bluuebunny/crossref_metadata_2025 huggingface dataset:
The Decline of Zostera Marina L. at Salcombe and its Effects on the Shore
Authors: Wilson Douglas P.
Published: May 2009

A comparison of photographs taken on the eastern shore of Salcombe harbour before and after the disappearance of much of the Zostera marina L. shows that where previously there existed extensive sand banks, stabilized by the growth of this plant, there has been a lowering of ground level of 2 ft. or more, due to the washing away of the sand where the Zostera has died. Much of the ground is more stony than before and has become largely covered with seaweed attached to the stones. The buried fauna is not as rich as it was and some species previously common are rare or have disappeared altogether. A few small patches of Zostera still survive, but the plants are shorter with narrower leaves than before.
The Behaviour ofArenicola MarinaL. in Sand, and the Role of Spontaneous Activity Cycles
Authors: Wells G. P.
Published: May 2009

Worms were allowed to burrow in sand in the laboratory. The general form of their burrows resembled that found in the field. Their behaviour was studied by continuously recording the water movements through the burrows for periods up to 3 weeks.

Whenever the worms were feeding from a gradually subsiding cone and piling up castings, as they do in the field, a characteristic cyclical pattern was traced. This was marked by conspicuous diphasic excursions at intervals of about 40 min. Defaecation occurs at the summit of the first phase. By comparison with records got from worms in glass tubes (Wells, 1949), it is inferred that the first phase consists of tailward locomotion to the sand surface, and the second to headward irrigation accompanied by gentle creeping back to the feeding point. The whole cycle is identical with the intermittent irrigation cycle shown in glass tubes.
Contributions to the Biology of the Mackerel Scomber Scombrus L. II. A Study of the Fishery in the South-West of England, with Special Reference to Spawning, Feeding, and ‘Fishermen's Signs’
Authors: Steven G. A.
Published: May 2009

In a previous paper (Steven, 1948), brief accounts are given of three distinct mackerel fisheries that at one time existed in the south-west of England—an inshore fishery in the English Channel carried on from Plymouth, a deep-sea fishery from Newlyn, Cornwall, and an inshore fishery from Newlyn and some other Cornish ports. One of these fisheries, the Plymouth one, no longer exists. After a few years of considerable activity following the termination of the 1914–18 war, this fishery collapsed in 1924 (Table I) and came entirely to an end a few years later. The small quantities of mackerel landed at Plymouth in subsequent years have been incidental catches by vessels fishing for herrings or pilchards.
The Distribution of Lugworms (Arenicola Marina L.) over the Flats at Whitstable
Authors: Chapman Garth , Newell G. E.
Published: May 2009

It has been shown that the main factor which influences the local distribution of the lugworm at Whitstable is the depth of the muddy sand overlying the clay stratum below.

In places this clay is furrowed by straight channels which are revealed only by the arrangement of the lugworm castings. These are more numerous along the channels.

Migration of adult lugworms has been shown to occur, most freely in the spring.
The Later Larval Life of Arenicola Marina L
Authors: Newell G. E.
Published: May 2009

Larvae with three and four chaetigerous segments and also an early post-larval stage of Arenicola marina are described with figures. These are all bottomdwelling stages enclosed in mucous tubes and were collected from the pebble and Fucus zone at Whitstable.

The rinding of these larvae furnishes additional evidence for the view that, except when migrating in the water to new habitats, the lugworm possesses no pelagic larval stage in its life history.
The Mechanism of Opening and Closing ofCalliactis Parasitica
Authors: Chapman Garth
Published: May 2009

Experiments are described which suggest that Calliactis behaves as a closed animal in its movements, although its stomodaeum appears to be widely open to the exterior.

Observations of the movements of the animal are correlated with variations of the internal pressure. It is shown that expansion is not merely ‘passive relaxation’, but is generally accompanied by a rise in pressure which is, however, much lower than that which accompanies rapid closing.

It is concluded that the fluid-muscle system ofCalliactisbehaves in a similar way to that of other soft-bodied invertebrates, but that the system works at a much lower pressure.
A Quantitative Method for Estimating the Periodicity of Diatoms
Authors: Aleem Anwar Abdel
Published: May 2009

The method described below was evolved as a substitute for counting, which is unsatisfactory for epiphytic marine diatoms. It depends upon the estimation of the amount of diatom-silica associated with unit dry weight of the sub-stratum. The sea-weed samples are first freed from sand particles and are then treated with strong nitric acid in the usual way. In order to convert the insoluble silica of the diatoms into a soluble form suitable for chemical estimation, the material is fused in a platinum crucible with a mixture of K2CO3 and Na2CO3 and the fused mass is dissolved in (silica-free) distilled water and filtered. The amount of silica in the filtrate is determined colorimetrically according to the method of Dienért and Wandenbulcke (cf. Atkins, 1926). The method is simple in practice and saves considerable time and labour. The full procedure is illustrated by reference to a study of the periodicity of Grammatophora marina (Lyngb.) Kütz. at Swanage, Dorset.

