bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reproduction inAbra Alba(Wood) andAbra Tenuis(Montagu) (Tellinacea: Scrobiculariidae)
Authors: Nott P. Laskaridou 
Published: May 2009

Abra albaandAbra tenuisare closely related marine bivalves. They both inhabit similar types of sandy-mud sediments but they prefer different localities. The smallerA. tenuisis found in a few scattered intertidal mudflats, whereasA. albais more widely distributed and in great abundance in the coastal waters of north-west Europe. The latter can be found at any depth between low-water mark and 80 m (Tebble, 1966; Ansell, 1974) and often forms the dominant species of shallow water benthic communities.The reproductive cycle of the two species has been studied and compared as a part of a wider ecological investigation. There is minimal literature concerning the reproduction ofA. tenuisbutA. albahas received a lot of attention, because it forms a major source of food for flatfish. However, most of the earlier investigations are confined to the time that spawning occurs with the evidence derived from either the time of the year that larvae appear in the plankton (Lebour, 1938; Jorgensen, 1946; Fosshagen, 1965; Muus, 1973; Rasmusen, 1973), or the time of the year that juveniles first appear in the bottom samples (Orton, 1924; Ford, 1925; Stephen, 1932). The inadequacy of such indirect methods has been discussed by Seed (1969,1975, 1976). Ansell (1974) derived the reproductive cycle of A.albafrom seasonal changes in the biochemical composition. In the present investigation, histological techniques have been used, since they are considered to offer the most reliable information about the reproductive cycle (Seed, 1969, 1975, 1976).
Survival of Hypoxic Conditions by the PolychaeteCirriformia Tentaculata
Authors: Dales R. P. , Warren Lynda M. 
Published: May 2009

The cirratulid polychaeteCirriformia tentaculata(Montagu) may be found in gravelly mud or sand often beneath large stones in pools between tide marks. It is usually associated with reducing conditions indicated by blackened mud or sand and the distinctive odour of hydrogen sulphide. It occurs also in crevices that retain stagnant water at low tide. The worm does not make a permanent burrow but lies in different postures to enable the branchiae and feeding tentacles to be extended on to the surface, where they are bathed by the overlying water. The mucus-lined burrow is not irrigated.Cirriformia tentaculataencounters two respiratory problems. When covered by water the branchial filaments can take up oxygen which is then circulated by means of the well-developed vascular system with blood containing haemoglobin in solution. While the branchiae may lie in a well-oxygenated medium the main body of the worm lies in a highly reducing substrate. The sediment immediately surrounding the worm is commonly black and there is no oxygenated layer as occurs in burrows which are irrigated and provide an envelope separating the animal from a potential oxygen-sink. If exposed by the tide the branchiae are withdrawn or clump together and cannot function effectively. Even when covered by the tide the branchiae can be rapidly with-drawn, presumably to avoid loss by predation, and under all these conditions the animal must experience hypoxic or anoxic conditions of varying duration of up to several hours.We have examined the ability ofCirriformia tentaculatato maintain oxygen uptake under decreasing oxygen tension, the oxygenational properties of the haemoglobin, the oxygen capacity and blood volume.
A Note on Parastenocaris Phyllura Kiefer and P. Vicesima Klie (Copepoda: Harpacticoida) in Britain
Authors: Geddes D. C. 
Published: May 2009

The Parastenocaridae constitute a family of minute vermiform copepods, principally occurring in subterranean waters, including the subsurface waters of marine beaches. The two species of Parastenocaris referred to in this note were collected in Britain for the first time in 1966, during a survey of the harpacticoid fauna of some beaches on the Isle of Anglesey, North Wales (Geddes, 1972). Numerous females and males of both species were obtained from sand at the source of a spring emerging (at high water mark) on to the beach at Rhosneigr (O.S. Grid Ref. SH 315730).The previously known distribution of these two Parastenocaris species has been summarized by Enckell (1969), whose paper should be consulted for full references and distribution maps. Briefly, P. phyllura Kiefer has been recorded from fresh water in the central and northern parts of middle Europe, and from brackish-water beaches bordering the Baltic and the North Sea coast of continental Europe, while P. vicesima Klie has been recorded from marine and brackish-water beaches around the Baltic and adjacent parts of the North Sea.
Isozyme Variation in Three Nereis Species from Five Localities in the U.K.
Authors: Mustaquim Javed 
Published: May 2009

