bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ferritin Crystals in the Gut Caeca of a Deep-Sea Hydrothermal Vent Stegocephalid (Crustacea: Amphipoda)
Authors: Moore P.G. , Rainbow P.S. 
Published: May 2009

Ferritin crystals and calcium granules are reported from the ventral ceaca of Steleuthera ecoprophycea (Amphipoda: Stegocephalidae) collected from the Snake Pit hydrothermal vent, Mid-Atlantic Ridge (3520 m).In a series of earlier papers (Moore & Rainbow, 1984, 1989, 1992; Moore et al., 1994), the authors described the widespread occurrence of intracellular, octahedral crystals of ferritin in the ventral caeca of a range of stegocephalid amphipod species from the continental shelf epibenthos and oceanic plankton. The discovery at 3500 m of a new Steleuthera species (S. ecoprophycea), from a hydrothermal vent on the Mid-Atlantic Ridge was announced recently by Bellan-Santini & Thurston (1996), and a complete description is provided therein.Oceanic ridge sites are notable for their tectonic activity and the presence of a diversity of trace metals at high concentrations is to be expected in hydrothermal plumes emanating from such regions (German & Angel, 1995). The detoxification of accumulated trace metals in the ventral ceaca of stegocephalid amphipods from uncontaminated environments is now relatively well known (see above), so it was of interest to investigate whether a vent stegocephalid showed an atypical presence of trace metals in detoxified form in cells of the ventral caeca. The results following from an opportunity to investigate this are reported herein.Material was derived from a dive made by the submersible ‘Alvin’ at Snake Pit hydrothermal field, Mid-Atlantic Ridge (23°23′N 44°56′W), 3520 m, on 16 June 1993 (see Bellan-Santini & Thurston, 1996). Steleuthera ecoprophycea was preserved in 70% alcohol. Subsequently to dissection, the single pair of ventral caeca from each of the four damaged amphipods investigated were post-fixed in 4% glutaraldehyde. For electron microscopy and x-ray microanalysis in STEM mode, ventral caecal tissues were then dehydrated through 95% and absolute ethanol, cleared in propylene oxide, embedded in TAAB resin, sectioned at 0·5 μm (semi-thin sections) on a Reichert OmU2 ultramicrotome and examined without staining in a JEOL 100C electron microscope equipped with LINK system EDX energy dispersive x-ray microanalyser.
Activity Rhythms Of The Squat Lobsters, Galathea Squamifera And G. Strigosa (Crustacea: Decapoda: Anomura) In South-West Ireland
Authors: De Grave S. , Turner J.R. 
Published: May 2009

This short note describes the in situ activity cycles of Galathea squamifera and G. strigosa (Crustacea: Decapoda) through SCUBA diving observations in south-west Ireland. Both species exhibited nocturnal activity peaks, although they were not exclusively nocturnal. Fluctuating tidal current strength and direction had no discernible influence on either species’ activity cycles. It is suggested that shelters, particularly in terms of both predator avoidance and as foraging areas, play an important role in the ecology of both species.Both the anomuran decapod crustaceans Galathea squamifera Leach and G. strigosa (L.) are widespread throughout the rocky subtidal of the north-west European coastline. In contrast to the general body morphology and the structure of the mouthparts which have been well studied (Nicol, 1932; Pike, 1947), the biology and ecology of the genus Galathea remains poorly studied. These morphological studies have shown that the mouthparts are ill-adapted to living on muddy substrates, essentially restricting the distribution of both G. squamifera and G. strigosa to rocky areas, where their food is obtained by detrital deposit feeding and scavenging. Turner & Warman (1991) have studied the activity patterns of the genus Galathea at Lough Hyne, southwest Ireland and concluded that the genus exhibits nocturnal activity peaks. However, the different species were not distinguished, nor was the potential effect of the aberrant tidal patterns in the area considered. As at least three species (G. squamifera, G. strigosa, G. intermedia) are known to occur at the study site (Holmes, 1985), the present study was initiated to elucidate the activity cycles at a species-specific level.
Circatidal Moulting Rhythm in The Shore Crab Carcinus Maenas
Authors: Abello P. , Warman C.G. , Naylor E. 
Published: May 2009

