Southwest Coast Of Ireland Research Articles

Rapid determination of polyether marine toxins using liquid chromatography–multiple tandem mass spectrometry

The diarrhetic shellfish poisoning (DSP) toxins, okadaic acid (OA), dinophysistoxins (DTX); pectenotoxin-2 (PTX2) and pectenotoxin-2 seco acids, were determined in marine phytoplankton, Dinophysis acuta, and mussels (Mytilus edulis) collected along the southwest coast of Ireland. Liquid chromatography–multiple tandem mass spectrometry (LC–MS/MS) was employed for the simultaneous determination of a series of marine toxins with large polarity differences. Separation of five DSP toxins was achieved on a C18 column (Luna-2, 150 mm × 2.1 mm, 5 μm) using an acetonitrile–water gradient with ammonium acetate as an eluent modifier. Electrospray ionisation (ESI) in negative mode, was used to generate the molecule related ion, [M − H]−, for each toxin. To develop a multiple reaction monitoring (MRM) method, fragmentation studies were performed to determine the optimum precursor-product ion combinations: OA (803/255), DTX2 (803/255), DTX1 (817/255), PTX2SAs (875/137) and PTX2 (857/137). This highly sensitive method had detection limits better than 1 pg (on-column). Linear calibrations were obtained for shellfish extracts that were spiked with toxins, OA, 0.007–1.00 μg/ml (r2 = 0.9993, N = 3) and DTX2, 0.054–8.5 μg/ml (r2 = 0.9992, N = 3). Good reproducibility data were also achieved with %RSD values (N = 3) ranging from 3.15% (0.56 μg DTX2/ml) to 5.71% (0.14 μg DTX2/ml), for shellfish extracts. The method was sufficiently sensitive to permit the determination of DSP toxins in small numbers of picked phytoplankton cells (N = 12–40). In one sample of D. acuta the average toxin composition per cell was: OA (7.0 pg), DTX2 (11 pg) and PTX2 (7.2 pg).

Studies of polyether toxins in the marine phytoplankton, Dinophysis acuta, in Ireland using multiple tandem mass spectrometry

Diarretic shellfish poisoning (DSP) is a toxic syndrome associated with the consumption of bivalve molluscs. The DSP toxins are polyether compounds, which include okadaic acid (OA), dinophysistoxins (DTXs), pectenotoxins (PTXs) and pectenotoxin seco acids (PTX2SAs). These toxins originate in marine dinoflagellates, including Dinophysis spp. Phytoplankton samples were collected from the southwest coast of Ireland and D. acuta was the predominant species. Monocultures of D. acuta cells were prepared by hand picking from microscope slides in order to confirm their toxin profiles. There was a remarkable consistency in the toxin profiles in all of the phytoplankton samples collected during the summer months, irrespective of location, depth or mesh size. Analysis using liquid chromatography—multiple tandem mass spectrometry (LC-MS/MS) revealed that DTX2 and OA were the predominant toxins at a consistent ratio. The average toxin composition was: DTX2 (53±5%), OA (26.5±2.3%) and total pectenotoxins (20.8±4.7%). Toxin profiles in D. acuta from Europe were distinctly different from those found in New Zealand, where PTX2 was the predominant toxin and DTX2 was absent.

Rapid determination of polyether marine toxins using liquid chromatography–multiple tandem mass spectrometry

