The south to north development of the spring bloom in the North Atlantic Ocean was observed during four cruises from April to August 1989. Transects with towed undulating instrumentation packages and CTD profiles on station were made between 42°N and 54°N, along 17°W and 20°W in April and between 47°N and 60°N along 20°N in May, June and July/August, giving vertical sections of temperature and chlorophyll concentration derived from in vivo fluorescence. These sections show the relationship between the onset of seasonal stratification and the initiation of the spring bloom. Supporting data from microscopic analysis of the major phytoplankton species show that the seasonal succession commenced with diatoms, followed in turn by coccolithophores, flagellates and dinoflagellates. During the development of summer stratification the mesoscale distribution of chlorophyll was strongly determined by the depth of the mixed layer, but once stratification had been firmly established higher chlorophyll values tended to be found within the warmer eddies (meanders). One possible explanation of this result is that phytoplankton growth is higher in the warmer eddies.

Although workers in several European countries (England, Germany, Russia, Scotland) are stated (5) to be carrying out marking experiments on rays or skates, the writer is not aware of any recently published account of the results of any of these researches. Fulton (4, p. 191), however, records that in the years round about 1890 he marked 71 thornback rays (R. clavata) and 23 specimens of grey skate (R. batis) in Scottish waters. Two of the thornbacks and one skate were subsequently recovered. Of the former, one—about 36·5 cm. in width on marking—remained at liberty for about three months before being recaptured and had travelled about 13 miles from the place where it had been set free. The other—35 cm. in width—remained at liberty for 278 days and travelled about six miles. The single skate, recaptured after only 10 days, had in that time changed its position by 10 miles. No records of size increments are given.

The faunal analysis of forty-eight samples taken with a coarse tow-net across the intertidal waters of Kames Bay during 1936 shows that the night migrant crustacean population falls into two well-marked groups: (a) those species which live in the intertidal sand and perform simple vertical migrations at night-time into the intertidal waters, and (b) those which are carried in by the tide into the intertidal area from various habitats which lie beyond the low-water mark of spring tides. In the former group the species of the genera Bathyporeia and Pontocrates are dominant and they retain their zonation as migrants, the population consisting of individuals in all stages of maturity. This is in sharp contrast to the latter group, typified by Gammarus locusta and Idotea viridis, which occur over the whole tidal range with a population in which the young immature stages are dominant. The Haustoriids Urothoë brevicornis and Haustorius arenarius occur as inhabitants of the sand, the former appearing occasionally in the tow-net samples and the latter absent from them. The Cirolanid Eurydice pulchra performs both day and night migration for the purposes of feeding.

Discussion of the results indicates the lines along which further investigations may be carried out.

The adults of three new cyclopoid copepods are described and figured, namely Micropontius ovoides, gen. et sp.nov., occurring on spatangid echinoids; Lichomolgus leptodermatus, sp.nov., and Conchyliurus cardii, sp.nov., both associated with pelecypod molluscs. Micropontius is made the type of a new family, the Micropontiidae.

Some other copepods, Asterocheres violaceus (Claus), Scottomyzon gibberum (T. & A. Scott), Pseudanthessius liber (Brady & Robertson), Bomolochus confusus Stock, Euryte longicauda Philippi var. minor T. Scott and Peniculus fistula Nordmann, are recorded for the first time from the Plymouth region; and mention is also made of Tisbe elongata (A. Scott).

Points of interest in the biology, morphology, systematics and distribution of all these are discussed.

An inventory of fish and epibenthic macrocrustaceans of the surf zones of sandy beaches along the Belgian coast was constructed. The surf zones were sampled intensively with a 2-m beam trawl in April–May 1996 (12 stations) and 26 species were recorded belonging to caridean shrimps (4), brachyuran crabs (5), cephalopods (1) and fish (16). The brown shrimp Crangon crangon dominated almost all samples (>80%). Total densities exceeded several times 250 ind 100 m−2 and 10 ind 100 m−2 if C. crangon was excluded. An east–west distinction as found in other (epi)benthic studies in deeper waters of the Belgian coast, was not found in the surf zone during this study. Spatial variation was mainly correlated with local characteristics such as turbidity of the water and the morphodynamic features of both the beach and the adjacent subtidal area.