Late premoult females from precopula pairs of male and female Carcimts maenas (Crustacea: Brachyura) moulted at times of expected high tide in constant conditions in the laboratory. The data presents for the first time evidence of endogenous, circatidal (−12·4 h) moulting rhythms in a crustacean.Studies on the temporal patterns of moulting in crustaceans have elucidated rhythms of seasonal (annual or biannual), lunar (29·4 d), semilunar (14·7 d) and diel (24 h) periodicities (see Conan, 1985; Fernandez et al., 1994). Examples in the literature of so-called ‘tidal’ rhythmicity of moulting given by Conan (1985) are more correctly referred to as semilunar or neap/spring patterns. There appear to be no reported examples of true tidal (12·4 h) moulting rhythms. Also there is very little evidence in the literature that moulting rhythms phased to geophysical cycles are controlled endogenously. Most studies have been carried out in the field or under L:D cycles in the laboratory and only a few have been undertaken with animals in constant conditions (see Fowler et al., 1971; Bishop & Herrnkind, 1976; Nicol, 1989; Fernandez et al., 1994). Conan (1985) has reported moulting rhythms of circamonthly, circatidal (=circasemilunar) and circadian periodicities but his use of the prefix ‘circa’ is unusual since it more correctly describes free-running rhythms in constant conditions, not environmentally driven rhythms as in the examples quoted. In the present study we sought to determine whether moulting in the shore crab Carcimts maenas (L.) was tidally patterned and endogenous.Over a period of several days in the summer of 1991 large numbers of premoult female Carcinus maenas were obtained by searching for specimens associated with males in precopular pairs.
Factors affecting individual body weight in field populations of the mudsnail Hydrobia ulvae
Authors: Morrisey Donald J. 
Published: May 2009

Differences in average body size among allopatric and sympatric populations of hydrobiid mudsnails have been interpreted as the consequence of interspecific competitive interactions. Recently, however, doubts have been expressed concerning the certainty with which size differences can be ascribed simply to character displacement. Other environmental factors are known to influence body size in hydrobiids. In the present study one of these, sediment type, was investigated.Average body weight of Hydrobia ulvae (Pennant) living on fine mud was consistently higher than that of members of the same species living on adjacent muddy sand. Snails were transplanted from one sediment type to the other, confined within cages, and their growth rates compared with those of control animals caged on their native sediment. The results of this experiment suggested that substrate type is one factor controlling body size, but the inconclusive nature of the results indicate that others are also involved.
Changes in lipids during simulated herbivorous feeding by the marine crustaceanNeomysis integer
Authors: Bradshaw Stuart A. , O'Hara Sean C. M. , Cornert Eric D. S , Eglinton Geoffrey 
Published: May 2009

A laboratory study simulating herbivorous feeding was carried out with the marine crustaceanNeomysis integer(Leach) and the dinoflagellateScrippsiella trochoidea(Stein). Analyses of the total fatty acids, sterols and fatty alcohols in the food and faecal material, and in the animal tissue, have allowed the detailed changes in the dietary lipids during feeding to be characterised.The results show this feeding leads to a net decrease in total lipid in the material passing through the gut of the animal, particularly due to the bioassimilation of fatty acids. All fatty acid saturation classes are assimilated but the mono-unsaturated and particularly polyunsaturated fatty acids are preferentially assimilated over others. Herbivorous feeding does, however, lead to the quantitative and relative increase in ‘bacterial’-type odd C number branched-chain fatty acids in the faecal material.
The uptake of gold by marine sponges
Authors: Bowen H. J. M. 
Published: May 2009