The diarrhetic shellfish poisoning (DSP) toxins, okadaic acid (OA), dinophysistoxins (DTX); pectenotoxin-2 (PTX2) and pectenotoxin-2 seco acids, were determined in marine phytoplankton, Dinophysis acuta, and mussels ( Mytilus edulis) collected along the southwest coast of Ireland. Liquid chromatography–multiple tandem mass spectrometry (LC–MS/MS) was employed for the simultaneous determination of a series of marine toxins with large polarity differences. Separation of five DSP toxins was achieved on a C 18 column (Luna-2, 150 mm × 2.1 mm, 5 μm) using an acetonitrile–water gradient with ammonium acetate as an eluent modifier. Electrospray ionisation (ESI) in negative mode, was used to generate the molecule related ion, [M − H] −, for each toxin. To develop a multiple reaction monitoring (MRM) method, fragmentation studies were performed to determine the optimum precursor-product ion combinations: OA (803/255), DTX2 (803/255), DTX1 (817/255), PTX2SAs (875/137) and PTX2 (857/137). This highly sensitive method had detection limits better than 1 pg (on-column). Linear calibrations were obtained for shellfish extracts that were spiked with toxins, OA, 0.007–1.00 μg/ml ( r 2 = 0.9993, N = 3) and DTX2, 0.054–8.5 μg/ml ( r 2 = 0.9992, N = 3). Good reproducibility data were also achieved with %RSD values ( N = 3) ranging from 3.15% (0.56 μg DTX2/ml) to 5.71% (0.14 μg DTX2/ml), for shellfish extracts. The method was sufficiently sensitive to permit the determination of DSP toxins in small numbers of picked phytoplankton cells ( N = 12–40). In one sample of D. acuta the average toxin composition per cell was: OA (7.0 pg), DTX2 (11 pg) and PTX2 (7.2 pg).

The importance of micro and macro morphological variation in the adaptation of a sublittoral demosponge to current extremes

Sponges are known to show morphological acclimation in response to habitat variation. However, previous studies have concentrated on only one aspect of morphological variation, either gross morphology or spicule morphology. Cliona celata (Grant) is common in a variety of different habitats on the south-west coast of Ireland and has been investigated with respect to morphological variability on both scales. C. celata exhibited six different gross morphological body forms (ridged, burrowing, massive, massive/chimneys, encrusting, encrusting/chimneys). The body form exhibited was correlated to local environment, showing the extent of morphological adaptation in C. celata. Sponge size varied (from 548±75 to 2,345±433 cm2) between sites, with the largest (2,345±433 cm2) being found at the most stable site where flow rates were 23.24, P 15.36, P<0.05). Previously, spicule variation has been associated with increased stiffness in hostile environments. However, longer, thinner spicules, as found in C. celata, may result in a more flexible sponge. This is the first study to show both gross morphological (macro) and spicule (micro) variation in a single species of sponge. However, this study only reinforces some of the previously produced information on both of these adaptations of sponges to varying environments. This study also illustrates how the results of single studies should not be used to draw conclusions for group level adaptation.

Geographical variation in heat coma temperatures in Littorina species (Mollusca: Gastropoda)

Upper critical thermal limits were measured as heat coma temperatures in Littorina species (Mollusca: Gastropoda) from sites around the British Isles. Thermal tolerance was found to be stable within a population but extensive variation occurred between populations and species. The majority of species examined displayed heat coma values of around 30°C and did not show a positive correlation with shore height. The highest capacity for thermal tolerance was found along the coast of South Wales, while the lowest was found on the south-west coast of Ireland and on the east coast of Scotland.

A sponge diversity centre within a marine ‘island’

The exposed and gulf-stream warmed south-west coast of Ireland has a Lusitanean fauna composed of elements of the colder waters to the north and east, and others from the warmer Mediterranean Sea. Lough Hyne, a small marine body, is unusual on this coast in being very sheltered, but also in being characterised by many different niches within a small space (1 km2). Sponges are particularly abundant, morphologically varied and more than 100 species have been described. Species diversity was measured at 6 m intervals on vertical and inclined profiles (to a maximum of 30 m) at six sites, spanning a range of flow rate and sedimentation regimes. Diversity, richness, evenness and density varied significantly with both flow regime and depth, but was much lower on the surrounding Atlantic coast. Four different sponge communities were differentiated on the basis of sponge species assemblages which correlated with different environmental conditions. At sites of turbulent and fast flow conditions, sponge diversity and richness were lowest, with the highest values being found at the sites of moderate and high sedimentation. Significant differences were observed in all four ecological variables with respect to substratum angle with the exception of the site experiencing the most turbulent flow conditions. Lough Hyne was found to possess the second highest sponge species diversity (H=3.626) and richness (77 species) of all available figures from temperate, polar and tropical areas (of similar sized sampling area). The uniqueness, diversity and species composition of the sponge community at this location suggests Lough Hyne is, biologically, a marine island within the island of Ireland.

