ALBERT

Description: Stratigraphy is the fundament for the establishment and clarification of numerous questions in geology. The problem of the stratification of fossil sediments played a decisive role in the past, and continues to do so today. If one wishes to gain insight regarding the nature of the formation of today’s deposits, and avoid serious errors in the comparison of the same, one must, of necessity, first concern oneself with the sequence of recent sediment layers.

Description: The REE-Ti silicate chevkinite has been recognised previously in Miocene ignimbrites from Gran Canaria, and in correlative offshore syn-ignimbrite turbidites. We have estimated the partition coefficients of REE, Y, Zr and Nb for chevkinite and co-existing peralkaline rhyolitic (comendite) glass using synchrotron-XRF-probe analyses (SYXRF) in order to evaluate the role of this mineral in the REE budget of felsic peralkaline magmas. The Zr/Nb ratio of the chevkinite is 1.55–1.7, strongly contrasting with Zr/Nb of 6.5 in the associated glass. Zr shows a three-fold enrichment in chevkinite relative to the residual melt, whereas Nb is enriched by a factor 〉10. The enrichment of Ce and La in chevkinite is even more significant, namely 19 wt(%) Ce and 12 wt(%) La, compared to 236 ppm Ce and 119 ppm La in the glass. Chevkinite/glass ratios are 988±30 for La, 806±30 for Ce, 626±30 for Pr, 615±40 for Nd, 392±50 for Sm, 225±30 for Eu, 142±25 for Gd, 72±20 for Dy. For trace elements, we derived KdTE of 74±25 for Y, 〉8 for Hf, 〉50 for Th, 15±5 for Nb and 3.55±0.4 for Zr. Mineral/glass ratios for co-existing titanite are 28±10 for La, 86±20 for Ce, 98±30 for Pr, 134±35 for Nd, 240±50 for Sm, 50±20 for Eu, 96±25 for Gd, 82±25 for Dy, 99±30 for Y, 45±10 for Nb and 3±0.5 for Zr. Based on these data, the removal of only 0.05 wt% of chevkinite from a magma with initially 300 ppm Ce would deplete the melt by 93 ppm to yield 207 ppm Ce in the residual liquid. Chevkinite thus appears, when present, to be the controlling mineral within the LREE budget of evolved peralkaline magmas.

Description: Savo Island is the 6-km-diameter emergent summit of an andesitic-dacitic stratovolcano, rising from the Iron Bottom Sound, 35 km NW of Honiara, Solomon Islands. Savo has erupted at least three times within recorded history and the 3,000 inhabitants maintain extensive oral traditions of past events. Through description and interpretation of the volcaniclastic sequences on the island, in conjunction with historical accounts and oral traditions, we reconstruct the eruptive processes on Savo. Block-and-ash flow (BAF) deposits are volumetrically dominant on the island within three main depositional environments: near-vent sequences, thick medial channel sequences and distal fan sequences. The deposits comprise universally non-vesicular and highly porphyritic (40–70% phenocrysts), high-silica andesite and dacite clasts. These appear to have been derived from collapsing lava domes during an 1560–1570 a.d. eruption. However, eyewitness descriptions and crater morphology suggest that similar deposits formed from dome explosions or collapses of eruption columns during later eruptions (1830–1840a.d.).Thehigh-sodiummagmas(ca.5–7wt% Na2O) apparently crystallised and strongly degassed prior to eruption. Shallow explosions were possibly caused by entrapment of magmatic gases beneath a dome or conduit plug of highly crystalline, near solid magma. Repeated sealing of the vent may have been due to inward collapse of the highly altered rocks of the surrounding hydrothermal system; these rocks probably were saturated due to contemporaneous high intensity rainfall events. BAFs were hot enough to char vegetation and attain aligned clast TRM (thermal remnant magnetism) up to 3 km from the vent, many being accompanied by ash-cloud surges. Changes with distance in the BAF deposits appear mostly dependent on flow confinement and are limited to an overall decrease in thickness and maximum clast size, and an increased definition of weak planar fabrics. In distal fan sequences, there is strong evidence for syn- and posteruptive redeposition of primary deposits. Since the Savo population is concentrated on coastal volcaniclastic fans, we consider the greatest volcanic risk to life is from BAFs, associated ash-cloud surges and lahars. Hence, the main channels and fans are designated as the highest of three relative hazard zones on a simple map prepared to aid local education and planning initiatives on Savo.

