bluuebunny/crossref_metadata_2025 huggingface dataset:
Persistent, vertical-migration rhythms in benthic microflora: I. The effect of light and temperature on the rhythmic behaviour of Euglena obtusa
Authors: Palmer John D. , Round Frank E.
Published: May 2009

During daytime low tides on the River Avon at Bristol, England, the exposed river banks become a deep green colour owing to the presence of enormous numbers of Euglena obtusa which emerge out of the black mud. Cell densities on the surface surpass 105 cells/cm2. Before the tide returns to cover the area, the cells re-burrow back into the mud and remain there during high tide and throughout the night.

The cells can be prevented from emerging on to the surface mud at low tide by artificially darkening the area with an opaque covering just as the tide recedes. Cells which are already on the surface can be made to re-burrow by similarly placing them in darkness.

The vertical-migration rhythm will persist in the laboratory in constant illumi-nation, constant temperature, and away from the influence of the tide, for nearly one month. In these conditions the rhythm is diurnal, rather than tidal. The rhythm will not persist in constant darkness.

Because of the excessive turbidity of Avon water, each high tide imposes a period of darkness on the surface mud. It is thought that these dark periods transform the fundamental diurnal rhythm into one of tidal frequency.

Various intensities of constant illumination alter the form and amplitude of the rhythm, but not the period. The stable nature of the period, under different light intensities, is thought to be due to a unique, self-stabilizing feature inherent in this type of rhythm.

The rhythm is inhibited at 2° C. Between 5° and 15° C, the period of the rhythm is virtually unaltered; it remains approximately 24 h in length.
The fecundity of long rough dabs in the Clyde Sea area
Authors: Bagenal T. B.
Published: May 2009

The fecundity of 180 long rough dabs caught in the Clyde Sea Area from 1957 to 1961 ranged from 9700 eggs in a 12.2 cm fish to 251,300 eggs in one of 30.0 cm. The mean lengths of the fish in the samples each year were different so the comparisons between one year and another were based on the fecundity expected of a 22 cm fish. The differences between years were statistically significant, though successive years did not differ significantly when tested in pairs. The trends of increase and decrease in fecundity were very similar to those of the witch (and different from the plaice). It is suggested that, since witches and long rough dabs (in contrast to plaice) both prefer a muddy bottom, the fecundity variations from year to year might be caused by fluctuations in the abundance of some common food organisms.
Breeding and fecundity of Praunus inermis [Crustacea, Mysidacea]
Authors: Mauchline J.
Published: May 2009

Praunus inermis (Rathke) breeds at all times of the year in the Clyde, the pro-portion of breeding females being minimal in January and maximal in August. The progeny produced by the winter stock during the period March to July are known as the summer generation, the eldest members of which commence breeding in July/August, and the new winter stock is formed in the autumn from the surviving members of this generation and their progeny. The number of young carried in the marsupium varies seasonally, being about 30–40 in May/June and 10 during the period November to January. Larger females tend to carry more young than smaller females. Comparisons are made between the population in the Clyde and those at Port Erin, Isle of Man, and at Nyborg Fjord, Denmark.
Polarization of light reflected from the silvery exterior of the bleak,Alburnus alburnus
Authors: Denton E. J. , Nicol J. A. C.
Published: May 2009

A method is described for measuring, for various angles of incidence, the polarization produced by reflexions from natural surfaces.

This method was tested by measurements on matallic surfaces of known properties and then used to study reflexions from the silvery gill cover of the bleakAlburnus alburnus(L.).

Althouth the reflecting surfaces of the gill cover are crystals of a dielectric guanine, there is no polarizing angle, and the reflecting properties of the gill cover resemble those of a sputtered aluminium mirror

The biological significance of these results is briefly discussed.
Reflexion of light by external surfaces of the herring, Clupea harengus
Authors: Denton E. J. , Nicol J. A. C.
Published: May 2009

The orientations of the reflecting layers in the external surfaces of the herring have been found both by light-measurements on the fresh fish and by histological studies on preserved specimens.

The reflecting platelets which lie under the scales are orientated, with respect to the surface of the fish, in a similar way to the platelets found in the bleak and described earlier by Demon & Nicol (1965). However, on the curved dorsum of the fish, although the reflecting platelets are much more perpendicular to the sea surface than the scales on which they lie, these platelets are still inclined some 20° to the perpendicular. It is shown that, in this region, the fish reflects the fraction of the light striking the platelets which is sufficient to match the background against which the fish is seen. The platelets on the curved dorsum have the property of reflecting green light well if it falls obliquely on them but reflecting it poorly when it strikes them at angles close to normal incidence. On the broad flank of the herring the scales have reflecting platelets under most of their surfaces, and the individual scale has several distinctly coloured regions. When we look at any particular region of the flank of an intact fish we are always looking at several overlapping layers differing greatly from one another in their spectral reflecting properties.

