Seasonal changes in altimeter data are derived for the North Atlantic Ocean. Altimeter data are then used to examine annually propagating structure along 26°N. By averaging the altimeter data into monthly values or by Fourier analysis, a positive anomaly can be followed from 17°W to ∼50°W along ∼26°N. The methods give a westward travel speed of 1° of longitude a month and a half-life of one year for the average decaying structure. At ∼50°W 26°N, the average structure is about 2·8 years old with an elevation signal of ∼1 cm, having travelled ∼3300 km westward. The mean positive anomaly results from the formation of anticyclonic eddies which are generally formed annually south of the Canary Islands by late summer and which then travel westward near 26°N. Individual eddy structure along 26°N is examined and related to in situ measurements and anomalies in the annual seasonal concentration cycle of SeaWiFS chlorophyll-a.

A multi-technique approach was used to map the spatial distribution of seabed biotopes (i.e. physical habitats and their associated benthic assemblages) in the vicinity of Hastings Shingle Bank in the eastern English Channel, part of which is licensed for the extraction of marine aggregates for the construction industry. An area of seabed, approximately 12×4 km in size, was surveyed using a high-resolution sidescan sonar system, and a mosaic of the output was produced, covering 100% of the survey area. The area was then divided into acoustically distinct regions based on the sidescan sonar data, and the benthic communities and sediment types within each of the regions were ground-truthed using a Hamon grab fitted with a video camera, and using a heavy duty 2-m beam trawl. Additional information concerning the seabed was obtained through the application of video and photographic techniques. Sediments within the survey area ranged from cobbles and coarse gravels on the Shingle Bank, to various grades of sands to the north and south. Analysis of faunal data revealed the presence of statistically distinct biological assemblages within each acoustic region. Using all available data, four discrete biotopes were identified and their spatial distribution mapped across the survey area.

The crescent shaped Mascarene Plateau (south-western Indian Ocean), some 2200 km in length, forms a partial barrier to the (predominantly westward) flow of the South Equatorial Current. Shallow areas of the Mascarene Plateau effectively form a large shelf sea without an associated coastline. Zooplankton sampling transects were made across the plateau and also the basin to the west, to investigate the role the partial interruption of flow has on zooplankton biomass and community structure over the region. Biomass data from optical plankton counter (OPC) analysis, and variability in community structure from taxonomic analysis, appear to indicate that the obstruction by the plateau causes upwelling, nutrient enrichment and enhanced chlorophyll and secondary production levels downstream.  The Mascarene Basin is clearly distinguishable from the ridge itself, and from the waters to the south and north, both in terms of size-distributed zooplankton biomass and community structure. Satellite remote sensing data, particularly remotely-sensed ocean colour imagery and the sea surface height anomaly (SSHA), indicate support for this effect. A correlation was found between OPC biovolume and SSHA and sea surface temperature (SST), which may indicate the physical processes driving mesozooplankton variability in this area. Biomass values away from the influence of the ridge averaged 24 mg m−3, but downstream of the ridge biomass averaged 263 mg m−3. Copepods comprised 60% of the mean total organisms. Calanoid copepod numbers varied considerably between regions, being lowest away from the influence of the plateau, where higher numbers of the cyclopoid copepods Oithona spp., Corycaeus spp. and Oncaea spp., and the harpacticoid Microsetella spp. were found.

The spread of the oil spill from the tanker ‘Prestige’ was analysed in relation to the occurrence of the exceptional 2002/2003 Navidad using airborne and AVHRR satellite measurements. Altimeter-derived geostrophic velocity and Envisat ASAR observations were also used to investigate the structure of this Cantabrian extension of the poleward current around Iberia.

