Irish West Coast Research Articles

Floating breakwater pontoon pilot cast with carbon textile reinforcement-based ultra high durability concrete: Materials development and testing, and implementation in the North Atlantic (Irelands west coast)

A floating unit with three pontoons made of epoxy-coated carbon textile reinforced, ultra-high durability concrete (ECF UHDC), mineral impregnated carbon fibre-reinforced UHDC (MCF UHDC) and, as references, steel-reinforced concretes has been designed and installed in the Northern Atlantic. While marine structures with steel reinforcement require large cover depths, which cause problems in size, cost, environmental friendliness and short service life, carbon textile reinforced concrete (TRC) cannot suffer from chloride-induced corrosion of a metal reinforcement. In the EU H2020 project “ReSHEALience” (rethinking coastal defence and green-energy service infrastructures through enhanced-durability highperformance cement-based materials), TRCs have been modified with functional admixtures from consortium partners. A mineral self-healing promoter and alumina nano-fibers have, among others, been implemented to boost high-performance concretes towards UHDCs. Resulting composite variants have been applied in a full-scale floating unit that has been launched in the harbor of Galway at the Irish West Coast in June 2020. Such a floating body is a representation of breakwaters installed to reduce wave impacts to the coast. Besides, TRC-based UHDC can be applied as strengthening and repair layer on concrete structures to enhance their service life in general.

SEAWEED PRESENCE DETECTION USING MACHINE LEARNING AND REMOTE SENSING

Abstract. The human pressure over coastal areas is becoming increasingly relevant, due to the combinations of resource depletion, climate change effects and ocean eutrophication. Coastal ecosystems are so exposed to a huge number of stress factors that endanger their ecosystem services, like carbon uptake and biodiversity maintenance, that can be crucial in facing the effects of climate changes. With a particular focus on seaweeds, these ecosystems are becoming rapidly relevant both for carbon sinks and as a source of high value products, for example thanks to cosmetic and food industries that produce high added values products.In this contest the capability of conducting efficient monitoring is crucial to monitor environmental dynamics and resources trends. Traditionally seaweed monitoring was carried out with on field surveys that could be based on botanic analysis combined with genetic study, depending on the aims. Recently Remote Sensing techniques, combined with Artificial Intelligence ones, gave a new perspective to seaweed monitoring, introducing tools that are always more efficient.In this contest the present work aims to test the potentiality of remote sensing and artificial intelligence techniques for seaweed monitoring along the Irish west coast, building the basis for a fully automated tool for monitoring. The results showed that, with a supervised classification approach, it is possible to train Random Forest (RF) to perform very precise classification over the entire West Coast of Ireland. In particular, with all the RF configurations tested the Overall Accuracy (OA) was greater than 98.61, with the best performance obtained with the configuration Ntree = 600 and mtry = 2 that produced an OA = 98.87.

Temporal and spatial distribution of Azadinium species in the inland and coastal waters of the Pacific northwest in 2014–2018

Azaspiracids, produced by some species of the dinoflagellate genera Azadinium and Amphidoma, can cause a syndrome in humans called azaspiracid shellfish poisoning (AZP). In 1995, mussels from the Irish west coast contaminated with azaspiracids were, for the first time, linked to this human illness that has symptoms of nausea, vomiting, severe diarrhea, and stomach cramps. The only confirmed cases of AZP to date in the United States occurred in Washington State in 2008 from mussels imported from Ireland. Shortly after this case, several others involving similar gastrointestinal symptoms were reported by shellfish consumers from Washington State. However, no detectable diarrhetic shellfish toxins or Vibrio contamination were found. Cursory analysis of Solid Phase Adsorption Toxin Tracking (SPATT) samplers suggested the presence of azaspiracids in Washington State waters and motivated a study to evaluate the presence and distribution of Azadinium species in the region. During the spring and summer months of 2014–2015, quantitative polymerase chain reaction (qPCR) analyses detected the presence of the toxigenic species Azadinium poporum and A. spinosum on the outer coast and throughout the inland waters of Washington State. In 2016–2018, standard curves developed using A. poporum isolated from Puget Sound and A. spinosum isolated from the North Sea were used to quantify abundances of up to 10,525 cells L−1 of A. poporum and 156 cells L−1 of A. spinosum at shore-based sites. Abundances up to 1,206 cells L−1 of A. poporum and 30 cells L−1 of A. spinosum were measured in the coastal waters of the Pacific Northwest in 2017. Other harmful genera, including Alexandrium, Dinophysis, and Pseudo-nitzschia, were observed using light microscopy at coastal sites where A. poporum was also observed. In some samples where both A. poporum and A. spinosum were absent, an Amphidomataceae-specific qPCR assay indicated that other species of Azadinium or Amphidoma were present. The identification of Azadinium species in the PNW demonstrates the need to assess their toxicity and to incorporate their routine detection in monitoring programs to aid resource managers in mitigating risks to azaspiracid shellfish poisoning in this region.