Gold has been determined in six marine sponges by neutron activation analysis. The amounts found (1·8–12·6 × 10−8 g/g dry sponge) are higher than would be expected from measurements of the distribution of 198Au between sea-water and dead sponge samples.Many attempts have been made to devise methods for concentrating gold from sea water, but none of them are commercially viable. Recent work has shown that gold can be concentrated by adsorption or absorption on certain artificial polymers (Hummel, 1957; Bowen, unpublished). This note describes some measurements of the accumulation of gold by marine sponges whose scleroprotein structure resembles some of the artificial polymers employed.
Consistency of Towing Speed and Sampling Depth for the Continuous Plankton Recorder
Authors: Hays G. C. , Warner A. J. 
Published: May 2009

The mean annual towing speed of the Continuous Plankton Recorder (CPR) varied systematically between 1946 and 1991. By mounting a pressure transducer on the CPR to record towing depth, it was shown, however, that changes in towing speed did not cause a significant change in towing depth, although the mean towing depth (6–7 m, SD=l-7 m, N=77) was shallower than the previously assumed towing depth of 10 m. Thus the observed changes in towing speed are unlikely to have caused discontinuities in the CPR time-series by affecting sampling depth.Long-term data sets play an important role in attempts to understand the causes of fluctua- tions in plankton abundance. The Continuous Plankton Recorder (CPR) survey provides multi- decadal information on plankton abundance in the North Sea and North Atlantic (McGowan, 1990), and is one of the longest standing marine plankton abundance time-series. However, while the CPR time-series has great potential, as with all other data sets spanning many years, questions may be asked regarding the consistency with which the data have been collected and hence the true continuity of the time-series.
Some Observations on Morphological Variation in the Red-Water Ciliate Mesodinium Rubrum
Authors: Crawford David W. 
Published: May 2009

Living cells of the ciliate Mesodinium rubrum were observed and photographed during summer red-water events in the Southampton Water estuary, southern England. These blooms were characterized by increases in maximum cell diameter and range of cell size, a pronounced morphological variation of the ‘oral’ hemisphere, and the presence of free-swimming ‘fragments’ of larger cells.Red-water occurrences caused by the planktonic, phototrophic ciliate Mesodinium rubrum (Lohmann) Hamburger & Buddenbrock, have been characterized by some of the highest recorded levels of chlorophyll and primary productivity for natural populations of marine phytoplankton (Lindholm, 1985; Taylor, 1982). However, as these events are rather unpredictable and all attempts to culture M. rubrum have failed, descriptions of the morphology of living cells have been rather limited. A study into the impact of red-tides caused by M. rubrum in the Southampton Water estuary presented a useful opportunity to observe morphological variation in living cells. Water samples were taken with a ‘Van-Dorn’ sampler, and transported in polyethylene bottles in a cool box. Living cells were observed and photographed at 400x magnification using the phase-contrast optics of an Olympus BH2 photomicroscope. Autofluorescence of living cells was examined using a Zeiss fluoresence microscope.
Effects of Daylength on Growth and Reproduction of the Conchocelis-Phase of Porphyra Tenera
Authors: Dring M. J. 
Published: May 2009

The conchocelis-phase of Porphyra tenera Kjellman has been grown in in vitro culture, and subjected to a variety of daylength treatments.Details of the culture apparatus designed for these treatments are given, and quantitative techniques, which have been devised for estimating the growth and reproduction of the alga, are described and discussed.Growth was found to be directly proportional to daylength within the range 8–16 h, but abundant sporangia were only formed in daylengths of 10 h or less. The interruption of a 16 h dark period by 1 h of light completely inhibited the production of sporangia, but exposure to 8 short-day cycles, followed by long days, induced the formation of as many sporangia as were found after 25 short days. These results are discussed with reference to the photoperiodic responses of flowering plants.
Platymonas Impellucida Sp.Nov. From Puerto Rico
Authors: Mclachlan J. , Parke M. 
Published: May 2009