Multifractal analysis of hourly precipitation

The multifractal nature of the rainfall field is analysed using the methodology of singular measures. The analysis is applied to a long time series (54 years) of hourly rainfall intensities recorded at Valentia on the South-West Coast of Ireland. The empirical probability distribution function suggests a hyperbolic intermittency with the divergence of the statistical moments being higher than the second order. The latter is in agreement with findings of other authors for similar climatic regions (e.g. Sweden). The Fourier transform statistics of the data are used to obtain the scaling range in which the data obey a power law with a coefficient of ∼0.5. The scale invariance as identified by the spectral power law, ranges from 2 hours to about 24 hours. This is a narrower range than has been found for similar studies using continental sites where the range was found to be from 2 hours to about 3 days. Studies of Valentia rainfall using conventional statistics suggest that two distinct periods, (1940–1975 and 1976–1993) are clearly present. The second period is characterised by a greater annual rainfall depth than the first, and the increased depth was found to be concentrated primarily in the months of March and October. The intermittency analysis of the rain field of the two periods reveals two different K(q)-functions. The curvature of the K(q) convexity has been found to be larger for the second period suggesting lower intermittency or more frequent rain events. The intermittency function C1 for the period 1976–1993 is shown to be quantitatively less than C1 for the period 1940–1975, for the annual, March and October time series verifying increasing precipitation since 1975.

Recent trends in diurnal variation of precipitation at Valentia on the west coast of Ireland

An investigation of 54 years of hourly precipitation at Valentia, on the south-west coast of Ireland, shows a change point in the annual amounts in the years around 1975 (identified by the Pettitt—Mann—Whitney statistic). This results in a 10% increase in the mean annual precipitation from a pre-1975 value of 1375 mm to a post-1975 value of 1507 mm. Most of that increase is absorbed in the months of March and October. The frequency of hourly precipitation in March in the post-1975 period is 57% greater than that of March in the pre-1975 period. However, the magnitude of the hourly intensity of precipitation in March for both periods was similar. Significant changes in wet hour frequency also occurred in October with no corresponding change in hourly intensity. These results compliment findings by others, that regions in Northern European latitudes have experienced an increase in precipitation since the mid-1970s.

Transient Coastal Upwelling and Water Circulation in Bantry Bay, a Ria on the South-west Coast of Ireland

Water column stratification and circulation were measured in Bantry Bay, a ria on the south-west Irish coast, during the Summer of 1991. Upwelling and downwelling appeared on several time scales. During July, cool dense offshore water penetrated the bay at depth for several weeks, lifting up the thermocline at a mean rate of 1·2 m day −1. In early August, the cool shelf water receded, thermocline depth rapidly deepened at 8·5 m day −1and water in the bay was replaced by warmer coastal surface water. Strong oscillatory residual flows with longer excursion scales than tidal oscillations were also detected throughout the water column. They were caused by the passage of a series of Atlantic depressions, giving a periodicity of a few days. During upwelling, currents were predominantly towards the head of the bay in the bottom 20 m, and seaward in the upper 20 m: at middle depths, the direction of flow varied according to the position of the thermocline. During downwelling, this flow pattern was reversed. A simple two-layer model of frictionally damped wind-driven flows constructed on the basis of hydrostatic equilibrium was used to examine the contribution of local winds to upwelling and downwelling on time scales of about a day or more. Two unknown parameters in the model were fitted statistically but took physically realistic values. The model accounts for about three-quarters of the variance in the record of the residual current and mimics the observed fluctuations in thermocline depth. It successfully reproduces the general late July upwelling and August downwelling and also the shorter period of cyclic upwelling and downwelling associated with the passing Atlantic depressions. Some of the small discrepancy between the model and observed residuals may owe to changing density on the shelf.