It is the combination of the reflexions of several layers which gives the very bright silvery reflexions of the intact fish. A system of overlapping scales of this kind is needed even to reflect one waveband of light well over a wide range of angles of incidence.
Observations on the fine structure of two species of Platymonas with special reference to flagellar scales and the mode of origin of the theca
Authors: Manton I. , Parke M.
Published: May 2009

The morphology and microanatomy of two species of Platymonas have been investigated and certain stages of cell division studied. The anatomical features closely resemble those recently described for the motile phase of Prasinocladus except for characteristic differences in pyrenoid structure (cf. Parke & Manton, 1965). The flagella ofPlatymonas are indistinguishable from those of Prasinocladus, being covered with two layers of scales beneath a layer of structureless mucus which obscures their presence except in sections. Caducous hairs resembling those ofPrasinocladus and related genera are also borne on the flagella.
A comparison of plant production estimates using14C and phosphate data
Authors: Steele John H.
Published: May 2009

Organic production in the sea can be measured by studying the changes in phosphate throughout the water column. Results obtained by this method are compared with estimates of carbon uptake using 14C made on the Fladen Ground during 1955 and 1956. There is good general agreement between the two methods but some differences in the vertical distribution.

The results are also used to calculate filtering rates of phytoplankton and sinking rates of zooplankton, and to compare observed and predicted vertical distributions of chlorophyll.
On a new species of scyphomedusa,Atolla vanhoffenin.sp.
Authors: Russell F. S.
Published: May 2009

In 1902 Ernst Vanhöffen drew attention to the occurrence of eight dark pigment spots inAtollawhich he thought might be excretory organs.

It is shown that these spots are a specific character occurring only in some specimens, and medusae with this character have been namedAtolla vanhöffenin.sp. This species can now be distinguished fromA. wyvilleiby other characters.
The biology of a commensal copepod,Ascidicola roseaThorell, in the ascidianCorella parallelogramma(Müller)
Authors: Gotto R. V.
Published: May 2009

A study has been made of the feeding activities and reproductive behaviour of the copepodAscidicola roseawithin one of its ascidian hosts,Corella parallelogramma.

Ascidicola roseafeeds on particles which it removes from the food string as the latter is passing through the oesophagus of the host. When active feeding is not taking place, the copepod remains quiescent in the oesophageal bend. An inverted position within the oesophagus is sometimes adopted; this is generally associated with a meagre development of the food string. Certain peculiar structural features—notably the spinous pad on the penultimate segment and the long endopodal setae—are considered to be adaptations which assist the copepod while clinging to the food string.

The eggs ofA. roseaare deposited in the ascidian's stomach and the nauplii pass through the host's alimentary canal still enveloped by the inner egg membrane. On reaching the anus, hatching takes place and the nauplii are expelled from the atrial siphon. There are four naupliar and two copepodid stages. Free-swimming life lasts for about 6 days.
Phosphorus and silicon in sea water off Plymouth during 1955
Authors: Armstrong F. A. J.
Published: May 2009

Temperatures and salinity, phosphate, total phosphorus and silicate analyses of water from the International Hydrographic Station E1 during 1955 are discussed. The seasonal variation is shown, and it appears that consumption of nutrients by plants in the spring was: phosphate 0·42 μg atom P/L, ‘total phosphorus’ 0·40 μg atom P/l., silicate 2·43 μg atom Si/1., these being means for the whole water column. Some irregularities are pointed out; they are probably attributable to changes in the water mass.
The adaptations of Lasaea rubra (Montagu), a small intertidal lamellibranch
Authors: Morton J. E. , Boney A. D. , Corner E. D. S.
Published: May 2009

A study has been made of the ecology of the small intertidal lamellibranch Lasaea rubra at various tidal levels at Plymouth and Wembury. In addition, experiments have been carried out to investigate physiological and behavioural differences arising from varying amounts of submersion at different tidal levels, and the following findings have been made.

During the first hour after their submersion by sea water, L. rubra from high up the shore filter at a rate approximately twice that of animals which live lower down. After 2 h, however, both sets of animals filter at the same rate.

High-level animals respond significantly faster to wetting by splash and can tolerate a considerable range of salinity. They also respire at a rate approximately twice that of low-level animals. Respiration, however, is not detectable when the animal is not immersed in sea water.
The distribution of Polychaeta in offshore deposits in the Irish Sea
Authors: Southward Eve C.
Published: May 2009

During 1952–54 a survey was made of the Polychaeta living in the offshore bottom deposits of the south of the Isle of Man. These deposits range from stones and coarse gravel to soft mud; samples were obtained with a van Veen grab sampler and various dredges.

It was found that, although some species were widely distributed, each bottom deposit had a typical fauna, and that where the deposits graded into one another the polychaete fauna was also mixed. The distribution of each species appears to depend mainly on its mode of life and feeding habits; some can exist in several types of deposit or habitat, while others are very much restricted in their distribution.

The Polychaeta formed a high proportion, numerically, of the macrofauna, exceeding any other animal group, except possibly in the coarse gravels. However, the density of the polychaete population was low compared with other areas of the British Isles, and this may be correlated with the comparatively low biomass in the area.
A note on Stichococcus bacillaris Naeg. and some species of Chlorella as marine algae
Authors: George E. A.
Published: May 2009

Several strains of Stichococcus bacillaris Naeg. and of the marine S. cylindricus Butcher were all found to fit morphologically in Naegeli's species. Both the marine and non-marine strains grow well in either fresh- or sea-water media. S. cylindricus must therefore be regarded as a synonym of S. bacillaris. Three marine Chlorella strains including C. ovalis Butcher and C. stigmatophora Butcher were also found to be quite unexacting about salinity. The significance of small differences, particularly of growth rate, is discussed with regard to non-sexual organisms. In general, widely based species are advocated for such organisms, with the clonal lines, where appropriate, designated by the reference number of a recognized culture collection.
Observations on the resistance of Tigriopus fulvus (Fischer) to changes in temperature and salinity
Authors: Ranade M. R.
Published: May 2009

Tigriopus fulvus can live normally within a salinity range of from 4·2 to 90%.

