The fine-scale structure of a bloom of the coccolithophorid Emiliania huxleyi has been mapped for the first time with an airborne thematic mapper (ATM) scanner (visible bands at 420–450 nm, 450–520 nm, 520–600 nm, 605–625 nm and 630–690 nm). The airborne results are in close agreement with simultaneous satellite observations from the visible band (580–680 nm) of the advanced very high resolution radiometer (AVHRR

The macrobenthic invertebrates in the shallow (<0·5 m), medium-depth (0·75–1·0 m) and deep (2·0–2·5 m) waters of the lower and upper regions of the large basin of the seasonally closed Wilson Inlet were sampled, using corers, in each season between the winters of 1989 and 1990. The fauna was dominated by capitellid, spionid and nereid polychaetes and mytilid, venerid and tellinid molluscs. Almost 75% of the total numbers were contributed by the polychaetes Heteromastus filiformis (Claparède) (30·2%), Capitella capitata (Fabricius) (17·4%), Prionospio cirrifera (Wirén) (7·9%) and Boccardia chilensis (Blake & Woodwick) (5·4%), and the gastropod Hydrococcus brazieri (Tenison Woods) (12·4%). The numbers of species recorded in Wilson Inlet (41) were relatively very low for an estuary. This presumably reflects (i) the low salinities, which would restrict colonization by stenohaline marine species, (ii) the prevention of recruitment from the sea by the closure of the estuary mouth during the summer, at which time many macrobenthic species are producing pelagic larvae, (iii) the very limited tidal movements, and thus mechanisms for transporting larvae from the sea, when the estuary mouth is open, and (iv) the lack of a pronounced salinity gradient and the small variation in sediment composition along the estuary. Characteristics (ii–iv), together with the dispersal of pelagic larvae within the basin by wind mixing, would also account for the fact that faunal composition was influenced less by the region within the basin than by water depth. The densities of species, such as Ceratonereis aequisetis (Augener), Capitella capitata and H. brazieri, were greater in the shallow and medium depths than in deeper water, while the reverse pertained with P. cirrifera. Since densities of the first three species are correlated with the biomass of Ruppia megacarpa Mason, the greater amounts of this aquatic macrophyte in the shallow and medium-depth waters may thereby provide more food and/or protection from predators in those waters than would be the case in deep water. In contrast, P. cirrifera, which is a detritivore, would benefit from the greater proportion of particulate organic material in the deep waters. The greater habitat complexity in the shallow and medium-depths, that is provided by the greater amounts of R. megacarpa and shell debris in those waters, was associated with a greater species richness, diversity, density and biomass of benthic invertebrates. The composition of the fauna underwent cyclical changes, which were related, in part, to the patterns of recruitment of certain major taxa following spawning.

Submarine caves with sulphurous springs at Cape Palinuro, Campania, Italy, have a richer fauna than expected from the known oligotrophic nature of the cave habitat. Warm water containing sulphide issues from springs and rises above the cooler ambient sea-water with a sharp thermocline/chemocline between. The warm water then escapes from the caves mixed with cooler sea-water, probably inducing an inflow of ambient sea-water. Bacterial mats, often dominated by large species of attached bacteria resembling Beggiatoa, line the upper parts of the inner caves and act as primary producers, fixing CO2 by means of the autotrophic enzyme ribulosebisphosphate carboxylase. Many of the animals in the innermost parts of the caves live close to the chemocline or just below, where they would experience fall-out of bacterial organic matter, and some carry filamentous bacteria on their tubes and hard parts. Dominant members of the community include sponges, cnidarians, and tubicolous polychaetes.

