bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factorial Analysis in the Ecology of Rocky Subtidal Areas Near Brest (West Brittany, France)
Authors: Castric A. , Chasse C. 
Published: May 2009

In order to investigate the characteristic species and the relative importance of selected environmental conditions of rocky bottom communities in coastal waters and to estimate their richness, 27 sites in the Brest area were surveyed by diving. The abundances of underwater species, from a check-list of 115, were plotted as number of individuals or colonies in m2 or in percentage cover of the rock, against the environmental conditions (depth, bedrock slope, substrate type and sediment nature of the nearest soft bottom). Raw data were converted to biovolume expressed as mm3 m–2 and expressed as log 10 (x + 1).Various correspondence analyses were applied to these data: the first included bedrock slope (lit/dark surfaces) and takes into account the four biological formations according to the depth. It shows zonation with depth and decreasing light as factor 1, hydrodynamic conditions (waves or current) as factor 2, mixing of estuarine and oceanic waters as factor 3 and turbidity as factor 4. Four species assemblages emerge from these four axes, for which the main species contributing to the four axes may be considered as characteristic species. These correspond well to four broad communities described in British waters: very exposed to wave-action, semi-exposed to wave-action, exposed to strong tidal current, very sheltered sites. The second analysis, in which lit and dark surfaces are distinguished, but some very close sites are fused together, shows in detail the photophilous or sciaphilous nature of the species. Values of hydrodynamic conditions and percentage of surface light plotted on the 'stations-points' of the graphs allow drawing of a factorial network which may be used as hydrodynamic and illumination scales.
Foraging Activity of Limpets in Normal and Abnormal Tidal Regimes
Authors: Little Colin , Partridge Julian C. , Teagle Linda 
Published: May 2009

Activity of Patella vulgata was monitored in the asymmetrical tidal regime of an Irish sealough, Lough Hyne, and also outside the lough in a normal tidal regime. An automated method was used, allowing continuous records to be made over two weeks. Most activity occurred at night while the limpets were emersed. Rainfall depressed activity. There was little activity during daytime emersion, contrary to the results of previous studies in which low-shore limpets foraged diurnally as well as nocturnally. Timing of activity in relation to tidal coverage was similar inside the lough and outside.Activity of high-shore limpets within the lough was greater at spring tides than at neaps, but that of low-shore limpets was greater at neaps. Outside the lough, both high-shore and low-shore limpets showed greater activity at spring tides. Reasons for the differences are discussed.Using Maximum Entropy Spectral Analysis, three periodicities underlying limpet activity were indicated. These were at h, 124 h and 8–2 h. When limpet activity was simulated by adding three sine waves of appropriate periodicity, rhythms very similar to those recorded from the shore were produced.
The Learning of Detours by Wrasse (Ctenolabrus rupestrisL.)
Authors: Spooner G. M. 
Published: May 2009

1. This paper deals with certain experiments on training fish (Ctenolabrus rupestrisL.) to swim round obstructions to reach food, for the purpose of investigating how their learned response was developed. The whole question as to how learning which involves “problem-solving” is rightly to be interpreted and harmonized with our knowledge of conditioned responses, presents difficulties which have not yet been adequately faced.2. A description is given of the results of experiments carried out on eleven fish. The fish had to learn a detour route either into a pot or round glass plates. Attention may be drawn to the great diversity in the behaviour of individual fish, both in their reactions to the obstruction at different stages of training, and in the method by which they succeeded in passing it. Some individuals are evidently more capable of profiting by experience than others.
A Review of the Amphipod Genus Corophium, with Notes on the British Species
Authors: Crawford G. I. 
Published: May 2009

During 1934–5 I collected in Plymouth Sound and neighbouring waters seven species of the genus Corophium of which two were undescribed. I also collected one other species, and had sent to me two other species (one new) from other localities in South England. A list of these ten species, with the single other species known from Britain, is given in Appendix II, and their British distribution summarized.In the course of identifying them I examined 23 of the 32 species of Corophium, and saw all the literature to which I could find references.
The Biology ofAporrhais pes-pelecani(L.) and A.serresiana(Mich.).
Authors: Young C. M. 
Published: May 2009

