ALBERT

Description: Prey availability is one of the factors determining the distribution of seabirds at sea. Northern fulmars Fulmarus glaclalis and black-legged kittiwakes Rissa tridactyla were the most regular and frequent ship-followers across the central and northern North Sea during 2 surveys with a fishery research vessel in May-June and July-August 1992. Sixteen other species occurred less often and/or in lower numbers. Birds consumed 84 % of experimentally discarded roundfish and 8 % of discarded flatfish. On average, northern gannets Morus bassanus took the largest individuals of most fish specles, black-legged kittywakes the smallest The average size choices of herring gulls Larus argentatus, lesser black-backed gulls Larus fuscus and northern fulmars lay between these 2 extremes. The choice of fish lengths by birds vaned with different fish species. Northern gannet was the most successful species in consuming discards. Northern fulmars success rates decreased with the presence of larger ship-followers but were never high. Black-headed gull Larus ridibundus and common gull Larus canus were less successful than the more frequent typical ship-following species.

Description: The degradatlon of phytodetritus In the deep sea was studied in sediment samples of the NE Atlantic In spring and summer 1992 using I4C-labelled algal cells (Anacystis sp , Cyanophyceae) fed to the benthic population in ship-board experiments and measuring the liberation of labelled I4CO2 over time. The mineralization process showed a 2-step behaviour with an initial rapic rate whhich later slowed down, indicating the initial attack of easily degradable material of the complex food and the later utilization of less labile matter. The profile of degradation activity with sedimend depth showed no clear vertical gradient in March, but in August the activity in the top horizon increased by a factor of 6.1 to 7.8, which was coherent with increased bacterial numbers or biomass (factor of 1.3 to 1.7), respectively, and might be caused by the seasonal input of phytodetritus to the deep-sea bottom. The degradation measured was positively influenced by elevated incubation pressure mostly in summer, indicating that the summer stimulation of microbial activity in 1992 was based on the metabolic activation of the indigenous benthic community while surface-derived organisms attached to sedimented particles were of lesser importance whith respect to consumption of phytodetritus. Several aspects on quality of phytodetritus for nutrition of the deep-sea benthos, seasonality of detritus degradation, and influence of pressure on microbial activity are discussed

Description: An RMT 25 opening/closing net was used to sample the nekton comunity at 2 stations in the ice free zone (IFZ) of the Scotia Sea (Stn 1 approximately 10 nautical miles south of the Antarctic Polar Front, Stn 2 on the edge of the South Georgia Shelf Break to the northwest of the island) Oblique hauls sampled 200 m depth layers to 1000 m during both day and night. Total and individual volumes of each species in each 200 m layer were measured by displacement The data were used to generate biomass and numerical spectra for day and night at each station for the whole water column to 1000 m. At both stations the relationship between log10 biomass density (B/A) and log10 individual body mass (M) were strongly positive. Slopes of the biomass spectra were not significantly different among the day and night stations and an overall regression showed that biomass density scaled as M061. Analysis of biomass spectra revealed that although the species composition and biomass density vaned between the 2 stations, energy turnover in the nekton community in the 2 areas was similarly dominated by animals of larger size. Considering energy turnover in terms of taxonomic groups revealed that Stn 1 turnover was dominated by tunicates (salps) followed by fish and cnidarians and at Stn 2 turnover was dominated by crustaceans followed similarly by fish and cnidarians. Use of biomass spectra in this case study was shown to enhance insight into the comparative function of 2 pelaglc systems obtained using a conventional taxonomc approach The analysis of biomass spectra in the absence of taxonomic data would have had limited value as it would not have emphasised the major difference between the 2 stations: the domination by tunicates, an energetic dead end, at Stn 1 and crustaceans, which are available to predators, at Stn 2.

Description: The nekton community was sampled by a Rectangular Midwater Trawl (RMT 25) over the upper 1000 m of the Scotia Sea dunng January 1991. A total of 81 nekton and micronekton species were collected from 2 sites, one in the oceanlc western Scotia Sea (Stn 1) and the other on the northwestern slope of the South Georgia shelf (Stn 2). Species composition, abundance, biomass and day/night vertical distribution were investigated. Crustaceans were the most important group in terms of species numbers (28 species) followed by mesopelagic fish (24), molluscs (15) and coelenterates (11). Species diversity increased with depth and was higher at Stn 2 (76 species) than at Stn 1 (62 specles). Biomass in the upper 1000 m was considerably higher at Stn 1 (94.6 g wet wt m-2 during daytime, 87 g wet wt m-2 during night) than at Stn 2 (10.2 and 23.7 g wet wt m-2, respectively), mostly due to dense concentrations of the tunicate Salpa thompsoni (41.6 g wet wt m-2 during night). The other main contributors to the high biomass at Stn 1 were coelenterates (28.3 g wet wt m-2 during night) and mesopelagic fish (4.9 g wet wt m-2 during night). Euphausiids (Euphausia triacantha and E. superba) accounted for 1.5 g wet wt m-2 at Stn 2 during night, with E. triacantha the more important of the two (1.4 g wet wt m-2). Except for Bathylagus antarcticus all common mesopelagic fishes showed a marked diurnal vertical migration (i.e. Electrona antarctica, Gymnoscopelus brauen, Krefftichthys anderssoni, Protomyctophum bolini). During daylight they stayed in the core of the Circumpolar Deep Water (CDW, 400 to 800 m) and at night they were mainly distnbuted in the Antarctic Surface Water (ASW, 0 to 400 m). Other species with pronounced vertical migration were the hydromedusa Calycopsis borchgrevinki, the squid Brachioteuthis ?picta, and the euphausiid Euphausia triacantha. The scyphomedusae Atolla wyvillei and Periphylla periphylla and the crustaceans Cyphocaris richardi, Gigantocypris mulleri and Pasiphaea scotiae did not appear to migrate and remained concentrated in the CDW. Spatial variability was analysed by multivariate data analyses (clustering techniques) and related to hydrography. Four main groups, characterised by different nekton communities, were derived: (1) a lower mesopelagic nekton community from the deeper layers of the CDW, apparent at both stations, (2) an upper mesopelagic nekton community from the core of the CDW, apparent at both stations, (3) an epipelagic nekton community from the ASW over the South Georgia slope (Stn 2) and finally (4) an epipelagic nekton community from the ASW of the oceanic Scotia Sea (Stn 1). The performance of the midwater trawl is discussed as it has a substantial impact on the catchability of the nekton. The presented data provide new information on the structure and spatial variability of Antarchc nekton communities and emphasise the geographical and vertical discontinuities between communities.

Description: The influence of sampler type on quantitative estimates of deep-sea meiobenthos is examined by an indirect statistical comparison of box corer and multiple corer samples collected throughout the northeast Atlantic, and by a direct comparison of contemporaneously collected multiple corer and box corer samples from a single abyssal location. The data strongly support the suggestion that the greater down-wash/bow wave associated with box corers results in displacement of surface sediments and any superfic~al detrltus layer together with thelr associated fauna. Total metazoan meiobenthos density estimates from box corer samples are about half those from corresponding multiple corer samples Sampler type may also influence the fauna1 composition of both the metazoan and protozoan components of the meiobenthos.