This species (PL. I) is found all the year round on Cladophora rupestris in a pit in one of the reefs at Peverel Point, Swanage. In summer it is the only epiphytic diatom on the Cladophora, while in spring and autumn small numbers of other epiphytes (Cocconeis, Opephora, Rhoicosphenia) are present. In order to obtain a fairly representative picture of the abundance of Grammatophora at different times, samples of the Cladophora were collected monthly from a definite area in the pit, each including 3–4 cm. of the apices of five to ten Cladophora tufts cut at random.
A Balance-by-Depth Method for the Photoelectric Measurement of the Vertical Extinction Coefficient of Water
Authors: Atkins W. R. G. , Poole H. H. , Warren F. J.
Published: May 2009

Vertical extinction coefficients can be determined in water using selenium rectifier cells and colour filters. The cells are connected positive to negative with a simple 0-50 microammeter across the circuit, as in the Campbell-Freeth method. There is no deflexion when the two points of contact are brought to the same potential. This is done by lowering one cell into the sea to balance the rather less sensitive deck cell. The light reaching the latter is then reduced by the successive addition of opalized plates, to approximately 60, 30, 20 and 10 %, and the sea cell is lowered further to balance at each stage. The extinctions can then be calculated by the usual formula from the known percentage transmissions and the observed depths of balance. For each plate or combination a factor may thus be obtained which when divided by the appropriate depth gives the extinction. The method is rapid in operation and the drift error can be rendered negligible. The results agree with those found by the standard potentiometer method, but the applications of the new method are necessarily more limited.
The Food of the Dogfish, Scyliorhinus Caniculus L.
Authors: Eales Nellie B.
Published: May 2009

During the past eight years records have been kept of the contents of the stomachs of all dogfish dissected in the Zoology Department of Reading University. The specimens, numbering about 450 altogether, came from Swansea Docks, and were caught off the west coasts of the British Isles. Students were asked to spread out the contents of the stomach of the fish they were dissecting in a dish, and to make notes of those animals they could identify. I then, as far as was possible, checked the identifications, and removed for more detailed investigation any specimens of particular interest. In the circumstances it was impossible to make accurate numerical records of each species, or to work out fragments from partially digested material, but the rare specimens were recorded by numbers. Sometimes a record of one means one perfect specimen.
The Occurrence of British Aplysia
Authors: Grigg Ursula M.
Published: May 2009

On 13 November 1947 a specimen of the sea hare, Aplysia depilans L., which had been trawled in Babbacombe Bay, was sent to the Plymouth Laboratory. When it was realized that the animal was not the common A. punctata Cuv., collecting trips to likely places were undertaken in the hope of finding more. No others were found, but on one of the expeditions Dr D. P. Wilson picked up a specimen of A. limacina L.

Both A. depilans and A. limacina are found in the Mediterranean and on the west coast of Europe: A. depilans has been found in British seas before, but so far as is known A. limacina has not.

These occurrences provide the main reason for publishing this study. The paper also includes an account of the distribution of aplysiids in British waters and a review of the controversy over the identity of large specimens. As the animals are not usually described in natural history books, notes on the field characters are added.

I would like to thank the Director of the Plymouth Laboratory for affording me laboratory and collecting facilities and for his interest in the work. I am most grateful to Dr G. Bacci, who went to much trouble to send me specimens from Naples; to Dr W. J. Rees, who arranged for me to have access to the British Museum collection; to Dr D. P. Wilson, who has provided the photographs of A. punctata (Pl. I) and A. limacina (Pl. II); and to D. J. Slinn, who prepared the map.
Studies on the Growth of Marine Phytoplankton I.Asterionella Japonica Gran
Authors: Kain Joanna M. , Fogg G. E.
Published: May 2009

A planktonic marine diatom, Asterionella japonica, has been grown in unialgal, but not bacteria-free, culture under controlled conditions and its growth has been measured by means of optical density determinations and cell counts in combination.

The relative growth constant has been found to be usually between 0·7 and 1·2 loge units per day, and to be little affected by variation of the concentration of nitrate, phosphate and silicate within wide limits. Rapid growth occurred in waters having salinities between 20 and 40‰ S. The optimum temperature for growth was 20–25° C and the optimum light intensity from 4000 to 10,000 lux. The relative growth rate was affected most markedly by variation in hydrogen-ion concentration. This was manifest in stagnant cultures in which the rise of pH above 8·3, caused by absorption of carbon dioxide, resulted in the inhibition of growth. This could be countered by increased aeration or by the addition of the buffer tris(hydroxymethyl)aminomethane.

Evidence has been obtained which suggests that A. japonica requires a thermostable substance present in natural sea water and that a thermolabile substance stimulating its growth is produced in culture.

Final yields of the order of 4000 cells per mm3 were obtained and, within limits, were dependent on the amounts of nitrate and silicate supplied. The nitrogen requirements per cell was determined as 0·255 μμg atom. Indications were obtained of the presence of a growth-inhibiting substance in the filtrates from old cultures.

The optical density of the cells was increased at high nitrate concentrations and when exhaustion of silicate prevented cell division.
On the Biology of Calanus Finmarchicus X. Seasonal Changes in Oxygen Consumption
Authors: Marshall S. M. , Orr A. P.
Published: May 2009

The seasonal changes in the respiration of Calanus are considerable and are, on the whole, related to size and therefore to weight. Length alone is not enough to account for the differences since ripe females, although the same length as unripe, have a markedly higher respiration. In addition, by taking samples of large and of small Calanus of a single stage, it was shown that the difference in respiration was small. Neither is weight by itself enough to account for the difference between groups. Stage V Calanus are, for a given length, heavier even than ripe females and yet their oxygen utilization is low. In this instance, however, an important part of the weight consists of fat which is a food reserve and not actively metabolizing. The difference of weight between ripe and unripe females is not known, but ripe females must be heavier and this will account for their higher oxygen consumption.