1.Aporrhais pes-pelecanioccurs on muddy gravel at moderate depths and is specialized for burrowing in this.2. The mode of burrowing is described and also the formation of mucuslined inhalent and exhalent openings by the proboscis.3. There is a powerful respiratory current through the mantle cavity which also possesses three sets of ciliary currents for disposing of sediment carried in with this.4. The animal is a specialized detritus feeder selecting only material of plant origin. The radula consists of one central and three lateral teeth on each side, an indication that it is used for seizing as opposed to scraping,notthat the animal is carnivorous.5. The stomach possesses a well-developed ciliary sorting mechanism. The large crystalline style and gastric shield indicate that the animal is herbivorous, but there is no cellulase.
Notes on the Culture of some Marine Plankton Organisms
Authors: Gross F. 
Published: May 2009

The methods are described which made possible the establishment of pure cultures of a number of centric plankton diatoms and of the dinoflagellateProrocentrum micans.By means of a modified technique cultures were obtained of some nannoplankton autotroph flagellates varying in size from 2 to 10u. Attention is drawn to their great number in the plankton and to their importance as food in the sea.Herring, Angler and Pilchard larvae were reared for respectively 27, 29 and 15 days after hatching. The young Herrings and Pilchards fed onChlamydomonassp. andProrocentrum, the Anglers on nauplii ofArtemia salina. Some evidence is given for the conclusion that the ultimate failure in rearing these species was caused by too high and variable temperatures.
The life histories and population dynamics of monogenean gill parasites of Trachurus trachurus (L.)
Authors: Llewellyn J. 
Published: May 2009

Gastrocotyle trachuri and Pseudaxine trachuri infect young Trachurus trachurus at Plymouth as soon as the 3- or 4-month-old adolescent fishes descend to the sea bottom in October. The parasites normally mature in 3 or 4 months, but, exceptionally, in about 1 month, and the life-span is normally no longer than 1 year. Trachurus specimens at the beginning of their second year pick up a largely new infection of parasites.G. trachuri and P. trachuri are much less frequent on 2- and 3-year-old specimens of Trachurus and probably occur only very rarely on still older fishes, the limiting factor being not an age-immunity but a post-spawning migration of the host from the concentration of free-living infective stages of the parasites in coastal waters.The parasites have adapted themselves to a seasonal change in the feeding habits of Trachurus by ceasing to produce larvae in anticipation of the summer disappearance of scad from the sea bottom in pursuit of pelagic food-organisms.
Spirorbis corallinaen.sp. and some other Spirorbinae (Serpulidae) common on British shores
Authors: De Silva P. H. D. H. , Knight-Jones E. W. 
Published: May 2009

Spirorbis corallinaesp.nov. is very similar toS. borealisbut can be distinguished by its orange colour, small size, bifid opercular talon and particularly by the fact that the larvae choose to settle onCorallina officinalisrather than onFucus serratus.Other species dealt with, in a key to identification and notes on distribution, areS. granulatus, S. malardi, S. pagenstecheri, S. rupestris, S. spirillumandS. tridentatus.
Nitrogen and phosphorus required for the growth of phytoplankton
Authors: Harvey H. W. 
Published: May 2009

A method is described for obtaining growths of phytoplankton in samples of crude sea water, similar in composition but several hundred times more dense than phytoplankton communities occurring in the sea.The ratio of nitrogen to phosphorus utilized by such communities has been determined.They use ammonium in preference to nitrate, although the latter may be many times more concentrated than the former.They use urea and uric acid as sources of nitrogen.Certain amino-acids when added as sources of nitrogen were attacked by the bacteria in the community and either the ammonium set free or both the ammonium and the amino-acid were used by the phytoplankton. Others, asd-leucine, were not utilized, or, asl-leucine, only slowly utilized.Sodium nucleinate and caseinate were rapidly broken down when added to crude sea water by bacterial action, and the phosphate produced utilized by phytoplankton. There was no significant utilization of glycerophosphate.
The ecology of the Tamar Estuary VI. An account of the macrofauna of the intertidal muds
Authors: Spooner G. M. , Moore H. B. 
Published: May 2009