Description: Bacterial epiphytes of Gracilaria conferta were quantified. Saprophytic bacteria reached 350 times and agar degraders 25000 times higher numbers g-1 algal wet wt on tissues infected with the 'white tips disease', as compared to healthy tissues. A bacterial inducing agent of the 'white tips disease' was detected. Addition of 10(2) to 10(3) cells of this isolate ml-1 medium led to increased rates of infection. This effect did not occur if the isolate was autoclaved before addition. The virulent bacteria could always be isolated from infected tissues. It frequently, but not always, infected G. conferta and should be regarded as a facultative parasite. Several factors influenced the disease development. Temperatures above 20-degrees-C, in combination with photon flux densities of more than 200 muE m-2 s-1, increased the rate of infection. Relatively low amounts (more than 25 mug ml-1) of certain organic nutrients (peptone and yeast extract) led to strong manifestations of the disease. Addition of agar did not cause any symptoms, while 5 mg l-1 of the antibiotic rifampicin prevented the alga from being infected.

Description: The responses of natural bacterial populations in the waters of the Kiel Fjord, Germany, and in Lake Kinneret, Israel, to additions of organic substrates were followed by determining changes over 24 h either in direct cell counts or in 3H-thymidine incorporation, and in the Kiel Fjord additionally in 3H-leucine incorporation. In parallel, 1 ym filtered water samples were stored for 3 or 4 d in order to starve the indigenous bacterial populations prior to repeating the substrate addition experiments. Generally, upon substrate addition, relatively higher incorporation of radiotracers was noted in the preincubated samples. Growth response to substrate addition even in starved populations was only significant after 24 h. Incorporation rates of 3H-thymidine and 3H-leucine were more sensitive indicators of bacterial response to substrate additions than cell counts. Continued cell replication in unsupplemented controls, and insignificant increase over time of radiotracer incorporation in most of the fresh samples with added supplements, indicated that the indigenous bacterial populations in Kiel Fjord and Kinneret were apparently not substrate limited. Comparison of actual bacterial production after 24 h (direct counts) to that predicted by 3H-thymidine incorporation after 1 h showed that although reasonably good predictions of daily production were obtained in the unsupplemented samples, this was usually not the case when substrates were added.

Description: Competition experiments were performed first with 4, then with 11 species of marine phytoplankton at various ratios of si1icate:nitrate and various light intensities. Diatoms became dominant at Si:N ratios 〉25:1 while flagellates were the superior competitors at lower ratios. The light supply did not influence the competitive position of diatoms and non-siliceous flagellates in general, while it was important in determining the outcome of competition at the species level. In the 11 species expenments, Stephanopyxis palmenana was the dominant diatom at high light intensities. It shared dominance with Lauderia annulata at medium and low light intensities and high Si.N ratios. Pseudonitzschia pungens was the dominant diatom at low light intensities and relatively low Si:N ratios. The green alga Dunaliella tertiolecta was the dominant flagellate at high light intensities, while at low light intensities the prymnesiophycean Chrysochromulina polylepis and the cryptophyte Rhodomonas sp. were also important.

Description: The individual marking of flying and flightless birds has a long history in ornithology. It is the only technique which is cheap, simple and effective, yielding results on bird migration, age-specific annual survival and recruitment. Consequently, hundreds of thousands of birds are annually ringed worldwide. Unfortunately, researchers all too often tend to neglect problems associated with rings and tags. In Antarctic penguins, flipper bands have been used extensively by a variety of nations, and banding is an integral part of the Council for the Conservation of Antarctic Marine Living Resources' (CCAMLR) monitoring programme (Standard method A4). This programme suggests that mortality in penguins wearing bands can be attributed to either (a) prey species availability, (b) predation, (c) weather conditions or (d) other. In this paper, we have attempted to quantify energetic costs associated with wearing a flipper band. For that purpose, freshly caught Adelie penguins (n = 7) were introduced, in Antarctica, into a 21 m long still-water tunnel, where their behaviour and energy consumption were determined via observation and gas respirometry. Birds were either immediately marked with a flipper band and tested in the tunnel for ca 2 h, and then taken out and tested again after removal of the band, or vice-versa. Flipper bands significantly (ANOVA, p = 0.006) increased the power input of Adelie penguins during swimming by 24 % over the speed range of 1.4 to 2.2 m S-', from 17 W kg-' to 21.1 W kg-' (n = 115 and 157 measurements, respectively). The implications of banding on foraging performance and sunival of penguins are discussed. Implantable passive transponders could help overcome such problems.

Description: In April 1990, 488 marine fish, belonging to 30 species from central Philippine waters, were investigated macroscopically for the occurrence of parasites in their flesh and for anisakid nematodes in their body cavity. Twenty-four fish were found to be infected by 1 of 4 different types of parasites. Unidentified Microspora were found in 4 host species from different families. Plerocercoids of the trypanorhynchid cestode Otobothrium penetrans occurred in the flesh of hemirhamphids and belonids only. Adult nematodes of the genus Philometra were found in the garfish Tylosurus crocodilus. The only parasite found which might be transferable to warm-blooded animals was the L-III stage of Anisakis sp. from the body cavity and the muscle of Muraenesox cinereus. The risk of human infections by parasites through consumption of raw marine fish in the central Philippines therefore is considered to be low.

Description: Organic material entering the oceanic mesopelagic zone may either reenter the euphotic zone or settle into deeper waters. Therefore it is important to know about mechanisms and efficiency of substrate conversion in this water layer. Bacterial biomass, bacteria secondary production (BSP). extra­cellular peptidase activity (EPA) and particulate organic nitrogen (PON) were measured in vertical pro­files of the North Atlantic (46° N 18° W; 57° N 23° W) during the Joint Global Ocean Flux Study (JGOFS) cruise in May 1989. The magnitude of these parameters decreased differently with depth. The strong­est decreases were observed for bacterial production (3H-thymidine incorporation) and peptide turn­over (using the substrate analog leucine-methylcoumarinylamide). Bacterial biomass and peptidase potential activity were not reduced as much in the mesopelagic zone. Peptidase potential per unit cell biomass of mesopelagic bacteria was 2 to 3 times higher than that of bacteria in surface water. Nevertheless bacterial growth at depth was slow, due to slow actual hydrolysis. Values of theoretical PON hydrolysis were calculated from PON measurements and protein hydrolysis rates. These corre­sponded well to bacterial production rates, and the degree of correspondence increased from a factor of 0.63 (PON hydrolysis/ESP) in the mixed surface layer to 0.87 in the mesopelagic zone. Thus we hypothesized an effective coupling between particle hydrolysis and uptake of hydrolysate by bacteria, which depletes the deeper water of easily degradable substrates as hydrolysates usually are. The low enzymatic PON turnover rate of 0.04 d- 1 in the subeuphotic zone suggests that residence time of parti­cles within a depth stratum may be important for its contribution to export. storage and recycling of organic matter.

