the 122 taxa enumerated, 62 were annelids (segmented worms), 21 were molluscs (mussels,

cockles, snails etc.), 21 were crustaceans (crabs, shrimps, prawns), 10 were echinoderms

(brittlestars, sea cucumbers), 5 species were cnidarians (sea anemones, jellyfish, corals etc), 1 was a

nemertean (ribbon worm), 1 was a nematode (round worm), and 1 was a phoronid (horseshoe

worms).

4.1.1. Univariate Analysis

Prior to the statistical analyses, those taxa that were recorded as juveniles AND partial/damaged

were combined to give just one count for the taxa e.g. Edwardsiidae sp. (juvenile) and Edwardsiidae

sp. (partial/damaged) were combined to give Edwardsiidae sp.

Univariate statistical analyses were carried out on the station-by-station faunal data. The following

parameters were calculated and can be seen in Table 4.1; taxon numbers, number of individuals,

richness, evenness, Shannon-Weiner diversity and Simpson’s Diversity. Taxon numbers ranged from

35 (Station GB 03) to 71 (Station GB 04). Number of individuals ranged from 84 (Station GB 03) to

357 (Station GB 04). Richness ranged from 7.67 (Station GB 03) to 11.91 (Station GB 04). Evenness

ranged from 0.82 (Stations GB 03) to 0.93 (Station GB 02). Shannon-Weiner diversity ranged from

4.65 (Station GB 03) to 5.09 (Station GB 01). Simpson’s diversity ranged from 0.95 (Station GB 04) to

0.97 (Stations GB 01, GB 02 and GB 05).

Table 4.1: Univariate measures of community structure.

Station No. Taxa

No. Individuals

Richness Evenness Shannon-Weiner Diversity

Simpson's Diversity

GB 01 48 135 9.58 0.91 5.09 0.97

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GB 02 44 102 9.30 0.93 5.08 0.97

GB 03 35 84 7.67 0.91 4.65 0.96

GB 04 71 357 11.91 0.82 5.06 0.95

GB 05 43 112 8.90 0.91 4.95 0.97

4.1.2. Multivariate Analysis

The dendrogram and the MDS plot can be seen in Figures 4.1 and 4.2 respectively. SIMPROF analysis

revealed 2 statistically significant groupings between the 5 stations (the samples connected by red

lines cannot be significantly differentiated). The stress level on the MDS plot indicates an excellent

representation of the data with no prospect of misinterpretation.

A clear divide can be seen between Group a (Station GB 04) and Group b (Stations GB 01, GB 02, GB

03 and GB 05). Group a and Group b separated at a 29.76% similarity level.

Group a contained 71 species comprising 357 individuals. Of the 71 species, 43 were present twice

or less. Seven species accounted for 50% of the faunal abundance in this group: the polychaete

Melinna palmata (52 individuals, 14.6% abundance), the gastropod Turritella communis (35

individuals, 9.8% abundance), Nematoda sp. (31 individuals, 8.7% abundance), Nemertea sp. (16

individuals, 4.5% abundance), the polychaete Monticellina cf dorsobranchialis (16 individuals, 4.5%

abundance), the crustacean Tanaopsis graciloides (16 individuals, 4.5% abundance) and the bivalve

Thyasira flexuosa (14 individuals, 3.9% abundance). SIMPER analysis could not be carried out on this

group as it only contained 1 station. This station was classified as gravelly muddy sand. This group

conforms to the JNCC habitat SS.SMU.ISaMu.MelMagThy Melinna palmata with Magelona spp. and

Thyasira spp. in infralittoral sandy mud (EUNIS Code: A5.334).

Within Group b, stations GB 02 and GB 05 were 58.96% similar and stations GB 01 and GB 03 were

56.48% similar. All four stations formed a group at a similarity level of 53.22%. This group contained

83 species comprising 433 individuals. Of the 83 species, 44 were present twice or less. Ten species

accounted for 50% of the faunal abundance: the polychates Chaetozone setosa (33 individuals, 7.6%

abundance) and Spiophanes bombyx (31 individuals, 7.2% abundance), the bivalve Thyasira flexuosa

(29 individuals, 6.7% abundance), the polychaetes Mediomastus fragilis (24 individuals, 5.5%

abundance) and Owenia fusiformis (18 individuals, 4.2% abundance), the phoronid Phoronis sp. (18

individuals, 4.2% abundance), the polychaete Tharyx killariensis (17 individuals, 3.9% abundance),

the amphipods Ampelisca brevicornis (17 individuals, 3.9% abundance) and Ampelisca diadema (17