The taxonomy of marine worms belonging to family Nereidae is still in an uncertain state. There are many species, like Nereis diversicolor Müller, N. japonica Izuka and N. limnicola Johnson, which are morphologically similar but have different reproductive habits. Clark (1977) reviewed many examples of reproductive isolation without morphological differentiation in polychaetes including members of the family Nereidae. He also stressed the need for detailed study in such polychaetes where taxonomic confusion exists.Electrophoretic techniques have contributed a great deal in solving taxonomic problems (see Avise, 1975 and Burton, 1983). All electrophoretic methods have proved useful to varying degrees in characterizing specific organisms. In particular, acrylamide gel electrophoresis has seen extensive use because it has excellent resolving power (Brewer, 1970). Studies of the electrophoretic variation of nereid isozymes have not been reported, except by Jones (1970), who examined various polychaetous annelids for the presence of certain dehydrogenases. This present report contains preliminary observations concerning the applicability of isozyme electrophoresis to the study of nereid worms.
Biodiversity of Shallow-Water Red Sea Echinoids: Implications For the Fossil Record
Authors: Nebelsick James H. 
Published: May 2009

Determination of fossil echinoid diversities is an important aspect of detailed palaeon- tological studies. The comparison of recent and fossil associations can be used to elucidate the problems of determination of fossil echinoid distributions. Actuopalaeontological studies of echinoids from the Red Sea (northern Bay of Safaga, Egypt) have shown that the study of fragments within bulk sediment samples greatly increased the possibilities for determining echinoid presence and distribution. The results show the restricted distribution as well as the differential preservation potential of the various echinoids.The distribution of echinoids is primarily controlled by grain size, food availability, exposure to current activity, and predation pressure. Regular and irregular sea-urchins show the expected disjunct distributions with the former showing a more undifferentiated distribution to various hard substrates. Irregular echinoids are tightly restricted to particular types of soft substrates reflecting their adaptation to the specific grain size of the sediments. Co-occurring irregular sea-urchins show a spatial differentiation into shallow (clypeasteroids) and deeper burrowers (spatangoids). This investigation shows that important echinoid species known to occur in the Red Sea are lacking or are very rare within the study area, although a large number of different facies types are present. Patchy distributions are present for both regular and irregular sea-urchins. The determination of biodiversity is therefore seen to be largely dependent on the scale of investigation.An important implication for fossil echinoid presence are the differential effects of taphonomic agents on the various test architectures. Some species are well represented due to their common occurrences, and their comparatively robust tests or test fragments.
The Biogeography of Islands: Preliminary Results from a Comparative Study of the Isles of Scilly and Cornwall
Authors: Kendall M.M. , Widdicombe S. , Davey J.J. , Somerfield P.P. , Austen M.C.V. , Warwick R.M. 
Published: May 2009

Studies of the interplay of immigration, emigration and extinction in shaping the fauna of islands (McArthur & Wilson, 1967) have influenced the terrestrial ecologists view of the creation and maintenance of diversity. Although in the deep ocean, hydrothermal vents have been the subject of a number of biogeographic studies (Tunnicliffe, 1991), there have been few attempts to validate theories of island biogeography in the shallow marine environment. To rectify this situation, a study comparing the fauna of the mainland of Cornwall, with that of the Isles of Scilly, which lie 45 km from the mainland and were separated from it ~0·3 my BP has been undertaken.Evidence for some comparative impoverishment of the Isles of Scilly fauna was provided by Crisp & Southward (1958) who noted that a small number of cirripedes and molluscs with planktonic larvae, living close to their geographic limits of distribution in Cornwall, were unable to bridge the gap to the islands. They suggested that although species with long-lived planktonic larvae can be widely dispersed, excessive dispersal can lead to their loss from the fauna of small islands. This is clearly demonstrated on the remote island of Rockall where both Crisp (1956) and Moore (1977) noted that only animals with direct development occur. On the Island of Lundy, four species of gastropod were estimated to be less abundant than on the mainland which lies only 18 km away (Hawkins & Hiscock, 1983). However, such studies only deal with a small number of conspicuous intertidal species, and there is a requirement to expand observations to the community level. The present study attempts to question the following hypotheses: (1) α - diversity (that of single samples) is lower on the islands than the mainland; (2) the diversity of species with planktotrophic larvae is lower on the islands than on the mainland.
On a Fungus Allied to the Saprolegniaceæ found in the Pea-Crab Pinnotheres
Authors: Atkins D. 
Published: May 2009