The morphology and microanatomy of Platymonas impellucida sp.nov. have been investigated using light and electron microscopes and unusual stages of cell division studied. The anatomical features closely resemble those recently described for Platymonas convolutae (cf. Parke & Manton, 1967). As in that species the pyrenoid is penetrated from many directions by cytoplasmic canaliculi lined with the double plastid membrane but unlike that species a starch shell is not developed around the pyrenoid. In whole cells of P. impellucida therefore, it is extremely difficult, in most cases impossible, to detect the presence of the pyrenoid. This new information on the absence of a starch shell in a member of the Prasinophyceae is of importance since pyrenoid structure appears to be of major importance for taxonomic purposes. Apparent fusion stages have been shown to be a variation in vegetative division not previously encountered in the genus Platymonas.IntroductionRecent studies on members of the Prasinophyceae have assisted greatly in characterizing this class of green-pigmented algae although the limits are not as yet entirely defined. Fine-structure investigations have, in addition, elucidated certain features of generic significance. The genus Platymonas is now well described and can be unequivocally distinguished from Prasinocladus, a closely related genus. Previously these two genera were separated on the presence or absence of non-motile dendroid colonies, but such colonies are now known in both genera (Parke & Manton, 1967).The remaining significant diagnostic generic characteristic is the structure of the pyrenoid. In Platymonas the branched canaliculi invading the pyrenoid either from a direction facing the nucleus (Gibbs, 1962; Manton & Parke, 1965) or from many directions (Parke & Manton, 1967) contain cytoplasm rather than protrusions of the nucleus as in Prasinocladus (Parke & Manton, 1965).
The orientation of muscle fibres in the myomeres of fishes
Authors: Alexander R. McN. 
Published: May 2009

The superficial red muscle fibres of gnathostome fishes run more or less longitudinally, but the deeper muscle fibres are arranged in complex three-dimensional patterns in which some of them make angles of 30° or more with the long axis of the fish. There are two basic patterns, of which one is found in all the myomeres of selachians, primitive bony fishes,AnguillaandSalmo. In the other teleosts which were examined this pattern is restricted to the last few myomeres, and a quite different pattern is found more anteriorly.In a fish with muscle fibres running longitudinally the lateral fibres would be able to contract far more than those near the vertebral column. However, from mathematical analyses included in this paper it appears that both the patterns which have been found should result in all the white fibres in a myomere contracting to a fairly similar extent when the fish bends. This seems likely to be advantageous because a muscle fibre of given intrinsic speed produces maximum power output at one particular rate of contraction.A given rate of contraction of the muscle fibres results in faster bending if the fibres are arranged in the typical teleost pattern than if they are arranged in the selachian pattern.The selachian pattern is probably retained in the caudal peduncles of teleosts because the faster bending is obtained only at the expense of weaker bending moments. The caudal peduncle is slender and would be less able to transmit large forces to the caudal fin if the teleost pattern of muscle fibres were continued to its posterior end.
Photosynthetic carbon metabolism of size-fractionated phytoplankton during an experimental bloom in marine microcosms
Authors: De Madariaga I. , Fernandez E. 
Published: May 2009

Water samples, taken from station El in the English Channel, were incubated in 12–1 bottles and monitored for nine days. The distribution pattern of photosynthetically incorporated 14C was followed in three different size-fractions (0·2–2 μm, 2–10 μm and >10 μm) during the development of a bloom.A rapid increase in chlorophyll was observed just after enclosure, the highest values being reached by day 5, when a mixed community of diatoms and small flagellates formed the bulk of phytoplankton biomass. As the bloom developed, nutrients were depleted and, consequently, a decay of the phytoplankton populations occurred. Growth rates, estimated as chlorophyll-specific production rate, were higher for the largest size-fraction (0·53 d−1) than for the intermediate and smallest ones (0·32 d−1 for both).Throughout the bloom, the proportions of 14C incorporated into protein and low molecular weight metabolites (LMWM) were small, whereas the synthesis of storage products appeared to be enhanced. Carbon fixed into protein was higher during the exponential growth phase in all size-fractions, and incorporation into LMWM increased sharply when the bloom declined. Storage product synthesis varied between size-fractions.A close relationship was observed between growth rates, estimated as chlorophyll-specific production rate, and the protein/metabolite synthesis ratio (r2=0·90; n=24). These results suggest that, within the range of environmental variation we studied, this ratio would be a good estimator of growth rate for field studies.
Fast pressure pulses and communication between fish
Authors: Gray J. A. B. , Denton E. J. 
Published: May 2009