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individuals, 3.9% abundance) and the polychaete Diplocirrus glaucus (14 individuals, 3.2%

abundance). The SIMPER analysis revealed an average group similarity of 54.72%, with 10 species

contributing to 52.04% of the similarity: the polychaete Chaetozone setosa (7.59% similarity), the

bivalve Thyasira flexuosa (7.12% similarity), the polychaete Spiophanes bombyx (6.62% similarity),

the amphipod Ampelisca brevicornis (5.63% similarity), the phoronid Phoronis sp. (5.36% similarity),

the polychaetes Mediomastus fragilis (5.13% similarity) and Tharyx killariensis (5.06% similarity), the

amphipod Ampelisca diadema (4.91% similarity) and the polychaete Owenia fusiformis (4.63%

similarity). Table 4.2 shows the full SIMPER results. All of the stations in Group b were classified as

muddy sands. This group contains elements of two JNCC habitats: SS.SSA.CMuSa.AalbNuc Abra alba

and Nucula nitidosa in circalittoral muddy sand or slightly mixed sediment (EUNIS Code: A5.261) and

SS.SMU.ISaMu.MelMagThy Melinna palmata with Magelona spp. and Thyasira spp. in infralittoral

sandy mud (EUNIS Code: A5.334).

SIMPER analysis also revealed that Groups a and b had an average dissimilarity of 70.24%. Twenty-

eight species accounted for just over 50% of this dissimilarity and all can be seen in Table 4.2. The

top five species responsible for the dissimilarity are the polychaete Melinna palmata (4.85%

dissimilarity), Nematoda sp. (4.07% dissimilarity), the gastropod Turritella communis (3.83%

dissimilarity), the crustacean Tanaopsis graciloides (2.93% dissimilarity) and the polychaete

Monticellina cf dorsobranchialis. These species were abundant in Group a and either absent or rare

in Group b.

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Figure 4.1: Dendrogram

produced from Cluster

analysis.

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Figure 4.2: MDS plot.