A short research cruise was planned to trace the movement of a discrete body of water in the subtropical eastern North Atlantic Ocean. A subtropical ring or deep eddy called STORM was found budding off the Subtropical Front (STF) south-west of the Azores. A physical, chemical and biological survey to depths of 3·5 km was made of this 400 km scale body of water which was spinning cyclonically (anticlockwise). The azimuthal transport or the amount of water swirling in the eddy was 45 Sv. Storm was ‘hooked’ with ten drogued Argos buoys and a further five subsurface Alace floats were deployed. Storm is moving westward at ~3 km a day and is expected to reach the Mid Atlantic Ridge in rather less than a year unless it is destroyed by typography or reabsorbed into the Azores Current. With current technology, Storm's evolution and westward progress can be observed and analysed remotely, at a distance of ~3000 km in the laboratory. Realtime position data means that future sea surveys can be planned.

Monthly samples retrieved from the previously unstudied Plym Estuary, from January 1994 to November 1994, were analysed for living and dead Foraminifera. An assemblage composed of three hyaline species; Haynesina germanica, Elphidium williamsoni and Ammonia beccarii var. batavus, was identified. Further samples were taken to assess depth distribution, microdistribution and lateral distribution, to compliment the original sample suite. A comparison of the dead assemblage to the live assemblage revealed similar species proportions in both assemblages, reduced test abundance in the dead assemblage, and the presence of rare estuarine and marine species in the dead assemblage. This study has revealed a complex interplay of species resulting in several foraminiferal blooms throughout the year; the largest occurring in May.

Microzooplankton from water samples collected from depths of between 10 and 50 m at four stations between 47° and 60°N along the 20°W line of longitude during each of three cruises were classified into taxonomic groups and measured to estimate their abundance and biomass. Metazoan members of the microzooplankton were rarely found and their overall biomass was negligible in comparison with protists. The mean numbers of protistan microzooplankton cells >15 μn ranged between 3 and 11 cells ml-1, with mean biomass values between 2 and 14 μgC 1-1. Numbers and biomass increased towards midsummer and then decreased again, except at the most northerly station where the values were highest in the early August sample. The ratio of dinoflagellate to ciliate biomass tended to increase through the summer to levels of three or four and then decrease again, with later changes further north; this ratio also tended to be higher at deeper levels than in the mixed layer. Gymnodinioid forms usually dominated dinoflagellate numbers and biomass, but they were overshadowed by Protoperidinium and others at the two southern stations in June and July samples. Strombidium species were the dominant ciliates, commonly providing 25–50% of total microzooplankton biomass, while predatory haptorid ciliates were occasionally numerous, but tintinnids never formed more than 10% of the biomass.

In the Bay of Seine (English Channel) the polychaete Pectinaria koreni exhibits interannual stability in its abundance, despite its isolated distribution and its bentho-planktonic life cycle. To test the hypothesis of a high level of recruitment related to high survival rate of the post-larvae due to metamorphosis in the water column (transformation of metatrochophore into aulophore), we undertook a study of the morphology and the dynamics of the aulophore stage during May and June 1987. The morphological study snowed that aulophore larvae do not possess all the morphological features needed for benthic life on their first contact with the substratum. Fifteen days are needed to complete this development, and during this time the mortality rate is high. The possible role of this delayed metamorphosis on the transport of aulophore larvae towards sites favourable to adults is also discussed.

A testate amoeba with organic test, isolated from sediments in the Firth of Clyde, Scotland, has been assigned to a new genus as Ovulina parva (Protista: Filosea) based on its unique light microscopic and fine structural morphology. The hyaline to amber test is ovate (~15×ll µm) with a terminal aperture that is either unadorned or with a shallow collar. Hyaline, long-tapering, pointed, sometimes branched, pseudopodia emerge directly from the aperture or from the periphery of a thin web of hyaline cytoplasm. The nucleus (~5 μm) with a central nucleolus (~2 μm) is located at the posterior of the cytoplasm. The fine structure of the test, examined by scanning and transmission electron microscopy, shows it is entirely organic with an irregular to granular surface. Scattered elongate pits (~1 μm long) without perforations are distributed irregularly on the surface. Ectoplasm is distributed within a fine fibrillar envelope lining the test. The endoplasm is ovoid and contains anteriorly located vacuoles enclosing densely-staining bodies with chromatin-like filaments which appear to be bacterial prey in late stages of digestion. This is further corroborated by light microscopic observations that bacteria are cleared from the surface of the culture dish within the circumference of the pseudopodia. The mitochondria (0.5–1.0 μm) have tubular cristae and some are located in the vicinity of peroxisomes (~0.5 μm) surrounded by a single membrane and with a finely granular matrix. Minimum doubling time in our cultures was 28.4 h, and the testate amoeba exhibits remarkable salinity tolerance growing in media ranging from 0 to 35% salinity.