SUMMARYA fungus, most probably allied to the Saprolegniacese, has been found infecting Pinnotheres. Pea-crabs so infected always die, but there is not as yet sufficient evidence to determine whether the fungus is pathogenic or only invades tissue which has been destroyed by parasitic bacteria. Although having the general characters of the family it apparently differs from all members so far described in that it occurs in a marine invertebrate and is almost entirely internal in habit, the zoosporangia occurring within the tissue of the host.
The Larvæ of the British Sabellarians
Authors: Wilson Douglas P. 
Published: May 2009

SUMMARY1. Sabellaria alveolata Linnæus has been reared for the first time from the egg through the pelagic stages and metamorphosis to early bottom stages. The chief features in the development of the external characters are described and special attention is drawn to the existence of peculiar grasping-cilia on the telotroch. The manner in which the young worm builds its first tube of sand grains is also described.2. Sabellaria spinulosa Leuckart has similarly been reared for the first time from the egg to early bottom stages. Its development is very similar to that of the preceding species, but during the later pelagic life the two can easily be separated, as the primary palese of the crown, which appear among the long provisional bristles of the first pair of parapodia, show a marked specific difference. The early stages cannot be distinguished.3. A larva which is probably that of the rare Pallasia murata Allen is described.4. A tentative key to the British Sabellarian Larvaæ is drawn up.5. The observations of previous workers are discussed. It is shown that Sabellarian larvaæ have frequently been described as the larvaæ of Spio or of Polydora, in spite of the fact that the early stages of Sabellaria had been obtained more than once from artificial fertilisations. Caullery was the first to point out the error, and he is fully confirmed in this paper.6. It is shown that the caudal appendage of a full-grown Sabellaria alveolata possesses internally a series of fifty or sixty transverse septa.
Observations on Patella uulgata. Part III. Habitat and Habits
Authors: Orton J. H. 
Published: May 2009

SUMMARYThe inter-tidal habitats of the common limpet, Patella vulgata L,, have been investigated in relation to constant lunar tidal levels and tidal zones. The habitats of some common shore organisms which occur at approximately definite tidal levels or zones—and can therefore be used with discretion for zoning the habitats of Patella—are shown in a chart.A study of the distribution of the common limpet on the shores of Devon and Cornwall has shown that limpets are absent or rare on those parts of the foreshore above high-water neaps which are subjected to prolonged periods of direct insolation. In the same locality limpets may be totally absent from the high-water region on cliff-faces or rocks facing southerly, but present on adjacent ones facing northerly or north-westerly. Strongly insolated habitats appear to be unviable as a result of the direct effect of the insolation on the animal, but the apparent deficiency of food in such habitats is probably also a limiting factor of importance.The importance of the splash-line of any tidal level is emphasised. It is shown that in Devon and Cornwall the occurrence of low-water spring tides at about midday (and midnight) results in exposing to strong sunshine (and correlated factors) those regions of the shore above high-water neaps which face in a southerly direction. In other localities where high-water spring tides occur about midday, equivalent regions of the foreshore are not so strongly nor so persistently insolated as in the former.Viable habitats may therefore occur in different regions on the shore in different localities or at different latitudes according to the local orientation of the substratum and local tidal phenomena.
Fluctuations ofOphiothrix fragilisin the western English Channel
Authors: Holme N. A. 
Published: May 2009