Description: Laboratory experiments were carried out to investigate the effect of protozoan, copepod and combined grazing on Phaeocystis biomass. Phaeocystis cf. globosa single cells were offered to 3 different protozoan species, to the calanoid copepod Temora longicornis, as well as to mixtures of both grazer types. The heterotrophic dinoflagellate Oxyrrhis marina and the oligotrich ciliate Strombidinopsis acuminatum ingested Phaeocystis at much higher rates than did the copepod. Nevertheless, protozoan growth and ingestion rates were submaximal, indicating Phaeocystis to be suboptimal food. The oligotrich ciliate Strombidium elegans did not feed on Phaeocystis. In grazing experiments with mixtures of both predator types, the decline of Phaeocystis single cells could be explained by protozoan grazing alone, implying no grazing by the copepods on Phaeocystis. Instead, copepods ingested the protozoans at high rates. Predation on 0. marina and S. acuminatum by T. longicornis resulted in a reduction of the total grazing pressure on Phaeocystis of 21 and 67 % respectively. We conclude that mesozooplankton predation on herbivorous ciliates and heterotrophic dinoflagellates, which consumed Phaeocystis cells, can considerably reduce the overall grazing pressure and may enhance Phaeocystis bloomng.

Description: The benthic response to the sedimentation of particulate organic matter (POM) was investigated during 1985–1990 at 47°N, 20°W (BIOTRANS station). The first noticeable annual sedimentation of phytodetritus, as indicated by chlorophyll a concentrations in the sediment, occurred as early as late April-early May. Maximum amounts were found in June–July. Two different sedimentation pulses to the sea bed are described that demonstrate interannual variation: the occurrence of salp faecal pellets early in the year 1988 and the massive fall out of a plankton bloom in summer 1986, which deposited approximately 15 mmol C m−2. The benthic reaction to POM pulses was quite diverse. The mega-, macro- and meiobenthos showed no change in biomass, whereas bacterial biomass doubled between March and July. This corresponds to a seasonal maximum of total adenylate biomass. The relative abundance of Foraminifera among the meiobenthos increased during the summer. Benthic activity (ATP, ratio ATP/ETSA), as well as in situ sediment community oxygen consumption rates (SCOC), showed distinct seasonal maxima in July–August of 0.75 mmol C m−2 day−1. Based on SCOC and the carbon demand for growth, a benthic carbon consumption of 0.94 mmol C m−2 day−1 was estimated. This represents about 1.1% of spring bloom primary production and 9.6% of the export flux beneath the 150 m layer, measured during the North Atlantic Bloom Experiment. Bacteria and protozoans colonizing the epibenthic phytodetrital layer were responsible for 60–80% of the seasonal increase in SCOC. The strong reaction of the smaller benthic size groups (bacteria, protozoans) to POM pulses stresses their particular importance for sediment-water interface flux rates.

Description: While marine snow aggregates were devoid of Phaeocystis in 1989, a large fraction of the Phaeocystis biomass was associated with aggregates two years later. This discrepancy corresponds to a significant difference in aggregate size between the two years studied, interpreted to be a consequence of different levels of turbulent mixing. Phaeocystis colonies remained freely suspended during 1989 when aggregates were small, and adhered loosely to the large aggregates observed forming during 1991. Overall, the aggregation potential of Phaeocystis was low in comparison to diatoms. Independent of the degree of aggregation, sedimentation was the dominant loss factor of Phaeocystis biomass from the upper layer

Description: Chemoautotrophic bacteria live symbiotically in gills of Lucinoma aequizonata, an infaunal clam inhabiting an oxygen-poor environment. These intracellular symbionts respire nitrate, i.e. they use nitrate instead of oxygen as a terminal electron acceptor in the respiratory chain. Nitrate is only reduced to nitrite and not further to nitrogen gas. Nitrate is respired by the symbionts under fully aerobic conditions at the same rate as under anaerobic conditions. The bacterial symbionts contain a nitrate reductase that is associated with the membrane-containing fraction of the symbiont cell and that is sensitive to respiratory inhibitors; both features are consistent with the respiratory role of this enzyme. A review of nitrate reductase in chemoautotrophic syrnbionts suggests that nitrate respiration may be common among these symbioses. Symbiont nitrate reductase may be an ecologically important factor permitting the survival of animal hosts in oxygen-poor environments.

Description: Zooplankton sampling took place during cruise 5 Leg 3 of the R.V. Meteor (March-June 1987) in three hydrographically and ecologically different areas of the Arabian Sea (Indian Ocean): an upwelling area at the coast of Oman; an oligotroph area in the central Arabian Sea; and a shelf area off the coast of Pakistan. All three areas were expected to hace similar ichthyoplankton and cephalopod components and similar light conditions. These are important prerequisites for the present comparative study, which is concerned with the importance of the structure of the water column (physical stability and prey availability), compared with the influence of the light intensity (day/night) on the vertical distribution of species and size classes of fish larvae and cephalopod paralarvae in the subtropical pelagial. First results show that the vertical structure of the water column, especially the occurrence of a pynocline and the varying mixed-layer width, either directly or indirectly had important impact on the vertical distribution patterns of both fish larvae and cephalopod paralarvae. In addition, cephalopods were influenced more consistently by the diurnal change of light intensity than fish larvae. Both taxa occurred mainly below the mixed surface layer. However, cephalopod paralarvae preferred shallower depths than fish larvae in all three areas and were closer related to the pycnocline than fish larvae in most cases. In the absence of a significant pycnocline, larvae appeared close to the surface.

Description: During leg 1 of Meteor cruise 10 in March/April 1989 at 18 circ N, 30 circ W, the high spatial and temporal resolution of hydrographic CTD-stations indicated that the study site was in a hydrographically complex region in the transition zone between the Canary Current and the North Equatorial Current at the southern boundary of the subtropical gyre. Strong variability was found within the upper 120 m due to interleavings of warmer and saltier subtropical salinity maximum water with colder and less saline upper thermocline water. The interleavings caused unexpected nose-like temperature, salinity, nitrate and oxygen profiles yet not described in the literature. A second variability source was found in the Central Water area, because the study area was situated in the vicinity of the Central Water Boundary dividing North and South Atlantic Central Water. Hydrographic analysis of the study shows that interpretations of biological and chemical data can only be done in conjunction with high resolution CTD-profiling

Description: The RNA/DNA ratio is a useful indicator of the nutritional condition of fish larvae. The presented analytical procedure is an improvement of Clemmesen's (Meeresforschung 32: 134-143, 1988) methodology which involves purification of fish larvae tissue homogenates and subsequent fluorescence-photometric measurements using specific nucleic acid dyes. The modifications concern the homogenization and nucleic acid extraction procedures. A 'shaking mill' was compared to a potter Elvehjem microhomogenizer and a reduction in the washing and purification steps was achieved. Treatment of samples with ribonuclease A and subsequent fluorescence measurement using ethidium bromide was given preference compared to the DNA-bisbenzimidazole determinations due to problems arising from high self-fluorescence of the samples and the influence of 'quenching' substances disturbing the DNA-bisbenzmidazole determinations. Different RNase concentrations and their influences on RNA and DNA were checked. Recovery rates of standard RNA and DNA 'spikes' were determined. Fish larvae samples were analysed with the previous and the improved modified procedure and a correction factor to compare results measured with the 2 procedures was calculated. With the presented method the physiological condition of individual larvae and the amount of variability can be determined.