Although the oxygen and therefore the food required during the spring months is high, at that time the phytoplankton is at its maximum and is probably sufficient to fulfil all needs. Egg-laying depends on the food supply and it is then that Calanus starts breeding. In winter, on the other hand, the Calanus is present as Stage V and oxygen consumption is little more than half what earlier figures suggested. No ‘hibernation’ seems to take place but the population is living in an economical way for Stage V use little oxygen, live in deep water and do not undertake diurnal vertical migration.

At 10° C ripe female Calanus will require daily from 3·9–7·2% of their body weight as dry matter in summer and from 2·8–6·7% in winter. Stage V will require 2·3–3·1% in summer and 1·4–3·3% in winter. The higher values are for carbohydrate and the lower for fat.

It is difficult to believe that Calanus in winter will be able to find enough food by filtration alone. The fact that in the winter months it depends more on predation may account for its survival.
The Distribution of Gas and Liquid within the Cuttlebone
Authors: Denton E. J. , Gilpin-Brown J. B.
Published: May 2009

The newest chamber of a cuttlebone is always incomplete and full of a watery solution. This contains sodium and potassium in concentrations close to those of sea water.

The second newest chamber contains a gas space and sometimes contains liquid. This liquid is rarely localized at the siphuncular end of the chamber. It is not certain that liquid is initially extracted through the siphuncular wall of the chamber, although this is possible.

When liquid is pumped out of a newly formed chamber the salt which it initially contains is not left behind, either free or bound into the structure of the bone.

The 3rd to about the 10th newest chambers usually contain no visible liquid. But their siphuncular walls are permeable to liquid and liquid does enter these chambers when the cuttlebone becomes very dense.

At cuttlebone densities around 0·6, i.e. close to values which will make the cuttlefish neutrally buoyant, the older and more posterior chambers are almost full of liquid. This liquid can, however, be pumped out. When a cuttlebone has a density around 0·5 very little liquid can be seen in any of its chambers.

The pressure of gas within a newly ‘pumped out’ chamber is very low, but by the time a chamber has become the ninth newest the pressure of gas is close to the average value for the whole cuttlebone, i.e. about 0·8 atm.

The low pressure of gas found in the newest chambers is explained by the slowness with which gas diffuses into a space created by the active removal of liquid.
The Reproduction and Maintenance of Polydora Ciliata (Johnst.) at Whitstable
Authors: Dorsett D. A.
Published: May 2009

The germ cells of Polydora ciliata arise from cells lying just inside the ventral epithelium and later migrate into the gonads. They are released into the coelom when they are 30 μ in diameter and are transported posteriorly to the region of maturation. The eggs and sperm are shed through the modified nephridia of the region of maturation. The eggs are laid into a string of capsules apparently secreted by the nephridia and attached to the wall of the tube. The larvae take about a week to hatch and are released into the plankton at the three chaetiger stage. They spend some 6 weeks in the plankton before metamorphosis, and have grown to 17 or 18 segments.
Monthly samples of the worms living in the London clay at Whitstable in 1956 showed that the population was bimodal with respect to size and the two groups of adults gave rise to two larval settlements in late March and May. The two groups of juvenile worms that developed from these larvae retained their identities through the summer and the following winter. There is no apparent morphological character by which the adults of each type may be recognized, the time of spawning and the lower fecundity of the early breeding worms being the only distinguishing features. It is suggested that these groups are the consequence of an overlap of two populations of P. ciliata from different centres of distribution, each being adapted in its breeding requirements to a different part of the temperature range.
The Functional Morphology of the British Species of Veneracea (Eulamellibranchia)
Authors: Ansell Alan D.
Published: May 2009

The functional morphology of twelve British species of the Veneridae is described. The systematic position ofMysia undataand evolution within the Veneracea are discussed.

Structurally, the members of the family Veneridae show a lack of special adaptations. The ability to move horizontally as well as ventrally in soft substrata is retained; the pedal gape is large and the foot well developed. The siphons are relatively short and fused. The food-collecting mechanisms of the mantle cavity are largely unspecialized and function in maintaining a considerable flow of water, and retaining as much as possible of the suspended material. Members of the Veneridae show a considerable uniformity of structure, but trends of evolutionary change may be distinguished. The generaGafrariumandCallistaare least specialized. The genusDosiniahas evolved along an independent line and is specialized by the possession of a stream-lined, circular shell, deep lunule, and greatly elongated siphons, for a relatively deep-burrowing habit. Within the superfamily Veneracea major lines of adaptive evolution have given rise to the rock-boring Petricolidae and the deep-burrowing Glaucomyidae, and the generaVenerupisandIrusshow affinities with both these families.
Nervous Control of Gut Movements inLophius
Authors: Young J. Z.
Published: May 2009