The brittle-starOphiothrix fragilisforms dense aggregations on the sea bed off Plymouth, as well as in other parts of the English Channel. From about 1970 there was a marked decline in populations off Plymouth, and study of previous records suggests that there have from time to time been considerable fluctuations in abundance of this species — since beds were first reported by E. J. Allen in the 1890s. The decline did not extend to populations in the southern and eastern parts of the Channel. The distribution ofOphiocomina nigra, which sometimes occurs in mixed populations withOphiothrix, is also described. This species is more or less limited to the western Channel, and populations, which are nowhere very dense, showed no decline comparable to that ofOphiothrix.Predation by the starfishLuidia ciliarisandL. sarsiis thought to be a likely cause of the disappearance ofOphiothrix. Luidiaspp. are active predators on ophiuroids and other echinoderms, and numbers ofL. ciliariswere observed in the vicinity of theOphiothrixbeds at the time of the decline. Both species ofLuidiahave a ’western’ distribution in the Channel, and showed an increase in density off Plymouth after the late 1960s, which is probably related to a changeover from aSagitta setosato a 5.elegansplankton community from 1968 on. The distribution of theseLuidiais confined to stratified waters in the western Channel, surviving stocks ofOphiothrixbeing limited to mixed waters in the southern and eastern Channel whereLuidiadoes not occur.
Temporary adhesion of the barnacle cyprid: the existence of an antennular adhesive secretion
Authors: Walker G. , Yule A. B. 
Published: May 2009

It is conclusively shown that cyprids of the barnacleBalanus balanoides(L.) use a secretion released onto the antennulary discs for temporary attachment. This secretion does not stain with conventional histochemical techniques but was shown to be proteinaceous by staining blue in Bio-Rad protein-dye reagent normally used in protein assay. The discovery of this proteinaceous secretion adds further evidence to suggest that cyprids use a form of Stèfan adhesion for temporary attachment during exploration prior to settlement.IntroductionAlthough recent advances have been made in the measurement of cyprid temporary adhesion (Yule & Crisp, 1983), the question of the precise mechanism has remained speculative. Earlier suggestions that the attachment organs of the antennules operated by suction (see Saroyan, Lindner & Dooley, 1969) were challenged on morphological grounds by Nott & Foster (1969) and finally disproved by the force measurements of Yule & Crisp (1983).Nott (1969) and Nott & Foster (1969) were able to show numerous unicellular glands opening out, individually, onto the surface of the antennulary disc arranged in two concentric rings, one near the margin, and the other around the central sense organ. It was considered that these glands could produce a tacky secretion used for temporary adhesion. Yule & Nott (unpublished, reported in Yule & Crisp, 1983) failed to find any traces of such a tacky secretion on glass surfaces after cyprids had walked across them. To establish the presence or absence of a fluid secretion on the antennulary disc is fundamental to the further understanding of the type of temporary adhesion employed by cyprids.
The ultrastructural localization of metals in specimens of Littorina littorea collected from clean and polluted sites
Authors: Mason A. Z. , Simkiss K. , Ryan K. P. 
Published: May 2009

The ultrastructural organization of various metal-containing cells of Littorina littorea is described. These cells occur in the connective tissue, digestive gland, kidney, stomachand ctenidia. Specimens were compared from animals collected from clean and metal-polluted sites and it was shown that the majority of the metals were bound to intracellular ligands. These are usually compartmentalized within membrane-delineated structures.The basophil cells and connective tissue calcium cells appear to contain oxygen donor ligands which mainly bind class A metals (e.g. Ca, Mg, K, Mn). The pore cells and ctenidium contain sulphur donor ligands which mainly bind copper. Ligands of unknown composition occur in the nephrocytes and stomach epithelial cells. The ligands in the basophil cells and the nephrocytes appear to bind a wide range of metals and may therefore serve a detoxification function. Ligands in the connective tissue calcium cells and pore cells are very specific in their binding characteristics, and this presumably reflects some particular metabolic pathway within these cells. Ligands associated with the stomach and ctenidial epithelia appear to be responsible for preventing the penetration of metals through these layers.The effects of ligand specificity, induction and turnover rates are discussed in relation to the use of L. littorea as a monitoring system for metal pollution.IntroductionThe use of biological organisms to monitor the levels of pollutant metals in the environment has attracted extensive interest in recent years (Phillips, 1980). In the most arbitrary use of this procedure, the animal is simply regarded as a biological sink' which traps and accumulates the pollutants which gain access across its epithelial layers. The net result of the retention or excretion of these captured metals is represented by the final body load that is then related to the environmental levels of the metal.
A Note on the Development of Eggs and Larvae of the Bogue, Boops Boops
Authors: Coombs S. H. , Mitchell C. E. 
Published: May 2009