The macrofauna of the intertidal mud-flats of the River Tamar have been investigated. Quantitative samples were taken by sieving the mud through a o·8 mm. sieve. Traverses of series of stations were worked at successive intervals up the river, and the tidal level of each station ascertained.The characteristic species which inhabit the mud-flats are listed and the data secured regarding (1) population density, (2) up-river penetration, and (3) vertical distribution, are summarized and related to previous information on these points.While some species are more or less uniformly distributed intertidally, others show marked zonation, with maxima in one part or another of the intertidal zone. Marine species which penetrate into the estuary tend to show the same intertidal distribution as in marine habitats. All five of the more strictly estuarine species are concentrated in the upper tidal levels.In considering the limiting factors which cause a decrease of population at lower tidal levels, emphasis is placed on the probable importance of the increase in strength of water currents towards low water.
The osmotic relations of the plankton diatomDitylum brightwelli(West.)
Authors: Gross F. 
Published: May 2009

During resting spore formationDitylumloses the cell sap and the volume of the resulting resting spore is one-third to one-twentieth of the cell volume.Ditylum plasmolyses in 3·5–I.7% NaCl solutions, and in a few seconds the protoplast is reduced to the size and structure of a resting spore. In 0·5% NaCl there also occurs a considerable reduction in volume. The plasmolysed cells recover completely when removed into sea water. Rapid plasmolysis was also observed in isotonic and hypotonic dextrose and sucrose solutions and in solutions of CaCl2.
The ecology of some parasitic copepods of gadoids and other fishes
Authors: Sproston N. G. , Hartley P. H. T. 
Published: May 2009

The migratory habits of Gadus merlangus and G. pollachius are examined n i relation to the variations in the rate of infection of these fish with Lernaeocera branchialis. A sudden increase in infection in estuarine and inshore waters is found to coincide with the offshore migration of the main stock. The infected fish apparently linger behind and may live for some time in the old habitats after the arrival of the next recruitment. The offshore migrants are seldom infected, and it is probable that infection does not take place in water deeper than about 5 fathoms.The possible immediate causes of this “lingering” phenomenon are examined, and two suggestions are made as to the nature of the physiological upset brought about by the presence of L. branchialis on these gadoids. Other factors influencing the distribution of the parasite are discussed.The relative susceptibility of the different species of gadoids to infection with species of Lernaeocera is examined as far as the data allow.
Observations on the bionomics and physiology ofTrebius caudatusandLernaeocera branchialis(Copepoda)
Authors: Sproston N. G. , Hartley P. H. T. 
Published: May 2009

A study of the distribution ofTrebius caudatusfrom four species ofRajatrawled from two localities of different depths at Plymouth shows that there is a higher infection rate in the deeper water.Both at Roscoff (France) and at Plymouth the mean total rate of infection is about 20%, and the larger fish are more often infected than the smaller. Both sexes are equally parasitized and the copepods tend to collect near orifices on both surfaces of the fish (regions where the mucus secretion is maximum). Immature forms were found at Roscoff in the mucus of the orifices themselves. The collections from both places contained about equal numbers of male and female parasites.Intestinal respiration, a feature common to free living and parasiticcopepods, includes the gaseous exchange through the gut wall, the associated movements stirring the oxygen vector (which is either the external medium taken in by the anus, or the food current when this is the blood of the host), and the circulation of the body fluid as a direct result of these movements. The significance of the gut movements, which include the peculiar two-way peristalsis, is examined in detail inTrebius caudatus and Lernaeocera branchialis: the former has a functional anus which admits the external medium and the latter has a closed anus and employs the blood of the host as the oxygen vector.
Observations on the biology of Pandalina brevirostris [Decapoda; Crustacea]
Authors: Allen J. A. 
Published: May 2009