In waters of salinities above 90% it falls into a state of apparent death from which it can recover if transferred back to lower salinities.

The relation between immersion period and the recovery period is only slightly different at different salinities.

The lethal temperatures vary between 32·0 and 41·8°C depending on the salinity of the sea water, the lethal temperature being higher in higher salinities.

The fluctuations in salinity and temperature in the pools where the animals were collected are well within their tolerance limits.

T. fulvus is well adapted to its habitat.
Chromosome numbers of gammarids
Authors: Orian A. J. E. , Callan H. G.
Published: May 2009

The chromosomes of nine species of gammarids have been studied in oocytes and embryos. There is no evidence that polyploidy has played a part in gammarid evolution. Three of the species which we have studied,Gammarus pulex(L.),Marinogammarus marinus(Leach) andM. pirloti(Sexton & Spooner) show chromosomal polymorphism. There is no evidence that this polymorphism depends on the existence of a Robertsonian ‘fragmentationfusion’ system; rather it appears to be due to the presence of supernumerary chromosomes.
Seasonal variations in host-parasite relations between fish and their Protozoa
Authors: Noble Elmer R.
Published: May 2009

From July 1955 to June 1956 a study of host-parasite relations between three species of marine fish and their Protozoa was made at Plymouth.Callionymuslyra, a bottom-dweller, tends to be more abundant during the summer months, consumes a wide variety of food, and was more heavily infected with Protozoa than were the other two species offish.Gadus merlangusis an active predator, feeding on small fish, and although it has about the same numbers of kinds of Protozoa as doesC. lyra, it was less heavily parasitized.G. merlangus, however, was more heavily parasitized with worms than were the other two fish.Microstomus kittis a sluggish bottom-dweller, feeding on annelids, and, although over 99% were infected with myxosporidia, the intensity of infection was generally low. Very few other parasites were found inM. kitt.

An active predatory habit combined with a taste for a wide variety of food appears to predispose to heavy parasitism. Some evidence for seasonal variations in intensities of protozoan infection inCallionymus lyrawas obtained, but for conclusive results more precise methods of measuring numbers of parasites, and further studies carried on over a period of at least three consecutive years, must be made. The report is presented primarily to emphasize the importance of an ecological approach to the study of parasitology.
The toxin fromGymnodinium veneficumBallantine
Authors: Abbott B. C. , Ballantine Dorothy
Published: May 2009

Methods of extraction of the toxin from cultures ofGymnodinium veneficumare described. This is now done by dialysis and evaporation under reduced pressure. The toxin molecule must be large, as it cannot penetrate a dialysis membrane; it is soluble in water and the lower alcohols, but insoluble in ether and chloroform. It is unstable in acids, turning into another toxic product, and is decomposed by hot alkali, though in neutral solution is more or less thermostable. The toxin as it occurs in sea water is not the same as paralytic shellfish poison, but there are some resemblances between this and the 'acid extract', though much more work is needed to check this point.

The action of the toxin on a variety of animals is described, and an attempt is made to devise an approximate assay technique using gobies as the test animals.

The action has also been observed on a range of isolated preparations, and although the final conclusion as to the mode of action is not quite clear, we feel confident that the site of action in whole animals is in the nervous system, probably acting on ganglion transmission. With regard to the mode of action it depolarizes nerve and muscle membranes. It also abolishes the potential across frog skin without measurably altering the skin resistance.

This depolarization probably occurs by interference with the sodium exchange mechanism, allowing rapid entry of sodium into the cells.
Mucilage sheaths of spores of red algae
Authors: Boney A. D.
Published: May 2009

If newly released spores of red algae are placed in a suspension of Indian ink in sea water, a clear halo of mucilaginous material will be seen. A similar mucilage cover is also a well-known feature with certain phytoplankton organisms, in which cells of spiny appearance (e.g. freshwater desmids) assume a spherical form in Indian ink when the mucilage cover is also observed (Lund, 1959). The attachment of red algal spores is a process in which mucilage clearly plays some part (Suto, 1950; Nakazawa, 1958; Matsumoto, 1959; Boney, 1966; Linskens, 1966; Moorjani & Jones, 1972; Charters, Neushul & Coon, 1972; Chamberlain & Evans, 1973). Studies on the sinking rate and dispersal of red algal spores have been described (Suto, 1950; Boney, 1965, 1966; Coon, Neushul & Charters, 1972). There appears to be little information on the sizes of the spore mucilage sheaths, and on their likely significance in the planktonic phase of the spore's existence immediately after release. The present work gives the results of an investigation of the spore mucilage of fourteen species of red algae.
The distribution of the coralCaryophyllia smithiiS. & B. on the Scottish continental shelf
Authors: Wilson John B.
Published: May 2009

The published records of the occurrence of the Devonshire Cup CoralCaryophyllia smithiiStokes and Broderip in Scottish waters are widely scattered throughout the literature. Rees (1962, 1966) listed several of these and suggested that the paucity of records was a reflexion of the comparatively little systematic collecting that had been done on the Scottish coasts and on the continental shelf.