The lipid class and fatty acid composition of eight geographically disperse isolates of Emiliania huxleyi, grown under 12 h L:D cycles and harvested during logarithmic and stationary growth phases, were examined. Cell size and chlorophyll content tended to decrease from logarithmic to stationary growth phase, Methyl and ethyl ketones were the dominant lipid classes, although proportions exhibited no clear pattern either between strains or growth phases. Neutral lipid hardly accumulated over the course of the growth experiments, and triacylglycerol was either absent or only present at low levels. In all strains with the exception of a South African isolate, levels of total fatty acid per cell decreased markedly between logarithmic and stationary phases, primarily attributable to reductions in the levels of saturated and monounsaturated fatty acids. Major fatty acids in all strains during both growth phases were 14:0,16:0,18:1 (n-9), 18:4 (n-3), 18:5 (n-3) and 22:6 (n-3). Although all strains were rich in polyunsaturated fatty acids (47–72% of total fatty acids) stationary phase cultures consistently contained the highest proportions. The polyunsaturated fatty acid docosahexanoic acid (22:6, n-3) was the most abundant fatty acid in all strains, comprising a maximum of 38·4% of total fatty acids in strain M 181 during stationary phase. Multivariate analysis (PCA) allowed logarithmic and stationary phase cultures to be distinguished although no obvious intra-isolate variability was apparent. The results are discussed in terms of the importance of lipids for the ecophysiology of E. huxleyi and the role of this dominant coccolithophore in the marine food chain.

A new species of sponge, belonging to the genus Delectona, has been observed in the scleraxis of Corallium rubrum from three Mediterranean banks (Alboran, Elba Island and Bosa Marina). The species, described here as Delecfons ciconiae, shows a spicular complement composed of spiny rhabds, very irregular in shape and size, whose derivation from amphiasters has been suggested; toxiform centrotylote oxeas; slender, irregular amphiasters and subcircular or ovoid rough discs. The taxonomic position of this species, within the Clionidae, has been discussed.

Metazoan meiofauna were studied in replicated multiple-corer samples obtained at a bathyal site (1320–1360 m depth) in the Porcupine Seabight (51°36′N 13°00′W) before (April) and after (July) the delivery to the seafloor of a phytodetrital pulse originating from the 1982 spring bloom. In all samples the metazoan meiofauna was dominated by nematodes; harpacticoid copepods and their nauplii were the second most abundant taxon. Population densities and biomass were very similar in both sample sets, the only significant differences being in the numbers of ostracods (higher in April) and nauplii (higher in July). Furthermore, vertical distribution patterns in the top 5 cm of sediment indicate that the meiofauna did not migrate towards the sediment surface following the phytodetrital pulse. The lack of a metazoan meiofaunal response contrasts with published evidence, based on the same samples, for a substantial increase in the foraminiferal abundance following the sedimentation event. Thus our results suggest that metazoans (as a whole) fail to exploit and utilize phytodetritus as rapidly as foraminifera. This probably reflects the energetic expense of egg production coupled with frequently slower rates of somatic growth among metazoans. In addition, foraminifera may outcompete metazoans for detrital food because they possess extremely efficient food-gathering organelles (granuloreticulate pseudopodia) and are able to raise their levels of metabolic activity very rapidly. However, metazoan responses at the species level, or over longer time periods (>3 months), would not have been detected and so remain a possibility.

