A series of controlled, labelled feeding experiments were carried out on Neomysis integer in order to investigate its lipid metabolism. The techniques of thin-layer chromatography, preparative column chromatography, analytical and preparative gas-liquid chromatography and low-background 14C counting were used to follow the incorporation of a 14Clabelled fraction from a range of diets into the animal's lipid. Neomysis integer was found to be capable of converting dietary starch or short-chain saturated fatty acids to longchain polyunsaturated fatty acids, which were then incorporated into the TG and PL fractions.

Nephrops norvegicus (Linnaeus, 1758) is a valuable commercial shellfish species. UK landings in 1986 totalled 25,515 tonnes with a market value of over £39 million. It is difficult to estimate stock abundance using trawl surveys because of seasonal changes in the availability of females which tend to remain in their burrows whilst berried (ovigerous) (Chapman, 1980). An alternative method is to assess the number of mature adults in the stock using fecundity data and abundance estimates of larvae derived from plankton surveys (Thompson et al., 1986; Nichols et al., 1987). Estimates of the age of larvae are necessary to enable daily and seasonal production rates to be calculated from abundance data. Water temperature causes considerable variations in the development rate of planktonic Crustacea (Winberg, 1971; Thompson, 1982), and reliable estimates of larvae production therefore require knowledge of the relationship between stage duration and water temperature. This paper describes the results of laboratory experiments carried out from 1984 to 1986 to study this relationship in the three free-swimming stages referred to as zoea I-III by Farmer (1974). Stage IV is generally accepted as the first juvenile stage (Anger & Püschel, 1986). The morphology and general biology of Nephrops larvae are described by Farmer (1975) and Nichols et al. (1987); these authors comment on the scarcity of data concerning the effect of temperature on stage duration.

Ectocarpus distortus and E. landsburgii are shown to be conspecific and to constitute free-living ecads of E. fasciculatus. It is therefore recommended that the two should no longer be regarded as true species although it is pointed out that the specific epithet E. distortus may have priority over E. fasciculatus. If so, the entire complex, provisionally retained as E. fasciculatus, may have to be known as E. distortus. Meanwhile it is recommended that the list of British Ectocarpus spp. be reduced to two, namely E. fasciculatus and E. siliculosus.

Biofilm-dwelling protozoa are a primary component of microbiota and play important roles in the functioning of microbial food webs such as the mediation of carbon and energy flux from plankton to benthos in marine ecosystems. To demonstrate the vertical pattern of the protozoan communities, a 1-month baseline survey was carried out in coastal waters of the Yellow Sea, northern China. A total of 40 samples were collected using glass slides as artificial substrates at four depths: 1, 2, 3.5 and 5 m. A total of 50 species were identified, comprising seven dominant and eight commonly distributed species. Species richness and individual species abundances showed a clear decreasing trend down the water column from 1 to 5 m, although the former peaked at a depth of 2 m. Multivariate approaches revealed that protozoan community structure differed significantly among the four depths, except for those at 2 and 3.5 m. Maximum values of species richness, diversity and evenness generally decreased with depth although they peaked at either 2 or 3.5 m. These results suggest that water depth may significantly shape the community patterns of biofilm-dwelling protozoa in marine ecosystems.

The physiological response of ammonium-limited continuous cultures of Skeletonema costatum (Grev.)Cleve to steady-state and transient conditions was tested and compared to simulations with a Droop-type quota model and a four-state variable model (internal amino acid pool added to the quota model). External ammonium, free internal amino acids, protein, silicate and culture-cell volume were measured.

All cultures showed reproducible changes in growth and uptake kinetics due to spontaneous cell-cycle synchronization of the populations. Under steady-state conditions protein decreased with increasinggrowth rate from 82%; cell-nitrogen to 52% and free internal amino acids increased from 2·5% cell-nitrogen to 8%. Under transient conditions amino acids could reach 25% of cell-nitrogen.