There are not sufficient data available to allow any general statements about the earlier stages of evolution of the autonomic nervous system and of its various transmitter mechanisms. In the previous paper (Young, 1980) it was shown that control of the stomach of elasmobranchs is largely by the inhibitory action of the sympathetic nerves, probably mediated by 5-HT. In teleostean fishes on the other hand control seems to be mainly by the cholinergic excitatory action of the vagus, especially in the more advanced (acanthopterygian) groups (Grove & Campbell, 1979a,b; Fänge & Grove, 1979).
On the Morphology and Function of Red and White Skeletal Muscle in the AnchoviesEngraulis EncrasicolusL. andE. MordaxGirard
Authors: Walker M. Greer , Horwood J. , Emerson Lynn
Published: May 2009

During a survey of teleost skeletal muscle (Greer Walker & Pull, 1975) it was found that the morphology of the red or slow muscle fibres of the anchovy (Engraulis encrasicolusL.) was markedly different from that of other species. In transverse section the fibres appear flattened as lamellae and are considerably larger in area than those of comparable species. This paper describes some aspects of their morphology, function and growth in comparison with other species.
Reproduction in Acanthocot Yle Greeni n. sp. (Monogenea) from the Skin of Raia Spp. at Plymouth
Authors: MacDonald Sheila , Llewellyn J.
Published: May 2009

While collecting acanthocotylid monogeneans for various investigations (Kearn, 1967; Lyons, 1972; Macdonald, 1974) Mr J. E. Green of the Laboratory of the M.B.A. at Plymouth has very occasionally found specimens of what each of these authors has suspected may be a new species. In July 1978 nine more living worms were collected, the material was indeed found to require the erection of a new species and we propose to call the parasite Acanthocotyle greeni.
The Influence of Salinity on Behaviour and Oxygen Uptake of the Hermit Crab Pagurus Bernhardus L.
Authors: Davenport J. , Busschots P. M. C. F. , Cawthorne D. F.
Published: May 2009

Hermit crabs, Pagurus bernhardus L., are common inhabitants of the littoral zone where they may be found in pools and puddles on the lower and middle portions of rocky shores. Only small specimens are normally found between the tidemarks but large crabs are found sublittorally as deep as 450 m. Unlike many of the animals found at a similar level on the shore, such as mussels, barnacles and winkles, Pagurus does not penetrate estuaries to any great extent. However, the smaller animals found in the littoral zone are likely to encounter reduced salinity levels caused by rainfall and terrestrial runoff.
Metabolic End Products in Three Species of Marine Gastropods
Authors: Wieser Wolfgang
Published: May 2009

One commonly held opinion about the metabolism of intertidal gastropods has recently been expressed by Newell (1970) who stated that in moist air these - as well as other intertidal - animals will respire air ‘whereas under conditions of desiccation closure of… the operculum… may result in anaerobic respiration occurring with the production of lactic acid’ (pp. 266–267). However, although anaerobiosis certainly does occur in intertidal gastropods (Patané, 1957; McMahon & Russell-Hunter, 1978) the conditions controlling this type of metabolism are far from clear. Moreover, recent studies (summarized by de Zwaan, 1977) have revealed a complex pattern of anaerobic metabolism in invertebrates in which the production of lactate is only one - and certainly not the most important - element.
Copper-the Major Metal Component of Glycerid Polychaete Jaws
Authors: Gibbs P. E. , Bryan G. W.
Published: May 2009

Glycerids are carnivorous polychaetes and Glycera alba, for example, has been shown to feed mainly on errant polychaetes and small crustaceans, chiefly amphipods (Ockelmann & Vahl, 1970). Glycerids inject their prey with a venom containing a toxin and proteinases (Michel & Keil, 1975), produced in discrete glands (Michel, 1966, 1970), by means of four jaws placed symmetrically around the tip of the muscular proboscis. The distal, free half of each jaw is slender and curved, the basal section much broader and enclosing the ‘pulp cavity’. Attached to one side there is a jaw support (‘aileron’), usually V-shaped with unequal prongs but the shape varies considerably between species (see Wolf, 1977). The jaws are operated by strong longitudinal muscles attached to the jaw bases and supports (see Gravier, 1898). Nearly the whole length of the jaw is traversed by a fine venom canal, its position marked on the surface by a linear series of small pores (Fig. 1 A) through which the venom is probably emitted (Charletta & Boyer, 1974). In colour the jaws are a uniform shiny jet-black.
The Sea-Water Well System at the Fisheries Laboratory, Lowestoft and the Methods in Use for Keeping Marine Fish
Authors: Scholes P.
Published: May 2009

Facilities for keeping marine fish for experimental purposes or for display to the public are usually run on either an open system with direct supplies of water from the sea, as in the Bergen Aquarium (Rollefsen, 1962), or on a mainly closed system in which the sea water is continually recirculated (Saeki, 1958). The pros and cons of each system are well known and have been discussed in the published papers of the 1960 1st International Congress of Aquarology held in Monaco (Comité Scientifique et Technique du Congrés International d'Aquariologie, 1962–63) and in the report of the ad hoc meeting in 1975 on design and practical operation of research aquarium systems held at Texel, The Netherlands (International Council for the Exploration of the Sea, 1975). A combination of the two types of system is often used in research institutions and series of papers on sea-water aquarium designs and methods of operation have been collected by Clark & Clark (1964).
A Physico-Chemical Method for the Extraction of Marine and Estuarine Benthos from Clays and Resistant Muds
Authors: Barnett B. E.
Published: May 2009