The following is a continuation of the work described in a previous paper (Reid, 1930). The intention was to amplify that work by the investigation of the conditions of salinity interchange on sandy shores of less ideal type. It was considered likely that various factors might affect the condition of the water held by the sand. For instance, the rate of flow of the fresh water and its depth; irregularity in the slope of the beach; the depth of the sand and the nature of the floor on which it rests. The rate of flow of the water is not a simple factor however. It is correlated with the slope of the beach in that faster streams are usually on steeper beaches. The effect of this dual factor will be discussed later.

INTRODUCTION

Implicit in some recent models of the dynamics of planktonic systems, for example that of Steele & Frost (1977) is the concept that filter-feeding copepods may be scaled by size when considering feeding in relation to the size composition of their paniculate food. For a particular organism ingestion of phytoplankton has been considered to be a function of its own weight and the size composition of the phytoplankton available to it. Such scaling has been assumed to occur both in an intra- and interspecific sense, with model development involving a ‘large’ copepod {Calanus) able to feed and grow more efficiently on ‘large’ cells (diatoms) and a ‘small’ copepod {Pseudocalanus) better adapted to feed on ‘small’ cells (flagellates). However, although the general relationship between growth and metabolic rate and body size is widely accepted (Banse, 1976; Fenchel, 1974) this relationship between dietary particle-size composition and size of organism has remained a working hypothesis with little experimental support..

Salps swim by rhythmic contraction of the hoop-like bands of muscle which form a series of incomplete annuli along the body. The histology of these muscle bands was briefly examined by various early workers, such as Dolley (1887) and Knoll (1895), but was little known until Fedele (1932,1938) published the results of his careful investigations of a variety of species. His observations demonstrated the complexity and peculiarity of the muscle fibres forming the bands, which, as he pointed out, are in some respects comparable to those of arthropods in the arrangement of the sarcomeres. In all the species he examined, Fedele found that the muscle fibres were essentially similar in organization: a central granular core containing large nuclei was surrounded on the free borders of the fibre by a layer of myofibrils. However, this general arrangement differed in detail between different species, and Fedele recognized five types of muscle fibre, distinguishing these types upon such criteria as the fibrillar arrangement, and the disposition of the nuclei. In an earlier paper (Fedele, 1925) he had also given very clear figures of the manner in which these muscle fibres were innervated. He found that dis-crete motor end-formations occurred on the surface of the muscle bands, and that these were frequently intercalary, unlike the motor terminations of vertebrates.

Fedele's work was based upon very careful observation of living and fixed material at the light microscope level; in the present note, we extend his observations by describing the ultrastructure of these curious protochordate muscle fibres.

We examine the relationship of biomass B and length L in the eastern oyster Crassostrea virginica by focusing on the scaling exponent b in the allometric equation B = aLb using four datasets: Delaware Bay, Chesapeake Bay, Galveston Bay and a regionally extensive compilation from the NOAA Mussel Watch Program. The average value of the scaling exponent in Delaware Bay and Chesapeake Bay is about 2. For Galveston Bay, the value is distinctly higher, near 2.6. Over all Mussel Watch sites, the value is again near 2. Within Delaware Bay, the salinity gradient exerts an important effect. Shells are longer for their meat weight at lower salinities. The range of scaling exponents revealed by Mussel Watch data is exceedingly large (b < 1 to >3). Scaling exponents below 2.5 are unusual in bivalves. Among bivalves, only other oyster taxa have comparably low scaling exponents averaging near 2. We propose that oyster biomass routinely scales nearer the square of the length rather than the cube and that this is a constraint imposed by the exigency of carbonate production for reef maintenance and accretion in the face of high rates of taphonomic degradation. The adaptation as a reef builder requires the formation of carbonate that rapidly breaks down, thus requiring that carbonate produced be maximized. A biomass-to-length scaling exponent of 2 provides a mechanism to maximize shell production relative to biomass, while at the same time providing maximum surface area for the all-important settling of oyster spat to maintain the population.