A comparison of model and culture results yielded the following information: Both models could simulate steady-state and most transient conditions. The dependence of the quota on steady-state growth rate is not the result of changes in amino acid or protein pool size. The amino acid pool, an intermediary step in the nitrogen assimilation, does not serve to increase the time lag in growth response significantly. The four-state variable model reproduced under most conditions the behaviour of theamino acid pool without the use of feedback control mechanisms on the rate of uptake. The models could simulate a strong increase in growth rate except when it was initiated by impulse dilution of the culture. Then growth response was controlled by epigenetic mechanisms induction of enzyme synthesis). (6) The maximum nutrient uptake rate per culture cell volume of Skeletonema is inversely related to cell size.

Turbonilla elegantissima (Montagu), though one of the larger and more familiar members of the family Pyramidellidae, is known only by the shell and the appearance of the animal when crawling. Forbes & Hanley (1853) and Jeffreys (1867) state that it is common around the British Isles, and that its foreign distribution is from Tromsö to the Mediterranean. In the fauna list of the Marine Biological Association (1931) it is recorded as T. lactea (L.) ‘occasionally under stones, particularly where there is a certain amount of silt’ from low water to a depth of 10 fathoms, and, in the Salcombe estuary, ‘very common on the Zostera south of Pilworthy Pt., (Allen & Todd, 1900)’. Actually this opisthobranch has its own extremely specialized habitat, as do, apparently, all other members of its family (Fretter & Graham, 1949): like them it is an ectoparasite, restricted to the vicinity of its host. Specimens have been collected from the laminarian zone along the south coast of Devon and Cornwall, the largest number from Church Reef, Wembury, where silt and sand around boulders and between shale ledges provide suitable niches for such sedentary worms as Audouinia tentaculata and Amphitrite gracilis. When covered by the tide the tentacles of these polychaetes extend through the silt and sand and spread over the surface of the rocks for a considerable distance, and it is in the vicinity of these tentacles that Turbonilla lurks to suck liquids from them by means of a long proboscis (Fig. 1). Audouinia and Amphitrite were also recorded at Pilworthy Pt., but their association with Turbonilla was then unknown.

The rates of ingestion, egestion, ammonium excretion, and CO2 respiration of Tripneustes gratilla (Echinodermata: Echinoidea) from a shallow water embayment at eastern Mactan Island, central Philippines were examined. There was no significant difference in weight-specific feeding rate with the three macrophytes (Sargassum polycystum, Thalassia hemprichii, and Kappaphycus alvarezii). The power function equation, M=KWb fitted well with the weight-specific egestion rates ((r2=0·93), weight-specific CO2 respiration rates (r2=0·92) and ammonium excretion rates (r2=0·86). Weight-specific egestion rates, CO2 respiration and ammonium excretion were indirectly proportional to body weight. For weight-specific egestion rate (in μg DW faeces/g DW urchin-h), the regression coefficient, b and constant, K were −2·31±0·68 (mean±SE) (P=0·02) and 6359·55±5394·31 (P=0·29), respectively. The b and K for CO2 respiration were −1·28±0·48 (P=0·04) and 39·72±10·59 (P=0·01), respectively. For ammonium excretion, the b and K were −1·03±0·46 (P=0·11) and 262·51±56·89 (P=0·02), respectively.

An inventory of the main epibiont organisms on living specimens, on empty shells and on pagurized shells of Fusitriton magellanicus collected in Zygochlamys patagonica fishing grounds off Argentina is provided here. Additionally, considering that the presence of the thick, hairy periostracum could be an inhibitor of boring and encrusting species, we analyse the presence of a periostracum in living F. magellanicus in relation to the presence of epibionts. More than 70% of all shells bore encrusting organisms (of at least 30 taxa) but only a small proportion of shells was heavily fouled, the majority of living, empty and pagurized shells being lightly or moderately fouled. Polychaetes were the most common epibiont group (present on more than 60% of shells) while sponges and ascidians were responsible for the majority of the heavily fouled living gastropods. In general, specimens had a moderate level of encrustation and, simultaneously, a low or medium coating of periostracum. Hairy gastropods (only 14% of the sampled specimens) had few or no epibionts. A relationship between the size of the shell and the level of encrustation was only found in living gastropods. Fusitriton magellanicus is the second species in importance (after the Patagonian scallop) for the provision of a hard settlement substrate in the shelf-break frontal area of the Argentine Sea.

