bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal Variation in Physiological Energetics of Mytilus Edulis and Cerastoderma Edule of Different Size Classes
Authors: Smaal A.C. , Vonck A.P.M.A. , Bakker M. 
Published: May 2009

Seasonal variation of clearance, absorption and respiration rates of mussels Mytilus edulis (Mollusca: Bivalvia) and cockles Cerastoderma edule (Mollusca: Bivalvia) of various size classes have been measured under ambient temperature and sea-water conditions. Food availability was kept almost constant during the measurements.Allometric body weight coefficients were bcl=0.5 for clearance and about br=0.7 for respiration rate of both species. Stepwise multiple regression suggested no relation for clearance rate of mussels with temperature and reproductive condition throughout the year. Respiration rates of mussels were highest during the reproductive period. Excretion rate was measured for mussels only and showed an allometric coefficient of bex=0.7 and an increase with temperature in spring. For cockles a significant relation of clearance rate, body weight and temperature was observed; at low temperature, clearance rates of small animals were more reduced than for larger animals. Respiration rates of cockles showed a significant relationship with temperature and reproductive condition.
The relationship of larval shell morphology to mode of development in marine prosobranch gastropods
Authors: Lima Gail M. , Lutz Richard A. 
Published: May 2009

The larval shell of molluscs contains a preserved record of the organism's growth and developmental history. Many investigators have utilized the information recorded in the larval shell morphology to infer mode of development.Marine prosobranch gastropods were collected from intertidal sites from Maine to Florida and were cultured in the laboratory. Scanning electron microscopy was used to document the relationship of larval shell morphology to development. Four species with planktotrophic larvae, Crepidula fornicata, Crepidula plana, Cerithium atratum and Ilyanassa obsoleta, and four species with non-planktotrophic development, Crepidula convexa, Littorina obtusata, Busycon canaliculatum and Urosalpinx cinerea, were successfully reared through metamorphosis.
The ultrastructure of the flagellar root system of Isochrysis galbana (Prymnesiophyta)
Authors: Hori T. , Green J. C. 
Published: May 2009

The fine structure of the flagellar root system of Isochrysis galbana Parke (Prymnesiophyta) has been investigated and a reconstruction is presented. Associated with the left basal body and arising close to the base of the haptonema there is a root composed of a ribbon of approximately five microtubules running peripherally towards the ventral side of the cell. Near the basal body it is also associated with two additional bundles of microtubules which diverge from it and from each other passing deep into the cell.On the right-hand side of the right basal body there is a root consisting of four microtubules (2+2) which runs peripherally in a dorsal direction. Another root, consisting of a single microtubule only, originates close to the distal connecting band between the basal bodies, and passes around the ventral side of the left basal body before following a course deep into the cell. In addition, several fibrous bands connect the bases of the flagella and haptonema. The general arrangement of the root system of 1. galbana is comparable with many other members of the Prymnesiophyta, but attention is drawn to a number of important differences, particularly between Isochrysis and some other members of the order Isochrysidales. The results are discussed in the context of the evolution, phylogeny and taxonomy of the Prymnesiophyta.On the right-hand side of the right basal body there is a root consisting of four microtubules (2+2) which runs peripherally in a dorsal direction. Another root, consisting of a single microtubule only, originates close to the distal connecting band between the basal bodies, and passes around the ventral side of the left basal body before following a curse deep into the cell.
Tolerances to high temperature of infaunal bivalves and the effect of geographical distribution, position on the shore and season
Authors: Wilson James G. , Elkaim Bernard 
Published: May 2009