The life-cycle of a population of Pandalina brevirostris living off the Northumberland coast is described. Most specimens were taken over sandy gravel or sandy mud with a covering of zoophytes in depths ranging from 20 to 30 fm. A very few specimens were taken over soft mud in 50 fm.Eggs are laid during the period from January to the beginning of September. Females may lay two or possibly three broods in each breeding season. There is a period of 12–14 weeks between the laying of the eggs and the hatching of the larvae. The ova of those females that have a brood of eggs within the first half of the breeding season mature as the eggs develop, and are ready for laying following the release of the larvae. The adult P. brevirostris reaches maturity 8–12 months after hatching as a larva and lives on to breed again in the following season. They die at the end of their second breeding season. Thus, the probable life-span of the female is 24–30 months following its release as a larva, while that of the males is about 21–27 months.
On the nutrition and metabolism of zooplankton III. Nitrogen excretion byCalanus
Authors: Corner E. D. S. , Cowey C. B. , Marshall S. M. 
Published: May 2009

Nitrogen excretion byCalanus finmarchicus(Gunnerus) andC. helgolandicusClaus collected at Millport and Plymouth has been measured under various experimental conditions.Adult females feeding onBrachiomonas submarina, Cricosphaera elongataandSkeletonema costatumat cell concentrations corresponding to the mean annual level of particulate nitrogen in Plymouth Sound excrete 12·4, 9·0 and 6·4 μg N/mg dry body weight/day respectively. When the concentration of food is raised, as might occur during a spring outburst of phytoplankton, there is an increase in the quantity of nitrogen excreted. On the other hand, nitrogen excretion rapidly diminishes in the absence of food.
The developmental stages of Lernaeocera Branchialis (Linn.)
Authors: Sproston Nora G. 
Published: May 2009

The morphology of a complete series of developmental stages of Lernaeocera branchialis is described. Seven stages are passed through before reaching the gadoid (final) host.The structure of the mouth tube and appendages is discussed in detail and compared with those of related genera in which the resemblances are close.The free single nauplius and copepodid stages are immediately followed by four chalimus stages on Pleuronectes flesus; these show some dedifferentiation though segmentation is not lost. An explanation is given for the peculiar suspensory mechanism of the chalimus.A second dedifferentiation follows the second well-developed pelagic phase in which the adult form is attained and copulation takes place. Some irregularity is noted in the details of the retrogressive metamorphosis of the maturing female on the gadoid host.The rate of increase in body length in Lernaeocera decreases regularly up to the assumption of the adult form (stage VII). In this respect it is similar to the free-living copepods Diaptomus, Eurytemora and Calanus, but is in strong contrast to Caligus centrodonti which has an increasing growth rate up to the fourth chalimus stage. In the latter at this stage there is a marked acceleration in the growth rate unaccompanied by any change in shape or any other discontinuity, whereas in Lernaeocera there are early discontinuities in development, yet the growth rate is continuous when expressed graphically: it is a straight line rather than a logarithmic curve as would be expected from our knowledge of the higher Crustacea.The size of the female is greater than that of the male: that of the female overlapping the male of the succeeding stage. Variations in size of the larvae in a stage group are not seasonal, and an explanation is offered for giant larvae.Similar lernaeocerid larvae and males to those of Lernaeocera branchialis on Pleuronectes flesus were found on Solea solea and Cyclopterus lumpus. No characters of generic or specific significance could be found which would serve o t separate them from Lernaeocera branchialis so that their identity is not determined.
A study of a marine benthic community with special reference to the micro-organisms
Authors: Mare Molly F. 
Published: May 2009