Experiments on herring(Clupea harengusL.), sprat(Sprattus sprattus(L.)) and whiting(Merlangius merlangus(L.)) showed that when these fish make rapid swimming movements, such movements are preceded by fast pressure pulses in the surrounding sea water. Thefirst (a) phases of these pulses had durations of from 1–5 to 3–5 ms. The pulses could be excited in free-swimming fish by both visual and auditory stimuli and the latencies to the latter ranged from 5 to 8–5 ms. Identical pulses could be elicited by giving electrical stimuli to anaesthetized fish; these pulses had latencies from 34 to 7 ms.The pressure fields around the fish were measured on suspended anaesthetized fish stimulated electrically. At any instant the fields of the fast pulses produced by whiting had the same polarity at all positions round the fish and pressure decayed inversely with the 1–5 powerof distance. Theaphase of the fast pulse was usually a decompression.The fields around a stimulated herring were different. The pressures on both sides oppositethe centre of the fish were of one polarity while those around the head and the tail were of the opposite polarity, the pattern of pressure being symmetrical about the long axis of the fish.In our experiments the a phase opposite the centre of the fish was always a compression. The amplitudes of these pulses declined with distance by the power of 2–5. In all species in our experiments the fast pulses were followed by slower pulses associated with swimming movements; these slower pulses had opposite polarities at corresponding points on the two sides of the fish.
Eggs of the Microchirus species (Soleidae) from the Bay of Algiers
Authors: Marinaro J. Y. 
Published: May 2009

Soleid eggs caught in the plankton off Algiers were reared and identified. Thus, the egg and the yolk sac stages of Microchirus ocellatus (L.) and M. azevia (Capello) were described, compared and differentiated from the corresponding stages of M. variegatus (Donovan). For the latter species, a large perivitelline space was often discernible.In 1889, Cunningham referred some pelagic eggs caught near Eddystone (English Channel) to Solea variegata, owing to their similarity to the mature ovarian eggs of this species. Moreover, he considered the embryonic and larval stages described, illustrated and named ’species no. 1'by Raffaele (1888) as belonging to the same soleid. In further works, Cunningham studied the two-day-old larva (1890) and the newly hatched larva (1896). These papers and some others relating to Microchirus variegatus (Donovan, 1808) (present name of S. variegata) were reviewed by Ehrenbaum (1905), Padoa (1956), Nichols (1976) and Russell (1976).Such eggs are often collected in the plankton of the Bay of Algiers, but I noted a great variability in their features. According to Quero et al.
The first record of the short-beaked garfish Belone svetovidovi (Belonidae) in british waters
Authors: Swaby Silja E. , Potts Geoffrey W. , Wheeler Alwyne 
Published: May 2009

The capture of the short-beaked garfish,Belone svetovidovi Collette & Parin 1970, off the Cornish coast is of particular interest in that it represents an easterly extension to the known range of this species in the eastern North Atlantic, and the first record in British waters.In August 1990 seven garfish were angled, on mackerel bait, in Mount's Bay, Cornwall. The captor, Mr A.C. Cass, believing the garfish to be different from the common garfish,Belone belone (L.), sent the largest one to the laboratory of the Marine Biological Association for identification. The specimen was provisionally identified as the short-beaked garfish B. svetovidovi and later verified by one of us (A.W.). The other six specimens were not available for examination.Garfish, sometimes called needlefishes, have elongated bodies. Both upper and lower jaws are long and beak-like, with sharp teeth. They are epipelagic, feeding near the surface and are often observed leaping and skittering over the surface of the water. Only two species are recorded in the genus Belone in the north-eastern Atlantic.Belone belone (including subspecies) is commonly found off the European Atlantic coast as far north as Trondheim, Norway. It is also found in the North Sea, the southern Baltic seas, the Mediterranean and Black Sea where it is commercially exploited (Collette & Parin, 1986).Belone svetovidovi has only recently been distinguished from B. belone, and consequently its abundance and distribution are less well known. It was first identified in northern European waters by Dorman (1984,1987) from southern Ireland.