Description: Burrowing activities of the only European fiddler crab, Uca tangeri, and its resulting influence on biotope in mudflats were investigated during 1989-1990 at Ria Formosa, Portugal. Individuals use the same burrow for ca 1 wk, then occupy another or dig a new one. Overall a burrow is inhabited for ca 3 mo by several individuals before it is abandoned. Vacated burrows decay within 2 to 3 wk. Burrow size and number vary with the season. Burrow density was highest in spring and early summer with ca 17 burrows m-2, and then decreased. Deepest burrows (up to 90 cm long) were found in winter, the shallowest (up to 40 cm long) in summer. Volume of the sediment moved by U. tangen varied monthly between 3000 and 6000 cm3 per m2 of mudflat. Water is only found in the lower third of the burrow. Burrow water contains less oxygen and more nitrate than the surrounding water of the Ria Formosa.

Description: Respiration and activity of eelpouts Zoarces viviparus L. were measured in an underwater respiration chamber in Kiel Bay (Germany) under short-term hypoxia. Respiration and swimming activity both declined almost continuously with decreasing oxygen saturation...

Description: Methane seeps in shallow waters in the northern Kattegat off the Danish coast form spectacular submarine landscapes - the 'bubbling reefs' - due to carbonate-cemented sandstone structures which are colonized by brightly coloured animals and plants. These structures may be 100 m2 in area and consist of pavements, complex formations of overlying slab-type layers, and pillars up to 4 m high. The carbonate cement (high-magnesium calcite, dolomite or aragonite) is 13C-depleted, indicating that it originated as a result of microbial methane oxidation. It is believed that the cementation occurred in the subsurface and that the rocks were exposed by subsequent erosion of the surrounding unconsolidated sediment. The formations are interspersed with gas vents that intermittently release gas, primarily methane, at up to 25 1 h-' The methane most likely originated from the microbial decomposition of plant material eposited during the Eemian and early Weichselian periods, i.e. l00 000 to 125 000 years B.P. Aerobic methane oxidation in the sediment was restricted Lo the upper 4 cm in muddy sand and to the upper 13 cm In coarse sand. Maximum aerobic methane oxidation rates ranged from 4.8 to 45.6 pm01 dm-3 d". The rock surfaces and epifauna around the seeps were also sites of methane-oxidizing activity. Integrated sulphate reduction rates for the upper 10 cm of muddy sand gave 4.2 to 26.6 mm01 m-2 d-' These rates are higher than those previously reported from similar water depths in the Kattegat but did not relate to the sediment methane content. Since gas venting occurs over several km2 of the sea floor in the Kattegat it is likely to make a significant local contribution to the cycling of elements in the sediment and the water column. The rocks support a diverse ecosystem ranging from bacteria to macroalgae and anthozoans. Many animals live within the rocks in holes bored by sponges, polychaetes and bivalves. Stable carbon isotope composition (6'") of tissues of invertebrates from the rocks were in the range -17 to -24 'A, indicating that methane-derived carbon makes little direct contribution to their nutrition. Within the sediments surrounding the seeps there is a poor metazoan fauna, in terms of abundance, diversity and biomass. This may be a result of toxicity due to hydrogen sulphide input from the gas.

Description: During the Bremerhaven Workshop in the southern North Sea, REMOTS sediment profile lmages (SPI) were recorded in order to supplement the benthic component of the workshop and other environmentally relevant parameters investigated along a spatial gradient at an abandoned exploratory drilling site off the Dutch coast. The sampling stations were in accordance with the other studies, but due to bad weather conditions only a small proportion of the intended samples were taken. The profile data were supplemented by video recordings of the sediment surface features taken on a second cruise. The results presented here have important implications for the interpretation of other benthic and sediment samples, and may help to interpret some enigmat~cw orkshop data.

Description: Plgments are frequently used as biomarkers to study the fate of primary producers in the food web. We evaluated the effectiveness of pigment analysis in the giant aquatic isopod Saduna entomon, an important link in the food chain of the Baltic Sea. Specimens were collected on a transect across Puck Bay (Gulf of Gdansk, Poland) at stations comprising different sedimentary conditions and varying supply of micro- and macroalgal material. In laboratory experiments S. entomon was fed different kinds of prey. Different marker coinbinations were found in the intestlnal tissue, resulting from predation on herbivorous and carnivorous species. Analyses of field samples revealed that S. entomon, living in the sedlment surface, ingests freshly sedimented phytoplankton as well as plant detritus ß-carotene and the xanthophyll echinenone were found in the carapax and gonads, supporting the view that these substances are assimilated and servve as antioxidant protection of lipids and other macromolecules.

Description: The quality of the food, especially origin and size, of the only European fiddler crab, Uca tangeri (Eydoux, 1835), was studied over a 2 yr period. In experiments with fluorescent microparticles, all particles smaller than 250 pm were ingested regardless of thelr chemical composition. Comparisons of sediment, feeding pellets and faeces showed that U. tangeri feeds primarily on microalgae which are completely extracted from the sediment. It also consumes vascular macrophytes (Arthrocnemum spp.), macroalgae, detritus and fish carcasses.

Description: Abstract l. In Antarctica, two Adélie penguins were implanted with heart rate (HR) transmitters and released in their breeding colony where they resumed incubation. 2. HR while at rest and lying in the colony were 67 and 77 beats per min (bpm), respectively. 3. For diving experiments, the birds were introduced into a still-water canal, 21 m long, with one respiration chamber at each end. 4. The birds swam underwater for 49 and 76% of the time at speeds of 1.5 and 2.5 m/sec, respectively. 5. When floating quietly at the surface, HR in the first penguin was 89 bpm. 6. Pre-dive HR varied with duration of the inter-dive interval, being highest (250 bpm) when the bird dived in rapid succession (surface times 〈 5 see) and close to diving HR when surface time was 50 sec. 7. Mean HR while diving was constant (107 bpm) and did not vary either with surface time, or with time submerged (0–15 sec). 8. Pre-dive HR and diving HR were not correlated, 9. The extent of bradycardia upon immersion was dependent upon surface time. 10. There was a good correlation between HR and oxygen consumption in both birds, suggesting that HR might be used to determine energy expenditure.

Description: Occurrence of stomach wall granulomas in European smelt was studled at 6 locations along the German North Sea coast. Identification of larval nematodes inhabiting these granulomas is provided for the first time. Three species, isolated by pepsin-HC1 digestion, are involved: Hysterothylacium cf. cornutum, Cosmocephalus obvelatus and Paracuaria tridentata. 72% of all stomachs examined were affected. The ratio of number of granulomas to number of the 3 larval species free in the mesentery was 1:1.3. Differences in prevalences and intensities were significant among all locations. Granuloma abundance was highest in samples from the Elbe estuary decreasing in the other locations relative to their distance from the Elbe. There was no relationship between the number of larvae encapsulated on the stomach wall and the number of larval P decipjens in the musculature (r = 0.3). Host condition factor could not be related to number of granulomas. Smelt appaears to be an important transmitter of spiruroid nematode larvae to marine birds in this region.