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Table 4.2: SIMPER Results

Group a Less than 2 samples in group

Group b Average similarity: 54.72

Species Av.Abund Av.Sim Sim/SD Contrib% Cum.%

Chaetozone setosa 2.85 4.15 7.17 7.59 7.59

Thyasira flexuosa 2.67 3.9 20.89 7.12 14.71

Spiophanes bombyx 2.72 3.62 6.17 6.62 21.34

Ampelisca brevicornis 2.05 3.08 5.37 5.63 26.96

Phoronis sp. 2.08 2.93 3.82 5.36 32.32

Mediomastus fragilis 2.31 2.81 4.23 5.13 37.45

Tharyx killariensis 2.02 2.77 6.88 5.06 42.5

Ampelisca diadema 2.01 2.69 3.7 4.91 47.42

Owenia fusiformis 2.03 2.53 2.8 4.63 52.04

Diplocirrus glaucus 1.82 2.41 8.32 4.41 56.45

Spiochaetopterus typicus 1.47 1.99 5.74 3.64 60.09

Nephtys sp. 1.39 1.94 4.82 3.54 63.64

Nucula nitidosa 1.39 1.94 4.82 3.54 67.18

Echinocardium sp. 1.35 1.72 5.56 3.14 70.32

Ampharete lindstroemi 1.1 1.61 11.58 2.93 73.25

Magelona alleni 1.35 1.22 0.91 2.23 75.48

Phaxas pellucidus 1.22 1.14 0.91 2.08 77.56

Iphinoe serrata 1.04 0.92 0.86 1.69 79.25

Lumbrineridae sp. 1.31 0.85 0.89 1.55 80.8

Aricidea (Acmira) laubieri 1.22 0.85 0.89 1.55 82.35

Melinna sp. 0.96 0.85 0.89 1.55 83.9

Sthenelais limicola 0.75 0.8 0.91 1.47 85.37

Veneridae sp. 0.93 0.8 0.91 1.47 86.84

Leptopentacta elongata 0.75 0.8 0.91 1.47 88.3

Lumbrineris near cingulata 0.71 0.42 0.41 0.76 89.07

Leptosynapta sp. 0.6 0.3 0.41 0.54 89.61

Malmgreniella andreapolis 0.5 0.29 0.41 0.53 90.14

Groups b & a Average dissimilarity = 70.24

Species Group b Av.Abund

Group a Av.Abund

Av.Diss Diss/SD Contrib% Cum.%

Melinna palmata 0.6 7.21 3.41 6.6 4.85 4.85

Nematoda sp. 0 5.57 2.86 19.57 4.07 8.93

Turritella communis 0.68 5.92 2.69 5.66 3.83 12.76

Tanaopsis graciloides 0 4 2.06 19.57 2.93 15.69

Monticellina cf dorsobranchialis 0.25 4 1.93 6.74 2.75 18.43

Nemertea sp. 0.6 4 1.75 4.44 2.49 20.92

Lumbrineris near cingulata 0.71 3.46 1.41 3.8 2 22.92

Spiophanes bombyx 2.72 0 1.39 4.44 1.97 24.9

Hyalinoecia bilineata 0 2.65 1.36 19.57 1.94 26.83

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Species Group b Av.Abund

Group a Av.Abund

Av.Diss Diss/SD Contrib% Cum.%

Scalibregma inflatum 0 2.45 1.26 19.57 1.79 28.63

Ampelisca brevicornis 2.05 0 1.06 6.33 1.51 30.13

Pectinaria sp. 0 2 1.03 19.57 1.46 31.6

Tubificoides amplivastus 0 2 1.03 19.57 1.46 33.06

Metaphoxus pectinatus 0 2 1.03 19.57 1.46 34.52

Ampelisca sp. 0.25 2.24 1.02 3.86 1.45 35.98

Myrtea spinifera 0.5 2.24 0.89 3.04 1.27 37.25

Golfingiidae sp. 0 1.73 0.89 19.57 1.27 38.51

Podarkeopsis helgolandica 0 1.73 0.89 19.57 1.27 39.78

Aonides oxycephala 0 1.73 0.89 19.57 1.27 41.05

Diplocirrus glaucus 1.82 3.46 0.85 2.97 1.21 42.26

Lumbrineridae sp. 1.31 2.83 0.8 1.25 1.14 43.4

Galathowenia oculata 0.5 2 0.77 2.62 1.1 44.5

Nucula sp. 0.25 1.73 0.77 2.77 1.1 45.59

Cerianthus lloydii 0 1.41 0.73 19.57 1.04 46.63

Pholoe baltica (sensu Petersen) 0 1.41 0.73 19.57 1.04 47.66

Glycera alba 0 1.41 0.73 19.57 1.04 48.7

Cirrophorus branchiatus 0 1.41 0.73 19.57 1.04 49.73

Euclymene lumbricoides 0 1.41 0.73 19.57 1.04 50.77

4.2. Sediment

Table 4.3 shows the organic carbon results and Table 4.4 shows the sediment type and the sediment

classification (Folk, 1954) attributed to each station. Organic carbon levels ranged from 2.32% at

station GB 03 to 5.57% at station GB 04.

Table 4.3: Organic carbon results from the 5 grab stations sampled.

Station LOI @ 450°C (%)

GB 01 2.58

GB 02 2.50

GB 03 2.32

GB 04 5.57

GB 05 2.64

Station GB 04 contained the highest percentage of gravel (fine and very fine; 6%), very coarse sand

(17.8%), coarse sand (22.3%) and medium sand (10%). Station GB 01 had the highest percentage of

fine sand (35.2%), station GB 02 had the highest percentage of very fine sand (72.6%) and station GB

03 had the highest percentage of silt-clay (28.2%). The very fine sand fraction was the highest

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sediment fraction at four of the stations (GB 01, GB 02, GB 03 and GB 05) and the coarse sand

fraction was the highest sediment fraction at station GB 04. The sediment sampled along the

proposed cable route was classified as muddy sand and gravelly muddy sand according to Folk

(1954).

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Table 4.4: Sediment type and Folk (1954) classification.