There are four important influences on the temperature tolerance displayed by infaunal bivalves, namely their position on the shore, the depth to which they burrow, their geographical distribution and the seasonal cycle.The temperature tolerance of a species is closely related to shore position and burrowing depth, since these both modify the actual range of temperatures to which the organism is exposed and the tidal variation in temperature. As one might expect, southern populations of a species tend to be lower on the shore than equivalents in northern Europe, but at any one location it is difficult to detect a difference in tolerance between individuals from the top of the shore and those from the bottom. Southern populations do have a higher tolerance to high temperatures than northern, despite the shift in littoral distribution. A similar pattern of response and shift in tolerance is shown between summer- and winter-acclimated specimens.However, the seasonal shift in response to temperature is not entirely as might be expected, as oxygen consumption measurements show reverse acclimation (i.e. winter respiration rates lower than summer). Reverse acclimation has been demonstrated in a number of bivalve species, and the degree of reverse acclimation is here suggested to be related to the degree of deposit- or filter-feeding habit.There is evidence that bivalves are capable of regulating to some extent their metabolic rate, independent of temperature. Six groups of Macoma balthica were investigated, of which the four from relatively high temperature environments regulated from 20°C, while the other two did not, suggesting that this capability can be acquired.
A Comparison of some methods for analysing changes in benthic community structure
Authors: Warwick R. M. , Clarke K. R. 
Published: May 2009

Statistical methods for analysing changes in community structure fall under the three general headings of univariate, graphical/distributional and multivariate. These methods are applied to a variety of benthic community data (macrobenthos, meiobenthos, corals, demersal fish), from a variety of localities (intertidal/subtidal, temperate/tropical) and over both spatial and temporal scales. Four general conclusions emerge from this comparative study:(1) The similarity between sites or times based on their univariate or graphical/distributional properties is usually different from their clustering in multivariate analyses.(2) Species dependent (multivariate) methods are much more sensitive than species independent (univariate and graphical/distributional) methods in discriminating between sites or times.(3) In examples where more than one component of the fauna has been studied, univariate and graphical/distributional methods may give different results for different components, whereas multivariate methods tend to give the same results.(4) By matching multivariate ordinations from subsets of environmental data to an ordination of faunistic data, the key environmental variables responsible for community change may be identified.
The effect of predation on the life histories ofLittorina obtusataandLittorina mariae
Authors: Williams Gray A. 
Published: May 2009

Littorina obtusatais an epiphytic gastropod which lives for three to four years on its hostAscophyllum nodosum, a long-lived brown alga. Most of the population consists of adults, present throughout the year in the size range 14 to 17 mm. Newly hatched individuals appear between April and October with a peak in July; the immature winkles grow to merge with the adult cohort in May.In contrastLittorina mariaeis an annual; newly hatched individuals grow to maturity by the winter of their first year. Those reaching maturity overwinter as adults but very few live beyond spring of their second year. The population dynamics ofL. mariaeare closely linked with changes in the biomass of the algaFucus serratuson which it lives.
A Replica Method for the Study of Marine Biofilms
Authors: Marrs S. J. , Thomason J. C. , Cowling M. J. , Hodgkiess T. 
Published: May 2009

A replica method involving the use of a polyvinylsiloxane impression material with a resin cast, particularly suitable in the study of marine biofilms, is described. The technique has advantages over other methods in that it is quick, non-toxic, non-destructive and inexpensive. Replicas of critical-point dried eggcases of the dogfishScyliorhinus canicula(L.) (Elasmobranchii: Squaliformes) showed the replica to be true down to the size of bacteria. It was also possible to replicate larger areas such as patches of living barnacles on an intertidal rock.The study of marine biofilms often involves the use of destructive techniques such as conventional scanning electron microscopy (SEM), histology andin vacuospectroscopic methods (Baier & Meyer, 1986), so a single surface may not be examined repeatedly. Alternatively, the surface of interest may not be amenable to examination by standard techniques due to, for example, large size or incompatibility of the material of interest. In materials science the use of replica techniques to overcome such problems have been common (Goodhew, 1973), though techniques commonly involve the use of solvents (Loh, 1989) or silicone elastomers that may have a curing period of several hours (Gordon, 1984) and are consequently unsuitable for the study of biofilms. Scott (1982) reviewed the use of dental impression materials for field use in metallurgy and in recent years, dental impression materials have been used in the study of plant morphology (Green & Linstead, 1990). In this paper we consider the use of a hydrophilic polyvinylsiloxane impression material in the study of both microscopic and macroscopic marine biofilms.
Dynamics of Colonization by the Beadlet Anemone,Actinia Equina
Authors: Brace R. C. , Quicke D. L. J. 
Published: May 2009

