1. The data for five planktonic taxa sampled during the SOND cruise (autumn 1965) by R.R.S. ‘Discovery’ in a day and a night series of horizontally towed nets have been analysed by factor and cluster analyses.

2. The factor analyses of hauls showed that there were five biologically distinct zones in the water column between the surface and 1000 m. The zones were more distinct in the day series than in the night.

3. Factor analyses of the individual taxa gave sensible groupings of species and the factor score plots gave ‘averaged’ depth distributions for each group.

4. Cluster analyses of the individual taxa gave results consistent with the factor analyses. Both methods gave groupings which fitted the zonation patterns of the hauls, except for the two zones between 100 and 460 m at night.

5. Only cluster analyses could be carried out on the total data matrices. Although satisfactory interpretation was only possible with the aid of the analyses of the individual taxa, the zonation and species groupings were again largely retained.

6. The zonation of the planktonic taxa is shown to be very similar to that described for nektonic species sampled on the same cruise.

7. The usefulness of these analytical methods is compared with the conclusions of other investigators. It is concluded that the rotation of the matrices to simple structure in the factor analysis gave a marked improvement in the ease of interpretation.

8. For this data, principal component analyses gave very similar results to the full factor analyses.

Moult increments, annual moult frequency and hence annual growth were determined from suture-tagged edible crabs (Cancer pagurus L.) released and recaptured off Devon, Cornwall, and Dorset.

The average moult increments of males and females at a premoult carapace width of 100 mm were similar; at larger sizes the average moult increment of females was considerably less than that of males. Annual moult frequency of C. pagurus in south-west England decreased with increase in size, females more so than males.

As a result of the smaller moult increments and lower moult frequency of females, their annual growth is considerably less than that of males. This appears to be the result of three aspects of sex and reproduction: (1) reduction in moult increments, probably as a result of competition for nutritive resources between egg production and body growth; (2) the interruption of the moulting cycle by successive annual spawnings from a single impregnation at the previous moult; and (3) accentuation of the larger increments in weight at moulting of male crabs due to the allometric growth of their chelae. A consequence of the higher growth rate of males is the presence of very large male crabs – a distinctive feature of the population structure of the stock off south-west England.

The growth of C. pagurus in south-west England was compared with published data for stocks off the east and north-east coast. Moult increments were similar for both areas, but there were considerable differences in the moult frequencies. In the south-west, males moult more frequently than females; the opposite is the case for the east and north-east crab stocks. A valid reason for this difference has not yet been established.

The partitioning and utilization of energy reserves during embryogenesis were followed in the cirripede Balanus balanoides and related to the described sequence of developmental stages. Egg volume and dry weights were measured. Between the recently fertilized egg and eggs containing well-developed embryos at the end of natural incubation there is a doubling of egg volume.

The biochemical composition of the newly fertilized egg is dominated by TCA-insoluble protein (55 %). Neutral lipid accounts for 17 % of the dry weight, while phospholipid and polysaccharide contribute 3–5% and 5–7% respectively. About 36% of the TCA-insoluble protein is utilized during in vivo development, accounting for about three-quarters of the energy expenditure. During this time 40% of the carbohydrate and 20% of the neutral lipid reserves are also utilised. However, when starved adults retain their mature egg masses beyond the normal term, egg metabolism occurs largely at the expense of the remaining lipid reserves. These would be exhausted in a further 6–7 weeks and the embryos unable to survive. The ability of adults to postpone hatching may therefore have important implications for the energy reserves and viability of the newly hatched nauplii. Protein supplies most of the energy during embryogenesis, with neutral lipid assuming increased importance after development has been completed.

Oxygen consumption of the egg masses measured in vitro was converted through aerobic oxycalorific equivalent into biochemical loss. This showed good agreement with direct measurement of summed energy losses of the biochemical components. It was apparent that oxygen uptake rate in the later stages was restricted by diffusion resistance due to egg packing, since eggs freed from the egg mass matrix showed a 30% increase in oxygen uptake and a reduction in development time.