Station %

4000<8000 m (Fine Gravel)

%

2000<4000 m (Very Fine

Gravel)

%

1000<2000 m (Very Coarse

Sand)

%

500<1000 m (Coarse Sand)

%

250<500 m (Medium

Sand)

%

125<250 m (Fine Sand)

%

63<125 m (Very Fine

Sand)

% <63 m (Silt-Clay

Folk Classification

GB 01 0.1 0.1 0.6 1.4 1.9 35.2 48.2 12.5 Muddy sand

GB 02 0 0 0.6 1.4 2 6.2 72.6 17.1 Muddy sand

GB 03 0 0 0.4 1.2 2.1 5.8 62.3 28.2 Muddy sand

GB 04 1.8 4.2 17.8 22.3 10 9.5 18.9 15.5 Gravelly muddy sand

GB 05 0 0 0.4 1 1.8 4.8 72.8 19 Muddy sand

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4.3. Station Summary

Table 4.5 below summaries the station – by – station data.

Table 4.5: Station summary data

Station Depth

(m)

No.

Taxa

No.

Individuals

Dominant

Species

Sediment

Type

LOI Photo

GB 01 26.2 48 135 Mediomastus

fragilis

Muddy sand 2.58

GB 02 26.6 44 102 Thyasira

flexuosa,

Chaetozone

setosa and

Owenia

fusiformis

Muddy sand 2.50

GB 03 27.2 35 84 Chaetozone

setosa

Muddy sand 2.32

GB 04 24.5 71 357 Melinna

palmata

Gravelly

muddy sand

5.57

GB 05 25.2 43 112 Spiophanes

bombyx and

Thyasira

flexuosa

Muddy sand 2.64

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5. Discussion/Conclusion

The sediment type along the cable route varied from muddy fine sand to gravelly muddy sand. The

muddy fine sand stations were located west of the Ocean Energy Test Site outside the 20m contour

line and the coarser more gravelly substrate was encountered inside the 20m contour line closer to

the Spiddle coastline. Organic content was considered average at all stations except GB 04 where

levels were considered high. This same sediment type was recorded in the general area by O’Connor

et al. (1993).

O’Connor et al. (1993) in describing the benthic macrofaunal assemblages of Galway Bay recorded

tow variations of soft substrate facies in the area of the Ocean Energy and comment that the fauna

combines elements of Thorson’s Amphiura and Venus (Chamelea) communities.

Test SiteTwo different faunal groupings were identified from along the proposed cable route. These

groupings mirrored the two different sediment classifications along the route. Group a contained

station GB 04, the shallower coarser site. The polychaete Melinna palmata, the gastropod Turritella

communis, Nematoda sp, Nemertea sp., the polychaete Monticellina cf dorsobranchialis, the

crustacean Tanaopsis graciloides and the bivalve Thyasira flexuosa dominated this group. This group

conforms to the JNCC habitat SS.SMU.ISaMu.MelMagThy Melinna palmata with Magelona spp. and

Thyasira spp. in infralittoral sandy mud (EUNIS Code: A5.334).

Group b contained the deeper finer sediment stations (GB 01, GB 02, GB 03 and GB 05) The

polychates Chaetozone setosa and Spiophanes bombyx, the bivalve Thyasira flexuosa, the

polychaetes Mediomastus fragilis and Owenia fusiformis, the phoronid Phoronis sp, the polychaete

Tharyx killariensis, the amphipods Ampelisca brevicornis and Ampelisca diadema and the polychaete

Diplocirrus glaucus dominated this group. This group contains elements of two JNCC habitats:

SS.SSA.CMuSa.AalbNuc Abra alba and Nucula nitidosa in circalittoral muddy sand or slightly mixed

sediment (EUNIS Code: A5.261) and SS.SMU.ISaMu.MelMagThy Melinna palmata with Magelona

spp. and Thyasira spp. in infralittoral sandy mud (EUNIS Code: A5.334).

The polychaete Melinna palmata, Nematoda sp., the gastropod Turritella communis, the crustacean

Tanaopsis graciloides and the polychaete Monticellina cf dorsobranchialis were responsible for the

dissimilarity between the two faunal groups.

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All of the species present are typical of the area. No rare, sensitive or unusual species were recorded

during this survey.

6. References

Clarke, K.R. & R.M. Warwick. 2001. Changes in marine communities: An approach to statistical

analysis and interpretation. 2nd Edition. Primer-E Ltd.

Folk, R.L. (1954). The distinction between grain size and mineral composition in sedimentary rock

nomenclature. Journal of Geology 62 (4): 344-359.

Margalef, D.R. 1958. Information theory in ecology. General Systems 3: 36-71.