The structure and distribution of the sponge community in five sites and four habitats in Cagarras Archipelago, Rio de Janeiro, Brazil, are described. The archipelago has three major islands (Cagarra, Palmas, and Comprida), and four islets. Qualitative samples were taken by SCUBA diving in the three islands and in two islets, and quantitative samples were taken in Palmas Island only. Cluster analysis using Jaccard's coefficient on qualitative data grouped the two islets (Cagarra Bank and Cagarra Islet), which are more exposed to wave action, and the three islands formed a group of relatively sheltered sites. Cluster analysis using Bray–Curtis coefficient on quantitative data from different habitats in Palmas Island allowed distinction of three groups of samples: overhangs, shallow horizontal surfaces (6 m depth), and vertical walls plus deeper horizontal surfaces (17 m depth). Sponge abundance was greater in overhangs (61·2 ind m−2), which were dominated by Protosuberites sp. and Clathrina conifera. Abundance was reduced in vertical walls (31·1 ind m−2) and deep horizontal surfaces (16·8 ind m−2). Pachychalina sp. dominated the deep horizontal surfaces and Clathrina conifera was dominant in overhangs. Values of Shannon's diversity in overhangs, vertical walls (both with H′=2·1 bits ind−1) and deep horizontal surfaces (H′=1·7 bits ind−1) were moderate and similar, whereas in shallow horizontal surfaces the sponges were both less diverse (H′=0·37) and less abundant (8·5 ind m−2). Shallow horizontal surfaces were dominated by Hymeniacidon heliophila. The reduced species richness of the sponge community in Cagarras Archipelago when compared with other sites in Brazil and elsewhere is probably due in part to the pollution from the city of Rio de Janeiro. Wave action appears to reduce the number of sponge species at a local scale, whereas substrate inclination affects more strongly the species composition and abundance than the diversity of sponges.

The quantum yield and photosynthetic parameters of phytoplankton and sea ice microalgal communities were assessed from the Arctic Ocean and fjords of northern Svalbard. The phytoplankton community in Fram Strait was dominated by Phaeocystis while on Norskebanken it was dominated by diatoms. The quantum yield showed maximum values of 0·64 at 20–40 m below the surface and were consistent with nutrient replete waters elsewhere.

Sea ice infiltration communities were widespread and dominated by Phaeocystis. This is the first record of an Arctic infiltration ice community. Quantum yields were relatively low (0·247). Bottom ice communities, which were dominated by Nitzschia frigida, were extremely restricted and had moderate quantum yields (0·427). Communities growing on multiyear ice had quantum yields of only 0·126. All ice communities were well adapted to their light environment.

Spatial surveys of marine benthic habitats and biota based on the interpretation of acoustic data were carried out at two sites in the eastern English Channel each representing different scales of geographic area and intensity of survey. A small area (4×12 km) crossing the Hastings Shingle Bank was surveyed at a relatively high intensity (track spacing 400 m) and was nested within a larger area between Hastings and Dungeness (12×40 km), which was surveyed at a lower intensity (track spacing 2 km). Surveys were conducted with two acoustic ground discrimination systems (AGDS), RoxAnn and QTC-VIEW and the primary purpose of the investigation was to compare the performance of the two AGDS using a common approach to analysis of the different data outputs (E1 and E2 for RoxAnn and the Q eigenvectors from QTC-VIEW). Exploratory data analysis using variography indicated that interpolation between tracks was justified for the smaller site to create a complete coverage, but was limited to the creation of a digital image of the track data for the larger area. Grab and video sample data were available for supervised classification of the AGDS data and interpreted sidescan images for comparison with unsupervised classification. Both AGDS gave similar outputs, although RoxAnn consistently gave slightly better levels of performance than QTC-VIEW as measured using error matrices. Although the investigation was not designed to compare the performance of AGDS and sidescan, the outputs from AGDS were similar to the visual interpretation of the sidescan sonar data. It was concluded that despite the inherent limitations of AGDS, they may be suitable for providing distribution maps at a broad scale that can give a context for the interpretation of finer scale survey of smaller, nested areas.