Description: Tephra fallout layers and volcaniclastic deposits, derived from volcanic sources around and on the Papuan Peninsula, form a substantial part of the Woodlark Basin marine sedimentary succession. Sampling by the Ocean Drilling Program Leg 180 in the western Woodlark Basin provides the opportunity to document the distribution of the volcanically-derived components as well as to evaluate their chronology, chemistry, and isotope compositions in order to gain information on the volcanic sources and original magmatic systems. Glass shards selected from 57 volcanogenic layers within the sampled Pliocene–Pleistocene sedimentary sequence show predominantly rhyolitic compositions, with subordinate basaltic andesites, basaltic trachy-andesites, andesites, trachy-andesites, dacites, and phonolites. It was possible to correlate only a few of the volcanogenic layers between sites using geochemical and age information apparently because of the formation of strongly compartmentalised sedimentary realms on this actively rifting margin. In many cases it was possible to correlate Leg 180 volcanic components with their eruption source areas based on chemical and isotope compositions. Likely sources for a considerable number of the volcanogenic deposits are Moresby and Dawson Strait volcanoes (D’Entrecasteaux Islands region) for high-K calc-alkaline glasses. The Dawson Strait volcanoes appear to represent the source for five peralkaline tephra layers. One basaltic andesitic volcaniclastic layer shows affinities to basaltic andesites from the Woodlark spreading tip and Cheshire Seamount. For other layers, a clear identification of the sources proved impossible, although their isotope and chemical signatures suggest similarities to south-west Pacific subduction volcanism, e.g. New Britain and Tonga– Kermadec island arcs. Volcanic islands in the Trobriand Arc (for example, Woodlark Island Amphlett Islands and/ or Egum Atoll) are probable sources for several volcaniclastic layers with ages between 1.5 to 3 Ma. The Lusancay Islands can be excluded as a source for the volcanogenic layers found during Leg 180. Generally, the volcanogenic layers indicate much calc-alkaline rhyolitic volcanism in eastern Papua since 3.8 Ma. Starting at 135 ka, however, peralkaline tephra layers appear. This geochemical change in source characteristics might reflect the onset of a change in geotectonic regime, from crustal subduction to spreading, affecting the D’Entrecasteaux Islands region. Initial 143Nd/144Nd ratios as low as 0.5121 and 0.5127 for two of the tephra layers are interpreted as indicating that D’Entrecasteaux Islands volcanism younger than 2.9 Ma occasionally interacted with the Late Archean basement, possibly reflecting the mobilisation of the deep continental crust during active rift propagation.

Description: This chapter deals with the discovery of sorbicillactone A, as an illustrative example of the fruitful cooperation within BIOTECmarin — its isolation and chemical characterization, and its biological activities. Sorbicillactone A was isolated from a strain of Penicillium chrysogenum cultured from a sample of the Mediterranean sponge Ircinia fasciculata; it possesses a unique bicyclic lactone structure, seemingly derived from sorbicillin. Among the numerous known sorbicillin-derived structures, it is the first found to contain nitrogen and thus the first representative of a novel type of ‘sorbicillin alkaloids’, apparently originating from a likewise remarkable biosynthesis. Furthermore, the compound exhibits promising activities in several mammalian and viral test systems, in particular a highly selective cytostatic activity against murine leukemic lymphoblasts (L5178y) and the ability to protect human T cells against the cytopathic effects of HIV-1. These properties qualify sorbicillactone A or one of its derivatives for animal and (hopefully) also future therapeutic human trials.

Description: The recent application of molecular microbial ecology tools to sponge-microbe associations has revealed a glimpse into the biodiversity of these microbial communities, that is considered just ‘the tip of the iceberg’. This chapter provides an overview over these new findings with regard to identity, diversity and distribution patterns of sponge-associated microbial consortia. The sponges Aplysina aerophoba (Verongida), Rhopaloeides odorabile (Dicytoceratida) and Theonella swinhoei (Lithistida) were chosen as model systems for this review because they have been subject to both, cultivation-dependent and cultivation-independent approaches. A discussion of the microbial assemblages of Halichondria panicea is presented in the accompanying chapter by Imhoff and Stöhr. Considering that a large fraction of sponge-associated microbes is not yet amenable to cultivation, an emphasis has been placed on the techniques centering around the 16S rRNA gene. A section has been included that covers the potential of sponge microbial communities for drug discovery. Finally, a ‘sponge-microbe interaction model’ is presented that summarizes our current understanding of the processes that might have shaped the community structure of the microbial assemblages within sponges.