Pectenogammarus planicrurus Reid (Crustacea: Amphipoda) is an inhabitant of unstable gravel beaches. The reproductive output of females of this species was studied at Aberystwyth, on the west coast of Wales. There was marked seasonal variation in the size of eggs: the mean volume of eggs at an early stage of embryonic development ranged from 0·023 mm3 in summer to 0·030 mm3 in winter. Egg size was negatively related to brood size, but seasonal variation in brood size was greater than could be accounted for by egg size alone. Mean brood size ranged from 1·4 eggs in winter to 5·9 eggs in summer. Brood size was also strongly related to female body size, ranging up to 14 eggs in a large female. These findings are discussed in relation to adaptation to interstitial living in coarse intertidal gravels. A model of seasonal variation in reproductive output is suggested in which the importance of point reproductive output is related to the probability of females surviving to produce subsequent broods.

A new Myxillidae species from the Strait of Gibraltar, Myxilla tarifensis, is described. It is easily distinguished by a characteristic irregular isodictyal reticulation of acanthostyles which are smooth or slightly spined at the heads, as well as by strongyles as ectosomical megascleres, sometimes with very small and short spines at the ends. Moreover, the recent synonymization of the genera Dendoryx, Burtonanchora and Pseudomyxilla is accepted. A brief diagnosis is given of the Myxilla species found in the Strait of Gibraltar.

A biometrical study was conducted on two common cnidarians: Alcyonium digitatum (Octocorallia) and Urticina felina (Hexacorallia). The aim was to relate both the carbon and the nitrogen content of these species to a simple and rapid measurement. As the simplest measurement that can be done on A. digitatum is a measurement of size, relationships were determined between the height of a colony and its organic carbon (OC=0.0002 H2.0254, n=104, γ2=0·923) and nitrogen (N=0.00004 H2.0283, n=104, γ2=0.928) content. As no constant size could be determined on sea anemones, linear relationships were established between dry weight (DW) and organic carbon (OC=0.419 DW, n=65, r=0.995) and nitrogen (N=0.095 DW, n=65, r=0.997) content in U. felina. All these relationships were highly significant (P<0.1%) and appeared useful to express biomass of the two species in terms of carbon or nitrogen and then to consider dynamic processes such as respiration or excretion as fluxes of carbon and nitrogen.

The sublittoral off central Chile represents a dynamic border separating an oxic surface equatorward current and an oxygen-poor poleward undercurrent. This investigation dealt with whether megafaunal assemblage structure and its temporal and bathymetric distribution were affected by this feature. The problem was approached by investigating the empirical relations between an assemblage index of abundance and physical factors of the environment. The megafauna off Conceptión Bay, central Chile (36°32′S) was thus sampled with an Agassiz trawl on eight cruises performed during 1991 and 1992 at three fixed stations (40, 64 and 96 m depth). Simultaneous reference samples of sea-water were taken to measure temperature, salinity, and dissolved oxygen. Descriptive assemblage attributes, diversity indices, and principal component analysis (PCA) for assemblage study were used. Moreover stepwise linear regression, with the first principal component of the specific abundance matrix as dependent variable was used to study relationships between temperature, salinity and dissolved oxygen and an assemblage of 23 species. Species richness, biomass and abundance decreased significantly with depth while diversity was highest in the intermediate depth station. Discontinuities were thus evident between the shallow, intermediate and deep stations. The grouping of samples in the plane formed by the first and second principal components showed a similar bathymetric discontinuity. In the Euclidian plane, a seasonal cycle of variation of the shallow sampling site was evident. Between 46 and 64 m depth lies a boundary separating different states of the same assemblage, the shallow seasonally variable and the deep constant. The intermediate station shares characteristics of both these stations reflecting a more variable environment. The overall bathymetric and the shallow seasonal patterns of variation were statistically linked to dissolved oxygen.

