Study of the pH relations of the coralline algae has shown that there is good reason to believe that calcification may be brought about by the development of alkalinity by the cells of the thallus, while a slightly acid reaction may be detected on occasion on the outer surface (Digby, 1977). The mechanism of calcification is obscure, but in general two types of action might be involved, direct chemical action and active transport. In direct chemical action a chain of reactions may occur in which the laws of chemical equivalence must be obeyed. Active transport involves complex metabolic processes which may be much more efficient in moving ions from one place to another, the utilization of one chemical equivalent of oxygen providing the energy to transport more than one equivalent of a particular substance.

Densities and growth rates of Ensis directus (Bivalvia: Solenidae), a recent invader of the Wadden Sea, were monitored at 15 stations (12 transects and 3 squares) covering a wide range of intertidal levels and sediment types on Balgzand, a tidal-flat area in the western-most part of the Wadden Sea, during 1982–1994. In this period, recruitment was weak in all but one year (1991). Settlement took place in summer over a wide range of intertidal levels, but high survival of recruits was limited to stations below the level of mean low tides. Growth rates were also maximal at these low intertidal levels. In such areas they reached a mean length of about 6 cm in the first winter, about 12 cm in the second, and about 14 cm in the third winter. These growth rates were high compared with published records from other intertidal and shallow subtidal areas.

Relatively exposed parts of the lower intertidal zone, characterized by clean sands and infrequent emersion, are a poorly occupied habitat of the Wadden Sea and offer an available niche to a new species that is well adapted to such harsh environmental conditions. In such areas, E. directus has become a dominant member of the benthos and in 1992 and 1993 reached high biomass and production values of >10 g AFDW m−2.

Shell growth of the whelk Nassarius (=Hinia) reticulatus was studied in the Ria de Aveiro (north-west Portugal) between 1995 and 1998. Temporal analysis of shell height frequency distributions demonstrated that growth occurs during the first five years of life, whelks attaining a size of 6·7–7·8 mm in the 1st year, 12·1–14·5 mm in the 2nd year, 18–19·5 mm in the 3rd year, 22·7–23·6 mm in the 4th year and by the 5th year males have achieved an average size of ∼25 mm whilst females have reached ∼27 mm. Age estimates from internal microscopic annual growth lines present in the shell lip suggest that large whelks may achieve a longevity of at least 11 years. External annual rings become less discernible as the whelks increase in size and estimates of their age based solely on ring counts can underestimate their age. In males sexual maturation is reached between the 3rd and 4th years whilst in females it is attained between the 4th and 5th years. Imposex was visible in ∼2 year old females and attained maximum development by the 5th year.

the taxonomy of the genus centrophorus (squaliformes: squalidae) is currently in a great deal of uncertainty. the characteristics of the species subject to the present study most closely resemble those of centrophorus uyato, hence the use of centrophorus cf. uyato, though the species in question may be a species of centrophorus that has not been described previously. specimens were obtained via vertical and horizontal longline at depths of 250–913 m. the reproductive biology of 51 female and 8 male centrophorus cf. uyato were examined. this species is sexually dimorphic, with females attaining a larger size than males. the smallest mature male was 81.2 cm total length whereas the smallest mature female was 91.5 cm total length. females are aplacentally viviparous, with the pups acquiring nutrition via large external yolk sacs, and there was a maximum of two pups per litter. oocytes continued to develop throughout gestation. most females carrying developing embryos had two large (>3.3 cm), equally developed ovarian oocytes, which leads us to believe that they ovulate soon after parturition. this species seems to exhibit complete sexual segregation during the non-breeding season, with mature males absent from the study site during summer months. centrophorus cf. uyato may have one of the lowest fecundities among sharks, giving birth to a maximum of two pups every three years. all species in genus centrophorus have small litters (<6) making them vulnerable to over-exploitation.

The teeth and grasping spines of Sagitta are similar in structure, both having a central pulp cavity surrounded by two electron-dense chitinous layers. The cells of the pulp cavity contain microtubules arranged along the long axis. The two chitinous tubes are separated by a less-dense zone crossed by coarse fibrils linking the two. The teeth and spines insert into less electron-dense chitin (presumably flexible) and are moved by processes of anchor cells which pass into the basal chitinous zone. The inner region of the anchor cells is apposed to the connective tissue layer on to which the muscles of the teeth and spines insert. At the base of the pulp cavity, i.e. at the secretory zone where the teeth and spines are formed, the cells of the pulp cavity contain electron-dense granules in which zinc is found; zinc is also present in the inner and outer dense chitin layers at high concentration (0·5–1·0% of the dry wt).