Colonization of the littoral zone presents many problems to both sessile and relatively sessile invertebrates. These may be especially acute for inhabitants of the upper reaches of this zone, since suitable niches are usually sparsely distributed there, and are often ephemeral in nature. Consequently, both intraand inter-specific competition for space is likely to be particularly intense.The widely distributed and abundant, beadlet anemone,Actinia equinaL., in common with a number of other littoral anthozoans, is apparently capable of both asexual (apomixis or somatic embryogenesis; Polteva, 1963; Gashout & Ormond, 1979; Orr, Thorpe & Carter, 1982) and sexual (Carter & Thorp, 1979) reproduction. The former results in the production of young, which are brooded within the coelenteron and which appear most suited to local dispersal, whilst the latter, if it occurs, is assumed to involve either ovipary or larvipary followed by a planktonic phase. Study of this species therefore affords an opportunity to investigate the dynamics of colonization and dispersal in an heterogeneous environment, in relation to flexibility in reproductive tactics.
The Amphipod Sibling Pair Leucothoe Lilljeborgi and L. Incisa in British and Irish Waters
Authors: Myers A. A. , Costello M. J. 
Published: May 2009

Krapp-Schickel (1975) described three closely related species of Leucothoe Leach, which together make up a Leucothoe lilljeborgi species complex (L. lilljeborgi Boeck, L. incisa Robertson, L. occulta Krapp-Schickel) in European waters. Of these, the two species L. lilljeborgi and L. incisa have caused considerable problems to taxonomists. As pointed out by Lincoln (1979), ‘There has been a lot of confusion over the identification of lilljeborgi and incisa and it would be advisable to treat earlier records with caution.’ Despite Lincoln's (1979) work, however, the problem persists, several workers (P. G. Moore & J. M. C. Holmes, personal communications) having noted forms apparently intermediate between these two species.In order to clarify the situation, we have examined material from localities in Ireland and Britain. It is clear that the existence of apparent ‘intermediates’ is due to unfortunate choice of key characters by Lincoln, one of which requires phase contrast microscopy for correct determination. In his key to species of Leucothoe (1979, p. 172) he separates the two species by the anterodistal margin of coxa 4 being either angular (lilljeborgi) or rounded (incisa) and by the inner margin of the gnathopod 1 carpal process being either toothed (incisa) or smooth (lilljeborgi) (although in the description of L. lilljeborgi (p. 176) this process is described as weakly crenulate). Thus specimens with toothed gnathopod 1 carpal process and angular coxa 4 anterodistal margin, appear to be intermediate. It is apparent from our studies, that both L. lilljeborgi and L. incisa have a toothed gnathopod 1 carpal process, but that the structure of the teeth is quite different as revealed by phase contrast microscopy.
Life History Traits of Hoplostethus Mediterraneus (Pisces: Beryciformes) From the North-Western Ionian Sea (Mediterranean Sea)
Authors: D'onghia G. , Tursi A. , Marano C.A. , Basanisi M. 
Published: May 2009

The fish Hoplostethus mediterraneus is a bycatch of the deep-water trawling in the north-western Ionian Sea. Data on its life history traits were collected during twelve trawl surveys carried out at two month intervals, between August 1993 and July 1995.A vertical distribution according to size was observed for this species. The year's young were recruited mainly during the spring-summer period. Sex-ratio changed by size with females larger than males. Mature specimens were found mainly between May and November with a reproductive peak during late summer.Seasonal growth was detected in the otoliths; the maximum ages of 11 and 10 y were observed in females and males respectively. Von Bertalanffy growth parameters for the whole population were: L3C=287–08 mm, k=0–127 y, to=-2–131. No significant differences were detected between the growth patterns of the sexes. Overall growth perfomance depicted through size-distribution analysis was not significantly different from that obtained by otolith reading.Estimates of natural mortality rate for the whole population ranged from 0–14 to 0–20. Population structure, growth pattern, age at first maturity and low natural mortality rate indicate a life history mainly constituted by k-strategy characters and regulated by density-dependent mechanisms.
The energetics of tube production by Mercierella enigmatica (Polychaeta: Serpulidae)
Authors: Dixon David R. 
Published: May 2009