Description: The aim of this study was to isolate bacteria that are resistant to the strong antimicrobial metabolites characteristic of Aplysina aerophoba. For this purpose, bacterial isolation was performed on agar plates to which sponge tissue extract had been added. Following screening for antifungal and antimicrobial activities, 5 strains were chosen for more detailed analyses. 16S ribosomal DNA sequencing revealed that all isolates belonged to the genus Bacillus, specifically B. subtilis and B. pumilus. Using a combination of matrix-assisted laser desorption/ ionization mass spectrometry typing of whole cells and antimicrobial bioassays against selected reference strains, the bioactive metabolites were identified as lipopeptides.

Description: In order to assess the stability of the microbial community of the sponge Aplysina cavernicola under in situ conditions, sponges were transplanted from their original location (〉40 m depth) to shallower, more light-exposed sites (7–15 m depth). Transmission electron microscopy revealed that the microbial community remained visually unchanged and free of cyanobacteria over the experimental time period of 3 months. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified partial 16S rRNA gene sequences allowed a distinction between the variable and permanent fraction of the bacterial community. Comparative sequence analysis of four variable DGGE bands revealed high sequence similarity to representatives of the Alpha- and Gammaproteobacteria and the phylum Bacteroidetes, which have been recovered previously from Mediterranean seawater as clone sequences or by cultivation. Seven (out of 12) permanent DGGE bands showed high sequence similarity to a sponge-specific, monophyletic 16S rRNA gene sequence cluster within the Acidobacteria division, and to a sequence cluster of uncertain affiliation. These sequence clusters represent members of a common microbial community that is shared among distantly related sponges from different, non-overlapping geographic regions. Four additional permanent DGGE bands showed high sequence similarity to a Betaproteobacterium, Burkholderia cepacia, which is not typically known as a marine bacterium. High-performance liquid chromatography analyses of sponge tissues revealed no changes in metabolite pattern, indicating that these compounds are expressed constitutively irrespective of the variations resulting from the transplantation experiment.

Description: We present new data on mineralogical, major and trace element compositions of lavas from the northernmost segment of the Kolbeinsey Ridge (North Kolbeinsey Ridge, NKR). The incompatible element enriched North Kolbeinsey basalts lie on a crystal fractionation trend which differs from that of the other Kolbeinsey segments, most likely due to higher water contents (~0.2%) in the NKR basalts. The most evolved NKR magmas erupt close to the Jan Mayen Fracture Zone, implying increased cooling and fractionation of the ascending magmas. Mainly incompatible element-enriched basalts, as well as some slightly depleted lavas, erupt on the NKR. They show evidence for mixing between different mantle sources and magma mixing. North Kolbeinsey Ridge magmas probably formed by similar degrees of melting to other Kolbeinsey basalts, implying that no lateral variation in mantle potential temperature occurs on the spreading axis north of the Iceland plume and that the Jan Mayen Fracture Zone does not have a cooling effect on the mantle. Residual garnet from deep melting in garnet peridotite or from enriched garnet pyroxenite veins does not play a role. The incompatible element-enriched source has high Ba/La and Nb/Zr, but must be depleted in iron. The iron-depleted mantle is less dense than surrounding mantle and leads to the formation of the North Kolbeinsey segment and its shallow bathymetry. The enriched NKR source formed from a relatively refractory mantle, enriched by a small degree melt rather than by recycling of enriched basaltic crust. The depleted mantle source resembles the mantle of the Middle Kolbeinsey segment with a depletion in incompatible elements, but a fertile major element composition.

Description: Geochemical properties of gas hydrate accumulation associated with an active gas vent on the continental slope offshore northeast Sakhalin Island in the Sea of Okhotsk have been investigated. The pore water chemistry data suggest that the gas hydrates (GHs) were formed in an environment of upward-migrating fluid combined with a mechanism of pore water segregation. The upward infiltration of water enriched mainly by Cl− and K+ species appears to occur on the background of earlier diagenesis processes within the gas vent sediments. The GHs were formed from water with chlorinity ranging from 530 to 570 mM. The δ18O and δD of GH water varied from −1.4 to −1.8‰ and from −13 to −18‰, respectively, representing a mix of seawater and infiltrating fluid water. A complex interaction of pore water, water of ascending fluid and segregated pore water during hydrate formation is also supported by water content measurements and observed gas hydrate structure. The direction of segregated water is opposite to upward fluid migration. Decreasing activity of the gas vent is inferred by comparing the present top of the recovered hydrate layer with previous observations.