The ultrastructure of carpospore differentiation for the red alga Cryptopleura ruprechtiana is described. Carposporogenesis proceeds through three developmental stages. After cleaving from multinucleate gonimoblast initials the terminal gonimoblast cells differentiate to produce carpospores. These young carpospores possess a large nucleus and numerous proplastids with a peripheral thylakoid. During the later stages of young carpospores starch begins to polymerize. Mucilage is formed within dilating concentric membrane bodies, thus forming mucilage sacs. The latter, subsequently, release their contents initiating carpospore wall formation. Intermediate-aged carpospores have more plastids which develop their internal thylakoid system. The endoplasmic reticulum produces granular cored vesicles. Mature carpospores have numerous fully developed plastids, large floridean starch granules and fibrous vacuoles. Curved dictyosomes produce cored vesicles and adhesive vesicles. The nuclear envelope is crenulated and a two-layered wall surrounds the mature carpospore.

The morphology and infraciliature of the marine hypotrichous ciliate Holostichanagasakiensisi sp. nov. from the coastal waters of Nagasaki, Japan are described based on living and protargol-impregnated specimens. The new species is characterized by: medium-sized marine Holosticha,in vivo 100–150×30–40 μm with elongated body shape and slightly greyish to reddish cell colour; cortical granules arranged in conspicuously longitudinal rows; 24–32 adoral membranelles; ∼20 midventral cirral pairs and 7–10 transverse cirri; 28–42 left and 25–38 right marginal cirri; constantly 4 frontal cirri and 3 dorsal kineties; 23–63 macronuclear nodules.

Phytoplankton photosynthetic quantum efficiency (PQE), pigments, absorption characteristics, species composition (converted to phytoplankton carbon, Cph) and other variables were measured at an offshore site in the western English Channel throughout 2001, using an opportunistic weekly sampling schedule. The variation of chlorophyll-a (Chla) and other phytoplankton pigments followed the classical seasonal cycle, driven by incident light, patterns of stratification and nutrient availability. Phytoplankton and pigment concentrations were low in the winter, rising to a peak in the spring ‘bloom’, with episodic blooms throughout the summer, an autumn bloom and a decline to the winter minimum. Surface layer Chla and total pigment (Tpig) concentrations were highly correlated for the whole year, yet it was observed that the fraction of Chla in Tpig (Chla/Tpig) was not constant and had a distinct seasonal pattern, low in winter and higher in spring, summer and autumn blooms. Chlorophyll-a/Tpig was linearly correlated with recent ambient light fluxes and maximum PQE (PQEm) throughout most of the year, though more significantly within seasonal periods. Chlorophyll-a and Tpig were both linearly correlated to Cph and the Chla/Cph ratio was significantly correlated with both Chla/Tpig and PQEm. Also the optical absorption ratios, a674/a443 and a674/a490 were significantly correlated with PQE and Chla/Tpig, indicating probable optical signatures for these two parameters. The seasonal cycle of measurements of photosynthetic quantum efficiency provided a bench-mark against which all the photosynthetically-driven seasonal changes of biological properties can be understood, in terms of incident solar radiation and nutrient availability. We conclude that phytoplankton synthesize Chla preferentially to other pigments or carbon compounds in conditions beneficial to growth. The PQEm, the ratios of Chla/Tpig, Chla/Cph and a674/a443 are greater when plants are growing actively. In periods of nutrient sufficiency, PQEm, Chla/Tpig and a674/a443 are all linear functions of the mean total photon flux for the recent few days. Photosynthetically driven changes in Chla synthesis, cause observed changes of Chla/Tpig and Chla/Cph ratios.

Since the incursions of the introduced green macroalgae Codium fragile ssp. tomentosoides and ssp. atlanticum on European shores, the abundance and distribution of the native congeners C. tomentosum and C. vermilara have come under closer scrutiny. Hypotheses regarding the reported declines in the native(s) are largely speculative due to the paucity of quantitative information on the natives, the cryptic nature of the invaders and the unknown processes regulating Codium assemblages. As part of a field-based Codium study on north-eastern Atlantic shores, our surveys on Guernsey shores, Channel Islands, in September 2002 have revealed two unexpected and noteworthy results: (1) thriving populations of C. tomentosum are quite abundant on mid to low littoral shores; and (2) in marked contrast, sparse populations of C. fragile ssp. tomentosoides are restricted primarily to upper mid-littoral rock pools. Native Codium has not been displaced or eliminated from the southern end of the British Isles.