In 1908 Lohmann described a small dinoflagellate which appeared to lack a sulcus and was therefore placed in a new genus – Protodinium. The type species, P. simplex (Text-fig, IA) was broadly ellipsoidal with broad rounded apices, circular in cross-section and about 1–5 times as long as broad. The girdle was poorly defined, but was more or less median in position. The nucleus was relatively large and centrally located and yellow leaf-life chloroplasts, four to many in number, were arranged in the periphery of the cell.

A study has been made of the toxicities of mercuric chloride, mercuric iodide and methyl-, ethyl-, n-propyl-, n-butyl-, n-amyl-, iso-propyl-, iso-amyl- and phenylmercuric chlorides to larvae of the crustaceans Artemia salina and Elminins modestus. With both species it has been found that all the mercury compounds are more toxic than mercuric chloride, that primary alkylmercuric chlorides are more toxic than the corresponding secondary compounds, and that as the homologous series of primary compounds is ascended, toxicities increase. In addition, it has been found that Elminius is much more readily poisoned than Artemia by each mercury compound, and that differences between the toxicities of the poisons to Elminius are much smaller than corresponding differences observed in experiments with Artemia.

The phenomenon of acid secretion has arisen independently many times, for feeding, for penetrating calcareous material to make a shelter or to pursue prey, or for defence. This last category contains examples from many groups of marine organisms, in which acidic allomones may serve to deter fouling by epibionts or predation by teleost fish. Histochemical and histophysical methods have increased the precision with which acidic allomones can be identified within acid vacuoles, cells, glands, sacs or capsules. Acidic allomones are produced in pleurobranch molluscs by unicellular epidermal glands, by multicellular subepidermal sacs, or by an arborescent internal acid gland, connected to the buccal mass by a thick medio-dorsal duct. Some species have all three types. In the case of the epidermis, discharge is probably triggered directly by the trauma of attack by a predator (effectively, holocrine discharge), but the other types of gland are discharged by contraction of a strong muscle sheath, without tissue damage. Cypraeid molluscs have extensive, mobile mantle lobes which can ensheath the massive shell temporarily. The epidermal acid glands are orientated within the mantle so as to discharge away from the shell. The lamellariid and philinid molluscs have internal shells, well protected from chemical attack, and the multicellular, subepidermal acid glands are situated over all the surfaces of the body. In the tunicates investigated, both blood and tunic were neutral in Ciona intestinalis, but they were both acid (pH 1) in Ascidiella aspersa. In Ascidiella scabra and Ascidia mentula the blood was neutral, and the tunic alone was acid. The acid tunics contained abundant blind lacunae. It is unlikely that these acid-filled lacunae correspond to the blind-ending arterial ampullae described by other workers. Discharge is probably brought about directly through the trauma of attack. The perennial species of the alga Desmarestia, D. aculeata, exhibited a pH near to neutrality. Two annual species, D. dresnayi and D. ligulata, contained acid of pH 1–2, and showed strong precipitation of BaSO4 after BaCl2 treatment. Sections confirmed that the acid is normally held within the swollen parenchymatous cells which pack the sporophyte frond. The cuticle is comparatively thin in the acidic species. In conclusion, it is argued that acid secretion may be the allelochemical analogue of warning or aposematic coloration.

The biological characteristics of Elysia subornata (Mollusca: Opisthobranchia) were studied in an aquarium to assess its risks and chance of success as a potential biological control agent against the invasive alga Caulerpa taxifolia (Chlorophyta) in the Mediterranean Sea. This species feeds only on Caulerpa and has benthic larval development. Dietary switching is possible on some Mediterranean Caulerpales but feeding on other algae and sea grass is unlikely. The main limiting factor for the success of studied Caribbean strain of E. subornata are the Mediterranean winter temperatures which are lethal for that species. For the five months of the year which are favourable for feeding, growth and reproduction, the tested strain of E. subornata cannot reach a population density capable of controlling C. taxifolia.