Description: ATP content and metabolic activity of benthic foraminifera were determined from deepsea sediments of the Norwegian-Greenland Sea. Metabolic activity was analysed by measurements of Electron Transport System (ETS] activity and heat production. This, combined with live observations, revealed 2 survival strategies. Ruperlina stabilis, an obligate suspension feeder, is adapted to conditions in which it receives a steady input of particles throughout the year, enabling it to maintain a relatively high ATP content (153 f 23 ng ATP ind.-l) with a reduced ATP turnover rate (0.008 S-'). In contrast Cribrostomoides subglobosum, Pyrgo rotalaria and Rhabdammina abyssorum undergo large (up to 10-fold) fluctuations in seasonal values of ATP and heat production, but retain a high, relatively constant ATP turnover rate (i.e. seconds). Such a rapid turnover allows these foraminifera to take quick advantage of sudden nutrient inputs; this state of readiness, however, is maintained at the cost of the protoplasm, which benthic foraminifera are apparently capable of metabolizing in times of starvation. C. subglobosum and P rotalaria responded to several sedimentation events with an increase in ETS activ~tys;i ngle cells sometimes showed extremely high ATP values (50- to 100-fold increase), reflecting an individual physiological response to food input to the deep-sea.

Description: Since large, rapidly-sinking particles account for most of the vertical flux in the ocean, mechanisms responsible for particle aggregation largely control the transport of carbon to depth. The particle flux resulting from a variety of different phytoplankton bloom conditions was simulated with a numerical model in which phytoplankton growth dynamics were combined with physical aggregation, particle size-dependent sedimentation and degradation. Model results demonstrated that particle flux to the deep ocean be generated by solely invoking physical aggregation during phytoplankton blooms. Sensitivity of the model in response to variations of both physico-chemical and biological paramters was tested. The model outcome, described as the fraction of export production leaving the upper ocean carbon pool, proved to be most sensitive to biological variables such as phytoplankton cell size, stickness, and growth characteristics (i.e. solitary vs chain-forming). Changes in these factors strongly affect the efficiency of the “biological pump” and could be explain interannual and geographic variance in deep-ocean flux.

Description: Sediment cores from the Norwegian and Greenland Seas and the Nansen Basin were studied to determine the origin of sediment pellets, centimetre-sized aggregations of clay to sandsized sediment occurring in the cores. By comparing the grain size, grain shape and composition of the pellet sediments to sediments collected directly from the surfaces of sea ice in the Nansen Basin and from icebergs in the Barents Sea, the pelleted sediment was found to be more similar to that in the icebergs than that on the sea ice. The pellets may be formed on, in or under a glacier or during transport on/in an iceberg. When icebergs overturn or melt, the pellets fall out and are consolidated enough to survive a drop of up to 4 km to the ocean bottom and to retain their integrity even after burial on the seafloor.

Description: An association of Argonauta argo Linnaeus 1758 with Phyllorhiza punctata von Lendenfeld 1884 was observed in situ and collected north of Bohol Island in the Philippine archipelago. The argonaut held the exumbrella of the live lellyfish with its lateral and ventral arms. About half of the medusa bell surface was damaged and large pieces of mesogloea were lacking. The affected exumbrella area was charactenzed by the presence of masses of rod-like bacteria which did not occur on the undamaged ciliated surface. The center of the bell showed 2 holes interpretated as bite marks from the cephalopod. Five channels led from the holes to the medusa's gastric cavity. This connection possibly enabled the argonaut to feed on the tissue and to access particles caught by the secondary mouth papillae of the oral arms of P. punctata. Furthermore, the association could serve A. argo as protection or camouflage against predators because of the stinging capability of the scyphomedusa.

Description: During R.V. Polarstern expeditions ARK IV/3 and ARK VI/1, well preserved diatom assemblages were recovered from particle-laden sea ice collected from the western Barents Shelf and the Arctic Ocean between Svalbard (81°N) and the Nansen-Gakkel Ridge (86°N). Distinct variations in the abundance pattern and species composition of diatoms were found north and south of ca 83°N. Highest diatom concentrations were encountered in multi-year sea ice in the core of the Transpolar Drift Stream between 83 and 86°N. In this area diatom assemblages are dominated by marine-?brackish benthic species. Apparently, these assemblages originate in shelf waters north and east of Siberia, where they are incorporated into the sea ice as a bottom ice assemblage. During the transport of the ice floes across the Eurasian Basin within the Transpolar Drift Stream, seasonal basal freezing and surface melting processes may have led to an accumulation of diatoms at the sea ice surface. South of ca 83°N the sea ice samples contained significantly lower numbers of diatoms, dominated by freshwater taxa. Between 83 and 81°N these assemblages are dominated by planktonic freshwater taxa, but on the Barents Sea Shelf east of Svalbard significant numbers of benthic freshwater taxa and benthic marine-?brackish species also are found. This ice may originate in the Barents Sea and/or the Kara Sea, which receive a large influx of freshwater from Siberian rivers.

Description: Epibiosis on the shells of Littorina littorea (L.) varies between populations. While snails from the Helgoland intertidal zone (North Sea) rarely carry any epibionts, subtidal snails from the Kiel Bight (Baltic Sea) are frequently fouled. This study shows that L. littorea lacks typical anti-fouling defence adaptations such as mechanical, physical or chemical defences. Our enclosure experiments suggest that epibiosis on the shells is inversely correlated to L. littorea population density. At high densities snails frequently pass over one another and subsequent grazing, bulldozing and/or foot mucus secretion may contribute to the inhibition of epibionts. Consequently, the observed differences in shell epibiosis between the 2 L. littorea populations may to a large extent be explained by considerably higher L. littorea abundances in the Helgoland intertidal zone. Differences in habitat conditions probably play a secondary role. We suggest that the fouling inhibiting factors associated with high population density (mucus secretion, bulldozing, mutual grazing) are to be considered as a biological disturbance which effectively blocks recruitment by most potential colonizers.

Description: The term Cape Verde Frontal Zone is introduced to characterize the southeastern corner of the subtropical gyre circulation in the North Atlantic Ocean far west of the upwelling area off the Mauretanean shelf. Two water mass fronts, one overlying the other, are identified with a quasi-synoptic set of CTD-OZ and nutrient data from November 1986. In the warm water sphere we encounter North and South Atlantic Central Water (NACWISACW) superimposed on extensions of Mediterranean outflow and Antarctic Intermediate Water. The Central Water Boundary, as the separator of NACW from SACW, represents the southeastern side of the Canary/North Equatorial Current system. It acts as a barrier between the well-ventilated, nutrient-poor inner part of the basin-wide circulation of the North Atlantic and the shadow zone with its lowly oxygenated and nutrified cross-equatorial influx. Year-long current meter records, having fluctuations over typical time scales of 5(1`90 days, attest to the highly variable nature of the Cape Verde Frontal Zone. Incidentally, we observe in the data an intrathermocline eddy, called Meddy BIRGIT, which has a double maximum in the vertical salinity structure. Simultaneous Lagrangian observations by RiCHAttDSON et al. (1989, Journal of Physical Oceanography, 19, 371-383) confirm the expected anticyclonic motion of this salt lens, which must have travelled without significant mixing for at least 2500 km from its likely generation region in the Gulf of Cadiz.