Diarrhetic Shellfish Poisoning: Evaluation of Enzyme-Linked Immunosorbent Assay Methods for Determination of Dinophyslstoxin-2

Abstract Dinophysistoxin-2 (DTX-2), an isomer of okadaic acid (OA), recently has been found in Irish waters. DTX-2 was the predominant toxin during prolonged infestations in cultivated mussels along the southwest coast of Ireland. Substantial variations in toxin levels may exist both horizontally and vertically in the water column. The need to take multiple samples and the ethical concern about the use of mammals for routine quality control of shellfish prompted examination of 2 commercially available enzyme-linked immunosorbent assay (ELISA) methods, designed to detect OA, for determination of both OA and DTX-2. One ELISA method (DSPCheck, Sceti Co. Ltd., (Tokyo, Japan) showed good cross-reactivity (40 ± 5%) with standard DTX-2. This study showed that both ELISA methods show good correlation with the liquid chromatographic analysis of 9-anthryldiazomethane derivatives when OA is the predominant toxin present. The sensitivity was also good for OA determination using both methods, which allowed toxin measurement at 10 ng/mL (0.5 ng/well). This level is equivalent to 0.03 μg/g mussel meat. Blank mussel samples spiked with DTX-2 standards gave a good linear correlation (r = 0.997) with this ELISA method when toxin levels were 0.03-0.3 μg/g mussel meat. This range is appropriate for regulatory control of diarrhetic shellfish poisoning.

Gravity and magnetic studies of crustal structure across the Porcupine basin west of Ireland

Gravity, magnetic and seismic data from a profile across the Porcupine basin are used to suggest a model for the crustal structure in the region. The 280 km long profile bears WSW off the southwest coast of Ireland, and overlaps partially with the COOLE 3A and 3B lines of Makris et al. [13]. The gravity data are processed to produce an isostatic residual anomaly which is then modelled by two-and-a-half dimensional methods using the seismic data to provide geometrical constraints. Similar modelling techniques are used for the magnetic data. The final model shows crystalline crust which thins from 28 km at the eastern end of the profile to less than 8 km beneath the central part of the basin. The thinned crust is intruded by dense magnetic bodies, whilst the eastern margin is underlain by a large low-density body which is assumed to be a granite. These new findings have parallels in other basins on thinned and rifted crust.

The life history and reproductive biology of Odostomia eulimoides (Gastropoda: Opisthobranchia) on the south coast of Ireland

Populations of Odostomia eulimoides Hartley were sampled from mussel beds on an exposed rocky shore at Preghane Point on the south coast of Ireland from April 1984 to October 1985 and from sublittoral farmed mussels at Bantry Bay on the south west coast of Ireland from March to October 1986.At Preghane Point O. eulimoides had a area-annual life cycle with summer-autumn recruitment. Peak recruitment occurred from May to July in 1984 and from July to September in 1985. This aphasic recruitment was explained by the lower mean adult shell height recorded from April to June 1985 than in these same months in 1984.

Interactive interpretation of a submarine fan, offshore Ireland: A case history

During the Eocene, a series of submarine fans developed in the Porcupine basin off the southwest coast of Ireland. Interactive interpretation of one—the Clontarf fan—shows the successive development of four sequences. Seismic facies analysis of these sequences suggests a progressive evolution from a more distal to proximal environment during deposition of the fan. Seismic facies mapping reveals an extensive series of sand‐prone distributary systems in the youngest fan sequence. Amplitude anomalies suggest that this and other fans in the basin are favorable stratigraphic and/or structural traps for hydrocarbons.