Lophelia pertusa, a cosmopolitan cold-water coral, offers potential for new palaeoclimate proxies. This study investigated its skeletal growth patterns to aid in this development. Corallite characteristics (calyx diameter, height, thecal width and banding) of L. pertusa sampled from oil platforms in the northern North Sea were examined. The mean distance between daughter polyps along a growth axis (27.4 ± 5 mm, SD) was equivalent to the estimated annual growth rate; hence, the polyps bud once a year. The majority of growth occurred in the first year when the characteristic trumpet shape of a corallite was formed, while the thecal wall thickened more consistently. Further examination of two polyps showed a dark growth band and centres of calcification along the full length of the inner theca, which represents early skeletal growth. Skeletal sampling adjacent to this area along sequential polyps shows promise as an annual chronology in these North Sea corals.

Information on cetaceans off Gabon in tropical West Africa is summarized from boat-based surveys carried out between 7 March and 7 August 2009. Thirteen cetacean species were positively identified comprising two baleen whale species, one sperm whale species and ten species of delphinid. Bryde's whale (Balaenoptera brydei) and humpback whale (Megaptera novaeangliae) were the most frequently encountered species. Cetaceans were found throughout a range of sea surface temperature between 20.5°C and 27.5°C and a wide range of depths with the majority of effort and sightings occurring seaward of the shelf break. Of particular interest from the study were the following: (1) Gabonese waters have a broad cetacean diversity, especially with a large and diversified delphinid community in the northern part of the study area; (2) the variations in oceanographic conditions within Gabonese waters are likely to result in a temporal variation in species composition; (3) the sightings of Atlantic spotted dolphin (Stenella frontalis) are the first at-sea sightings confirmed for these waters, although not unexpected given their distribution and abundant presence in surrounding waters; and (4) the poorly known Clymene dolphin (Stenella clymene) was sighted on four occasions in deep oceanic waters and was the most abundant cetacean. These are the first confirmed records of Clymene dolphins in Gabonese waters.

In order to investigate the intensity and variability of fouling recruitment on artificial hard substrates, three sites were chosen in the First Inlet of the Mar Piccolo of Taranto (Southern Italy, Ionian Sea). Taxa richness and percentage coverage were examined in three different sampling times within each site. Differences were tested both by univariate and multivariate statistical analysis (ANOVA, SIMPER and MDS). The results show that each site seems to be characterized by its own structural make-up over the whole period of observation, underlying the presence of large-scale variability. By contrast, variability on a smaller scale within each site (replicates) appeared less marked, both in space and time. A set of a quite stable group of species characterized each site. Differences between sites were maintained over time with a difference in community evolution although with a tendency towards a higher similarity in species composition along the time.

Results of a comparative study on the distribution, growth and reproductive bionomics of two species of sand-dwelling oedicerotid amphipod, Pontocrates arenarius and P. Altamarinus are presented. Pontocrates arenarius is a littoral species with highest population densities between mean tide level (MTL) and low water springs (LWS) while P. altamarinus lives in the immediate sublittoral between LWS and -2 m Chart Datum. Both species are iteroparous, have female biased sex ratios, year-round breeding and life cycles largely based on two generations per year. The percentage of ovigerous females in the total population indicates breeding activity, and temporal changes in this percentage (arcsin transformed) have been tested for correlations against seasonal variation in five environmental factors (mean maximum weekly air temperature, mean minimum weekly air temperature, mean weekly sea temperature, day length, and mean weekly windspeed). Based on these analyses, differences in the timing of peak reproductive activity between these two species are interpreted as indicating the operation of different mortality agents, i.e. abiotic factors in the littoral P. arenarius and biotic effects (e.g. predation by fish) in P. altamarinus from the sublittoral.