Nephtys pente sp.nov. is described. The species is known to occur in shallow waters from the western Baltic to Greenland. It may occur with Nephtys ciliata, which it closely resembles. An amended definition for N. ciliata is proposed. A key is provided for the northern European species of Nephtys.

The 1989 discovery of a large dorsal eye on the hydrothermal vent shrimp, Rimicaris exoculata, debunked the prevailing opinion that all animals living around deep hydrothermal vents were blind. Recent dives with DSV ‘Alvin’ recovered new bresiliid shrimp [Chorocaris (Lucky Strike) and Chorocaris (Broken Spur)] from two new vent fields on the Mid-Atlantic Ridge. The Lucky Strike species has recently been named Chorocaris fortunata and may be the same as the Broken Spur species - the retinal morphologies reported here are very similar. Like R. exoculata, C. fortunata has a visual apparatus adapted to the very dim light of its environment. Although in both species enlarged, non-imaging eyes appear to have evolved from the stalked compound eyes typical of caridean shrimp, those of C. fortunata are forward-facing whilst that of R. exoculata is located dorsally. The massive array of photosensitive membrane (rhabdom) of C. fortunata lies beneath a smooth cornea within a matt, white, reflecting matrix and occupies 80% of the available volume of the photoreceptors compared to the expected 10–15% of shallow water decapods. All screening pigment is located out of the light path at the bottom of the retina. There is no ultrastructural evidence for cyclic rhabdom shedding or renewal. Thus the cellular organization of C. fortunata is remarkably similar to that of R. exoculata and distinct from its surface-dwelling relatives. This suggests that in these species imaging optics have been sacrificed to achieve the increased visual sensitivity necessary to detect the very dim light emitted from the throats of the black smoker chimneys around which they live

All animals do not display the same capacities for repairing injuries, i.e. they possess what may be termed different ‘regeneration potentials’. One parameter influencing the regeneration potential manifested by an organism is its developmental history, or ontogeny. Early in an animal's ontogeny many of its cells are still undergoing both structural and biochemical modifications. As the animal matures, its cells become increasingly differentiated, ultimately attaining a high degree of specialization (Hay, 1966; Balinsky, 1970).

Numerous studies support the contention that the younger an animal ontogenically, the greater is its regeneration potential. Investigations using amphibians have presented several cogent examples of this generalization (Balinsky, 1970). Analogous situations are also evident in the Cnidaria. In the hydrozoan, Hydra, the tentacles contain what are among the ontogenically ‘oldest’ cells in the organism (Tripp, 1928; Brien & Reniers-Decoen, 1949; Burnett, 1966; Campbell, 1967b). Unlike the remainder of the organism, these structures also reportedly possess no regeneration potential (Peebles, 1897; Kanaev, 1952).

Three explanations have been proposed to account for the absence of regeneration potential in isolated tentacles. Nussbaum (cited in Kanaev, 1952) suggested that the absence of interstitial cells in the tentacles precluded regeneration. However, other regions of the animal, when experimentally deprived of this cell type, retained their regenerative capacities (Brien, 1953; Diehl & Burnett, 1964).

A second explanation invoked the size of an isolated tentacle as a factor limiting regeneration. In disputing this suggestion, Peebles (1897) measured tentacle volume. Isolated Hydra grisea (Pallas) tentacles ranged from 0.01 to to 0.03 mm3, while the volume of the smallest body fragment capable of total regeneration was considerably smaller, 0.006 to 0.01 mm3. From these measurements she concluded that the size of isolated tentacles could not account for the inability to regenerate.