The annual variations in body-size spectra of planktonic ciliate communities and their relationships to environmental conditions were studied based on a 12-month dataset (June 2007 to May 2008) from Jiaozhou Bay on the Yellow Sea coast of northern China. Based on the dataset, the body sizes of the ciliates, expressed as equivalent spherical diameters, included five ranks: S1 (5–35 μm); S2 (35–55 μm); S3 (55–75 μm); S4 (75–100 μm); and S5 (100–350 μm). These body-size ranks showed a clear temporal succession of dominance in the order of S2 (January–April) → S1 (May–July) → S4 (August–September) → S3 (October–December). Multivariate analyses showed that the temporal variations in their body-size patterns were significantly correlated with changes in environmental conditions, especially water temperature, salinity, dissolved oxygen concentration (DO) and nutrients. In terms of abundance, rank S2 was significantly correlated with water temperature, DO and nutrients, whereas ranks S4 and S5 were correlated with the salinity and nutrients respectively (P < 0.05). These results suggest that the body-size patterns of planktonic ciliate communities showed a clear temporal pattern during an annual cycle and significantly associated with environmental conditions in marine ecosystems.

The Purbeck Marine Wildlife Reserve lies within the boundary of the Dorset and East Devon World Heritage Site on the south coast. This study investigated the influence of visitors on intertidal biodiversity at Kimmeridge Bay, the only accessible part of the reserve. The assemblages present on two rock ledges were compared: Washing Ledge, which is regularly visited and utilized by people, and Yellow Ledge, which is more isolated and visited much less regularly. At each ledge, three habitat types were investigated: open rock, rockpools and the fucoid zone. Multivariate statistical analysis revealed significant differences in assemblages between ledges and among habitat types. The differences observed in the communities of the two ledges can be explained to some extent by natural ecological processes, but human impacts were also detected. The most obvious contrast associated with trampling was a reduction in the larger, branching species of algae and an increase in ephemeral and crustose species in the more heavily utilized areas.

Seasonal variations in feeding physiology and scope for growth of green mussels Perna viridis (Bivalvia: Mytilidae) were investigated in Ma Wan, an estuarine mariculture site located in the southern waters of Hong Kong. Total particulate matter, particulate organic matter, particulate inorganic matter and organic fraction of seston (f), and food availability were monitored monthly from January to December 1998. Feeding rates, including clearance rate, filtration, ingestion and absorption, and absorption efficiency were higher in summer and autumn and lower in winter. Pseudofaeces were produced but the preferential selection of organic materials by P. viridis was not concluded. Scope for growth in  July and October were higher than in February. Activities of digestive enzymes including amylase and cellulase in the digestive diverticula and crystalline style were high in May and July and lower in February and October and correlated with f. Faster growth rates obtained for P. viridis in Hong Kong's summer are considered a result of enhanced feeding and absorption at high temperatures and f values.

The jumbo flying squid, Dosidicus gigas, support an important squid fishery off the Exclusive Economic Zone of Chilean waters. However, we only have limited information about their biology. In this study, age, growth and population structure of D. gigas were studied using statoliths from 533 specimens (386 females and 147 males) randomly sampled in the Chinese squid jigging surveys from 2007 to 2008 off the Exclusive Economic Zone of Chile. Mantle lengths (MLs) of the sample ranged from 206 to 702 mm, and their ages were estimated from 150 to 307 days for females and from 127 to 302 days for males. At least two spawning groups were identified, the main spawning peak tended to occur between August and November (austral spring group), and the secondary peak appeared during March to June (austral autumn group). The ML–age relationship was best modelled by a linear function for the austral spring group and a power function for the austral autumn group, and the body weight (BW)–age relationship was best described by an exponential function for both the groups. Instantaneous relative growth rates and absolute growth rates for ML and BW did not differ significantly between the two groups. The growth rate of D. gigas tended to be high at young stages, and then decreased after the sub-adult stage (>180 days old). This study suggests large spatial and temporal variability in key life history parameters of D. gigas, calling for the collection of more data with fine spatial and temporal scales to further improve our understanding of the fishery biology of D. gigas.

Opportunities for measurements on living Nautilus are rare, and such studies as there have been on its locomotion tend to treat it as primitive compared with modern cephalopod molluscs. But the few measurements we were able to make on a healthy captive Nautilus living for several months in the Monaco Aquarium reveal considerable sophistication in the control of swimming - particularly in the way the funnel operates - and that the system possesses neuromuscular properties that may be fundamental to cephalopods as a whole. The use of the shell for transmitting the pressure pulse and for the in- and out-movements of the body during jetting are, however, peculiar to this member of the group.