Description: For a 6 wk period covering the time before, during, and after the phytoplankton spring bloom, macroscopic aggregates (2 0.5 mm diameter) were repeatedly collected and water column properties simultaneously measured at a fixed station in the Southern North Sea. Distinct changes in aggregate structure and composition were observed during the study. Predominantly detrital aggregates during the early phase of the study were followed by diatom-dominated algal flocs around the peak of the bloom. Mucus-rich aggregates containing both algal and detrital components and with large numbers of attached bacteria dominated the post-bloom interval. The phytoplankton succession within the aggregates closely reflected the succession in the water column with a time delay of a few days. Algal flocculation did not occur as a simultaneous aggregation of the entire phytoplankton community, but as a successional aggregat~on of selected diatom species. Although the concentrations of inorganic nutrients diminished considerably during the development of the phytoplankton bloom, the termination of the bloom appeared to be mostly controlled by physical coagulation processes. The importance of biologically-controlled factors for physical coagulation is discussed.

Description: Aggregate size and abundance were monitored in situ at a fixed station in the southern North Sea during a 6 wk investigation which covered the phytoplankton spring bloom and the pre- and post-bloom periods. Particle aggregates were abundant dunng the entire period of study. Biologically derived material, such as algal cells, played a central role in aggregate formation. Maximum total aggregate volume coincided with the peak of the bloom. Maximum aggregate size did not correlate with either phytoplankton biomass or total suspended matter Despite a distinct increase in the amount of aggregated material during the development of the bloom, maximum aggregate size remained at about 1 mm diameter during most of the investigation. The formation of large, marine-snow-sized aggregates up to 5 cm in longest dimension, which was restricted to a short period following the decline of the phytoplankton bloom, coincided with comparatively low shear rates. Results are consistent with physical coagulation models. Aggregate formation can be described by a 2-state system in which the amount of aggregated matter is low dunng the development and following the decline of a bloom, and high during the peak of a bloom.

Description: After acclimation to 100, 75 and 50 % of sea water (SW) external salinities, a significant reduction in MET (Mean Epithelial Thickness) and MDR (Mean Diverticular Radius) indicates a decrease in the digestive cell volume dependant on the lowering of environmental salinity. The interstitial connective tissue seems to be unable to osmoregulate and hence stand severe changes in cell size depending on external salinity. 50 % SW acclimated periwinkles show a general pattern of general stress response (decreasing MET and MDR, and increasing ND ~Numerical Density of lysosomes- and lysosomal size). A reduction in number and size of digestive lysosomes in winkles acclimated to 75 % of Sea Water evidences the functioning of reglatory mechanisms of digestive cell volume.

Description: Geostrophic volume transports in the upper 500 m are computed from historical hydrographic data for the area off the Brazilian coast west of 30°W and between 7° and 20°S. On the basis of water mass distributions, potential density surfaces of σθ = 27.05 kg m−3 (360–670 m) and σθ = 27.6 kg m−3 (∼1200 m) are used for referencing the meridional and zonal components of the geostrophic shears, respectively. Near 15°S a northwestward flow of 8 Sv crosses 30°W. This current reaches the shelf near 10°S in February and March, the only two months for which observations are available near that latitude along the coast; of the 8 Sv, about 4 Sv continue towards the northwest into the North Brazil Current while another branch also carrying 4 Sv turns southward as the beginning of the Brazil Current. Between 10° and 20°S the Brazil Current does not appear to strengthen appreciably, but because of the likely existence of flow on the shelf these transport values represent lower limits to the actual ones. At 30°W, another westward flow of approximately 8–10 Sv enters the area near 10°S and serves to strengthen the North Brazil Current. The total transfer of 12 Sv or more from the South Equatorial Current into the North Brazil Current and later to other currents and the northern hemisphere may be an important factor contributing to the well-known weakness of the Brazil Current in its more northerly latitudes.

Description: The accuracy of species-specific phytoplankton growth rates estimated by cell cycle analysis was tested with the dinoflagellate Prorocentrum minimum (Pav.) Sch. under conditions of altered nitrogen and phosphorus availability. Reduced nutrient availability caused major changes in the duration of cell cycle phases. At the nutrient level of complete f/2 media, the length of the combination of S, G2, and M phases was about 8 h at growth rates of 0.53 to 0.56 d-' A decrease in ~ 0 ,o~r N-O3 concentration extended the S+G2+M phase to about 15.5 to 17.7 h at growth rates ranging from 0.41 to 0.30 d-' Changes in phase durations dld not significantly affect growth rate estimates. In addition, a minimum growth rate, calculated from the maximum values on phase fraction curves, was shown to be usable as an error detector in some cases. Results support the validity of cell cycle analysis to measure in situ growth rates.

Description: Two stacked outflow cores of the Mediterranean Water undercurrent pass through a broad “gateway” between Cape St. Vincent and Gettysburg Bank entering the Iberian Basin. The upper core (depth ∼750 m, σ1=31.85) shows a strong tendency to follow the contours of the Portuguese continental rise. Yet, the lower core (depth ∼1250 m, σ1=32.25) primarily meanders west and northwestward forming large blobs of Mediterranean Water. The predominance of isolated Meddy structures embedded in a background field is reflected in a long-term current meter record from the deep Iberian Basin.

Description: Geostrophic computations from historical data across the Brazil Current at 23° and 24°S lead to transports of 10.2 and 9.6 Sv, respectively. Data exist from all four seasons at about 24°S, but no seasonal signal can be seen in the baroclinic transport of the Brazil Current there. At 33°S the Brazil Current transport is estimated to be 17.5 Sv. A recirculation cell of 7.5 Sv is found in the western South Atlantic south of 28°S. The major problem in computing transport of the Brazil Current is not with determining the correct reference depth, but with the Brazil Current flowing partially over the shelf and therefore not being sampled completely by deep-water hydrographic stations. As long as the vertical distribution of water masses is taken into account for choosing a reference depth, geostrophic computations lead to results consistent with previous estimates.

Description: Sinking and sedimentation rates of a natural phytoplankton community were simultaneously measured during the course of a diatom winterkpring bloom in a 13m3 experimental mesocosm. Sinking rate was determined directly in settling columns and was calculated from sediment trap catches. The 2 methods yielded significantly different results. Whole-community as well as speciesspecific sinking rates varied over time. These variations were related to changes of the environmental conditions. Over a 26d study period, a total of 7.5g cm-' was collected in the sediment traps. Viable phytoplankton cells were the primary component of the sedimented matter while zooplankton fecal pellets contributed on average less than 10 %. Assuming the Redfield atomic ratio for the collected material, the amount of carbon which sedimented during the winterkpring bloom could be predicted from pre-bloom nutrient concentrations. The daily sedimentation rate varied considerably over time and displayed a characterisbc pattern. This pattern is evidently a function of both suspended phytoplankton biomass and the temporal variation in whole-community sinking rate.