The purpose of the present paper is to collate and review the published records of the distribution ofC. smithiiand to present new data derived from extensive investigations carried out by the Institute of Oceanographic Sciences, Wormley, as part of a study of shelly faunas and sediments on the continental shelf west and north of Scotland. Additional records obtained from several other sources are also included.
Escape reactions of zooplankton: Effects of light and turbulence
Authors: Singarajah K. V.
Published: May 2009

Hensen (,1887) drew attention to the possibility of using a pump for quantitative sampling of surface plankton and, since then, a hose-pump method has been widely used for such sampling at desired depths by Juday (1916), Lohmann (1898,1901), and Thorson (1946). A comparative study by Gibbons & Fraser (1937) suggested that such a pump had outstanding advantages over the vertical net, in quantitative work. However, Korringa (1941), working on oyster larvae, suggested that some plankton animals may be able to escape by swimming against the currents which approach the mouth of the suction hose. Brook & Woodward (1956) noticed an apparently rheotactic response shown by plankton organisms in evading water currents.
Feeding and gut structure of Parathemisto gaudichaudi (Guerin) (Amphipoda, Hyperiidea)
Authors: Sheader M. , Evans F.
Published: May 2009

Previous (workers who have examined the gut contents of members of the genus Parathemisto, and who have kept and fed specimens in laboratory conditions, have concluded that they are chiefly carnivorous in habit, feeding largely on zooplankton, and to a lesser extent on phytoplankton (Conover, 1960; Baker, 1963; Kane, 1967).

The gut of P. gaudichaudi has been found to contain almost intact copepods, especially Calanus and occasionally Temora (Bigelow, 1926 – Gulf of Maine); young specimens of Euphausia superba (Hardy & Gunther, 1935 – Antarctic); and copepods (Nemoto & Yoo, 1970). Siegfried (1965 – west coast of S. Africa) found P. gaudichaudi to be a rather indiscriminate feeder, its gut contents reflecting the composition of the plankton.
The role of the haemolymph in the carbohydrate metabolism of Carcinus Maenas
Authors: Williams Adele J. , Lutz Peter L.
Published: May 2009

The importance of the blood in crustacean metabolism was first raised by Johnston, Davies & Elder in 1971. Until then the conventional view had been that the crab hepatopancreas had a role similar to that of the vertebrate liver (Vonk, 1960), the blood presumably acting as a carrier of soluble sugars. It has recently been shown, however, that blood tissue holds almost four times the amount of polysaccharide than the hepatopancreas and that glucose is actively incorporated into glycogen in the blood (Johnston & Davies, 1972). Polysaccharides were located in deposits in the haematocytes (Johnston, Elder & Davies, 1973). Many previous studies have shown that the main plasma sugar, glucose, varies widely in concentration and appears very sensitive to the animals physio-logical state (see Hohnke & Scheer, 1970). It would seem, therefore, that glucose metabolism in crabs may be readily modified and that by looking at the effect of a physiological stress (starvation and feeding) on the blood/hepatopancreas system one might get some information on the dynamic relationship between these two organs. Previous work (P. L. Lutz, unpublished) had shown that in Carcinus maenas plasma glucose could fall to negligible values on prolonged starvation.
Blood cell types in Carcinus maenas and their physiological role
Authors: Williams Adele J. , Lutz Peter L.
Published: May 2009

As recent studies have shown that in Crustacea the haemolymph plays an important role in carbohydrate metabolism (Johnston & Davies, 1972, Williams & Lutz, 1975) it is clear that a proper understanding of this phenomenon depends on an accurate knowledge of the variety of cell types found. However, an examination of the literature revealed a wide divergence of opinion in the recognition of various kinds, their relationships and their composition, with, for example, the same authors reaching quite different conclusions from similar evidence (Johnston, Davies & Elder, 1971, Johnson, Elder & Davies, 1973) (Table 1). This suggested that the subject required further examination. As both the type and number of cells may vary according to the condition of the animal (Sniesko & Taylor, 1947), it was decided to look at the blood of fed and starved specimens.
Some effects of stress in the adult on the eggs and larvae of Mytilus edulis L.
Authors: Bayne B. L. , Gabbott P. A. , Widdows J.
Published: May 2009

In previous papers we have shown that high temperature and low food levels result in a decline in the body condition of mussels, Mytilus edulis, which have been kept in the laboratory (Bayne & Thompson, 1970; Gabbott & Bayne, 1973). In spite of the loss of body reserves, M. edulis is able to continue gonad development at an increased rate, when the temperature is above ambient (Gabbott & Bayne, 1973; Bayne, 1975). Although gametogenesis appears to be normal under these conditions, there is evidence that stress in the adult affects subsequent larval development in M. edulis (Bayne, 1972) and in the oyster, Ostrea edulis (Helm, Holland & Stephenson, 1973). In mussels, stress resulted in an increase in abnormal embryonic development during cleavage, gastrulation and development to the first shelled larval stage (Bayne, 1972). In oysters the viability of the larvae, assessed in terms of growth rate and percentage yield of spat, was less in larvae from adults kept at low ration than in larvae from adults kept at high ration. Irrespective of the feeding regime, the viability of the larvae fell as the length of the conditioning period increased, and this was related to a decline in the body condition of the adult oysters. The growth of the larvae in the 96 h period following liberation was significantly correlated with the lipid level in the newly released larvae (Helm, Holland & Stephenson, 1973).
The biochemical composition ofLepas anatifera(L.) cement (Crustacea: Cirripedia)
Authors: Walkera G. , Youngson A.
Published: May 2009