Although anaesthetic techniques are well established for most of the vertebrates, methods for the invertebrates are generally not well documented. The decapod Crustacea are widely used for neurophysiological studies involving the implant of chronic electrodes and other techniques. With sluggish species such as Cancer pagurus some workers simply give the animal an object to grasp and perform their operations in the unanaesthetized condition. Others use hypothermia to immobilize their animals, although this may result in autotomy of appendages. Other methods include immersion in solutions of ethanol, magnesium salts (Pantin, 1946), or carbon dioxide. Conventional aquatic vertebrate anaesthetics such as MS-222 (Sandoz) are generally ineffective by immersion in decapods. This short investigation has set out to find out if a suitable anaesthetic drug is available for experimental work and for live dissections.

Meiobenthic community structure was investigated at different spatial scales (from 100 metres to centimetres) on and adjacent to a group of coral-topped sandy mounds in the bathyal north-east Atlantic (Darwin Mounds, Rockall Trough) and related to the environmental conditions in the area, mainly differences in sediment organic carbon content and presence of biogenic structures. Meiobenthos abundances were similar to those observed in other deep-sea sites, with nematodes representing at least 94% of the total community. The dominant nematode genera were Microlaimus, followed by Sabatieria, Richtersia, Rhynchonema and Trefusia, together with typical deep-sea genera (e.g. Halalaimus and Acantholaimus). Multivariate analysis of nematode generic relative abundances at the different stations indicated that there was no significant influence on distribution resulting from large scale topographic and biogeochemical conditions around the mounds. The same genera were associated with dead tests of the xenophyophore Syringammina fragilissima and in the surrounding sediments. The vertical distribution of nematodes on and adjacent to the mound showed some unusual features, as the deeper layers of the sediments were inhabited by stilbonematids. These genera harbour ectosymbiotic, chemoautotrophic bacteria and have not previously been recorded from the deep sea. The occurrence of stilbonematids in notable numbers in the subsurface layers of the sediments in the vicinity of the Darwin Mounds provides evidence for the occurrence of anoxic microenvironments.

1. The most noticeable response of marine plankton to light, under laboratory conditions, is the formation of groups on the lighted (or opposite) side of the vessel containing them.

2. Specimens from such groups were tested under different conditions of illumination, and in all cases they moved in the direction of the light quite irrespective of accompanying changes of intensity in the surroundings.

3. Groups form around the line of direction of the light, or the resultant direction when the light is scattered or falling from more directions than one, this being the direct result of individuals moving along the mean path of incidence of the light.

4. The behaviour of individuals was examined more closely to distinguish between the two possible ways in which the directed movement could have been brought about, viz. (i) reactions to bilateral inequalities of illumination (here called “true topotaxis”), and (ii) reactions to changes in total illumination of light-receptors (a type of “phobotaxis”). For a number of species it was clearly a case of “true topotaxis,” and very probably for at least the majority of the rest.

5. In two very different cases, namely, Acartia clausi and Poecilochaetus serpens, there was no orientation of the body, but nevertheless efficient orientation of the path of movement. It is believed that this is the first occasion on which such behaviour has been described.

6. The observations described point to the fact that movement in the direction of incidence of the light, however this may be affected, is general among a wide range of the smaller, free-living, bilaterally symmetrical, marine animals, and would tend to dominate other possible response to light. This behaviour on the part of individuals provides a substantial basis for attempted explanations of the correlations, that have been demonstrated by ecological workers, between the vertical distribution of populations and light-intensity.

The micro-erosion patterns of some sponge species belonging to the boring genera Cliona and Aka have been compared. The scanning electron microscope analysis of the excavations of species of the two genera sharing the same substratum clearly indicates that the scars produced on the walls of the boring chambers are different. The pits of Cliona are regular, almost circular and smooth; those of Aka are more irregular and show a multi-layered concentric pattern. These differences constitute a successful means of distinguishing the bio-erosion agents both in recent and in fossil substrata.

The process of moulting in Pseudoprotella phasma is described. Sixteen instars have been found with a discontinuity in growth at the third stage. The instar lengths differ by a common ratio of 1·169 in the male and 1·148 in the female, the animals becoming differentiated at the twelfth stage. There are no secondary sexual characteristics except the brood pouch. The growing parts display simple positive allometry. The growth rates of the chelae and antennae alter after stage XII but remain the same in the third body segment. Changes in shape in the chelae, antennae and spinous armature are described.