Description: During the Anglo-German Antarctic expedition in February 1982 macroplankton was collected in the waters off the Antarctic Peninsula. Macroplankton compos~tions at 36 stations were compared and degrees of similarity submitted to hierarchical cluster analysis. Results demonstrate strong spatial heterogeneity, which could be attributed to the different water masses in this region. These dissimilarities demarcate 4 provinces, each characterized by a distinct macroplankton community: (l) The 'Oceanic Community' comprises the stations influenced by the Westwind Drift; oceanic forms are typical (e.g. the hyperiid amphipod Vibilia antarctica, and the polychaete Vanadis antarctica). (2) The 'Bellingshausen Water Community' is influenced by Bellingshausen Sea water and oceanic specles are scarce; large numbers of Antarctic krill Euphausja superba occur but shallow water forms are also abundant. (3) The 'Nentic Community' consists of stations in the shelf water of the southern Bransfield Strait; it is charactenzed by postlarvae of several fish species, and meroplanktonic larvae of benthic forms. Large krill concentrations, however, are also encountered. (4) A 'Transitional Community' exists in environments where various water masses mingle (e.g. at shelf slopes). This community lacks typical forms.

Description: A new species of giant unicellular parasite inhabiting the gills of squid hloroteuthis robusta is described from specimens collected from the northeastern Pacific Ocean. Hochbergia moroteuthensis gen. et sp. nov. belongs to a recently reported group of protistans whose taxonomic affinities are as yet unknown. Members of the group parasitize cephalopods and have a characteristic aspect: most of the body wall is raised into close-fitting triangular plates and there is a holdfast region, devoid of plates, by which the parasites attach to the host. H. moroteuthensis is the first species of the group to be named. The general form of the body, the precise number and arrangement of plates, and the morphology of the holdfast reglon are described.

Description: Existing information is synthesized and new data presented to describe the flow of near-bottom water from the Weddell Sea into the Scotia Sea and westward through Drake Passage along the continental slope. The water characteristics and currents along the northern margins of the South Sandwich Island Arc are examined. Long-term current measurements in the bottom waters at locations over the outer shelf and slope and along the continental rise show persistent flow from Atlantic to Pacific along isobaths at speeds of 10–20 cm s−1. Three sources for the waters in these currents are identified and discussed. At the deepest levels, Weddell Sea Deep Water enters the Scotia Sea near 40°W through a depression in the South Scotia Arc and then flows westward, constrained by the bottom topography. This cold, fresh, oxygenated bottom water then flows west to enter Drake Passage via a gap in the Shackleton Fracture Zone at the base of the continental slope northwest of Elephant Island. Mid-depth water may flow from the Weddell Sea to the Scotia Sea through the Powell Basin (sill depth approximately 2000 m) located west of South Orkney Island near 48°W. The westward flowing waters along the shelf and upper continental slope, which are denser than those immediately offshore, may be a continuation of the Polar Slope Current from the Weddell Sea or may be derived principally by convection from the shelves of the South Sandwich Island Arc. A vertical section north of Elephant Island shows downslope convection off the shelf, analogous to the observed at many locations around Antartica.

Description: Continuous current measurements at the 1000 m level were obtained in the central Canary Basin of the northeast Atlantic near 33°N, 22°W for 2398 days. Even with this very long time series no statistically significant mean current could be estimated at that level, because the energetic fluctuations are large compared to the weak mean. In the eddy scale range, i.e. at current fluctuations are scales between 47 and 455 days, a pronounced anisotropy between zonal and meridional components is apparent. For the first time in the subtropical North Atlantic gyre our data allow confirmation of the expected spectral decrease beyond the eddy scale peak in an eastern basin. With respect to future global experiments we wonder if our results from an eastern basin location are representative for the general circulation at mid-ocean sites?

Description: Helium data from the waters of the Bransfield Strait, the southern Drake Passage and the northwestern shelf of the Weddell Sea are presented. The 3He profiles from the eastern and central basins of the Bransfield Strait show maxima (δ3He ≈ 7%) below the sill depths that separate the strait from the surrounding open ocean. The 3He excess is interpreted as a local injection of a 3He-rich helium component into the deep waters of the Bransfield Strait from backarc rifting. Tritiogenic 3He and excess 3He from mixing with Circumpolar Deep Water are excluded as possible sources. The estimated 3He/4He ratio of the injected helium component (2.4–5.0 × 10−6) is less than that of pure mantle helium and may contain radiogenic helium from continental crustal material which underlies the Bransfield Strait.

Description: The microstructures and crystal fabrics associated with the development of an amphibolite facies quartzo-feldspathic mylonitic shear zone (Torridon, NW Scotland) have been investigated using SEM electron channelling. Our results illustrate a variety of microstructures and fabrics which attest to a complex shear zone deformation history. Microstructural variation is particularly pronounced at low shear strains: significant intragranular deformation occurs via a domino-faulting style process, whilst mechanical incompatibilities between individual grains result in characteristic grain boundary deformation accommodation microstructures. A sudden reduction in grain size defines the transition to medium shear strains, but many of the boundaries inherited from the original and low shear strain regions can still be recognized and define distinctive bands oriented at low angles to the shear zone margin. Grains within these bands have somewhat steeper preferred dimensional orientations. These domains persist into the high shear strain mylonitic region, where they are oriented subparallel to the shear zone margin and consist of sub-20 μm grains. The microstructures suggest that the principal deformation mechanism was intracrystalline plasticity (with contributions from grain size reduction via dynamic recrystallization, grain boundary migration and grain boundary sliding). Crystal fabrics measured from the shear zone vary with position depending on the shear strain involved, and are consistent with the operation of several crystal slip systems (e.g. prism, basal, rhomb and acute rhomb planes) in a consistent direction (probably parallel to a and/or m). They also reveal the presence of Dauphine twinning and suggest that this may be a significant process in quartz deformation. A single crystal fabric evolution path linking the shear zone margin fabric with the mylonitic fabric was not observed. Rather, the mylonitic fabric reflects the instantaneous fabric which developed at a particular location for a particular shear strain and original parental grain orientation. The mature shear zone therefore consists of a series of deformed original grains stacked on top of each other in a manner which preserves original grain boundaries and intragranular features which develop during shear zone evolution. The stability of some microstructures to higher shear strains, the exploitation of others at lower shear strains, and a continuously evolving crystal fabric, mean that the strain gradient observed across many shear zones is unlikely to be equivalent to a time gradient.