Validation of a wave forecast system for Galway Bay

ABSTRACTAn operational wave forecast system for the area of Galway Bay is presented. Three numerical models are implemented: Weather Research and Forecasting (WRF), Wavewatch III (WWIII) and Simulating Waves Nearshore (SWAN). GFS (Global Forecast System) winds, from NCEP (National Centres for Environmental Prediction), are used to force the WWIII model, while WRF winds are used to force the SWAN model. Bathymetries for WWIII and SWAN were obtained from NOAA’s GEODAS (Geophysical Data System) data base and from GEBCO (General Bathymetric Chart of the Oceans), hosted by BODC. The wave generation model, WWIII, is used to simulate waves for the whole North Atlantic, whereas the SWAN model runs for the Irish west coast, with a nested grid for Galway Bay. Forecast products of 7 days are produced daily, with a warm up of 4 days. The validations of the forecast system were made for both wind and wave parameters with data from buoys located in the Irish coast and inside Galway Bay. Comparisons in the time domain as well as a statistical analysis were performed. Overall, the wave forecast system gave good results closely reproducing the real data, with a low error.

Boulder transport by storms – Extreme-waves in the coastal zone of the Irish west coast

This study is concerned with large boulders located along exposed shorelines in higher latitudes, which have become dislocated onshore by winter storms and have moved against gravity. To identify the transportation processes that these boulders have undergone in detail, their direct investigation during storm wave conditions is necessary, or at least near time inspections after extraordinary wave events. As both methods are rare, a wide range of questions and contradictions with regards to the processes that have acted on these boulders, remains. Despite a lack of applicable methods as for fine sediments, the depositional environment and processes of boulder movement can be determined from geomorphologic evidence in the landscape itself. Examples are presented in this paper. To progress understanding of boulders in rocky coastal environments, qualitative and quantitative data are acquired during a near time inspection following extreme storms in winter 2013/14 with special focus on an extraordinary boulder site near Doolin at the entrance to Galway Bay (central west coast of Ireland). The comparison of these data to previously published research on coastal boulder movement results in agreements and discrepancies (e.g. on boulder forms and mode of transport, difference in wave and bore transport) which are discussed.

Identification of Azadinium species and a new azaspiracid from Azadinium poporum in Puget Sound, Washington State, USA

The identification of a new suite of toxins, called azaspiracids (AZA), as the cause of human illnesses after the consumption of shellfish from the Irish west coast in 1995, resulted in interest in understanding the global distribution of these toxins and of species of the small dinoflagellate genus Azadinium, known to produce them. Clonal isolates of four species of Azadinium, A. poporum, A. cuneatum, A. obesum and A. dalianense were obtained from incubated sediment samples collected from Puget Sound, Washington State in 2016. These Azadinium species were identified using morphological characteristics confirmed by molecular phylogeny. Whereas AZA could not be detected in any strains of A. obesum, A. cuneatum and A. dalianense, all four strains of A. poporum produced a new azaspiracid toxin, based on LC–MS analysis, named AZA-59. The presence of AZA-59 was confirmed at low levels in situ using a solid phase resin deployed at several stations along the coastlines of Puget Sound. Using a combination of molecular methods for species detection and solid phase resin deployment to target shellfish monitoring of toxin at high-risk sites, the risk of azaspiracid shellfish poisoning can be minimized.