In an earlier study of the biochemical composition of barnacle cement, Walker (1972) found that the cements of two sessile barnacles,Balanus hameriandB. crenatuscontained small amounts of lipid (< 1% of total dry wt.) and carbohydrate (♎ 2% of total dry wt.) but were mainly composed of protein ( > 85 % ° of total dry wt.). Lindner & Dooley (1973) similarly found that a large proportion ofB. crenatuscement was protein (80%), but Cook (1970) found only 70% protein, lipid (27.4%) being the other major constituent. There is therefore general agreement that barnacle cement is mainly a proteinaceous secretion, but controversy still exists over the amount of lipid present.
On the biology ofCalanus finmarchicus: XIII. Seasonal change in weight, calorific value and organic matter
Authors: Comita G. W. , Marshall S. M. , Orr A. P.
Published: May 2009

The length, weight, calorific value and organic matter content ofCalanus finmarchicus, Stage V, males and females, were measured in monthly samples taken from April 1962 to June 1963.

There is considerable variation throughout the year and all stages had their maxima of weight and calorific value in spring, 1962, and winter 1962–63.

The calorific value and weight are closely correlated so that, knowing the dry weight, the calorific value can be calculated from it. The correlation is closest in Stage V and, for these, only the dry weight need be known. Since the relation-ship is slightly different for males and females the sex of the adult must be known as well as the dry weight; curves showing these relationships are given.

The calorific value obtained from organic-matter analysis at times deviates widely from the values obtained in direct bomb calorimetry, and it is concluded that in the method used not all the fat is accounted for.

In weight, calorific value, and organic matter, but not in length, Stage V for a good part of the year show higher figures than adults.

In comparing the weights with those of other years and other places, the annual pattern is found to vary considerably. The spring maximum seems to occur every year, but there may be either a maximum or a minimum in autumn and winter.
Observations on the bivalvesMontacuta substriataandM. ferruginosa, ‘commensals’ with spatangoids
Authors: Gage John
Published: May 2009

Field and laboratory observations were made of the erycinacean bivalvesMontacuta substriataandM. ferruginosa, which are usually considered as ‘commensals’, respectively, with the burrowing spatangoidsSpatangus purpureusandEchinocardium cordatum. These species were obtained mainly from the Plymouth area, whereM. substriatawas also found withE. flavescensandE. pennatifidum, and also very occasionally withE. cordatum.Similarly,M. ferruginosawas also found with 5.purpureus, E. flavescensandE. pennatifidum.This indicated that the associations are not as specific as had been thought.
A new species of Lumbricillus, with a revised check-list of the British Enchytraeidae [Oligochaeta]
Authors: Tynen Michael J.
Published: May 2009

A new species of enchytraeid worm, Lumbricillus christenseni, is described and compared with some closely related members of the genus Lumbricillus.

Twelve other species of enchytraeid, recorded in the British Isles for the first time, are listed.

The habitats and localities in which these new records have been found in North Wales and Europe are also listed.

A revised check-list of the British Enchytraeidae is given.

Following the publication (Nielsen & Christensen, 1959) of a critical revision of the taxonomy of European enchytraeids, which resolved much of the confusion in the existing literature, the task of identifying the members of this family has been made much easier. Between 1961 and 1964, during an investigation of the littoral Enchytraeidae of the coasts of Anglesey and the Menai Straits, twelve species of enchytraeid new to the British Isles and one species new to science were identified. The new species, a member of the genus Lumbricillus Ørsted 1844, is hereby named Lumbricillus christenseni, after Dr Bent Christensen of the University Zoological Museum, Copenhagen, in recognition of his contribution to our knowledge of enchytraeid taxonomy.

Lumbricillus christenseni sp.nov.

Location and habitat

This worm has been found in only one location, namely, Porth Eilian, a small bay at the north-east corner of the island of Anglesey, North Wales. The worm was most common at about high-water mark of the neap tide, in a mixture of sand and pebbles with a sparse covering of undecayed weed. The specimens examined were all taken within 5 cm of the surface. There was a large proportion of mature specimens at the time of collection, that is, late spring and early summer of 1964.
The biology ofEchinocardium cordatum[Echinodermata: Spatangoidea] from different habitats
Authors: Buchanan John B.
Published: May 2009

An offshore and a littoral population ofEchinocardium cordatumhave been observed for a period of 7 years, starting from the time of their simultaneous larval settlement and establishment.

The littoral population was found in clean sand of low organic content. Individuals burrowed to a depth of 15 cm and could move through the sand at a speed of 6–8 cm/h. The test length increased at an average increment of 8 mm/annum. Breeding first took place in the third year and continued each year after.