Description: The metazoan parasites and stomach contents of the small-sized demersal fishes Agonus cataphractus, Buglossidium luteum, Callionymus lyra and Rhinonemus cimbrius were studied and analysed. The fishes were captured using various sampling gears at 12 stations in the central North Sea. A total of 16 metazoan parasite species were isolated: six adult Digenea, three larval and adult Cestoda, four larval and adult Nematoda and three larval and adult Crustacea. With nine parasites species each, A. cataphractus and R. cimbrius harboured the highest parasite diversity, while B. luteum and C. lyra hosted only six and five parasite species, respectively. Eighteen new hosts and four new locality records were established. No Myxozoa, Monogenea or Acanthocephala were found. Most of the detected parasites showed a wide geographical range and a low host-specificity. The composition of the parasite fauna differed between the fish species, in accordance with their different feeding behaviours. The diet of bentho-pelagic feeders ( A. cataphractus, R. cimbrius) was more diverse in comparison with the more specialised benthic feeders ( C. lyra, B. luteum). This correlated with the lower diversity of heteroxenic parasites within both small-sized benthic fish species.

Description: Triassic calciturbidites were studied in a 100-m long core and nearby outcrops of the basinal Buchenstein Formation to determine composition and thickness variations. The quantity of recognized turbidite sediment relative to background sediment changes from 15% (by volume) in the lower part to 60% in the upper part, reflecting the steady progradation of nearby platforms. The composition of the sand fraction of 214 turbidites was point-counted in thin sections. Micrite peloids (average 23%) and lithoclasts (16%) are by far the most dominant constituents. They are interpreted as two different varieties of in-situ precipitated micrite (automicrite), which probably formed under the influence of microbes and constitute the principal building material of the adjacent platforms. Platform-derived skeletal grains amount to only 0.5%. Variations in turbidite composition were quantified using Spearman's rank correlation and cluster analysis. The most significant compositional variations seem to be related to hydrodynamic sorting in the turbidity currents and to the gradual shift from distal to more proximal turbidites in the core as the platforms prograded basinward. Cluster analysis of the 214 samples shows a major subdivision into micrite and sparite dominated turbidites. Clusters associated with micrite-dominated turbidites are enriched in Radiolaria and thin-shelled bivalves, whereas the clusters related to sparite-dominated turbidites show an abundance of lithoclasts. This subdivision seems strongly related to sorting effects in a turbidity current. Point-counting of turbidites in nearby outcrops revealed a lateral variation in composition. Proximal turbidites are sparite-dominated and enriched in lithoclasts, distal portions are chiefly micrite with an open-ocean biota (thin-shelled bivalves, Radiolaria). This differentiation resembles the vertical change in composition of thick turbidite beds, and is attributed to different settling rates of the various grains in the turbidity current. There is no indication that turbidite composition fluctuated significantly under the influence of sea-level fluctuations. This is not surprising because the dominant automicrite facies of the platforms only migrates laterally, but does not change much during sea-level cycles.

Description: Recent studies have suggested that sea surface temperature (SST) is an important source of variability of the North Atlantic Oscillation (NAO). Here, we deal with four basic aspects contributing to this issue: (1) we investigate the characteristic time scales of this oceanic influence; (2) quantify the scale-dependent hindcast potential of the NAO during the twentieth century as derived from SST-driven atmospheric general circulation model (AGCM) ensembles; (3) the relevant oceanic regions are identified, corresponding SST indices are defined and their relationship to the NAO are evaluated by means of cross spectral analysis and (4) our results are compared with long-term coupled control experiments with different ocean models in order to ensure whether the spectral relationship between the SST regions and the NAO is an intrinsic mode of the coupled climate system, involving the deep ocean circulation, rather than an artefact of the unilateral SST forcing. The observed year-to-year NAO fluctuations are barely influenced by the SST. On the decadal time scales the major swings of the observed NAO are well reproduced by various ensembles from the middle of the twentieth century onward, including the negative state in the 1960s and part of the positive trend afterwards. A six-member ECHAM4-T42 ensemble reveals that the SST boundary condition affects 25% of total decadal-mean and interdecadal-trend NAO variability throughout the twentieth century. The most coherent NAO-related SST feature is the well-known North Atlantic tripole. Additional contributions may arise from the southern Pacific and the low-latitude Indian Ocean. The coupled climate model control runs suggest only the North Atlantic SST-NAO relationship as being a true characteristic of the coupled climate system. The coherence and phase spectra of observations and coupled simulations are in excellent agreement, confirming the robustness of this decadal-scale North Atlantic air–sea coupled mode.