Description: The spatial distribution of the subtropical salinity maximum is identified using historical and recent data from the eastern North Atlantic. In the regions with high frequency of occurrence of the salinity maximum, the relative contributions of advection, eddy diffusion and double diffusion to the salt balance below the maximum salinity layer are determined. McDougall's (1984, Journal of Physical Oceanography, 14, 1577–1589) salt balance equation for neutral surfaces is used in this analysis. The data base consists of two meridional CTD sections along 33° and 27°W between 10° and 35°N, mean temperature-salinity profiles in 5° × 5° squares presented by Emery and Dewar (1982), and mean velocity profiles in 3° × 3° squares evaluated by Stramma (1984, Journal of Marine Research, 42, 537–558). The tropical salinity maximum tongue is found to be quite persistent in its salinity value and its geographic distribution, but less clearly in its vertical or isopycnal position. Double diffusion due to salt-fingering appears to be an important process for the salt balance below the salinity maximum layer. An approximate estimate of the double-diffusive salt flux is obtained. Near the subtropical source region, the double-diffusive salt flux is balanced primarily by isopycnal advection; further to the south it is also balanced by isopycnal eddy diffusion. Maximum double-diffusive fluxes correspond in magnitude to the mean salt flux caused by the excess in evaporation at the surface in the central subtropics. The resulting isopycnal and diapycnal eddy-mixing coefficients derived by a linear inversion technique have the reasonable values of Ki = (11 ± 5) × 102 m2 s−1 and Kd = (4 ± 2) × 10−5 m2 s−1. Considering the intermittency of the double-diffusive process, limiting values for the mean eddy-mixing coefficients are determined by neglecting the contribution of the double-diffusive salt fluxes. This leads to Ki = (5 ± 2) × 102 m2 s−1 and Kd = (5 ± 1) × 10−5 m2 s−1 for the isopycnal and diapycnal mixing coefficients, respectively.

Description: An analysis of published results on the dispersion behavior of SOFAR floats indicates a systematic depth dependence of the mixing length in the North Atlantic subtropical gyre. In contrast to the integral time scale, the length scale appears to be independent of eddy intensity in the thermocline (Lx, Ly ∼ 80, 45 km) and in the deep ocean (Lx ∼ Ly : 20 – 30 km). A similar decrease with depth is revealed by particle dispersion in an eddy-resolving circulation model and interpreted as an enhanced effect of wave behavior in the weaker, subthermocline flow. The only weak anisotropy of deep float dispersion suggests an influence of bottom roughness on the structure of eddy variability.

Description: A cyclonic cold-core eddy in the Northeast Atlantic of about 100 km in diameter at the sea surface was investigated in May 1985, approximately 3 wk after it had separated from the Polar Front. A strong thermocline, which was shallower but more pronounced than in the ambient water, separated a warm surface layer within the eddy from deeper cold water, while horizontal salinity gradients marked the boundary to the ambient water. The cold-core eddy could be distinguished from amblent Northeast Atlantic water in terms of its nutrient chemistry, phytoplankton species distribution and abundance, bacterial numbers and cell size. The surface layer of the eddy was distinct from deeper eddy water, and was characterized by high concentrations of chlorophyll a, total phytoplankton biomass, dinoflagellates and bacteria. At the eddy's margin diatoms were predominant. It is argued that the physical isolation of the eddy surface layer due to the formation of a shallow thermocline led to rapid utilisation of nutrients. This probably enabled the development of a dinoflagellate-dominated phytoplankton population and of organisms capable of heterotrophic regenerative processes.

Description: The orientation of shear bands relative to foliations defined by elongated mineral aggregates, is often used to determine the large-scale sense of displacement in ductile faults. Data from contact strain zones at the bases of large overthrust complexes in the Eastern Alps and the Betic Cordilleras demonstrate that there is not always a simple geometrical relation between shear band orientation and sense of vorticity in bulk non-coaxial flow. In addition to single shear band sets that show displacements synthetic with the large-scale displacement, there are single sets with antithetic displacements, and conjugate sets. The last two observations are at variance with published data and interpretations, and cast doubts on the general applicability of shear bands as indicators of large scale flow kinematics.

Description: Time-course measurements of 15N tracer kinetics in particulate organic and in N+4 pools from tropical and temperate regions were used to test several compartmental models describing the exchange of I5N tracer in microplankton communities. Several lines of evidence suggested the involvement of a third, dissolved pool, arbitrarily labelled dissolved organic nitrogen (DON). Although the kinetic patterns of tracer movement were different between the tropical statlons and the temperate one, the same 3-compartmental model in which PON and DON can exchange material only through the intermediate of NH: gave the best fit. Only the transfer coefficients were modified. Results show that compartmental analysis is useful for the estimation of compartmental transfer rates and for testing the assumptions implicit in any given model.

Description: Large Protista of unknown taxonomic affinities are described from 3 species of coleoid squids, and are reported from many other species of cephalopods. The white to yellow-orange, ovoid cyst-like parasites are partially embedded within small pockets on the surface of the gills, often in large numbers. Except for a holdfast region on one side of the large end, the surface of the parasite is elaborated into low triangular plates separated by grooves. The parasites are uninucleate; their cytoplasm bears lipid droplets and presumed paraglycogen granules. Trichocysts, present in a layer beneath the cytoplasmic surface, were found by transmission electron microscopy to be of the dinoflagellate type. Further studies are needed to clarify the taxonomic position of these protists.

Description: In a regional study of the eastern North Atlantic Ocean east of 35°W between 41°N and 8°N the mean meridional ocean temperature flux was computed from oceanographic and meteorological measurements using the direct method. In the area of the permanent subtropical gyre between 36°N and 22°N, a southward geostrophic temperature flux dominates. The Ekman temperature flux is weak and changes from a southward flux north of 32°N to a northward flux south of 32°N. In the area of the North Equatorial Current and in the tropics the Ekman temperature flux is comparable in magnitude to the geostrophic temperature flux. Therefore, the total temperature flux changes to a northward direction at 20°N, where the geostrophic transport is still to the south, and becomes large in the tropics, where both components show northward temperature fluxes. The heat flux divergence for the area investigated leads to an ocean heat gain of 0.19 PW. A comparison of annual mean temperature fluxes with temperature fluxes of east-west CTD sections from the winter half-year shows a small seasonal signal in the geostrophic temperature flux in the subtropical gyre but large differences in the tropics. The seasonal changes for the Ekman temperature fluxes are weak.

Description: The process of biotope occupation by the anenome Metridium s en~l ein the absence of pelagic larvae has been investigated by an in situ monitoring experiment lasting from July 1981 to April 1982. This process is composed of several behavioral phases: dispersion of the anemones on the new substrate by h ~ g hlo comotory activity, colonization of the 'chosen' habltat by intensive asexual reproduction and finally, a stationary phase. One characteristic of the particular ecological situation in the Flensburg fjord (Western Baltic) seems to be the absence in M senile of sexual reproduction and larvae resulting in a mono- or oligoclonality of the Fjord population. This study shows that even if pelagic dispersal is missing, local dispersion and proliferation can be assured by locomotion and laceration.

Description: Analysis of stomach contents and predator-prey relations of 168 swordfish from the western North Atlantic Ocean is presented. The predominant food of swordfish is squid (82% by frequency of occurence) followed by fish (53%) consisting primarily of gladis, scombrids, butterfish, bluefish, and sand lance. Average food volume in stomach is 1% of average body weight. Estimates of daily ration range from 0.94% to 1,6% of avergae body weight, with yearly consumption ranging from 3.4 to 5.8 times average body weight per year. The prey biomass consumed by the sowrdfish population in the Georges Bank area is estimated to range from 2,100 to 11,000 mt over a residency time of 5 mo.