Exploring the utility and effectiveness of the IEC (International Electrotechnical Commission) wave energy resource assessment and characterisation standard: A case study

For wave energy to become a commercially viable source of energy, a complete understanding of the wave resource characterisation is needed. In this context, the IEC (International Electrotechnical Commission) has developed a technical specification for the assessment of the wave resource, IEC-TS 62600-101: Marine energy-Wave, tidal and other water current converters-Part 101: Wave energy resource assessment and characterisation (IEC-62600-101), which presents a series of recommendations for standardising wave resource characterisation. The IEC-62600-101 classifies resource assessment studies into three different classes: reconnaissance, feasibility and design. The model setup requirements (mesh resolution, boundary conditions) and the effort (validation process, computational times) vary considerably from one class to the other. On these grounds, the objective of this work is to explore this methodology using the Irish West Coast as a case study. Overall, it was found that the methodology proposed performs well, offering a detailed characterisation of the resource; however, with the aim of making the technical specification more manageable, some aspects related to the seasonality of the wave resource and the validation and model setup procedures may be revisited for future editions.

The timing of early life events and growth rate estimates of age‐0 year group brill Scophthalmus rhombus along the west coast of Ireland

The timing of spawning and hatching, larval durations and growth exhibited by juvenile brill Scophthalmus rhombus captured along the Irish west coast were estimated using otolith microstructure analysis. Scophthalmus rhombus were estimated to have hatched between February and May, with fish settling onto nursery grounds between March and June. Fish collected later on in the season exhibited higher otolith growth rates in comparison to earlier collected fish. This is the first study to describe the early life history of a commercially valuable but understudied flatfish species.

Fatty acid contents and profiles of 16 macroalgae collected from the Irish Coast at two seasons

Due to the established health benefits of omega-3 long-chain polyunsaturated fatty acids (LC-PUFA), there is a globally increasing demand for alternative natural resources with appropriate fatty acid profiles. To assess the suitability of macroalgae as a source, 16 species (nine Phaeophyceae, five Rhodophyta and two Chlorophyta) were collected at two seasons (June and November) from the Irish west Coast, and total fatty acid contents and specific profiles were determined. Total fatty acid contents, expressed per percentage of dry weight, ranged from 6.4 % ± 0.3 (Pelvetia canaliculata, Phaeophyceae) to 0.8 % ± 0.2 (Porphyra dioica, Rhodophyta). Most common fatty acids were palmitic (16:0), oleic (OLE, 18:1 n-9), α-linolenic (ALA, 18:3 n-3), arachidonic (ARA, 20:4 n-6) and eicosapentaenoic (EPA, 20:5 n-3) acids. Fatty acid profiles were highly variable between and within algal groups; red and brown seaweeds were generally richer in LC-PUFA (e.g. 20:4 n-6 and 20:5 n-3), while high levels of saturated fatty acids such as palmitic acid (16:0) were observed in green species. Most omega-3 PUFA-rich species investigated had a omega-6/omega-3 fatty acid ratio close to 1, which is favourable for human health. The two seasonal sampling times revealed significant differences in total fatty acid and 20:5 n-3 (EPA) contents, with changes depending on species, thus implying varying suitability as potential target species for EPA production. At both times of the year, Palmaria palmata was identified as most promising species as a source of 20:5 n-3 (EPA) amongst all species investigated, with levels ranging from 0.44 to 0.58 % of dry weight in June and November, respectively.

Composition and temporal variation of the algal assemblage associated with the haplosclerid sponge Haliclona indistincta (Bowerbank)

Although interactions between seaweeds and sponges have been studied in detail, general information concerning the whole epibiontic algal assemblage associated with a sponge species is virtually non-existent. We present here the first study in which the macroalgal community associated with a sponge, Haliclona indistincta (Bowerbank), was examined in detail. In the period October 2009–September 2010, the seaweed assemblage epibiontic on H. indistincta at a site of the Irish West coast was composed of 66 algal taxa (48 red algae, 7 green algae, 11 brown algae). The red algae Gelidium spinosum and Rhodothamniella floridula were the only epibionts associated with H. indistincta for the whole annual cycle. Most of the algal epibionts were filamentous species, which colonized the surface of the sponge and did not penetrate deeply into it. The algal assemblage was most abundant and species-diverse in the period late winter-spring; multivariate analyses revealed a significant variation of the community on the temporal scale of season and sampling date (weeks to months). The results indicate that the algal communities associated with sponges may be very diverse, showing that this type of assemblage deserves further detailed studies.