The offshore population was found in very silty sand at depths of 30–40 m. Here individuals burrowed to a very shallow depth, 2 cm. or less, and moved very slowly through the sediment. The annual increment of test growth was only about 3 mm. Estimations showed that the littoral population had a production rate four times greater than the offshore. The offshore population did not reach sexual maturity during the period of observation. No new settlement was observed anywhere in the area during the period of observation.

The offshore population occurred in large discrete patches, each displaying a quantitatively concentric pattern with a central area of high density. Samples taken at single stations within the patch showed that the distribution was random for most of the year but that aggregations formed in June, July and August.

Both populations showed a steady mortality rate of about 15 % per annum and the longevity was estimated to be in the region of 15 years.

Based on prolonged aquarium observations of the feeding behaviour, reasons are given for believing that the surface collecting activities of the penicillate tube-feet of the anterior ambulacrum should be considered as a true feeding mechanism.
The ecological and geographical aspects of the fecundity of the plaice
Authors: Bagenal T. B.
Published: May 2009

During the last 30 years the fecundity of the plaice, Pleuronectes platessa L., has been widely studied over its complete geographical range. In this paper all this previous work is brought together and a distinct pattern (with two exceptions) emerges. The fecundity is lowest in the Southern Bight of the North Sea, and radiating from there in all directions the fecundity increases, while in Faxa Bay (Iceland) and in the Barents Sea it is lower again. The possible factors producing this pattern are examined in detail and it is concluded that the amount of food available, which in turn is related to population density, is the most important. Only in Trondheim Fjord and in the Baltic is the fecundity so different that it is necessary to postulate racially distinct populations. Finally the importance of fecundity variations in natural population regulation is stressed.
Natural fluctuations in a soft bottom benthic community
Authors: Eagle R. A.
Published: May 2009

Benthic faunal communities have usually been described from data collected during a single survey, and it has been assumed that most benthic communities are reasonably stable. However, in areas such as important fishing grounds or around effluent disposal areas where surveys have been repeated periodically, the results quite frequently show marked changes. These do not always correlate to annual breeding cycles but are more unpredictable and of a different period.
Factors influencing change in the phenotype of the planktonic amphipod Parathemisto gaudichaudi (Guerin)
Authors: Sheader Martin
Published: May 2009

Parathemisto gaudichaudi (Guerin) exists in a range of morphological forms comprising the compressa extreme, in which the fifth pereopod (P5) is only slightly greater in length than the sixth pereopod (P6), the bispinosa extreme, in which P5 is about twice the length of P6, and a complete range of intermediate forms. Other features such as the shape of the carpus and merus of the third and fourth pereopods and the shape of the uropod peduncles also vary between the two extremes. In an earlier paper on the taxonomy of the genus (Sheader & Evans, 1974) it was noted that specimens of Parathemisto gaudichaudi kept in the laboratory could moult towards either of these extremes.
Small-scale cultivation of cells and tissues from gobiid teleosts
Authors: Webb C. J.
Published: May 2009

Although freshwater teleost cell and tissue culture is an established field, the in vitro maintenance and growth of marine or estuarine fish tissues and cells is less well reported (Wolf & Quimby, 1969). Small demersal gobiid teleosts of the genus Pomatoschistus Gill, 1864 are widely distributed and very abundant around the coast of Britain and play an extremely important role in estuarine and coastal ecosystems (Hartley, 1940; Miller, 1963, Ph.D. Thesis, University of Liverpool; Green, 1968). Excluding the in vitro maintenance of whole organs (e.g. Bonnin, 1971a, b and Doneen & Bern, 1974) the culture of cells or tissues from gobiids has not been reported.
Advantages of heart reversal in pelagic tunicates
Authors: Heron A. C.
Published: May 2009

Most work in tunicate heart physiology has been directed towards finding the actual physiological cause of heart reversal rather than the adaptive advantage of it to the animal (see reviews by Krijgsman, 1956; Kriebel, 1968; Goodbody, 1974). Krijgsman (1956) concludes: ‘We do not know whether there is any functional significance in the periodic reversal of beat. One can see no reason why a permanent one-way circulation should not be efficient. Presumably the cause of reversal is the periodic exhaustion of the pacemakers, which has no physiological significance.’ Because of the abundance of pacemaker systems in nature in which periodic exhaustion does not take place, this conclusion should be re-examined.
A Comparative study of Reproductive Cycles in Four polychaete Species belonging to the Family Cirratulidae
Authors: Gibbs P. E.
Published: May 2009

Gametogenesis has been studied in four cirratulid polychaetes: Caulleriella caput-esocis, Tharyx marioni, Cirriformia tentaculata and Cirratulus cirratus.

In all four species, sperm development follows a similar course of events, with the sperm cells being grouped in spheres and then platelets before developing tails to give rosettes which finally disintegrate to release the active spermatozoa. Except in Cirratulus, there is a well-defined annual cycle in the development of sperm.

Oogenesis in Caulleriella and Cirriformia is similar in that the growth curve of the oocytes is roughly sigmoid. In Tharyx the release of the oocytes to the coelom is delayed and discrete ovaries are formed, only the later stages of oocyte growth taking place within the coelom. In contrast to the above three species, oogenesis in Cirratulus does not show an annual cycle.