In making benthic surveys it is often difficult to extract all the animals from the various sediments in good condition. Even the IBP Handbook (Holme & Mclntyre, 1971) does not give comprehensive details of methods for extracting animals from the complete range of sediment types. The greatest difficulty is presented by clays and compacted silt. In recent work we have had very satisfactory results by using the following procedure. Core and grab samples taken in the field are stored in seal-tight buckets for processing in the laboratory. In the case of grab samples taken from boats, preliminary sieving is performed on site and only the resistant sediments returned to the laboratory. The samples are broken into pieces of approximately 100 cm3 or less and stored in 5 % formaldehyde solution using a volume about three times that of the sediment. This serves to fix and preserve the fauna and also helps in the breakdown of clays. At this stage samples may be stored for a long time. Wherever layers of soft mud are found among the resistant material they are washed off, sieved and the fauna preserved separately. The resistant samples are then frozen in a domestic freezer and left for 24 h before thawing. The freezing is very effective in breaking down resistant sediments into small particles, thus releasing the animals, which can readily be removed by elutriation. Normally, most animals seem to be adversely affected by freezing in much the same way as some vegetables lose their consistency when frozen (an exception to this are members of the polychaete family Phyllodocidae). However, the prior treatment with formalin seems to protect the tissues from damage by freezing.
On the Feeding of the Hagfish Myxine Glutinosa in the North Sea
Authors: Shelton R. G. J.
Published: May 2009

The myxinoid cyclostomes, of which the hagfish Myxine glutinosa L. is one of the best known examples, are of unique biological interest as representatives of a group of jawless vertebrates which probably had their origin in the pteraspidomorph ostracoderms of the Ordovician era (Nybelin, 1973). They have been much studied by comparative anatomists and physiologists but somewhat neglected by ecologists. There is, for instance, very little critical information on their normal feeding biology. Perhaps one reason for this is that, although hagfish may be extremely abundant locally (their principal habitat requirements are stable, soft muddy sediments and a salinity in excess of 31 %, (Gustafson, 1935)), they tend to be missed by most exploratory fishing and biological sampling programmes. This is because benthic sampling techniques are often ill-adapted for the capture of large active organisms capable of swimming and burrowing and because, unless blocked by the catch, the cod-end mesh sizes of the trawls used by most British commercial fishermen would easily permit the escape of even the largest hagfish. However, the research otter trawls used by the Department of Agriculture and Fisheries for Scotland (D.A.F.S.) for surveying the North Sea stocks of the deep water pink shrimp, Pandalus borealis Krøyer, are fitted with cod-end covers of small mesh, and it is found that the catches frequently include small numbers of hagfish, presumably caught while swimming close to the bottom, or possibly when buried in the surface of the sediments. The present study is largely based on the examination of hagfish collected during the D.A.F.S. Pandalus surveys of 1975 and 1976. The remaining material was kindly provided by Dr J. B. Buchanan of the Dove Marine Laboratory at Cullercoats, Northumberland.
Combined Effects of Body Size, Food Concentration and Season on the Physiology of Mytilus Edulis
Authors: Widdows J.
Published: May 2009

The majority of studies of the physiological ecology of organisms have been concerned with changing a single environmental variable at a time, but more information on the relationships between biological responses and environmental factors would be provided by experimental techniques that emulate the multi-dimensional character of the natural environment.
Bryozoa from the Bay of Biscay and Western Approaches
Authors: Hayward P. J. , Ryland J. S.
Published: May 2009

The bryozoan benthos of the European continental slope is attracting attention after a long period of neglect. Expedition reports, such as those of the ‘Challenger’ (Busk, 1881, 1884, 1886; Waters, 1889), ‘Travailleur’ and ‘Talisman’ (Jullien, 1882; Calvet, 1906), and ‘Hirondelle’ (Jullien & Calvet, 1903) made important contributions to our knowledge. Such monographs have been supplemented by shorter papers dealing with the Bryozoa of offshore banks and island groups (Guérin-Ganivet, 1911; Norman, 1909) or of limited areas within the European region (Duerden, 1893; Nichols, 1911). Following the recent increase of interest in offshore benthos generally, the papers of d'Hondt (1970, 1973a,b, 1974, 1975) provide much new information on the slope and outer shelf bryozoan fauna. However, many of the often enigmatic species of earlier authors have yet to be redis-covered, and d'Hondt has shown that a high proportion of the Bryozoa collected comprises species new to the area or new to science. Clearly, the study of many more collections will be necessary before any comprehensive account can be given.
The Annual Cycle and the Short Term Periodicity of Breeding in a Northumberland Population of Spirorbis Spirorbis (Polychaeta: Serpulidae)
Authors: Daly John M.
Published: May 2009