The macrofauna of molluscs associated with soft bottoms in the Bay of Cádiz (southern Spain) was studied monthly from February 1994 to January 1996. The number of species (63) is high for a soft bottom and is related to environmental characteristics (growth of macrophytes) and the biogeographical setting of the studied area. Corbula gibba (∼90%) was the dominant species in this taxocoenosis together with the gastropod Nassarius pygmaeus and the bivalves Pandora inaequivalvis, Parvicardium exiguum and Macoma melo. The most frequent species during the two years was also the bivalve Corbula gibba (100%) followed by the gastropods Nassarius pygmaeus, Tricolia tenuis, Rissoa membranacea and the bivalve Macoma melo. Total abundance of the taxocoenosis in both years reached higher values in spring. The dynamics of the ecological indices such as diversity or evenness, and the species richness showed a similar pattern in both years, with low values of diversity and evenness together with high species richness in spring and summer months and the reverse in autumn and winter. The qualitative correspondence analysis of monthly samples shows an ordination related to seasonality in both studied years, however the values of Jaccard's coefficient do not indicate significant boundaries among the monthly samples. The quantitative correspondence analysis shows an ordination and grouping of samples related to the biology of species, particularly with the recruitment of C. gibba, the dominant species. The existence of similar trends in the structure of the taxocoenoses over both years, and the seasonality highlighted by the qualitative correspondence analysis, seems to indicate a certain stability of the ecosystem.

Cytological and biochemical changes in the digestive gland of Pecten maximus throughout a one-year period were investigated in the Bay of Brest (France) relative to lipid storage and glycogen and α-amylase concentrations in tubuloacinar terminations. Seasonal variations in both cell structure and biochemical composition were observed. These changes were independent of the tidal cycle, but correspond to phytoplankton abundance. From November to January, cells of digestive acini were hypertrophied due to the high lipid storage. From February to May, these reserves were markedly reduced, cell size decreased, and the acinar lumen was clearly apparent. From May to September, the RNAs transcribing for α-amylase increased, and a correlation was found between digestion events and lipid storage in acinar cells. The relationships between metabolite transfers from digestive gland to gonad and other tissues are described. Distinct lipid storage sites appear to be associated with maintenance energy and acute demand energy, such as gametogenesis when adductor muscle reserves have been depleted. The digestive gland may thus function as a relay organ during periods of energetic stress, notably during the first gametogenesis in February and March and for shell growth in early spring.

The emergence of metagenomics-based approaches in biology has overcome historical culture-based biases in microbiological studies. This has also enabled a more comprehensive assessment of the microbial ecology of environmental samples. The subsequent development of next-generation sequencing technologies, able to produce hundreds of millions of sequences at improved cost and speed, necessitated a computational shift from user-supervised alignment and analysis pipelines, that were used previously for vector-based metagenomic studies that relied on Sanger sequencing. Current computational advances have expanded the scope of microbial biogeography studies and offered novel insights into microbial responses to environmental variation and anthropogenic inputs into ecosystems. However, new biostatistical and computational approaches are required to handle the large volume and complexity of these new multivariate datasets. While this has allowed more complete characterization of taxonomic, phylogenetic and functional microbial diversity, these tools are still limited by methodological biases, incomplete databases, and the high cost of fully characterizing environmental biodiversity. This review addresses the evolution of methods to monitor surface waters and characterize environmental samples through the recent computational advances in metagenomics, with an emphasis on the study of surface waters. These new methods have provided an abundance of opportunities to expand our understanding of the interaction between microbial communities and public health. Specifically, they have allowed for comprehensive monitoring of bacterial communities in surface waters for changes in community structure associated with faecal contamination and the presence of human pathogens, rather than relying on only a few indicator bacteria to direct public health concerns.