Subtidal assemblages of epibiota on vertical and on horizontal surfaces of two natural reefs and two concrete breakwalls were sampled photographically during autumn and winter of 1998. Differences in the assemblages on the two types of substrata (natural reefs and concrete breakwalls) were detected between assemblages on horizontal surfaces, but not on vertical surfaces. The covers of several individual taxa (e.g. Herdmania momus, serpulid polychaetes, coralline encrusting algae) and number of sponge taxa showed clear differences between the two types of substrata. There were great differences between the assemblages on vertical and horizontal surfaces on each natural reef and artificial structure. Invertebrates consistently covered a larger area on vertical than on horizontal surfaces with sponges (as a group) and the ascidian Herdmania momus, the dominant invertebrates on these reefs, clearly showing this pattern. Nevertheless, this pattern was complex for sponges because several species covered a larger area on horizontal than on vertical surfaces and there was no difference in the number of taxa of sponges between the two orientations on natural reefs. Algae, contrary to the results of previous studies, did not show any consistent differences in their covers on vertical or on horizontal surfaces. The results of this study indicated that orientation may be of greater influence on the biological diversity of epibiota on subtidal reefs than whether reefs are natural or artificial.

The living morphology and infraciliature of a marine ciliate, Certesia quadrinucleata, isolated from an abalone-farming pond near Qingdao, China, have been re-investigated, and some new information about this ‘well-known’ species documented: a caudally located contractile vacuole and the highly stable ciliary pattern on dorsal side. Based on previous and present studies, an improved diagnosis is supplied: size 50–90×35–70 μm in vivo; ovoid body shape with a sharp-angled projection on the right anterior edge; adoral zone with 22–27 membranelles and a prominent paroral membrane; 11–12 frontoventral and 4–5 transverse cirri; left marginal row with 5–7 cirri; five dorsal kineties; generally four macronuclear nodules; contractile vacuole positioned at posterior end; marine.

Slope Water anticyclonic Oceanic eDDIES (SWODDIES) are typical mesoscale features of open-ocean waters of the southern Bay of Biscay which usually develop in winter by shedding from the seasonal poleward current flowing along the northern Spanish slope. These eddies have been intensively studied from the physical perspective. However, their effect on the distribution of biological properties and on the functioning of the pelagic ecosystem has not been assessed so far. To this aim, a sea-truth, multidisciplinary and comprehensive study of a SWODDY was carried out in summer 1998. The eddy, radius of ≈50 km, was initially centred at 45·5°N 6·0°W, being characterized by a relatively homogeneous core of water in the centre of the eddy extending from 80 to about 200 dbar. In the central region of the core, temperature (12·55–12·75°C) and salinity (≈35·70) values were higher than outside the eddy. The optical properties of the eddy also differed from those of the surrounding waters. A distinct biological signature was found associated with the eddy. Depth-integrated chlorophyll-a concentrations were 25% higher at the eddy centre where upward doming of the seasonal pycnocline (up to 30 dbar) occurred. Enhanced phytoplankton biomass was related to a higher contribution of >10 μm cells, mainly represented by diatoms and chrysophyceans. Phytoplankton and mesozooplankton species composition in and outside the eddy differed significantly reflecting the coastal origin of the water parcel trapped by the eddy. The sharp modification of the planktonic community composition, biomass and associated size-structure caused by slope water oceanic eddies are likely to exert a significant effect upon the upper trophic levels of the pelagic ecosystem of the southern Bay of Biscay.