Bivalve spat were grown in an on-shore upwelling nursery using a landlocked heliothermic marine basin (Norwegian oyster-poll) as a food production system and thermal source. Several manipulations, involving artificial fertilization (N, P and Si), were performed in order to enhance the production capacity. Based on data from a monitoring programme (May-August) on physical, chemical and biological variables in the system, main paths of nitrogen flow and dynamics of bivalve production and nitrogen conversion efficiency were described. The conversion efficiency of the system, bivalve N production over estimated new N, of which 86% was fertilizer nitrogen, was 16·2% for the experimental period of 93 days. During this period the decrease in efficiency from levels of 22–25% to 8% was probably due to the transition from nitrate-limited to light- and grazing-limited phytoplankton production. The food utilization efficiency, bivalve N production over available particulate N in the nursery, was 19·8% for the experimental period. The efficiency increased in July from 19·4% for the first two weeks to 27·0% during late July. This was probably due to a higher food value of the phytoplankton community in late July, dominated by Skeletonema costatum (Bacillariophyceae) and Nitzschia sp., than the phytoplankton community in early July, dominated by Fragilaria sp.

The natural feeding of the two most abundant ommastrephid squid (Cephalopoda: Ommastrephidae) in Galician waters was studied and compared. A sample of 334 stomach contents of Todaropsis eblanae (34–222 mm ML) and 267 stomach contents of Illex coindetii (50–379 mm ML) caught by commercial trawlers was examined. A total of 21 (T. eblanae) and 23 (I. coindetii) different prey items, belonging to three zoological groups (Teleostei, Crustacea and Cephalopoda), were taken by these cephalopods. However, 43% of the T. eblanae diet comprised only one fish species, Micromesistius poutassou. The diet of these squid species was significantly influenced by the geographical area (both species), size (T. eblanae) and maturation (I. coindetii). Feeding rate of both species decreased with size, but the percentage of stomachs with food remains increased in maturing and mature females. Weight of prey captured was dependent on available prey sizes and, in small individuals, maximum prey weight was very close to the squid weight. Both squid species are mainly neritic nekto-benthic predators, but I. coindetii seems to have a broader and more pelagic diet.

This paper discusses a number of biological aspects, concerning a new sea anemone species (Paranemonia vouliagmeniensis Doumenc et al., 1987 ) (Actiniaria: Anthozoa), discovered in Lake Vouliagmeni, near Athens, Greece. The specialized environment of the lake, with elevated and stable temperatures throughout the year, brackish waters and large mineral content presents a very specialized biotope in which Paranemonia wuliagmeniensis is an important member. Certain aspects of its life cycle were investigated, especially population structure, feeding habits and life history. The population was found to be made up of two sub-populations; one established on algae in deeper parts of the lake, and an older one living on gravel in shallower habitats. Feeding preferences depended on the anemone's ability to catch prey, combined with the composition of the prey. The anemone was also found to be viviparous and demonstrated r-characteristics in its life history (short lifespan and large number of embryos).

Two types of electron-dense inclusions are described using transmission electron microscopy from the marine nematode Tripyloides marinus (Nematoda; BÜtshli, 1874) isolated from a metal-enriched site and a site of low metal contamination. These were classified as granular, intracellular inclusions in the intestinal syncytium, and fluid-filled vesicles along the cuticular margin of the epidermis. Energy-dispersive x-ray analysis (EDX) showed that the intestinal granules were largely comprised of P and S, with variable levels of Ca, Cu, Zn, Fe and Br, and that the epidermal vesicles contained high levels of Br and S with variable levels of Ca, Cu, Zn, Fe and P. It is suggested that intestinal granule formation may be involved in the detoxification of heavy metal sulphides and might result in a heightened ability of the species to colonize metal-enriched sediments. The function of the cuticular vesicles is unclear, but might be linked to a predatory or microbial defence mechanism (Woodin et al., 1987), or as part of a metal detoxification system.

The size distribution of benthic nematodes was investigated along different gradients of food availability in various regions of the north-eastern Atlantic: I, across the continental margin and II, with increasing distance from the continental rise. An overall trend for miniaturization with increasing distance from the food source was found. Moreover, our results indicate that seasonally varying food supply or a periodically pulsed input of organic matter to the sea floor affects nematode size spectra. The hypothesis is proposed that the life cycle of deep-sea nematode species and hence the size structure of their populations are related to seasonal energy availability. This dependence might result in one year life spans of deep-sea nematodes and probably other meiofauna.