O’Connor, B., McGrath, D., Konnecker, G. and Keegan, B. (1993). Benthic macrofaunal assembles of

Greater Galway Bay. Proc. Roy. Ir. Acad., 93B : 127 – 136.

Pielou, E.C. (1977). Mathematical ecology. Wiley-Water science Publication, John Wiley and Sons.

pp.385.

Shannon, C.E. & W. Weaver. 1949. The mathematical throry of communication. University of Illinois

Press, Urbana.

Simpson, E.H. 1949. Measurement of diversity. Nature 163: 688.

Thorson, G. (1957). Bottom communities (sublittoral or shallow shelf). Mem. Geol. Soc. Am., 67: 461

– 534.

Appendix 1

Photographic Sample Log

GB 01

GB 02

GB 03

GB 04

GB 05

Appendix 3

Sediment Analysis Methodologies

Granulometry

1. Approximately 25g of dried sediment is weighed out and placed in a labelled 1L glass beaker to which 100 ml of a 6 percent hydrogen peroxide solution was then added. This was allowed to stand overnight in a fume hood.

2. The beaker is placed on a hot plate and heated gently. Small quantities of hydrogen peroxide are added to the beaker until there is no further reaction. This peroxide treatment removes any organic material from the sediment which can interfere with grain size determination.

3. The beaker is then emptied of sediment and rinsed into a. 63µm sieve. This is then washed with distilled water to remove any residual hydrogen peroxide. The sample retained on the sieve is then carefully washed back into the glass beaker up to a volume of approximately 250ml of distilled water.

4. 10ml of sodium hexametaphosphate solution is added to the beaker and this solution is stirred for ten minutes and then allowed to stand overnight. This treatment helps to dissociate the clay particles from one another.

5. The beaker with the sediment and sodium hexametaphosphate solution is washed and rinsed into a 63µm sieve. The retained sampled is carefully washed from the sieve into a labelled aluminium tray and placed in an oven for drying at 100ºC for 24 hours.

6. When dry this sediment is sieved through a series of graduated sieves ranging from 4 mm down to 63µm for 10 minutes using an automated column shaker. The fraction of sediment retained in each of the different sized sieves is weighed and recorded.

7. The silt/clay fraction is determined by subtracting all weighed fractions from the initial starting weight of sediment as the less than 63µm fraction was lost during the various washing stages.

Organic Content

1. The collected sediments should be transferred to aluminium trays, homogenised by hand and dried in an oven at 100º C for 24 hours.

2. A sample of dried sediment should be placed in a mortar and pestle and ground down to a fine powder.

3. 1g of this ground sediment should be weighed into a pre-weighed crucible and placed in a muffle furnace at 450ºC for a period of 6 hours.

4. The sediment samples should be then allowed to cool in a dessicator for 1 hour before being weighed again.

5. The organic content of the sample is determined by expressing as a percentage the weight of the sediment after ignition over the initial weight of the sediment.

Appendix 3 Faunal Abundance

Station

GB 01 GB 02 GB 03 GB 04 GB 05 CNIDARIA D 1

ANTHOZOA D 583 HEXACORALLIA D 627 CERIANTHARIA D 628 Cerianthidae D 630 Cerianthus lloydii D 632

2 ACTINIARIA D 662

Actiniaria sp. (juvenile) D 662

1

Edwardsiidae D 759 Edwardsiidae sp. (partial/damaged) D 759 2

Edwardsiidae sp. (juvenile) D 759

1 Edwardsia claparedii D 766

1

NEMATODA HD 1 Nematoda sp. (indet) HD 1

31 NEMERTEA G 1

Nemertea sp. (indet) G 1

1

16 2

SIPUNCULA N 1 SIPUNCULIDEA N 2 GOLFINGIIFORMES N 10 Golfingiidae N 11 Golfingiidae sp. (partial/damaged) N 11

3 Phascolionidae N 29

Aspidosiphon (Aspidosiphon) muelleri muelleri N 47

1

ANNELIDA P 1 POLYCHAETA P 2 PHYLLODOCIDA P 3 Polynoidae P 25 Malmgreniella andreapolis P