The production of tubes by the serpulid polychaete Mercierella enigmatica is compared with somatic growth and reproduction, and is shown to account for the greatest portion of production energy expenditure.INTRODUCTIONThe tube of a serpulid polychaete consists of two major fractions, a conspicuous calcareous component comprising small crystals of aragonite or calcite, and a more diffuse organic matrix (Hedley, 1956; Neff; 1971). The continuity of the organic matrix was demonstrated by Hedley (1956), who showed that careful decalcifkation failed to disturb the form of the tube of Pomatoceros triqueter (L.).The serpulid Mercierella enigmatica Fauvel (Ficopomatus enigmaticus cf. ten Hove & Weerdenburg, 1978) secretes a hard, calcareous tube shortly after it settles from the plankton (Rullier, 1955; Vuillemin, 1965). Initially, tube growth is relatively fast, but as the tube increases in length so the rate of growth declines. However, the tube of the adult worm can be as much as 80 mm in length, or more than four times the length of its body.
An account of the eggs and developmental stages of Montagu's blenny, Coryphoblennius galerita (L.), with notes on the reproductive behaviour of the adults
Authors: Fives Julie M. 
Published: May 2009

Montagu's blenny, Coryphoblennius galerita was reared to late larval stage under laboratory conditions. The adult male guarded the eggs and aerated them with its tail during the incubation period. The larvae had a small amount of yolk on hatching and although they appeared to be feeding on the variety of food introduced, no food was observed in the gut. The gas bladder, observable above the gut in all larvae, was filled with gas only in the one specimen, killed at 45 mm T.l., which survived after the yolk was utilized, and in some 4 mm specimens taken from the plankton off Mweenish.Descriptions are given of the larval stages and of juveniles taken from rock pools.
A correction to the Poole and Atkins Secchi disc/light-attenuation formula
Authors: Walker Terriss A. 
Published: May 2009

Re-examination of the original and subsequent data from Secchi disc studies leads to a revised constant in the light attenuation formula applicable to general field-work.In theory, the depth at which a Secchi disc disappears from an observer's sight, Ds, is inversely proportional to the sum of attenuation coefficients for diffuse and collimated photopic light (Tyler, 1968). By definition, photopic light is measured by a sensor with the same spectral response curve as the normal human eye. In practice, the usefulness of the theoretical equation is restricted. More commonly, a simple empirically derived formula is used to estimate the attenuation coefficient for diffuse downwelling light, k, directly from Ds. Poole & Atkins (1929), in their pioneering work on light penetration in the sea, derived the relationship k × Ds – 17 for water in the English Channel. This formula is used extensively by workers who are unable to measure k directly and it is given regularly in oceanography and marine biology texts. More recently, a number of investigators have proposed alternative equations relating k to Ds in different regional seas (Table 1). However, Idso & Gilbert (1974) have fitted data of some of these authors, together with measurements of their own, to the original Poole and Atkins formula with good correlation. They suggest that k × Ds = 1.7 is a universal approximation for all natural waters. In view of the continuing importance of the Secchi disc as a measure of underwater light for primary production calculations and other studies, a universal formula is certainly desirable. However, re-examination of the Poole & Atkins measurements has revealed an error in the method of calculation of k.
The occurrence of the barnacle Elminius modestus in Shetland
Authors: Hiscock K. , Hiscock S. , Baker J. M. 
Published: May 2009