Description: In this study, progradation and the subsequent retrogradation of a late Paleocene isolated carbonate platform (Galala Mountains, Eastern Desert, Egypt) is demonstrated by variations of distinct facies associations from the platform margin in the north to the hemipelagic basin in the south. A combination of a sea-level drop and tectonic uplift at around 59 Ma (calcareous nannofossil biozone NP5) favored the initiation of the carbonate platform. From this time onwards, the facies distribution along the platform–basin transect can be subdivided into five facies belts comprising nine different facies associations. Their internal relationships and specific depositional settings are strongly coupled with the Maastrichtian–Paleocene seafloor topography, which resulted from local tectonic movements. Patch reefs and reef debris were deposited at the platform margin and the horizontally bedded limestones on the upper slope. Slumps and debris flows were stored on the lower slope. In the subhorizontal toe-of-slope facies belt, mass-flow deposits pass into calciturbidites. Further southwards in the basin, only hemipelagic marls were deposited. Between 59 and 56.2 Ma (NP5–NP8), the overall carbonate platform system prograded in several pulses. Distinct changes in facies associations from 56.2 to 55.5 Ma (NP9) resulted from rotational block movements. They led to increased subsidence at the platform margin and a coeval uplift in the toe-of-slope areas. This resulted in the retrogradation of the carbonate platform. Furthermore the patch-reef and reef-debris facies associations were substituted by the larger foraminifera shoal association. The retrogradation is also documented by a significant decrease in slump and debris-flow deposits on the slope and calciturbidites at the toe of slope.

Description: A total of 37 juvenile Etmopterus spinax from the Norwegian Deep were examined for stomach contents and metazoan ecto- and endoparasites. These squaliform elasmobranchs were caught by benthopelagic net in May 2001 at a depth of 194–214 m. The euphausiid Meganyctiphanes norvegica and the teleost Maurolicus muelleri were the principal prey organisms. With increasing total length of E. spinax, the frequency of Meganyctiphanes norvegica prey decreased and that of M. muelleri increased. Seven different metazoan parasite species were found: adult Monogenea (2), larval and adult Cestoda (3), and larval Nematoda (2). The predominant parasites were an unidentified monocotylid monogenean and the cestode Aporhynchus norvegicus, with respective prevalences of infestation of 83.8% and 81.1%. The sites of infestation were the gills (Squalonchocotyle spinacis, Monogenea), nasal cavities (Monocotylidae indet.), body cavity (Lacistorhynchus tenuis, Cestoda), stomach wall and organs of the body cavity (Anisakis simplex, Nematoda), and stomach and spiral valve (A. norvegicus and Pseudophyllidea indet., Cestoda; Hysterothylacium aduncum, Nematoda). No other metazoan parasite taxa were found, and the musculature was free of parasites. Five new host and three new locality records were established. M. muelleri seems to be an important intermediate host for the endoparasitic nematodes which were found, with E. spinax serving as a paratenic host. E. spinax also serves as an intermediate host for the trypanorhynch cestode L. tenuis, and as the definitive host for the two monogeneans and the trypanorhynch A. norvegicus. The latter uses Meganyctiphanes norvegica as the second intermediate host in the Norwegian Deep. The relationship between the feeding ecology, habitat, and vagility of E. spinax and the resulting parasite fauna is discussed.