Analyses of the ampharetid polychaete Melinna palmata have shown that this species consistently contains a high concentration of copper. The related species Melinna cristata also has a high copper content but Ampharete acutifrons and Amphicteis gunneri have low copper contents. M. palmata usually contains copper in concentrations in excess of 600 μg/g (dry weight) and often above 1100 μg/g; much of this copper is embodied in the branchiae which have concentrations of 0·4–1·2% copper and, although these organs account for only 3–4% of the dry body weight, their copper content represents 30–40% of the total body burden. X-ray microanalysis shows the copper in the branchiae to be concentrated in special epidermal cells. The function of the copper in these cells does not appear to be associated with detoxication, luminescence or an antifouling mechanism but feeding trials have shown the branchiae of Melinna palmata, but not of Ampharete acutifrons, to be distasteful to certain small fish. Thus it is thought the copper may reduce the palatability of the tissues and is accumulated by Melinna palmata as a chemical defence against predation.

The rocky shore of Punta Este, Golfo Nuevo (Patagonia, Argentina), was sampled by means of the standardized NaGISA (CoML) protocol, that was aimed to generate biodiversity baseline data in six levels, from high intertidal to 10 m depth. Based on the generated data, we analysed the benthic assemblage structure, species richness, mean abundance and the distribution pattern of invertebrate functional groups, typifying species in each intertidal and subtidal level. The intertidal sampled is exposed to extreme physical conditions higher than any other rocky shore system studied, with air temperature variation of 40°C during the year, maximum winds of 90 km/h and semidiurnal tides of 5 m amplitude; on the other hand subtidal presents less thermal variation (ΔT 10°C throughout the year) and more homogeneous physical conditions. We identified 64 taxa represented by six animal phyla: Mollusca, Arthropoda, Annelida (Polychaeta), Echinodermata, Cnidaria and Nemertea; and three algal phyla: Chlorophyta, Rhodophyta and Heterokontophyta (class: Phaeophyceae). Ordination non-metric multidimensional scaling plots showed three different assemblages in terms of species composition (intertidal, subtidal 1 m level and subtidal 5–10 m levels). The intertidal was represented by suspension feeders, mainly Mollusca. The tiny mussels Brachidontes rodriguezii and Brachidontes purpuratus, and the algae Corallina officinalis dominated the intertidal and promote positive interaction (amelioration), preventing other species from the extreme physical stress. The subtidal was mainly represented by grazers. Our results showed a tendency of suspension feeders to decrease and grazers and predators to increase from high intertidal to subtidal, probably driven by decreasing physical stress. The gastropod Tegula patagonica, the sea urchins Arbacia dufresnii and Pseudechinus magellanicus and the invasive algae Undaria pinnatifida were the most abundant species in 1 m–10 m levels. Based on previous work performed in the region, we hypothesize that the differences registered between intertidal and subtidal levels could be explained in part by an increase in physical stress at the intertidal, with low predation pressure that promotes positive interactions, while in the subtidal the increase in consumers and decrease of physical stress could lead to associational defences. Our results could be useful as baseline data to develop a sustainable network for long-term monitoring of benthic community changes due to anthropogenic activities.

Lasaea rubra, like other small Erycinacea, is unusual among eulamellibranchs in its relatively great mobility on the surface of the substrate. It can crawl about as freely as a small gastropod and lays down a mucous trail for the attachment of its progressing foot, drawing the shell and body rhythmically forward after each advance thrust of the foot. Unlike some other Erycinacea, L. rubra has no well-defined sole; it attaches by the sharp lower edge and part of the side of the foot, which is strongly ciliated and well supplied with mucous glands. In most burrowing eulamellibranchs, the site of communication with the surrounding water has shifted to the paired siphons at the posterior end. The Erycinacea, however, have an anterior inhalant siphon; and—as in forward moving prosobranch gastropods (Morton, 1958)—there is an obvious adaptive advantage in receiving the ingoing current from the water into which the animal is moving.