An attempt has been made to deal briefly but quantitatively with all size groups of the fauna and flora in a marine mud deposit.It has been necessary to propose the following new terminology: theMacrobenthos, which is here equivalent to the macrofauna, theMeiobenthos, under which term are included copepods, nematodes, foraminifera, etc., and theMicrobenthos, comprising the rest of the protozoa, bacteria, bottom diatoms and other algae; planktonic diatoms and coloured flagellates also occur on the bottom in the region investigated but are not regarded as true microbenthos.A quantitative ecological study of the microbenthos has been started and the habitat is first described, stress being laid on points of importance to the microorganisms.The census method for bacteria was an agar-plate method and that for the protozoa and diatoms was a dilution culture method modified from that used by soil microbiologists.These methods give minimal values for the total population and may safely be used for comparative purposes. The results are still tentative.Typical figures for the minimal numbers and volumes of living protoplasm per gram of dry mud in the top ½ cm. layer are given in Tables I-IV.The surface layer is much richer in all types of organisms than is the mud deeper in the cores. There is considerable local horizontal variation in numbers of bacteria and protozoa, suggesting dense aggregations.Diatoms contribute by far the greatest bulk to the total volume of living micro-organisms; planktonic diatoms, particularly during the summer, completely outweigh the true microbenthos.
The displacement method of weighing living aquatic organisms
Authors: Lowndes A. G. 
Published: May 2009

The method by which the weight, volume, density and sinking factor of living aquatic organisms can be determined has been extended. By sinking factor is meant the ratio of the density of the organism to that of its environment at the time of the actual determination. The density of the environment is always raised to 1000, and the density of the organisms computed on this basis.A quick and accurate method for determining the percentage of water in a living organism has been described and discussed.On the assumption that a sponge consists of protoplasm and spicules only, the density of the protoplasm has been computed.The sinking factor of several fish and of the embryos of some Crustacea at different stages has been determined. One effect of the swim-bladder in teleost fishes is to reduce the sinking factor and thus facilitate swimming.The effect of the sinking factor on swimming in general and the effects of spinous outgrowths in pelagic Crustacea are discussed.
Studies onPolystomellaLamarck (Foraminifera)
Authors: Jepps Margaret W. 
Published: May 2009

Part I. After a brief statement of the present unsatisfactory position regarding the life history ofPolystomella crispa, an account is given of experiments with various fixatives onP. crispa, collected near Drake's Island, Plymouth. A method is described for the cultivation ofPolystomellain diatom cultures, especially withNavicula muticavar., with which a flagellate (Bodosp.) was constantly present. The identification of individual Foraminifera, and determination of growth, were often possible by some irregularity in the shell, or by noting the attachment of one or more stalked egg cocoons of an unknown turbellarian worm. The feeding ofPolystomellaon diatoms seized by the pseudopodia outside the shell is described; the structures previously taken for ingested algal cells inside the shell are shown to be foraminal plugs (‘bouchons’ of le Calvez) which are discarded from time to time and thrown out of the shell along with the excretory granules (xanthosomes), mostly via the canal system.Part II. Notes are given on the microspheric form and its reproduction, through the spring and summer, by schizogony. The rearing of two broods in laboratory cultures is described, with an account of the formation of a new chamber to the shell. It is concluded that a complete life cycle consisting of one microspheric and one megalospheric phase occupies a period of about two years.Part III. Sporulation of the megalospheric form is described as seen during life; and various factors are discussed which might affect the process. The relatively small size of the reproducingPolystomellawith which Lister worked is ascribed to their having lived under less favourable conditions. From a study of stained preparations, certain details are added concerning the opening up of the shell, presumably to facilitate the eventual escape of the flagellate swarm spores; also concerning the accompanying cytoplasmic and nuclear changes. Some account is given of the form and structure of the swarm spores, both alive and in permanent preparations. Experiments are described which constitute an attempt to carry the life cycle beyond the stage of sporulation. They are so far unsuccessful, with one possible exception, under all the various experimental conditions which are briefly discussed in their turn.
On the biology of the small copepods in Loch Striven
Authors: Marshall S. M. 
Published: May 2009

The seven species of small copepod common in Loch Striven have been studied from vertical tow-net hauls taken there throughout the year 1933. These copepods were Pseudocalanus minutus, Paracalanus parvus, Microcalanus pygmaeus, Centropages hamatus, Temora longicornis, Acartia clausi and Oithona similis.In general, the copepods began to reproduce about the time of the spring diatom increase in March or April, and produced a succession of broods throughout the summer; apart from the first these broods were not as a rule so clearly marked as in Calanus. Microcalanus begins to breed before the spring increase and has clearly marked broods like Calanus.