Description: Volcanic gases such as SO2, H2S, HCl and COS emitted during explosive eruptions significantly affect atmospheric chemistry and therefore the Earth's climate. We have evaluated the dependence of volcanic gas emission into the atmosphere on altitude, latitude, and tectonic setting of volcanoes and on the season in which eruptions occurred. These parameters markedly influence final stratospheric gas loading. The latitudes and altitudes of 360 active volcanoes were compared to the height of the tropopause to calculate the potential quantity of volcanic gases injected into the stratosphere. We calculated a possible stratospheric gas loading based on different volcanic plume heights (6, 10, and 15 km) generated by moderate-scale explosive eruptions to show the importance of the actual plume height and volcano location. At a plume height of 15 km for moderate-scale explosive eruptions, a volcano at sea level can cause stratospheric gas loading because the maximum distance to the tropopause is 15–16 km in the equatorial region (0–30°). Eruptions in the tropics have to be more powerful to inject gas into the stratosphere than eruptions at high latitudes because the tropopause rises from ca. 9–11 km at the poles to 15–16 km in the equatorial region (0–30°N and S). The equatorial region is important for stratospheric gas injection because it is the area with the highest frequency of eruptions. Gas injected into the stratosphere in equatorial areas may spread globally into both hemispheres.

Description: A new system is presented for assessing the movement of animal limbs including, after suitable calibration, quantification of limb stroke frequency and amplitude, which may be used to derive limb angular velocity and acceleration. The system is based on use of an archival unit logging data from a Hall sensor, itself set to sense magnetic-field strength at frequencies of up to 30 Hz. Typically, the Hall sensor is placed on the animal body adjacent to the limb being monitored, while a small magnet is glued to the limb. Changes in limb position result in variation of the magnetic-field strength perceived by the sensor. Captive trials were successfully performed on a harbour seal (Phoca vitulina), an Australian sea lion (Neophoca cinerea) and a hawksbill turtle (Eretmochelys imbricata), as well as on 18 free-living Magellanic penguins (Spheniscus magellanicus). The unit performed well in almost all cases, illustrating that stroke frequency was relatively invariant in any species tending, however, to be higher in smaller animals and showing that the primary variance was manifest in stroke amplitude. As an example of the utility of the system, the importance of buoyancy was demonstrated in the penguins, which had longer glide phases and lower flipper beat amplitudes at greater depths, because body air was compressed, which reduced upthrust. The small size of the system (ca. 25 g in air) makes it suitable for a wide range of marine vertebrates. Potential problems of system sensitivity, the suitability of particular recording frequencies and the value of appropriate calibration are discussed.

Description: The scientific community is engaged in a lively debate over whether and how venting from the gas-hydrate reservoir and the Earth’s climate is connected. The various scenarios which have been proposed are based on the following assumptions: the inventory of methane gas-hydrate deposits is locally enormous, the stability of marine gas-hydrate deposits can easily be perturbed by temperature and pressure changes, enough methane can be released from these deposits to contribute adequate volumes of this isotopically distinct greenhouse gas to alter the composition of oceanic or atmospheric methane reservoirs, and the mechanisms exist for the transfer of methane from deeper geologic reservoirs to the ocean and/or atmosphere. However, some potential transfer mechanisms have been difficult to evaluate. Here, we consider the possibility of marine slumping as a mechanism to transfer methane carbon from gas hydrates within the seafloor into the ocean and atmosphere. Our analyses and field experiments indicate that large slumps could release volumetrically significant quantities of solid gas hydrates which would float upwards in the water column. Large pieces of gas hydrate would reach the upper layers of the ocean before decomposing, and some of the methane would be directly injected into the atmosphere.

Description: Metastable intermediate Na–K mica represents a product of hydrothermal alteration in volcanic rocks from the alteration halo of the Waterloo massive sulfide deposit, Australia. The XRD pattern of this solid solution between paragonite and muscovite is characterized by a rational series of basal reflections with d values intermediate between the end members. Transmission electron microscopy revealed that the intermediate Na–K mica forms thick stacks that belong to a two-layer polytype. Na-rich intermediate Na–K mica typically occurs together with paragonite whereas K-rich intermediate Na–K mica is intergrown with muscovite. The intermediate Na–K mica is interpreted to have formed as a result of the incomplete transformation of K-rich mica to Na-rich mica through dissolution and recrystallization processes driven by compositional changes of the hydrothermal fluids interacting with the volcanic rocks. Alteration must have proceeded under non-equilibrium conditions because the composition of the solid solution falls into the miscibility gap separating paragonite and muscovite.