Weather window analysis of Irish west coast wave data with relevance to operations & maintenance of marine renewables

This paper presents the results of a weather window analysis of wave data from the west coast of Ireland in order to quantify the levels of access to marine renewables for operation and maintenance activities. Operating and maintaining marine renewables offshore requires suitable weather windows when devices can be accessed. It is important to quantify what the levels of access are off the Irish west coast, given its high wind and wave resource. Wave data from two wave buoys are analysed to quantify the levels of access that exist off the west coast. The general wave regimes at both sites are quantified. The levels of access at various operations and maintenance (O/M) access limits are presented together with waiting periods between windows. The levels of access observed off the west coast are then compared to levels of access observed at other marine renewable locations. The results indicate that the levels of access off the west coast are far below those observed at other marine renewable locations. The implications of these low levels of access suggest that maintaining wave energy converters, off the west coast, may not be feasible and devices will need to be brought ashore for O/M activities.

SCALES OF VARIABILITY IN FIN RAY COUNTS OF FLOUNDER, PLATICHTHYS FLESUS L. ON IRISH AND WELSH COASTS

Meristic variation within a fish species can arise due to environmental factors and can aid investigation between fish stocks and closely related juvenile fish species. The aim of this study was to investigate the spatial variation in meristic characteristics for juvenile flounder Platichthys flesus from Irish and Welsh coasts. Five meristic fin ray counts were taken from 120 fish from nursery grounds in three regions (west Irish coast, east Irish coast and Welsh coast). Statistical analysis revealed regional variability for two of the meristic counts (dorsal and anal fin rays). A discriminant function analysis revealed a weak separation of the three regions. This separation improved when samples from the east Irish region were eliminated, with 65% of the fish from the Irish west coast and 73% of the fish from Wales correctly classified.

Variability in the early life stages of juvenile plaice (Pleuronectes platessa) on west of Ireland nursery grounds: 2000–2007

Plaice (Pleuronectes platessa) are the most abundant juvenile flatfish present on west of Ireland nursery grounds. 0-group plaice were collected from eleven sandy beach nursery areas along the west coast of Ireland by beach seining (2000–2007). In the majority of years examined, certain beaches were found to support a higher abundance of juvenile plaice, or individuals that were larger in size and exhibited good condition, suggesting that differences in habitat quality exist between beaches. Monthly mean densities of plaice ranged from 2.4 (± 2.4) to 100 (± 1.3) individuals 1000 m−2. Mean lengths of plaice ranged between 6.0 (± 1.0) and 10.1 (± 0.5) cm. No evidence of density dependent growth was detected over the eight years of the study. The length and condition of juvenile plaice also differed between hauls, indicating the existence of microhabitat effects and emphasizing the importance of selecting an appropriate spatial resolution to adequately assess an area. Similar to other locations in Europe, juvenile plaice abundances on nursery grounds were inversely related to mean spring seawater temperatures during the pelagic stage. Abundances of 0-group plaice were not related to the number of either 1- or 2-group individuals collected during bottom-trawl surveys off the Irish west coast, demonstrating the difficulties associated with developing a recruitment index for plaice.

The feeding ecology of 0 year-group turbot Scophthalmus maximus and brill Scophthalmus rhombus on Irish west coast nursery grounds

On sandy beach nursery grounds along the west coast of Ireland, 0 year-group turbot Scophthalmus maximus were found to consume six types of crustaceans, in addition to polychaetes. The 0 year-group brill Scophthalmus rhombus fed almost exclusively on mysids, even though nine taxonomic prey groups were identified in the sediment across the investigated beaches. Both species avoided non-motile organisms such as gastropods and bivalves, which were present in high abundances in the sediment and their growth and condition was not significantly related to the quantity or type of prey consumed, temperature or salinity. A high incidence of feeding was detected for both species over the duration of the study, suggesting that food was not limiting on west of Ireland nursery grounds. Temporal partitioning of settlement was detected between S. maximus and S. rhombus, indicating that inter-specific competition for food does not occur between these two flatfish species on west of Ireland nursery grounds.