Taxonomic Studies on British and Irish Amphipoda. the Genus Gammaropsis

INTRODUCTIONLincoln (1979) stated that ‘four species (of Gammaropsis Liljeborg) are reported from the British Isles, Gammaropsis maculata (Johnston), G. palmata (Stebbing &amp; Robertson), G. nitida (Stimpson) and G. sophiae (Boeck)’. In fact, six species of Gammaropsis have been reported from the British Isles in the literature, the records of G. lobatus (Chevreux) (Spooner, i960) and G. melanops (Sars) (Jones, 1948) having apparently been overlooked by Lincoln (1979). Spooner's (1960) material is apparently no longer extant, but the material attributed to G. melanops by Jones (1948) has been re-examined by us and found to be referable to G. lobata. Recent collections of G. lobata from the west coast of Ireland confirm a rather wide distribution of this species in the southwest of these islands.Five species of Gammaropsis are therefore now known from these islands, and G. melanops can, at least for the present, be deleted from the British and Irish list of species.Lincoln (1979) was unable to examine any British material of G. sophiae, everything labelled as such, in the material examined by him (including the Norman collection at the B.M.N.H.)* being referable to G. nitida. He therefore figured the species from West African material. G. sophiae is quite widespread along the southwest coast of Ireland and since it differs somewhat from the material described by Lincoln (1979) it is figured herein from the Celtic Sea.Krapp-Schickel &amp; Myers (1979) reviewed the Mediterranean species of Gammaropsis and segregated the species into two groups, group ‘A’ species characterized by the possession of a toothed urosome, toothed coxa 1 and long acute epistome, and group ‘B ‘ species characterized by having a smooth urosome, smooth coxa 1 and short epistome.

The Factors Influencing the Distribution of Saccorhiza Polyschides in the Region of Lough Ine

Saccorhiza polyschides (Lightf.) Batt. is a laminarian alga found in the sublittoral region. It is widely distributed around the shores of the British Isles and is particularly common on the south west coast of Ireland. A puzzling aspect of the distribution of the species in Southern Ireland is its absence from Lough Ine, in County Cork.

Societies and Academies

DUBLINRoyal Irish Academy, May 27. WINIFRED E. FROST: Larval stages of the Euphausiids Nematoscelis megalops and Stylocheiron longicorne taken off the south-west coast of Ireland. The euphausiids form an important part of the fauna of the inshore and deep waters off the south and west coast of Ireland. The present paper deals with the life-histories of two of these animals, the development of which has not previously been described. Sufficient larval stages have been found to give a good idea of the life-history of the organisms and the descriptions make it possible to identify the larvse in the plankton. Some notes are given on the reproductive cycles of the two euphausiids.

Letters to the Editor

RECENT letters by Dr. Kemp and Mr. F. S. Russell1 and Mr. A. C. Stephen2 have directed attention to the occurrence of Atlantic organisms on the coasts of Great Britain and Ireland. It may be of interest to add another example to the list. While the Fishery Cruiser Muirchu of the Department of Lands and Fisheries was engaged in taking physical observations off the south-west coast of Ireland, fifty miles south-south-west of Fastnet Light, on August 9, 1932, considerable numbers of a large salp, 3–8 cm. long, were noticed drifting a few feet below the surface and some were captured. These proved to be the sexual stage of Cyclosalpa bakeri, Ritter. Several other specimens occurred in a tow-netting taken on the same station, and also in another taken seventy miles south-south-west of the Fastnet, suggesting that the shoal may have been twenty miles across. Cyclosalpa bakeri appears to be mainly a tropical species and I do not know of any previous record from British or Irish waters.

XI.—New deep-sea fishes from the South-west Coast of Ireland

XI.—<i>New deep-sea fishes from the South-west Coast of Ireland</i>

XLVIII.—Preliminary notice of new and remarkable Cephalopods from the South-west coast of Ireland

(1907). XLVIII.—Preliminary notice of new and remarkable Cephalopods from the South-west coast of Ireland. Annals and Magazine of Natural History: Vol. 20, No. 119, pp. 377-384.

On the structure of coccospheres and the origin of coccoliths

At the beginning of September last year, I visited Valencia, Co. Kerry. It occurred to me there that coccospheres might possibly be drifted in on the warm current of the Gulf Stream, which impinges on the south-west coast of Ireland, and as they float in would become entangled in the sea-weeds on the coast. With this idea, I gathered some of the finer marine algae, such as species of Cladophora, Polysiphonia, and Plocamium, &amp;c., from the rock pools in Valencia Harbour. Taking care to wash as little of the silt or sediment as possible from them, I fixed the mass in dilute formalin.