The fact that Spirorbis spirorbis (= S. borealis) has a summer breeding season during which several successive broods of larvae are produced has been known since the work of Garbarini (1933,1936). A recent summary of the taxonomy, ecology and distribution of S. spirorbis has been given by Knight-Jones & Knight-Jones (1977). The two aspects of the species' reproductive biology which have received most attention are the role of sea temperatures in initiating breeding and the correlation of brood production with lunar and tidal cycles. In the present work a study has been made of gametogenesis as well as of the more easily observed cycle of brood production. The results obtained have indicated, in respect of one population of S. spirorbis at least, the need for a major re-assessment of earlier studies of the species.
Sources of Variability in the Benthic Macrofauna off the South Northumberland Coast, 1971–1976
Authors: Buchanan J. B. , Sheader M. , Kingston P. F.
Published: May 2009

The interest in the temporal variability of the Northumberland benthos derives from a continuing time-series of samplings initiated in January 1971. Intensive sampling was started at a single station for the purpose of computing the secondary production for the years 1971–72 (Buchanan & Warwick, 1974). It became clear in the course of this exercise that there was a considerable degree of variation in species numbers and ranking, both between the two years and, seasonally, within single years. Sampling at this station was continued for a further two years - 1973–74 – and the data were interpreted as an un-broken rising trend in numbers of individuals with changes in species ranking and diversity (Buchanan, Kingston & Sheader, 1974). Since the magnitude of change over the four years was unexpectedly high, and largely unexplained, it was decided to continue the observations for an indefinite period and to expand the programme of sampling to cover several stations over a wider area of different sediment types.
The Ultrastructure and Taxonomic Identity of the Symbiotic Algae ofHeterostegina Depressa(Foraminifera: Nummulitidae)
Authors: Schmaljohann R. , Röttger R.
Published: May 2009

There are numerous examples of symbiotic associations between Foraminifera and unicellular algae. Most of these Foraminifera are larger Foraminifera which occur in the shallow, oligotrophic waters of tropical seas (Table 1). Some of the symbiotic algae have been studied by light microscopy (Table 1, nos. 1–6). Dietz-Elbrächter (1971) suggested that the symbionts ofHeterostegina depressamight be diatoms. She was, however, unable to prove this statement satisfactorily. Hottinger & Dreher (1974) published electron micrographs of the symbionts ofH. depressaandOperculina ammonoides. From these micrographs identification of the symbionts was not possible. To date, only the symbionts of the following Foraminifera have been classified by electron microscopy:Archaias angulatus, Sorites marginalis, Globigerinoides ruber, Hastigerina pelagicaandGlobigerinoides sacculifer(Table 1, nos. 7,10,12,13,14).
The Genus Pterosperma (Prasinophyceae): Species With a Single Equatorial Ala
Authors: Parke Mary , Boalch G. T. , Jowett Rosemary , Harbour D. S.
Published: May 2009

This study of the genus Pterosperma followed on from our work on the genus Halosphaera (Parke & Adams, 1961; Parke & Hartog-Adams, 1965; Boalch & Mommaerts, 1969) since while studying the latter we found abundant pterospermatacean material. In recent books on algae the family Pterospermataceae Ostenfeld (1902) is placed in the class Chrysophyceae (Papenfuss, 1955; Bourrelly, 1957, 1968; Fott, 1959, 1971; Prescott, 1969). The family, however, rightfully belongs in the class Prasinophyceae (Parke in Parke & Dixon, 1964, 1968; Christensen, 1966) in the order Pterospermatales (Parke & Green in Parke & Dixon, 1976).
The Hydroid of the Anthomedusa Bougainvillia Britannica
Authors: Edwards C.
Published: May 2009

The hydroid of the Anthomedusa Bougainvillia britannica Forbes has not been known with certainty, though its identity with B. flavida Hartlaub has appeared probable.

From colonies found on Aporrhais pespelecani in the Firth of Clyde medusae of B. britannica have been reared. A description and figures of the hydroid and the young stages of the medusa are given.

Bougainvillia flavida Hartlaub and B. linearis (Alder) are junior synonyms of B. britannica Forbes.
Observations on the Biology of the Marine Oligochaete Tubifex Costatus
Authors: Brinkhurst R. O.
Published: May 2009

Tubifex costatus is a marine euryhaline species of tubificid, commonly found in brackish water. It is common in estuaries, where it colonizes a wide variety of substrata.

The species breeds sexually once a year in early summer, and it is likely that it takes 2 years to reach maturity, and after breeding it dies.

There is only one likely predator, Nereis diversicolor, and the population of T. costatus seems to be kept at a very constant level.
Some Aspects of Ionic and Osmotic Regulation inTisbe[Copepoda, Harpacticoida] in Relation to Polymorphism and Geographical Distribution
Authors: Battaglia B. , Bryan G. W.
Published: May 2009

Ability to tolerate low salinities has been compared in homozygous adult females of thetrifasciataandviolaceaforms of the polymorphic copepodTisbe reticulatafrom Chioggia (lagoon of Venice). Both forms appear to be equally capable of tolerating sea-water concentrations of between 100 and 33 %. Further comparison with thetrifasciataform ofT. reticulatafrom Plymouth and with three different geographical populations ofTisbe furcatahas shown that these copepods are rather less tolerant.