Calcareous sponges (Calcarea: Calcinea) are being described, for the first time, from São Paulo State, Brazil. A total of five species are described, two of which are new to science (Clathrina alcatraziensis sp. nov. and Leucascus roseus sp. nov.). The remaining three species have their distribution widened (Clathrina aurea, C. conifera and C. tetractina).

A comparative study of some tagging methods for the great scallop (Pecten maximus) is reported and intended to increase reliability and reduce costs associated with tagging. Tags were tested for ease of application, legibility, visibility and retention prior to a 17-month study of Pecten maximus in suspended (pearl net) culture. Of the six adhesives tested (standard epoxy resin, rapid epoxy resin, underwater epoxy resin, dental cement, cyanoacrylate fluid and cyanoacrylate gel), rapid epoxy resin and both cyanoacrylates were successful, bonding strongly and quickly to scallop shells. Of the three tag types used, Shellfish Tags (Hallprint) were favoured because they were simpler to apply, more visible, easier to read, and held more data than both Micromarkers (Brady) and engraved codes. In long-term trials 550 scallops were double tagged with Shellfish Tags using cyanoacrylate gel. Loss rates were 16% for tags on the umbo and 0·4% for tags positioned in grooves near to the shell margin. Loss rates did not increase over the 17-month period.

(1) The effect of temperature on the viscosity of the protoplasm has been determined in the unripe eggs of Nereis diversicolor by the centrifuge method.

The viscosity rises as the temperature falls, the rise becoming rapid near 0°C.

(2) These changes of viscosity with temperature are similar to those described by Weber (21) in the protoplasm of certain plant cells.

(3) Attention is drawn to the fact that the temperature coefficients of biological processes should be corrected for the viscosity of the protoplasm in which they occur.

(4) It is shown that the relative changes of protoplasmic viscosity with temperature are probably of the order required to make the temperature coefficients of biological processes constant when corrected for the viscosity factor.

(5) The magnitude of the temperature coefficients of biological processes when corrected for viscosity changes is probably of the same order as that of the temperature coefficients of a chemical process when corrected for changes in the viscosity of its medium.

Mytilus edulis (Mollusca: Bivalvia) collected as spat from the wild in 1990 and held in the laboratory for 18 months were divided into four groups: fed (control); starved; fed with 100 ppb added copper; and starved with 100 ppb added copper. Following >60% mortalities in the starved and copper stressed groups (but negligible mortalities in the control) surviving mussels from all four groups were genotyped at seven allozyme loci (Gpi, Lap, Pgtn, Idh, Odh, Gsr and Est). Allele frequencies did not vary significantly between any of the four groups at any loci, except Gsr where fed and starved groups differed. Mortalities were not genotype dependent at the Pgm locus but, in contrast, genotype frequencies at most other loci varied significantly between groups. At the Gpi, Lap, Gsr and Odh loci there were significant changes in proportions of heterozygotes following copper induced mortalities such that, in general, heterozygotes survived longer and homozygotes succumbed sooner. No similar pattern was evident in relation to mortalities caused by starvation; at only one locus (Idh) was there evidence of a significant effect but this was not apparently independent of the effect of copper.

The taxonomic identity of the common subtidal ctenostomate bryozoan Alcyonidium diaphanum is resolved using comparative morphological and molecular genetic techniques. The newly recognized lectotype series and topotype specimens are described and illustrated. The incorporation of spicules and foreign particles during colony growth is described. Colony morphology and genetic characters of the three commonly occurring morphotypes are examined, showing that just a single genetic species may be recognized, based on the 12s rRNA and CO1 mtDNA genes. Mitochondrial haplotypes show no general correlation with either colony morphotype or geographical location.