The early life history of turbot ( Psetta maxima L.) on nursery grounds along the west coast of Ireland: 2007–2009, as described by otolith microstructure

The early life history of turbot ( Psetta maxima Linnaeus) was investigated over a three year period (2007–2009). 0-group turbot were collected in September of each year, from three nursery areas along the Irish west coast. The timing of hatching and settlement and the duration of the larval stage were estimated using otolith microstructure analysis. Otolith increment widths were used to derive an index of relative growth rates before and after settlement. Turbot were estimated to have hatched between May and June and settled onto nursery grounds between June and July over the 3 years of the study. No inter-annual differences in the timing of hatching or settlement were observed. Spatial variability was detected, with turbot collected from one location hatching and settling significantly earlier compared to other locations. Turbot from the same location also displayed higher post-settlement otolith growth rates suggesting that this may be a nursery of high habitat quality. Turbot captured in 2009 exhibited significantly shorter larval durations and higher larval otolith growth rates compared to turbot collected in other years. Post-settlement growth rates displayed the opposite trend, with turbot showing lower post-settlement growth in 2009. The results provide valuable baseline data on critical events in the early life history of a data-poor species.

Variability in growth, development and reproduction of the non-native seaweed Sargassum muticum (Phaeophyceae) on the Irish west coast

This study compared seasonal growth, development and reproduction of the invasive brown macroalga Sargassum muticum in habitats with different wave exposure on the Irish west coast. Three field sites with different degrees of wave exposure were chosen for monthly observations to reflect different habitats that were characteristic of the Irish west coast. Growth and receptacle development differed considerably between sites. Growth and receptacle development was lower at the most sheltered site. Here, S. muticum showed signs of early fragmentation in April/May during the two years of investigation (2007 and 2008), whilst the population at an exposed site developed normally and plants grew to a maximum average length of 163 cm by July, with the onset of fragmentation in August. Sargassum muticum in a tide pool exhibited a similar seasonal growth cycle as plants at the exposed open shore site. Overall growth however was stunted, with plants reaching a maximum length of only 30–40 cm in July. Receptacle development was also inhibited at the sheltered site, with a maximum of only 10% of plants found to be fertile during spring and summer 2008, while plants at the exposed site and the tide pool exhibited 100% plant fertility by August. An extensive occurrence of the native epiphyte Pylaiella littoralis on S. muticum was noticed during field sampling at the sheltered study site which may have contributed to inhibited development of S. muticum observed in this area. Seasonal biomass production, photosynthetic activity and plant/frond ratio development were contrasted between Sargassum muticum at the open shore and the tide pool. Sargassum muticum biomass production in the tide pool was 3.5 times lower than that of plants on the open shore. Receptacle development and seasonal photosynthetic activity were similar for tide pool and open shore plants, irrespective of morphological differences. Highest photosynthetic rates (fluorescence yield, Y o) were measured during active growth in February and lowest values during development of reproductive tissue and senescence. Numbers of S. muticum plants on the open shore decreased significantly during the year, whilst frond number per plant increased, possibly suggesting self-thinning through shading processes. The high variability in Sargassum muticum productivity and reproductive development between habitats suggests that the degree of competition and impact on native flora could be site-specific, and their local effect on displacements will require further investigations.

Wave-Emplaced Coarse Debris and Megaclasts in Ireland and Scotland: Boulder Transport in a High-Energy Littoral Environment: A Discussion

Scheffers et al. (2009) describe a reconnaissance survey of boulder accumulations along parts of the Atlantic coasts of the British Isles. A substantial part of their report concerns the characteristics of wave-transported boulder deposits found high above sea level on cliffs. These boulder deposits reach perhaps their ultimate development along the coasts of the Aran Islands, Galway Bay, western Ireland, and Eshaness, Shetland, northern Scotland, where evidence of wave action reaches elevations of 50 m above sea level (a.s.l.). We have previously investigated in detail these and numerous other similar localities and concluded that the boulder deposits are cliff-top storm deposits (CTSDs), part of an assemblage of features found on certain cliffs on these very high-energy coasts that relate to the impacts of extreme waves during major storms (Williams and Hall 2004; Hall et al. 2006, 2008; Hansom et al. 2008; Hansom and Hall 2009). However, Scheffers et al. (2009, p. 571) claim that at these and other sites “no evidence ... exists for storm wave dislocation of ... boulders found at altitudes of 120 m a.s.l.” Indeed, “no calculations of possible storm wave heights, storm wave physics, or ages of the deposits and no descriptions of extraordinary storms are sufficient to explain these displacements” (p. 568), and “alternative explanations, such as tsunamis, should be considered” (p. 571). Here we rebut these claims by briefly restat-