Description: Mineralogical and chemical characteristics of reworked suevite material recovered from Graupensand deposits (Grimmelfingen Formation, North Alpine Foreland Basin, Middle Miocene) are identical to those recorded in Ries suevite. 40Ar/39Ar laser probe analyses of two glass particles from Graupensand components and of a glass fragment from the Ries suevite yielded ages ranging between 14.3 and 14.4 Ma, identical within analytical uncertainties. Hitherto, the Ries impact event was dated at 15 Ma (conventional K/Ar and 40Ar/39Ar methods) whereas the Graupensande have been placed into the Ottnangian (around 18.5 Ma), on the basis of mammal biostratigraphy. Small sample masses involved in laser probe technique allowed rigorous preselection of highly pure glass particles, thus reducing possible age determination errors through partly molten (or even unmolten) mineral fragments from the Variscan crystalline basement. Our results reconfirm previous statements considering the Graupensande as reworked products of the Ries impact ejecta blanket, thus placing the age of the Grimmelfingen Formation into the Badenian (of Middle Miocene) rather than into the Ottnangian (Early Miocene).

Description: A new microplate assay for Ca(2+)-induced platelet aggregation as detected by Giemsa dye was used to screen marine invertebrate samples from the Philippines for inhibitors of human platelet aggregation. Out of 261 crude methanol extracts of marine sponges and tunicates, 25 inhibited aggregation at 2 mg/ml. Inhibition of agonist-induced aggregation in an aggregometer was used to confirm results of the microplate assay and to determine the specific mode of inhibition of 2 samples. The marine sponge Xestospongia sp. yielded a xestospongin/araguspongine-type molecule that inhibited collagen-induced aggregation by 87% at 2 micro g/ml, and epinephrine-induced aggregation by 78% at 20 micro g/ml, while the marine sponge Aplysina sp. yielded 5,6-dibromotryptamine, which inhibited epinephrine-induced aggregation by 51% at 20 micro g/ml. In this study we have found that the microplate assay is a simple, inexpensive, yet useful preliminary tool to qualitatively screen a large number of marine samples for antiplatelet aggregation activity.

Description: The massive sulfide deposits of the Kristineberg area, Sweden, occur within a 2- to 3-km-thick succession of felsic volcaniclastic rocks belonging to the Skellefte Group. The volcanic pile is intruded by a synvolcanic Jorn-type granitoid (Viterliden intrusive complex) and is overlain by a thick sequence of metasedimentary rocks (Vargfors Group). Mineralization occurs at two main stratigraphic levels, at the base of the felsic volcanic succession and at the contact with the metasedimentary rocks of the Vargfors Group. The Kristineberg Cu–Zn mine is the largest deposit (approximately 21Mt) and occurs at the base of the volcanic pile, close to the contact with the Viterliden intrusive complex. Four smaller deposits (Ravliden, Ravlidmyran, Horntrask and Nyliden) occur along the upper ore horizon. These deposits are thought to be related to a late intrusive phase of the Viterliden complex which cuts the altered volcanic rocks at the Kristineberg deposit. Within an area of about 50km 2 surrounding the Kristineberg deposit, felsic volcanic rocks between the two ore horizons are affected by extensive albite-destructive alteration (sodium depletion) and development of chlorite and muscovite (strong co-enrichment in magnesium and potassium). The Kristineberg deposit is enveloped by a large and partly transposed quartz–chlorite alteration zone, approximately 2km in diameter, and a distal but coherent pyrite–quartz–muscovite alteration zone extending as far as 4km from the deposit. Chlorite(talc) in the mine area is notably magnesium-rich and contains anomalous F, Ba, Zn and Mn. High fluorine is also present in coexisting muscovite and phlogopite. The magnesium-rich chlorite alteration contrasts sharply with the iron enrichment observed in many other felsic, volcanic-hosted Precambrian massive sulfide deposits. This may indicate fixation of iron by large amounts of pyrite in the section or entrainment of large amounts of seawater in the hydrothermal upflow zones. Kyanite is developed locally in the chlorite-rich pipe at Kristineberg in response to regional thermal metamorphism of highly aluminous alteration in the immediate foot-wall rocks. Spectacular, andalusite-bearing quartz–muscovite schists and quartz–biotite–cordierite schists also occur where the altered felsic volcanic rocks are intruded by the late Revsund granite. However, similar metamorphic mineral growth is not observed where the volcanic rocks at the contact are less altered. Deposits near the top of the felsic volcanic succession are characterized by magnesium-rich chlorite alteration in the foot wall and proximal calc-silicate assemblages (dolomite, calcite, tremolite, garnet, margarite) where the host sedimentary rocks are carbonate-rich. In general, the calc-silicate alteration is restricted to the immediate hanging wall and zones lateral to the deposits and does not represent a regionally extensive exploration target. The two main ore horizons in the Kristineberg area are not linked by any obvious discordant structures or alteration zones. However, mineral-chemical studies highlight several possible fluid flow pathways leading from the Kristineberg deposit to the Ravliden ore horizon, more than 2km upsection. Overprinting regional metamorphic minerals have inherited the hydrothermal signature of the ore-related alteration. Electronic Supplementary Material is available at http://dx.doi.org/10.1007/s00126-002-0299-y. On that page (frame on the left side), a link takes you directly to the supplementary material.