An automated photographic technique was used to collect quantitative information on the activity patterns of Fissurella crassa under heavy-exposed sea conditions.The activity of this key-hole limpet was confined to nocturnal low tides. Total length of excursions was significantly greater during spring tides than neap tides, as was the maximum distance reached from the refuge. Total duration of excursions and their average speed did not vary significantly according to the spring/neap cycle. While the direction angle of excursions relative to the refuge was not influenced significantly by the spring/neap cycle, the lowest zone within the intertidal was reached by F. crassa during spring low tides only.

Fissurella crassa showed a spatial activity pattern fluctuating intra/inter-individually between a central place foraging and a ranging strategy, with a marked propensity for the former. Looped excursions were characterized by higher speed for the movements away and toward the limpet's refuge, than the movements at maximum distance from the refuge. As the outward and inward branches of looped excursions often overlapped extensively, trail-following is suggested as the main mechanism of orientation used by F. crassa to relocate the refuge.

Vitamin A and carotenoids were measured in six species of Penaeidae and seven species of Sergestidae.

Vitamin A was present in at least one sample of all species except Gennadas borealis at concentrations mostly of the same order as previously found in other Decapoda, but usually higher in the Sergestidae than in the Penaeidae.

Carotenoids in the Penaeidae included astaxanthin and its esters, carotenes and xanthophylls, but only astaxanthin or its esters with occasional traces of xanthophylls were found in the Sergestidae.

The trophic structure of organisms is an important aspect of the ecosystem as it describes how energy is transferred between different trophic levels. Here, we studied the diet and foraging ecology of 144 individuals belonging to five abundant fish species of subtidal habitats at Isla Robinson Crusoe. Sampling was conducted during the austral spring and summer of 2007 and 2008, respectively. The shallow subtidal habitat is mainly characterized by the abundance of two types of habitat: foliose algae and encrusting invertebrates. Diet and trophic characteristic of fishes were obtained by volumetric contribution and frequency of occurrence of each prey item. Of the five species studied, one is herbivorous (juvenile Scorpis chilensis), four are omnivores (Nemadactylus gayi, Malapterus reticulatus, Pseudocaranx chilensis and Scorpis chilensis adult), and one carnivore (Hypoplectrodes semicinctum). The dietary diversity index was relatively low compared to other temperate reef systems, which could indicate a low availability of prey items for coastal fishes. The morphological parameters indicated that cranial structures and pairs of pectoral fins influence the foraging behaviour. Differences in fin aspect ratio among species provided insight about fish depth distribution and feeding behaviour. These results suggest important adaptive changes in the depth gradient of fishes in the subtidal environments of this island. According to our records, this is the first attempt to characterize the trophic ecology of the subtidal fish assemblages at Juan Fernandez Archipelago, revealing the need for testing hypotheses related to selective traits that may enhance species coexistence in oceanic islands.

The development of a unispecies bloom of phytoplankton in the Rade de Villefranche (N.W. Mediterranean, near Nice) during June 1982 coincided with the disappearance of salps from the area. A phytoplankton haul was taken on 24 June and examined in detail. The sample consisted of virtually a unispecies diatom population; Rhizosolenium spp., together with a few small medusae and crustaceans. The diatom cells were unusual in that they appeared to be associated with large amounts of extracellular mucus.

The appearance of this virtually monospecies bloom provided a rare opportunity to examine in detail the biochemical composition of a natural field diatom species (see discussion in Ballantine, Lavis & Morris, 1979 and Morris, 1984). After removal of zooplankton the phytoplankton were collected on a 30 μm clear nylon filter. A detailed biochemical analysis was carried out as previously described (Morris, McCartney & Robinson, 1983; Morris, 1984).

The Rhizosolenium spp. sample was composed of almost equal amounts of lipid (23 mg), insoluble carbohydrate (19 mg) and protein (24 mg) with much smaller amounts of soluble carbohydrate (009 mg). The lipid was composed mainly of polar lipids (70% total lipids), neutral glycerides (20% total lipids) and sterols (8% total lipids). The detailed fatty acid and sterol composition of these major lipid fractions are shown in Tables 1 and 2.