The spatial distribution of the reactive iodine species IO from simultaneous active and passive DOAS observations

Abstract. We present investigations of the reactive iodine species (RIS) IO, OIO and I2 in a coastal region from a field campaign simultaneously employing active long path differential optical absorption spectroscopy (LP-DOAS) as well as passive multi-axis differential optical absorption spectroscopy (MAX-DOAS). The campaign took place at the Martin Ryan Institute (MRI) in Carna, County Galway at the Irish West Coast about 6 km south-east of the atmospheric research station Mace Head in summer 2007. In order to study the horizontal distribution of the trace gases of interest, we established two almost parallel active LP-DOAS light paths, the shorter of 1034 m length just crossing the intertidal area, whereas the longer one of 3946 m length also crossed open water during periods of low tide. In addition we operated two passive Mini-MAX-DOAS instruments with the same viewing direction. While neither OIO nor I2 could be unambiguously identified with any of the instruments, IO could be detected with active as well as passive DOAS. The IO column densities seen at both active LP-DOAS light paths are almost the same. Thus it can be concluded that coastal IO is almost exclusively located in the intertidal area, where we detected mixing ratios of up to 29±8.8 ppt (equivalent to pmol/mol). Nucleation events with particle concentrations of 106 cm−3 particles were observed each day correlating with high IO mixing ratios. Therefore we feel that our detected IO concentrations confirm the results of model studies, which state that in order to explain such particle bursts, IO mixing ratios of 50 to 100 ppt in so called "hot-spots" are required.

HATCHING TIMES, LARVAL DURATION, SETTLEMENT AND LARVAL GROWTH OF PLAICE (PLEURONECTES PLATESSA (L.)) IN GALWAY BAY DETERMINED USING OTOLITH MICROSTRUCTURE

The otolith microstructure of juvenile plaice from two beaches in Galway Bay on the Irish west coast, Ballyloughaun and Silverstrand, was examined. Sampling was carried out monthly in the spring of 2003. The hatch date, larval duration, settlement date and larval growth rates were determined for 85 fish. Hatching occurred from late January to late March. The mean larval duration was 33 days, and fish settling earlier in the year had a longer larval life on Silverstrand. Settlement occurred between early March and late April. Settlement pulses closely corresponded to hatching times, indicating that hatching/settlement cohorts could exist for plaice in Galway Bay. Larval growth was consistent between locations assessed. There was a positive relationship between larval growth and hatch date, and an inverse relationship was noted between larval growth and larval duration. Results from this study were compared to studies from other European areas, and a relationship between larval duration and temperature was noted, with fish from cooler areas in Europe having longer larval durations. This is the first study of its kind on the west coast of Ireland and the first study within eastern Atlantic waters to focus on the early life history of plaice.

HATCHING TIMES, LARVAL DURATION, SETTLEMENT AND LARVAL GROWTH OF PLAICE (<i>PLEURONECTES PLATESSA</i> (L.)) IN GALWAY BAY DETERMINED USING OTOLITH MICROSTRUCTURE

The otolith microstructure of juvenile plaice from two beaches in Galway Bay on the Irish west coast, Ballyloughaun and Silverstrand, was examined. Sampling was carried out monthly in the spring of 2003. The hatch date, larval duration, settlement date and larval growth rates were determined for 85 fish. Hatching occurred from late January to late March. The mean larval duration was 33 days, and fish settling earlier in the year had a longer larval life on Silverstrand. Settlement occurred between early March and late April. Settlement pulses closely corresponded to hatching times, indicating that hatching/settlement cohorts could exist for plaice in Galway Bay. Larval growth was consistent between locations assessed. There was a positive relationship between larval growth and hatch date, and an inverse relationship was noted between larval growth and larval duration. Results from this study were compared to studies from other European areas, and a relationship between larval duration and temperature was noted, with fish from cooler areas in Europe having longer larval durations. This is the first study of its kind on the west coast of Ireland and the first study within eastern Atlantic waters to focus on the early life history of plaice.