A study of ionic regulation using the isotopes22Na,42K and137Cs has shown that in diluted sea waterT. reticulatadoes not control the body Na concentration but does control the K concentration. Exchange rates for42K and137Cs are higher in theviolaceathan in thetrifasciataforms ofT. reticulatafrom Chioggia and the difference may have an adaptive nature although its significance is not clear. With regard to42K, the difference between the two polymorphic forms from the same population ofT. reticulatais greater than that between the three different geographical populations ofT. furcata. This serves to add more emphasis to the fact that colour polymorphism inT. reticulatacan be associated with other processes.
On Scyphomedusae of the Genus Pelagia
Authors: Russell F. S.
Published: May 2009

The characteristics of the genus Pelagia are discussed.

It is concluded that two good species, P. noctiluca (Forskål) and P. flaveola Eschscholtz, are already described.

A third species P. colorata n.sp. has been erected for the medusa recorded from time to time from the coast of California which has been reported previously as P. noctiluca var. panopyra.
Observations on the Effects of Changes of Hydrostatic Pressure on the Behaviour of Some Marine Animals
Authors: Rice A. L.
Published: May 2009

An apparatus and experimental method for the investigation of the effects of changes of pressure on the behaviour of marine animals is described.

In 43 of a total of 53 species examined in this apparatus definite responses to abrupt pressure changes of 1000 millibars or less have been observed, increased pressure generally causing increased activity and movement upwards or towards the light, and decreased pressure causing decreased activity and movement downwards or away from the light. The relative importance of light and gravity in the orientation of these movements is generally correlated with the degree of development of the light and gravity receptors in the species concerned.

The possible significance of these pressure responses in nature is discussed and it is suggested that pressure may be an important factor affecting the distribution of marine plankton, particularly during the hours of darkness.
On the Biology of the Whiting, Gadus Merlangus, in Manx Waters
Authors: Nagabhushanam A. K.
Published: May 2009

The biology of whiting in Manx waters has been investigated at different stages of the life-cycle, with special reference to their diet. Planktonic postlarvae occurred chiefly in May, these measured between 4.5 and 16.5 mm, and had fed chiefly on Pseudocalanus. Larger whiting (between 21 and 52 mm) were taken in association with Rhizostoma. They were approximately 2–4 months old, and had fed on copepods supplemented with Hyperia and euphausiid furcilia. Immature whiting 77 mm long appeared in July in a shallow sandy bay—a nursery area. The fish were about 4–5 months old, and fed on swarming amphipods, isopods and mysids after dark, when these organisms were free-swimming. This diet was supplemented to an appreciable extent during the following April-June quarter by the inclusion of juvenile Ammodytes. After staying for nearly 1 year in the nursery area, the bulk of the fish appear to migrate to the open sea.

In the open-sea habitat, the immature fish fed chiefly on euphausiids, decapods and sprats—nektonic forms particularly. These whiting are themselves eaten by larger whiting in the same habitat. Adult whiting (over 220 mm) were taken only offshore, and fed chiefly on euphausiids, Crangon, Pandalus, Pasiphaea, Clupea and gadoids. A few samples taken off the east coast of I.o.M. indicated that the whiting are capable of feeding on infauna and plankton in an environment deficient in active epifauna and nekton. The whiting is an active feeder throughout the year.

Two length-weight relationships have been calculated for Manx whiting: nursery-area, and open-sea fish—the latter gain weight more rapidly than the former would be expected to do.
Studies on Marine Flagellates VII. Nephroselmis Gilva Sp.Nov. and Some Allied Forms
Authors: Parke M. , Rayns D. G.
Published: May 2009

A new species provisionally attributed to the genus Nephroselmis has been described with the aid of light- and electron-microscopy. Significant features include the presence of a single layer of scales over the flagellar and cell surfaces as in Micromonas squamata Manton & Parke, though the morphology of the flagellar scales is as in the outer scale layer of Pyramimonas and Halosphaera. Reasons are given for rejection of Thalassomonas on the grounds of nomen confusum and for homologizing various representatives of it with Micromonas squamata.

Some additional facts about the latter include details of the imbrication of the flagellar scales and demonstration, made possible by the use of lead staining of sections, of a close association between golgi bodies and the scale-producing vesicles.
Carbohydrate and Organic Matter in Suspension in Loch Striven during 1962
Authors: Marshall S. M. , Orr A. P.
Published: May 2009

The number of diatoms, and the carbohydrate and organic matter in suspension, were followed during most of the year 1962 in Loch Striven.

A rise in diatom numbers was always accompanied by a rise in both carbohydrate and organic matter, but the agreement was not quantitative.
Observations on the Fertility of the Oyster (Ostrea Edulis)
Authors: Walne P. R.
Published: May 2009

The production of larvae by Ostrea edulis L. was studied in collections made from brooding females obtained from oyster grounds on the east, south and south-west coasts of England and from the Menai Straits. The size of the brood was directly related to the size of the oyster, but considerable variation was found from oysters of the same size whether measured as diameter, volume between the shells or dry meat weight. Part of the scatter was due to variation in condition of the oyster at spawning; oysters in good condition at the time of spawning produced more eggs than those in poor condition. This cause of variation was also seen in different populations; those with a high average condition index had a higher average fertility than those in poor condition, although the correlation was not quite significant at the P = 0.05 level (r = 0.632). It is presumed that most of the remaining variation is of genetic origin.

Fertility was related to size rather than age, although it is suggested that in some old slow-growing oysters it may be reduced. No decline in fertility was found as the breeding season progressed, nor was there clear evidence that larvae are liberated at a smaller size late in the season.