1 1 1

Pholoidae P 90 Pholoe inornata P 92

1 2 Pholoe baltica (sensu Petersen) P 95

2

Sigalionidae P 96 Sthenelais limicola P 109 1

1

1

Phyllodocidae P 114 Phyllodocidae sp. (partial/damaged) P 114

1 Eteone longa aggregate P 118

1

Eumida bahusiensis P 164

1

Glyceridae P 254 Glycera alba P 256

2 Glycera tridactyla P 265

1

Goniadidae P 266 Glycinde nordmanni P 268

1 Goniada maculata P 271

2

1

Hesionidae P 293 Podarkeopsis helgolandica P

3

Exogoninae P 410 Exogone hebes P 421

1 Nereididae P 458

Nereididae sp. (juvenile) P 458 1

1 Nephtyidae P 490

Station

GB 01 GB 02 GB 03 GB 04 GB 05 Nephtys sp. (juvenile) P 494 2 1 2

3

Nephtys hombergii P 499 1

4

EUNICIDA P 536 Onuphidae P 537 Hyalinoecia bilineata P 539

7 Lumbrineridae P 569

Lumbrineridae sp. (juvenile) P 569 8 2

8 Lumbrineridae sp. (partial/damaged) P 569

1

Lumbrineris near cingulata P

2 2 12 Abyssoninoe hibernica P

1

ORBINIIDA P 654 Paraonidae P 674 Aricidea (Acmira) laubieri P 686 2 6

1

Cirrophorus branchiatus P 690

2 Paradoneis lyra P 699 1

2

SPIONIDA P 707 Spionidae P 720 Aonides sp. (partial/damaged) P 721

1 Aonides oxycephala P 722

3

Dipolydora flava P 754

1 Prionospio sp. (partial/damaged) P 763

1

Prionospio fallax P 765

3

1

Prionospio multibranchiata P

2 Spio sp. (juvenile) P 787

1

Spiophanes bombyx P 794 12 4 5

10

Magelonidae P 802 Magelona alleni P 804 3 5 2 1

Magelona filiformis P 805

1 Magelona minuta P 806 1

1

Chaetopteridae P 810 Spiochaetopterus typicus P 820 3 3 1 2 2

Cirratulidae P 822 Cirratulidae sp. (partial/damaged) P 822 3

3 1

Caulleriella zetlandica P 831

1 Chaetozone setosa P 834 6 7 12 3 8

Monticellina cf dorsobranchialis P 844

16 1

Tharyx killariensis P 846 5 6 2 2 4

FLABELLIGERIDA P 872 Flabelligeridae P 873 Diplocirrus glaucus P 878 4 2 2 12 6

CAPITELLIDA P 902 Capitellidae P 903 Mediomastus fragilis P 919 13 4 5 8 2

Notomastus latericeus P 921 1 Maldanidae P 938

Euclymene lumbricoides P 963

2 OPHELIIDA P 992

Scalibregmatidae P 1020 Scalibregma inflatum P 1027

6 OWENIIDA P 1089

Oweniidae P 1090

Station

GB 01 GB 02 GB 03 GB 04 GB 05 Galathowenia oculata P 1093 1

1 4

Owenia fusiformis P 1098 5 7 1 7 5

TEREBELLIDA P 1099 Pectinariidae P 1100 Pectinariidae sp. (juvenile) P 1100

1 Pectinaria sp. (juvenile) P 1106

4

Lagis koreni P 1107 1 2 Ampharetidae P 1118

Melinna sp. (juvenile) P 1120 2 1

2

Melinna palmata P 1124 2

52 1

Ampharete sp. (juvenile) P 1133 1 Ampharete lindstroemi P 1139 1 2 1 1 1

Trichobranchidae P 1171 Terebellides stroemi P 1175

1 Terebellidae P 1179

Terebellidae sp. (partial/damaged) P 1179

1 Pista cristata P 1217

1

Polycirrus sp. (partial/damahed) P 1235

1

OLIGOCHAETA P 1402 TUBIFICIDA P 1403 Tubificidae P 1425 Tubificoides amplivastus P 1489

4 CRUSTACEA R 1

OSTRACODA R 2412 MYODOCOPIDA R 2413 Philomedidae R 2417 Euphilomedes sinister R

2

EUMALACOSTRACA S 23 AMPHIPODA S 97 Leucothoidae S 175 Leucothoe lilljeborgi S 178