Maturation of the oocytes within the coelom prior to shedding has been established in Tharyx, Cirratulus and Cirriformia. In the former two species meiosis proceeds as far as the metaphase I stage and in the latter to the anaphase I stage, before the oocytes are released. Fertilizations were achieved only with oocytes which had matured in all three species. In the fourth species, Caulleriella, no fertile oocytes were discovered.

The diameters of the mature oocytes and the main spawning seasons of the four species at Plymouth are as follows: Caulleriella, about 110 μ (August to October); Tharyx, 200– 220 μ (late October to early November); Cirriformia, about 117 μ (late June to early July); Cirratulus, 135–150 μ (throughout the year).
Structure and Abundance of Receptors of the Unspecialized External Epithelium ofNassarius Reticulatus[Gastropoda, Prosobranchia]
Authors: Crisp Mary
Published: May 2009

The epithelial receptors ofNassariusare primary sense cells. The sensory endings are abundant on the tentacle tips, anterior border of the foot and ventral external surface of the siphon tip. Densities are a small multiple of 1032 endings/mm2.

Type 1 ciliated endings are of ubiquitous occurrence. The ultrastructure of type 1 endings is uniform, though the static and motile bundles of sensory cilia may be distinguished by the random or uniform orientation of the ciliary subfibrils and basal feet. Ciliated receptors probably include both chemo- and mechanoreceptors.

A distinct ultrastructural type of sensory ending (type 2), confined to the siphon tip, consists of a small pit in the peripheral dendrite close to the epithelialsurface. The pit contains whorled microvilli and a few cilia. It may be photoreceptive.

A small amount of convergence of sensory information may occur in peripheral nerve.
Observations on the Concentration of iron in Sea Water, With Particular Reference to Southampton Water
Authors: Head P. C.
Published: May 2009

Determinations have been made of paniculate iron in samples collected from Southampton Water over a period of 2 years. Concentrations of 106–1046 ug/l. were found. Total amounts of paniculate matter ranged from 1·3 to 48·6 mg/1., of which iron constituted 0–5–14%. Amounts of paniculate matter and paniculate iron showed a highly significant correlation. For one station where wind-speed data were available there was a highly significant correlation between the amount of particulate matter and the mean daily wind speed for the 4 days prior to sampling. No clearly defined seasonal variation in the amounts of particulate matter or particulate iron was found. The concentration of particulate iron in the estuary appeared to be dominantly controlled by meteorological and hydrological factors.
Aspects of the Circulatory Physiology and Muscle Systems of Deep-Sea Fish
Authors: Blaxter J. H. S. , Wardle C. S. , Roberts B. L.
Published: May 2009

Mesopeiagic fish without swim bladders, found in depths from 100 to 1000 m, have soft bodies with a very high water content (88–95%) low haematocrits (5–9%), smallhearts, a low proportion of red muscle, and large lymph ducts. Species possessing swim bladders have a lower water content (70–83%), higher haematocrits (14–35%), larger hearts, more prevalentred muscle and smaller lymph ducts. Some active surface species have still less water (64–74%) and higher haematocrits (48–57%).

The soft watery fish appear to use skeletal reduction and high water content asa buoyancy mechanism but there is no evidence, judging from analyses of freezing-point depression of the plasma and muscle fluid, that they maintain an extra low ionic content to assist buoyancy. Although oxygen is probably adequate in the deep water, there may be some constraint on activity because the oxygen-carrying capacity ofthe blood is low and oxygen may be limited at the tissues. This is partly compensated for by the high proportion of anaerobic white muscle and the large lymph system. These watery fish appear to be best adapted to short bursts of activity. Nevertheless they do make diel vertical migrations which may cause them to reach the limits of their aerobic metabolic systems.

The mesopeiagic species with swim bladders are much more similar in their circulatory characteristics to inshore fish. They also make quite substantial vertical migrations with the concomitant problem of adjusting buoyancy by varying the pressure within the swim bladder. Metabolically this is unlikely to be unduly difficult.
Fish and Fish-Leeches on Rocky Shores Around Britain
Authors: Hussain N.A. , Jones-Knight E.W.
Published: May 2009

Collecting water from rock pools just above rising tides, usually in winter and spring, yielded 1412 Lipophrys pholis, 255 Pholis gunnellus and 29 Coryphoblennius galerita, bearing respectively 172, 8 and 1 Oceanobdella blennii, 744 Taurulus bubalis bearing six Oceanobdella microstoma and 14 Sanguinothus pinnarum, and a Myoxocephalus scorpius with a single O. microstoma; fishes of 23 other species totalled 1243, but none bore leeches externally. Oceanobdella blennii was found mainly in February and March (some in gill chambers), at temperatures generally below 8°C, with lower numbers (all external) in April and May and none later. Infestation was highest in Northumberland. Leeches on P. gunnellus were smaller than those on L. pholis, which they would not attack. They were confined to Northumberland and Scotland, where L. pholis was scarcer. The southern limit of O. blennii seemed to be in north Cornwall, but O. microstoma, though more stenothermal, extends from the Arctic to south Devon, its hosts living mostly subtidally. It is hidden under the chin of Cottidae, whereas S. pinnarum is easily seen on the fins. Abundance in south-west Britain of the ‘cleaner fish’ Crenilabrus melops may explain why S. pinnarum, though common in Scotland and tolerant of summer temperatures, is scarce in Anglesey and not found further south.
Gonadotropic Mitogenic Activity of the Optic Gland of the Cuttlefish,Sepia Officinalis, During Sexual Maturation
Authors: Koueta N. , Camou-Boucaud E. , Renou A.M.
Published: May 2009

A cytological study was carried out on the main cells of the optic gland of male and femaleSepia officinalisL. during sexual maturation (animals collected in the field). The results were correlated with experimental data on the mitogenic action of optic gland extracts collected during a period of secretory activity.