During surveys of rocky shores in Shetland, the Australasian barnacle Elminius modestus was found at 3 out of 42 transect sites and at 6 out of 11 shores searched for its presence. Large populations were present only in Vidlin Voe with a few individuals present at other sites including Lerwick Harbour. These observations extend the northern recorded limit of distribution of E. modestus by approximately 450 km.The spread of the Australasian barnacle Elminius modestus Darwin along the coasts of the British Isles has been followed with interest by marine biologists since the animal was first found in the region of Portsmouth in 1946. Crisp (1958) describes the spread of Elminius up to 1957 and reviews the factors which are important in encouraging or restricting the spread of the species. On the west coast of Scotland, Elminius is common in the Clyde and a few individuals have been recorded on settling panels in Dunstaffnage Bay near Oban (Barnes & Stone, 1972). On the east coast of Scotland, Elminius is known to be common in the Firth of Forth and a few individuals have been recorded from the Tay Estuary (Jones, 1961). Thus, the previous recorded northern limit of distribution of Elminius modestus lies at about 56° 30′ N. Our brief report describes how Elminius has now been found in the northernmost part of the British Isles.As a part of the programme designed to monitor the effects of the oil terminal now being built at Sullom Voe on the north-east coast of the Shetland mainland, we have been concerned with the survey of plant and animal populations on rocky shores.
A Check-List of the Freshwater, Brackish and Marine Diatoms of the British Isles and Adjoining Coastal Waters
Authors: Hartley Bernard , Ross Robert , Williams David M. 
Published: May 2009

This is the first comprehensive check-list of the diatoms of the British Isles to cover all currently reported taxa from freshwater, brackish and marine habitats. It contains a classification of the genera in order of families, followed by a complete list of species and lower taxa set out in alphabetical order within each genus.The two main orders of the British Diatomaceae are represented in:- 5 sub-orders, 20 families, 3 sub-families, 152 genera, 1798 species, 6 sub-species, 745 varieties and 73 forms.The check-list also includes 2048 synonyms formerly in common use, together with 512 cross references to the names of taxa in current use.
Reducing activity and the formation of base in the coralline algae: an electrochemical model
Authors: Digby P. S. B. 
Published: May 2009

SUMMARY AND CONCLUSIONSIn the process of calcification in the coralline algae,Clathromorphum and Corallina, the energy is derived from photosynthesis; the outer surface evolves carbon dioxide while calcium carbonate is deposited between the algal filaments. Evidence suggests that calcification may be brought about essentially by separation of acid and base followed by preferential removal of an acid component in the form of carbon dioxide.These algae show strong oxidase, catalase and carbonic anhydrase activity, consistent with the processes postulated. The calcified algal thallus is normally reducing. Platinum electrode potentials, Eh, measured on and immediately below the outer surface of fresh and healthyClathromorphumcrust following abrasion ranged from 50 to 100 mV, some 150–370 mV negative to that of the surrounding water at the time. These potentials in the alga were most reducing after the material had been exposed to strong sunlight. Eh potentials, measured by electrodes of platinum foil attached to the outer surface ofClathromorphumin such a way as to shield it from light and from gaseous exchange from the sea water, reached values between 113 and -182 mV, or up to 480 mV negative to the Eh of the surrounding sea water.Oxidation of crude suspensions of crushed fresh material showing reducing activity resulted in the production of base by removal of hydrogen ions. The amount of base so formed was greater when suspensions were first incubated out of contact with air for periods of up to several days, reducing conditions being enhanced by respiration of the alga alone or in conjunction with bacterial growth.
Structure and general distribution of free neuromasts in the black goby, Gobius niger
Authors: Marshall N.J. 
Published: May 2009

INTRODUCTIONThis paper on Gobius niger describes the ultrastructure of free neuromast papillae of both standard and mandibular types, emphasizing the polarity of the hair cells in each row or column. Evidence to suggest a functional difference between mandibular and standard neuromasts is reviewed, together with an hypothesis concerning the developmental origin of the mandibular row, relevant to the evolution of lateral line organs in general.
B-cells and digestion in the hepatopancreas of penaeus semisulcatus (Crustacea: Decapoda)
Authors: Al-Mohanna S. Y. , Nott J. A. 
Published: May 2009

INTRODUCTIONThe current nomenclature for cells in the hepatopancreas of decapods is based on the classification of Jacobs (1928) and Hirsch & Jacobs (1928). They described the E-(embryonic), F-(fibrillar), B-(blister-like) and R-(resorptive or absorptive) cells. More recently the M-(midget) cell has been described (Al-Mohanna, Nott & Lane, 1984).Accounts of the structure of these cells are reviewed by Gibson & Barker (1979) and the B-cells most closely resemble those described and illustrated in this paper for the period 24 h after feeding.