Both spines and teeth are tipped with fibrous cones containing silicon. It is suggested that the zinc associated with the chitin serves to toughen the teeth and spines and render them less liable to fracture, and that the silicon in the tips confers hardness to this vulnerable region.

In order to determine if eastern Pacific green turtles (Chelonia mydas) exhibit feeding preferences samples of recently ingested food items were compared to the food resources available in the marine environment where C. mydas congregates. Stomach samples were collected by conducting gastric lavage and, at the same time, vegetation transects were conducted during spring and winter. Green turtles in our study selectively consumed seaweeds, with Codium amplivesiculatum and Gracialaria textorii as preferred species. Differences in the consumption of species were found across the two mentioned seasons and were consistent with changes in the availability of different algae species in the environment. Based on these results, it is recommended that sea turtle conservation plans along the Baja California Peninsula include Pacific coastal mangrove channels with a high diversity of algae species as priority areas for protection.

Most North Sea cetacean species are wide-ranging and consequently poorly studied. Spatial and temporal trends in the distribution of the harbour porpoise Phocoena phocoena, white-beaked dolphin Lagenorhynchus albirostris, and minke whale Balaenoptera acutorostrata were assessed at a coastal North Sea study area in Aberdeenshire, Scotland. Between March 1999 and October 2001, cetacean data were collected using both land- and vessel-based survey methods. A total of 174 sightings of these three cetacean species was recorded during approximately 330 h of combined survey effort (228 h land-based and 102 h vessel-based). Harbour porpoises were present throughout the year with peak occurrence during August and September. The presence of white-beaked dolphins and minke whales was strictly seasonal, with a peak in occurrence during August. The fine-scale distribution of all three species varied within the study area, with an apparent preference for sections of coast adjacent to deeper water. Most porpoise calves and juveniles were recorded between June and September, when 35% of harbour porpoise groups contained immature animals. The proportion of calves amongst porpoise sightings was higher during June than any other month. White-beaked dolphin calves were present in 32% of groups, and occurred in all three months that the species was recorded. Group size was higher in white-beaked dolphin pods containing immature animals. The strong seasonality in occurrence of all three species may relate to requirements for breeding habitat, movements of shared prey species and/or inter-specific competition with other species.

Five, possibly six, north European species are confirmed in the prosobranch genera Rissoa and Pusillina: R. parva (Da Costa); R. lilacina Récluz; R. membranacea (Adams) (types A & B); P. inconspicua (Alder) and P. sarsi (Lovén).

The five species differ ecologically in salinity tolerances, with R. membranacea and P. sarsi being the most tolerant and regularly occurring at salinities of 7–10%0, while R. parva, R. lilacina, and P. inconspicua tolerate salinities down to 20%0 (for shorter periods 15%0). There are also differences in the ability to survive occasional, short exposures to highly reduced salinity with 50% survival for R. membranacea after 80 h; R. lilacina, 30 h; P. sarsi, 25–30 h; and for P. inconspicua after 15 h exposure to freshwater at 8°C. At higher temperatures the survival is lower. There is a difference in the requirements on water circulation, with R. parva and R. lilacina preferring more current-swept and exposed environments.

Rissoa membranacea occurs in two types, possibly species, with planktotrophic and lecithotrophic larval development respectively. In Scandinavia, populations with lecithotrophic development have a restricted occurrence between Sjaelland and Jylland in Denmark, but may be more common in the UK and France. Such specimens are always accompanied by the planktotrophic form, and it can not be excluded that the two forms are conspecific and this is a case of poecilogony. There is also a possibility that P. sarsi actually constitutes a series of populations of P. inconspicua adapted to local, more brackish conditions by larger egg size and veligers, but the two are regarded as distinct species.

Since the appearance of the first documentation of marine algae from within the political boundaries of eastern Canada (South & Cardinal, 1970), a sufficiently large volume of new information has become available to warrant the revision presented here. Taxonomic and systematic changes, together with further additions, corrections and emendations are incorporated as far as possible. A total of 346 species, subspecies and varieties are listed, comprising 131 Rhodophyta, 127 Phaeophyta and 88 Chlorophyta. The treatment is largely restricted to macroscopic forms. Inclusion of microscopic species of Chlorophyta and representatives of other marine Phyla is planned for the future.