An opportunity was taken to carry out the artificial fertilization and incubation at different temperatures of eggs of the bogue, Boops boops (Linnaeus, 1758) during a cruise on R.V. 'Cirolana' organized by the Fisheries Laboratory, Lowestoft. Adult fish for use in the experiment were obtained by bottom trawling in 165 m depth of water at 43° 44' N02° 44' W on 10 May 1980 between 0449 and 0549 h GMT. The bottom temperature at the trawling position was estimated to be ~ 11 · 8 °C, based on measurements made at nearby stations. Eggs and milt from several males and females were added to a container of sea waterheld at approximately 11 °C; after 1 h the fertilized eggs were transferred as four separate subsamples each of approximately too eggs to clean sea water in the incubation beakers. Thesebeakers were then gradually acclimatized over a period of 2 h to the incubation temperatures of80, 131, 182 and 22·8°C.At all temperatures mortality was high during early embryonic development. At 228 °C all eggs were dead after 9J h of incubation at which time some of these specimens had formed a blastoderm cap, but with no sign of overgrowth of the yolk. In a few of the eggs held at 80 °C development proceeded normally until immediately before closure of the blastopore (~ 106 h after ferilization) when irregular vacuoles were seen in the area around the blastopore and development was disrupted; after 112 h of incubation all eggs held at 80 °C were dead.
Larval Fish East of the Shetland Islands, May 1978 and May 1979
Authors: Economou A. N. 
Published: May 2009

A list of larval fish species sampled during an ecological study of the gadoid larvae in the east of the Shetland Islands area in 1978 (6–21 May) and 1979 (9–30 May) is given in Table 1· 14157 fish larvae were caught in 1978 (in 154 oblique hauls with the High Speed Loch Ewe Net, an unencased sampler with a net of 0·250 mm mesh) and 13 769 larvae in 1979 (in 93 hauls), from which 13632 and 12440 larvae were identified and measured in these 2 years respectively. Most unidentified specimens were damaged. Larval fish taxonomy is given according to Russell (1976). The description of the sampling instrument and the working procedure at sea can be found elsewhere (Economou, 1983).The Gadidae family dominated all others accounting for more than 85% of the total, the three most abundant species being Norway pout(Trisopterus esmarkii (Nilsson)), haddock(Melanogrammus aeglefinus (L.)) and whiting (Merlangius merlangus (L.)).Whiting appeared under three pigmentation patterns, the normal one, another with very weak pigment and a third having the dorsal side of the body very strongly pigmented, sometimes with a gap free of pigment along the dorsal contour. The characters of the last two forms correspond somewhat with the descriptions of the whiting larvae from the southern North Sea and the Loch Etive (Russell, 1976). Norway pout displayed the typical form of melanophores but few specimens presented a pattern of fine but intense spots. There was some evidence that a few of the larvae identified as Norway pout at the end of May 1979 were actually Trisopterus minutus larvae.
The Distribution and Diet of the Dominant, Slope-Dwelling Eel, Synaphobranchus Kaupi, of the Rockall Trough
Authors: Gordon J.D.M. , Mauchline J. 
Published: May 2009

INTRODUCTIONThe deep-sea eel, Synaphobranchus kaupi, is widely distributed on the continental slopes of the North Atlantic (Saldanha & Bauchot, 1986; Haedrich & Merrett, 1988). It was a dominant fish species in epibenthic sledge and semi-balloon otter trawl (OTSB) hauls on the West African slope (Merrett & Marshall, 1981; Merrett & Domanski, 1985). Also in the eastern North Atlantic, it was the most abundant species on the slopes of the Porcupine Sea Bight off south-west Ireland (Merrett et al., 1991; Priede et al., 1994). In the western North Atlantic, it was the dominant species on the middle and lower slopes of the Middle Atlantic States of the USA and on the upper slopes of the Grand Banks off Newfoundland (Sedberry & Musick, 1978; Houston & Haedrich, 1986).