The Haptophyta comprises a group of microalgae of particular importance in marine habitats, often occurring in ‘bloom’ concentrations, sometimes with devastating effects where the bloom is composed of species toxic to other forms of life. The most familiar species are the coccolithophorids, unicellular organisms encased in calcified scale-like structures, the coccoliths, which are readily preserved in marine sediments and have for a long time been important indicators in micropalaeontological studies. In the middle of this century it was recognized that there was a need to compile and standardize the terminology used in coccolith morphology (Braarud et al., 1955; Halldal & Markali, 1955). This approach was continued by several authors (e.g. Hay et al., 1966; Okada & McIntyre, 1977; Tappan, 1980; Perch-Nielsen, 1985) in published articles, and in the report from a Round Table session at the Rome 1970 Plankton Conference (Farinacci, 1971), which included terms from both fossil and extant taxa. Over the last two decades many new terms have been introduced as observations on coccolith morphology have improved through the use of the electron microscope, and recent glossaries covering various aspects of haptophyte terminology have been published by Heimdal (1993), Kleijne (1993) and Margulis et al. (1993).

In aquatic food webs zooplankton constitutes an important link between primary producers and higher trophic levels. Copepods often dominate the zooplankton in coastal oceans and are the prey of the majority of planktivorous fish. Feeding behaviour, as well as the food quantity and quality are recognized factors that affect copepod growth, and therefore, the energy transfer efficiency throughout food webs. The natural occurrence and magnitude of these growth factors and their combined effects on marine copepods, as keystone grazers in the pelagic marine realm, are poorly understood. Here, we assessed how these different factors vary throughout the year, and then examine their relative influence upon copepods maximal growth rates. A multiple regression model, including all variables previously selected, and the inclusion of the sea temperature allowed us to estimate the pure influence of the studied factors, and the environmental effect on copepod growth rates. The results imply that ingestion of diatoms may induce a positive effect on specific growth rates of copepods, and the quality of this food item (high PUFA and HUFA availability) might explain such effect. Therefore, seasonal variability in diatom abundance, possibly driven by changes in the oceanographic regime, should be considered a critical factor controlling copepod growth in productive coastal ecosystems.

The white-beaked dolphin (Lagenorhynchus albirostris) and short-beaked common dolphin (Delphinus delphis) are two of the most abundant delphinid species in shelf waters around the United Kingdom (UK) and Republic of Ireland (ROI) in the summer season (May–October). As these two species have similar habitat preferences and diets, it might be expected that they would partition their otherwise shared niche to reduce the potential for competition at this time of year. This study used 569 sightings of the two species, collected from shelf waters (<200 m water depth) in the summer season between 1983 and 1998, to investigate whether there is evidence of widespread niche partitioning based on water temperature in this area. Below 13°C, white-beaked dolphins were dominant with 96% of sightings comprising this species. In contrast, above 14°C, 86% of sightings comprised common dolphins. A classification tree analysis found that of the four eco-geographical variables analysed (water depth, seabed slope, seabed aspect and sea surface temperature), temperature was the most important variable for separating the occurrence of the two species. These results are consistent with widespread temperature-based niche partitioning between white-beaked and common dolphins in shelf waters around the UK and ROI. As temperature is important in determining the relative distribution of these species, the range of the white-beaked dolphin might be expected to contract in response to increasing sea temperature resulting from global climate change, while that of the common dolphin may expand.

The range of temperatures over which the cirri were active and the frequency of beating at different temperatures were measured in four species of barnacles collected on the southern and south-western coasts of France. The extremes of high temperature at which the animal remained irritable or could survive were assessed in these species and in a further group of species from Trinidad, West Indies.

The results are discussed in comparison with previous evidence for species of more northern distribution, and related to the geographical range of the species and the ecological niche occupied. For example, the brackish water species, Balanus eburneus and B. improvisus, have similar patterns of cirral activity, but the greater tolerance of high temperatures shown by the former is obviously connected with its more tropical distribution. Differences in temperature tolerances of varieties of JB. amphitrite from Europe and Trinidad, possibly related to differences in the tide levels at which they live, tend to reinforce their separation on morphological grounds. More pronounced differences between Chthamalus depressus and C. stellatus confirm the separation of these two species which were formerly regarded as varieties. The relatively lower rate of beating of C. depressus which is not found north of the Mediterranean and its greater tolerance of high temperatures compared with C. stellatus, may be related to its more southern distribution and its ability to live at very high levels on the shore. These two species and C. fragilis from Trinidad all show greater tolerance of high temperatures than the species of Balanus and Tetraclita, which are found at lower levels on the shore

It is concluded that in the North Atlantic area there may be only two main distributional groups of species of acorn barnacles, Arctic and Tropical, overlapping in the Temperate regions, with few or no intermediate forms, and that there is as yet no evidence for the existence of physiological races in these species.