The main cells of the optic gland show some of the features of protein-secreting cells, although they are not very pronounced. The secretory activity of the cell was found to be correlated with a peak of mitogenic activity occurring in September/October in the case of the males and in November in that of the females. The secretion of gonadotropic mitogenic factor varies throughout the sexual cycle ofSepia officinalis. This activity is correlated with a rapid multiplication of spermatocytes and spermatogonia in the males, whereas in the females it corresponds to previtellogenesis.
Oxygen Supply and Limits on Aggregation of Embryos
Authors: Strathmann Richard R. , Strathmann Megumi F.
Published: May 2009

Effects of oxygen supply on development rates of embryos in gelatinous masses were tested with natural masses of three species of opisthobranch gastropods and artificial masses made with embryos of a sea urchin and agarose gel. When diffusive exchange was restricted for embryos in such masses, increased oxygen alone was sufficient to maintain development rates of embryos. Diffusive supply of oxygen is therefore a limiting factor for embryos clustered in gelatinous masses. Development rates were constant over a wide range of experimentally altered oxygen concentrations but retarded with oxygen below about 10% of air saturation. Some opisthobranch embryos exposed to low oxygen concentrations hatched with shorter shells. Delayed hatching and shorter shells at hatching were both associated with a central position in the globose gelatinous mass of one of the opisthobranch species, even in air-saturated and vigorously stirred water. The pH near the centres of the masses was lower when embryos were at more advanced stages; thus the intracapsular stirring caused by cilia of embryos at later stages does not compensate for their greater metabolic rates. The pH in some egg masses was about seven or lower, and this pH affected development in separate experiments. The masses approach limits for removal of wastes, although oxygen becomes limiting for rates of development before accumulation of wastes becomes limiting. Embryos of opisthobranchs that are normally aggregated and embryos of sea urchins that are normally dispersed were similarly tolerant of low oxygen concentrations and low pH. In respect to tolerance of hypoxia and accumulating wastes, embryos in many clades are preadapted for aggregation into masses, but there are limits on the size of the aggregation. Egg masses are commonly at those limits.
Fatty Acid Composition of Lipids from Sulphuroxidizing and Methylotrophic Bacteria from Thyasirid and Lucinid Bivalves
Authors: Fullarton J. Gregor , Wood P. , Sargent John R.
Published: May 2009

Lipids of sulphur-oxidizing bacteria isolated fromThyasim flexuosahad large amounts of 18:l(n-7) together with lesser amounts of both 16:l(n-7) and 16:0 as their major fatty acids. Smaller amounts of the cyclopropyl fatty acids, cyclic δ9,10 C16 and especially cyclic δll,12 C18 were also present. A similar pattern was found for methylotrophic bacteria isolated fromThyasira, MyrteaandLucinoma, except that 16:l(n-7) and 16:0 were both present in larger amounts than 18:l(n-7) and small amounts of cyclic δ9,10 C16 and lesser amounts of cyclic All,12 C18 were present in all cases. The fatty acids 18:l(n-7), 16:l(n-7), 16:0, cyclic δ9,10 C16, and cyclic δll,12 C18 were all present in varying amounts in several free-living, non-marine, sulphur-oxidizing bacteria analysed, and in one bacterium both cyclic δ9,10 C18 and cyclic δll,12 C20 were abundant. Branched-chain fatty acids and polyunsaturated fatty acids were not detected in any of the sulphur-oxidizing or methylotrophic bacteria analysed. The lipids of the sulphur-oxidizing and methylotrophic bacteria consisted largely of phosphatidylethanolamine, phosphatidylglycerol and cardiolipin. The results are discussed in terms of fatty acids as indicators of nutritional relationships in bacterial-invertebrate symbioses.
Coccolithophores and the Continuous Plankton Recorder Survey
Authors: Hays G.C. , Warner A.J. , John A.W.G. , Harbour D.S. , Holligan P.M.
Published: May 2009

Samples historically collected and analysed by the Continuous Plankton Recorder (CPR) survey were used to describe the distribution of coccolithophores (class Prymnesiophyceae) in the north-east Atlantic and the North Sea. In the routine CPR analysis, members of this group are simply identified as ‘coccolithophores’ and not to any further taxonomic level. From this analysis, the 200-m depth contour marked a point of distinct transition between high coccolithophore occurrence (off the shelf) and low coccolithophore occurrence (on the shelf). Thirty-three CPR samples that had been collected between 1979–1992, were re-examined and the coccolithophores identified to a more detailed taxonomic level. Among the species identified was the bloom-forming coccolithophore, Emiliania huxleyi. Thus archived CPR samples could potentially be re-analysed to assess regional, seasonal and decadal changes in the occurrence of this species.