In the previous numbers of this series (1923, 1925, 1926, 1928) it was fully established that the phosphate and silicate content of sea-water becomes greatly reduced in spring and summer. It is possible to calculate a minimum value for the phytoplankton crop from the amount of phosphate used up, also to ascertain the production up to and between various dates; such information has a direct bearing on the supply of food for copepods and other animals upon which young fish feed. The accumulation of data of this type should in time permit of some generalization as to the favourableness or otherwise of any season with respect to the survival of relatively large numbers of young fish of various species in the locality studied. The present paper is a further contribution towards the amassing of seasonal productivity data which has been in progress since March 1923, with a gap from March to October, inclusive, during 1927. Information has moreover been sought as to the extent to which the removal of the phosphate approaches completion; the analyses of water samples low in phosphate have been carried out with a rather greater degree of accuracy than heretofore, by using a more exact method of allowing for the reagent blank, by using weaker standard solutions and by ensuring that in nearly every case the analyses were performed on the day following that on which the water samples had been taken. When the cruise extended for two days this was not possible as regards samples taken on the first day. Furthermore, measurements have been made (Poole and Atkins, 1928) of the illumination, both aerial and submarine, obtaining when the samples were taken.

Twelve strains of psychrophilic, marine pseudomonads which grew readily on nitrate or a mixture ofamino acids, were tested for their content of the enzymes glutamine 2-oxoglutarate amino transferase (GOGAT) and glutamic dehydrogenase (GDH). All strains contained GOGAT activity when grown on nitrate and GDH when grown on amino acids. In all strains tested the synthesis of GOGAT was repressed by growth on amino acids and derepressed by growth on nitrate.

A collection of 17 cyanophage isolates able to infect the heterocystous, filamentous cyanobacterium Nodularia spumigena has been established from the Baltic Sea. These cyanophages have been characterized based on their morphology, cross infectivity and genetic structure. Short fragments (450 bp) of the gene encoding the major capsid protein (g23) were amplified and sequenced from several isolates, and the encoded protein was found to be 99% identical across all the N. spumigena-specific cyanophages tested. These results suggest that the Nodularia-specific cyanophages are very closely related. However, these cyanophages were found to be diverse in terms of their morphology and host range. Cyanophages belonging to two families within the order Caudovirales, Myoviridae and Siphoviridae, were included in the collection of isolates. The cyanophage particles are large in comparison with cyanophages previously isolated from the marine environment, with the largest capsid measuring 127×122×888 nm. Host ranges of the cyanophage isolates varied, some being able to infect up to five genotypically distinct strains of Nodularia spumigena, while others were very specific, infecting only one strain. We conclude that Nodularia-specific cyanophages form a diverse community in surface waters during summer and autumn months and that they may play a role both in the transfer of genetic information between Nodularia lineages and in promoting changes in the genetic structure of the host population.

The capture of crabs of the genus Callinectes is one of the oldest extractive activities practised by waterside communities, due to the abundance of brachyurans along the Brazilian coast. The present paper aimed to provide basic information on the population biology of C. sapidus and C. danae during the period of December 2003 to November 2004, in Babitonga Bay, Joinville, Santa Catarina. The size of the first maturation of C. danae was estimated as 7.1 cm in total carapace width for females, and as 8.6 cm for males. Fecundity of the 20 females of C. danae with carapace width from 7.0 to 11.0 cm varied from 618,667 to 811,267 eggs. Fecundity of C. sapidus was higher, with a median of 978,000 eggs per female, but carapace widths in this species were also larger, with the highest frequency of females attaining 19.01 cm on average. In both species, a tendency was observed for the egg mass to increase with size of females. The capture per unit of effort presented the lowest values in summer, while the largest values occurred from March, August and November. A total of 80 males and 117 females of C. sapidus were captured in the four collecting areas, with the largest abundances in Area III (45.18%), followed by Areas II, IV and I. The size of the first maturation of C. sapidus was estimated as 10.2 cm for females and as 9.0 cm for males. Fishing effort was in relative equilibrium for adult stock (males = 58.75% and females = 52.99%) and juveniles (males = 41.25% and females = 47.01%). The largest monthly rates of biomass of C. sapidus occurred from April to November, with a peak of capture in August, without significant differences in the participation of males and females.