A comparison of the average size of broods at an early stage of development with those that were nearly mature showed that there was no loss of larvae during brooding. Samples of shelled larvae from 204 broods were measured; less than 10 % exceeded 190 µ size.
A Study of the Diatoms of the Ouse Estuary, Sussex II. The Ecology of the Mud-Flat Diatom Flora
Authors: Hopkins J. T.
Published: May 2009

By estimating samples of diatoms taken from 0.2 m contour lines, over a horizontal range of about 85 m in the months of July 1953 a nd February 1954 the ecological factors influencing the distribution of eleven species of mud-flat diatoms were investigated. The three important factors were considered to be: the resistance to desiccation near the M.H.W.L., the ability to live under short periods of illumination near to the M.L.W.L., and the ability to tolerate the organic materials present in the black sulphureous layer. Table 7 summarizes the results for the eleven species.
The Feeding of Plaice and Sand-Eel Larvae in the Southern North Sea
Authors: Ryland J. S.
Published: May 2009

Larvae of the sand-eel,Ammodytes marinus, appear in large numbers in the Southern Bight during March, some 2–4 weeks after the peak hatching period of plaice eggs. The sand-eel larvae outnumber those of the plaice about tenfold, but the factor may be 60 or more locally.

The principal food components in sand-eel guts in 1961 were copepod nauplii and appendicularians, while plaice were feeding almost exclusively on the latter. Larvae of both species show identical feeding patterns, with activity ceasing at night, and both aggregate during the day at depths of about 2–6 fm. Thus the sand-eel larvae are not separated from the plaice larvae by any pattern of behaviour, and are partially exploiting the same food reserve.

Consideration of prey size suggests that any direct competition from the larval sand-eels would first affect the smallest plaice larvae, which are in any case the most vulnerable to shortage of food. But any reduction in the crop of small appendicularians will later be reflected in the number of larger ones, and in this way older plaice larvae might be affected. While the food supply appears to have been adequate up to the time of the investigation, the reserve apparently represented only 3 days' rations. The significance of this observation is unfortunately obscured by our ignorance of appendicularian biology; but, should the food reserve become so diminished, competition between plaice and sand-eel larvae might be expected. The extent of its impact on survival is only likely to emerge from more comprehensive surveys.
A Revised Check-List of British Marine Algae
Authors: Parke Mary , Dixon Peter S.
Published: May 2009

The Preliminary Check-list (Parke, 1953), with the three subsequent lists of additions and corrections (Parke, 1956, 1957, 1959) was intended to provide a fundamental basis for the preparation of a Flora of the British marine algae sponsored by the British Phycological Society. Changes, both taxonomic and systematic, have been so numerous in recent years that a new Check-list is now necessary for the six Classes dealt with in 1953. Five additional Classes, marked below with an asterisk, are also included in the new list. As there is still controversy regarding the status and arrangement of the major algal groups they are here given, as in Parke (1953), the rank of Class.
Life-history and culture of Gracilaria foliifera (Rhodophyta) from South Devon
Authors: McLachlan J. , Edelstein T.
Published: May 2009

Three species of Gracilaria, G. foliifera (Forsk.) Børg., G. verrucosa (Huds.) Papenf., and G. bursa-pastoris (S. M. Gmel.) Silva are recognized from the British flora (Parke & Dixon, 1976). In Britain G. verrucosa is widely distributed, although not common, whereas the other two species are rare and their distribution restricted (Newton, 1931). G. foliifera was described from the Red Sea as Fucus foliifer Forsk. (Børgesen, 1932). Plants referable to this species are now reported from various parts of the world, including both the eastern and western coasts of the north Atlantic (South & Cardinal, 1970; Taylor, 1957, 1960). However, considerable variation exists within species of Gracilaria (e.g. May, 1948), thus delimitation of species is often extremely difficult. Gracilaria foliifera from Britain (Fig. 1 A) is similar morphologically to the original material of Fucus foliifer as illustrated by Børgesen (1932, fig. 1), and therefore, we have limited our consideration to G. foliifera as it occurs in Britain (also see Harvey, 1846, pl. 15). However, little information is available on G. foliifera from the British Isles, and in the present instance we have investigated the life history of this alga in culture together with preliminary results on growth in small-scale tanks with running sea water.
The ecology of Chondrus crispus and Gigartina stellata (Rhodophyta) in Galway Bay
Authors: Pybus C.
Published: May 2009

In the Galway Bay area the carragheen species, Chondrus crispus Stackh. and Gigartina stellata (Stackh.) Batt., are still collected using traditional methods. The weeds are picked by hand, spread out on any convenient area of grass, allowed to dry and, in the case of Chondrus, bleach in the open air. Most collecting is done during the autumnal equinoctial spring tides and is virtually restricted to the intertidal zone.

The Irish seaweed industry has declined since 1960, when according to Chapman (1970) production reached its peak. When describing the industry in 1974, Cahill & Sweeney made the following comments. ‘A small number of firms are engaged in harvesting and primary processing. Between 1000 and 1250 people are seasonally employed. Almost 40000 tons of wet weed are harvested annually with a landed value of approximately £200000. Harvesting techniques are largely manual and there is a possibility that the industry may decline in the medium term as alternative and more lucrative employment opportunities become available.’