2

1

Phoxocephalidae S 252 Harpinia antennaria S 254 1 1

Metaphoxus pectinatus S 262

4 Ampeliscidae S 422

Ampelisca sp. (partial/damaged) S 423

1

5 Ampelisca brevicornis S 427 3 4 5

5

Ampelisca diadema S 429 2 3 7 10 5

Ampelisca spinipes S 438 6 Ampelisca typica S 442

1

Melitidae S 495 Cheirocratus sp. (female) S 503

1

1

Cheirocratus sundevalli S 506

1 Photidae S

Photis longicaudata S 552

1 2

TANAIDACEA S 1099 Anarthruidae S 1115 Tanaopsis graciloides S 1142

16 CUMACEA S 1183

Bodotriidae S 1184 Iphinoe sp. (partial/damaged) S 1200

1

Station

GB 01 GB 02 GB 03 GB 04 GB 05 Iphinoe serrata S 1201 1

2

3

Leuconiidae S 1204 Eudorella truncatula S 1208 1 1

1

Diastylidae S 1244 Diastylis laevis S 1251

1 Diastylis rugosa S 1254

2

DECAPODA S 1276 Decapoda larvae S 1276

1 Alpheidae S 1328

Alpheus glaber S 1330

1 PAGUROIDEA S 1436

Paguridae S 1445 Paguridae sp. (juvenile) S 1445

1 MOLLUSCA W 1

CHAETODERMATIDA W 3 Chaetodermatidae W 7 Chaetoderma nitidulum W 9 4 1

POLYPLACOPHORA W 46 NEOLORICATA W 47 Leptochitonidae W 48 Leptochiton cancellatus W 54

2 GASTROPODA W 88

Gastropoda sp. (partial/damaged) W 98

1 MESOGASTROPODA W 256

Turritellinae W 267 Turritella communis W 270

1

35 3

Iravadiidae W 406 Hyala vitrea W 410 1

Naticidae W 482 Euspira pulchella W 491 1

Eulimidae W 599 Melanella sp. (partial/damaged) W 633

1 Melanella alba W 634 2

NEOGASTROPODA W 670 Mangeliidae W 771 Bela brachystoma W

1

OPISTHOBRANCHIA W CEPHALASPIDEA W 1002

Cylichnidae W 1024 Cylichna cylindracea W 1028

1

1

PELECYPODA W 1560 NUCULOIDA W 1561 Nuculidae W 1563 Nucula sp. (juvenile) W 1565 1

3

Nucula nitidosa W 1569 2 1 2

3

VENEROIDA W 1815 Lucinidae W 1817 Myrtea spinifera W 1827 1

1 5

Lucinoma borealis W 1829

1

1 Thyasiridae W 1833

Thyasira flexuosa W 1837 7 7 5 14 10

Station

GB 01 GB 02 GB 03 GB 04 GB 05 Montacutidae W 1888

Kurtiella bidentata W 1906

3

2 Pharidae W 1995

Phaxas pellucidus W 2006 3 2

3

Semelidae W 2057 Abra sp. (juvenile) W 2058 1

1

Veneridae W 2086 Veneridae sp. (juvenile) W 2086 3

1

1

MYOIDA W 2140 Corbulidae W 2153 Corbula gibba W 2157

2 PHOLADOMYOIDA W 2220

Thraciidae W 2226 Thracia sp. (juvenile) W 2228 1 1

PHORONIDA ZA 1 Phoronidae ZA 2 Phoronis sp. (indet) ZA 3 5 2 5 5 6

ECHINODERMATA ZB 1 OPHIUROIDEA ZB 105 OPHIURIDA ZB 121 Amphiuridae ZB 148 Amphiuridae sp. (juvenile) ZB 148 3

1

Amphiura filiformis ZB 154

1 Amphipholis squamata ZB 161

1

1

ECHINOIDEA ZB 181 ECHINOIDA ZB 190 Echinidae ZB 194 Echinocyamus pusillus ZB 212

1 SPATANGOIDA ZB 213

Loveniidae ZB 221 Echinocardium sp. (juvenile) ZB 222 2 1 4

1

Echinocardium cordatum ZB 223

1

1

HOLOTHURIOIDEA ZB 229 DENDROCHIROTIDA ZB 249 Phyllophoridae ZB 258 Thyone fusus ZB 262

2 Cucumariidae ZB 266

Leptopentacta elongata ZB 280 1

1

1

APODIDA ZB 289 Synaptidae ZB 290 Leptosynapta sp. (partial/damaged) ZB 291

1 2 1 Leptosynapta bergensis ZB 292

1 2