Hyperiid amphipods are holoplanktonic marine crustaceans that are known as temporary symbionts of different groups of gelatinous zooplankton. The nature and dynamics of these associations are still poorly understood, particularly in deep waters. The mesopelagic and deep-living planktonic fauna off Monterey Bay, California (down to 4000 m) was surveyed using a remotely operated submersible (ROV) and blue-water diving (BWD) between September 2005 and January 2008. In this work we report our observations on a total of 51 symbiotic associations observed in situ (not from zooplankton samples), between hyperiid amphipods and various taxa of gelatinous zooplankton. We present the first information on the symbiotic relations of the hyperiid Vibilia caeca, and we provide data of 34 previously unknown symbiotic associations. The host range was expanded for several widely distributed hyperiid species. These findings suggest that the symbiotic associations between hyperiid amphipods and gelatinous zooplankton in deep waters deserve further study worldwide.

The aim of this study was to determine the abundance of cyanophages over an annual cycle in the Red Sea from the period April 1999 to December 1999 at a range of depths. Cyanophage numbers from 71 water samples were determined by the use of plaque assays using four different Synechococcus strains. The results indicate that cyanophage are found throughout the water column from surface waters to depths of 150 m, with a discrete maximum in the number of cyanophages in the summer months of July, August and September at a depth of 30 m. Eighty-seven cyanophages were isolated and characterized in terms of host range, genome size and possession of a myoviral portal vertex gene. Cyanophages were found to infect multiple strains of Synechococcus from different phylogenetic clades. The genome sizes of cyanophages were also found to be bigger than previously estimated.

Little work on vertical distribution of cephalopods was possible before the development, in the 1960s, of sophisticated opening-closing devices usable on midwater trawls such as the 10 ft Isaacs Kidd trawl (IKMT; Foxton, 1963; Aron et al. 1964) and the series of rectangular midwater trawls developed by the Institute of Oceanographic Sciences (previously the National Institute of Oceanography) (Clarke, 1969 a; Baker et al. 1973). These developments have resulted in three papers on vertical distribution of cephalopods in the North Atlantic (Clarke, 1969 ft; Gibbs & Roper, 1970; Clarke & Lu, 1974) and one for the Mediterranean (Roper, 1972). The present paper describes the vertical distribution of cephalopods caught at 40° N 20° W, 53° N 20° W and 60° N 20° W in the North Atlantic based upon day and night series of horizontal hauls between the surface and 2000 m using the RMT combination net (Baker et al. 1973).

Studies are reported of the behaviour of stored sea-water with regard to oxygen, ammonia, and bacteria content in relation to the conditions of storage and to the effect of various filtration procedures.

When sea-water is sterilised by filtration and stored in the dark, the oxygen content remains constant or diminishes only by less than 0·07c.c. per litre in several hundred hours.

In non-sterile experiments there is always an oxygen consumption roughly parallel to a bacterial multiplication which begins very suddenly after collection of the water. These effects are greatest in “raw” water, less in paper-filtered water and least in water which is doubly filtered.

The habitat and feeding preference of two gastropod mesoherbivore species, Ansates (Helcion) pellucida and Lacuna vincta, inhabiting the kelp Laminaria hyperborea were investigated by studying the distribution, habitat choice and food preference of the herbivores between new and old kelp fronds. Nitrogen content and chemical defence (phlorotannin) level of the kelp fronds were measured in order to determine whether they were correlated with the feeding preference of the herbivores. The habitat choice of Lacuna vincta was correlated with the food preference of this species, while the habitat choice of A. pellucida probably was due to some other factor, e.g. competition or mortality. Ansates pellucida preferred to reside on the old fronds of Laminaria hyperborea, but consumed an equal amount of both tissue types. Lacuna vincta, however, preferred the new Laminaria hyperborea fronds both as habitat and food. There was a large variation in the phlorotannin content among the tissue samples of L. hyperborea. However, there were no overall statistically significant differences in tissue nitrogen or phlorotannin content between the new and the old L. hyperborea fronds.

Recent measurements of benthic currents, within the depth range where the highest abundance of the hexactinellid sponge Pheronema carpenteri are found, have been made and compared to historical data for the northern Porcupine Sea Bight region where no Pheronema have been recorded. Bottom currents at a location where Pheronema have not been recorded are much higher than a location where the sponges have previously been sampled. The measurements provide some evidence to support the hypothesis that the sponges favour a location adjacent to regions where enhanced bottom tidal currents are found, but currents experienced by the sponges themselves are much reduced.

The presence of living organisms and their metabolic products introduce a further series of biochemical factors into the physical conditions of life on the sandy beach.

The gaseous exchanges of animals and plants lead to changes in the pH of the interstitial waters of the beach, but the calcareous matter associated with the sand acts as an alkali-reserve, preventing undue rise of acidity, and incidentally widening the potential range of carbonassimilation of the surface flora.