Two new species of lithistid sponges, Gastrophanellaphoeniciensis sp. nov. (Siphonidiidae) and Microscleroderma lamina sp. nov. (Scleritodermidae) are described from a submarine cave, depth 2–3 m, in Lebanon. They are the first Mediterranean records of two genera with a mainly tropical distribution, Gastrophanella being known from the western Atlantic (Caribbean, Brazil), central eastern Pacific (Mexico) and South Africa, and Microscleroderma from the Indo-Pacific and the eastern Atlantic (Senegal). They are interpreted as remnants of a warmer period in the Mediterranean that survived the subsequent cooling only in the warmer eastern basin. Gastrophanella phoeniciensis sp. nov. is closely related to G. cavernicola from Brazil and Belize, from which it differs essentially in its shape. Microscleroderma lamina sp. nov. is characterized by a lamellar shape, short oxeas and having hair-like oxeas arranged around the aquiferous openings.

Subtidal macroalgal assemblages differed among islands within the Recherche Archipelago, Western Australia, with respect to species biomass. To investigate whether macroalgal populations were maintained locally, settlement plates were moored in 10 to 15 m depths at a reef sampled for macroalgal diversity, and 20, 50, 100, and 500 m away from the reef. Plates were retrieved after eight months and assemblage differences were compared with distance from the sampled reef. Macroalgal richness decreased with distance from an island assemblage and molluscan richness increased. At 500 m away, the number of algal recruits was negligible and the number of bivalves was relatively high.

In Mar del Plata the octocoral Tripalea clavaria is highly abundant on the different quartzitic rocky outcrops 18–20 m deep. Reproductive aspects of T. clavaria including its distribution and population structure have been described. Monthly sampling and observations were carried out by SCUBA diving from November 2000 to October 2001 at Banco del Medio (38°10′S 57°28′W). Tripalea clavaria occurs in patches; most colonies were 3·0–8·9 cm in height. The species appears to be a gonochoric brooder. Female colonies were significantly more abundant than males, which could be identified only from February to June, when spermaries were present. Oocytes were found even in very small colonies (from 3·5 cm height), being 40 to 200 μm in diameter, the predominant size-group around the year. Development of the oocytes required several months, beginning in May and ending with the production of larvae from March to May. Young, stalked oocytes were found at the base of the polyps attached to the mesenteries in May–June. During the following six months they grew in size; maximal oocyte diameter was 700 μm, observed in April/May. Asexual reproduction was negligible, indicating that population maintenance is based on sexual reproduction.

The diversity and structure of meiobenthic nematodes and macrobenthic infauna were studied at four widely spaced subtidal sites around the UK coast in relation to a number of measured environmental variables. The stations were situated on soft sediments at water depths of 53 to 95 m and are intended as long-term monitoring locations as part of the UK National Marine Monitoring Programme. Similar benthic assemblages were encountered in comparable environmental conditions. The distribution of nematode and macrofauna species was mainly governed by the geographical location of the habitat and the granulometric composition of the substrate. There was no evidence of any adverse effect on the measures of benthic assemblage structure arising from trace metal concentrations in the sediment, indicating the relatively unpolluted nature of the offshore locations under investigation. Nematode and macrofauna assemblages exhibited stable patterns over time periods of three years.

Two new Mycalina (Porifera: Poecilosclerida) are described from the south-western Atlantic, collected during Programme REVIZEE (1996–2002)—South Score, off the São Paulo State coast, Brazil. Esperiopsis bathyalis sp. nov. is characterized by the possession of two well differentiated categories of sigmas, the smaller ones being sigmancistras. Hamacantha microxifera sp. nov. is set apart by its possession of abundant small microxea-like raphides, diancistras 100–150 μm long, and absence of sigmas.

This study investigated the synchrony of frond dynamics among patches of the intertidal seaweed Mazzaella parksii (=M. cornucopiae; Rhodophyta: Gigartinales) at local spatial scale. At Prasiola Point (Pacific coast of Canada), the mean synchrony of the seasonal changes in frond density among seven permanent, 100-cm2 quadrats was significant (mean Pearson's r=0·73, with 0·65–0·81 as 95% confidence limits) between 1993 and 1995. This indicates that predicting seasonal trends for non-monitored patches at local spatial scale can be done relatively well based on observations on a limited number of quadrats. The identification of the spatial scales at which seaweed populations covary synchronously will permit minimizing sampling effort while retaining the ability to make valid predictions for non-monitored sites.