Description: The Late Archean Blake River Group is a thick succession of predominantly mafic volcanic rocks within the southern zone of the Abitibi greenstone belt. It contains a number of silicic volcanic centers of different size, including the large Noranda volcanic complex, which is host to 17 past-producing volcanogenic massive sulfide deposits. The Noranda complex consists of a 7- to 9-km-thick succession of bimodal mafic and felsic volcanic rocks erupted during five major cycles of volcanism. Massive sulfide formation coincided with a period of intense magmatic activity (cycle III) and the formation of the Noranda cauldron. Hydrothermal alteration in these rocks is interpreted to reflect large-scale hydrothermal fluid flow associated with rapid crustal extension and rifting of the volcanic complex. The alteration includes abundant albite, chlorite, epidote and quartz (silicification), which exhibit broad stratigraphic and structural control and correlate with previously mapped whole-rock oxygen isotope zonation. The Mine Sequence volcanic rocks are characterized by abundant iron-rich chlorite (Fe/Fe+Mg 〉0.5), hydrothermal amphibole (ferroactinolite) and coarse-grained epidote of clinozoisite composition (10wt% Fe 2O 3) lacking the clinozoisite solid solution. Alteration in the Mine Sequence volcanic rocks persists along strike well beyond the limits of the main ore deposits (as far as several tens of kilometers) and can be readily distinguished from greenschist facies metamorphic assemblages at a regional scale. The lack of similar alteration in the pre-cauldron sequences is consistent with limited 18O-depletion and suggests that the early history of the volcanic complex did not support large-scale, high-temperature fluid flow in these rocks. Comparisons with a much smaller, barren volcanic complex in nearby Ben Nevis township reveal important differences in the alteration mineralogy between volcanoes of different size, with implications for area selection during regional-scale mineral exploration. The Ben Nevis Complex consists of a 3- to 4-km-thick succession of mafic, intermediate and felsic volcanic rocks centered on a small subvolcanic intrusion. Alteration of the volcanic rocks comprises mainly low-temperature assemblages of prehnite, pumpellyite, magnesium-rich chlorite (Fe/Fe+Mg 10wt% Fe 2O 3) and calcite. Actinolite magnetite alteration occurs proximal to the intrusive core of the complex, but the limited extent of this alteration indicates only local high-temperature fluid circulation adjacent to the intrusion. A distal zone of carbonate alteration is located 4–6km from the center of the volcano. Although iron-bearing carbonates are present locally within this zone, the absence of siderite argues against a high-temperature origin for this alteration. These observations do not offer positive encouragement for the existence of a fossil geothermal system of sufficient size or intensity to have produced a large massive sulfide deposit.

Description: The presence and the different functional aspects of cytokine-related molecules in invertebrates are described. Cytokine-like factors affect immune functions, such as cell motility, chemotaxis, phagocytosis and cytotoxicity. In particular, cell migration shows a species-specific effect for IL-1α and TNF-α and a dose-correlated effect for IL-8, PDGF-AB and TGF-β1. Apart from some exceptions, the phagocytic effect increases significantly at all the concentrations tested and with all the species used. PDGF-AB, TGF-β1 and IL-8 provoke conformational changes in mollusk immunocytes, involving the signaling transduction pathways of phosphatidylinositol and cAMP. PDGF-AB and TGF-β1 partially inhibit the induced programmed cell death in an insect cell line, and the survival effect is mediated by the activation of phosphatidylinositol 3- kinase, PKA and PKC. The exogenous administration of these growth factors in an invertebrate wound repair model showed that they are able to control the wound environment and promote the repair process by accelerating the coordinated activities involved. Moreover, IL-1α, IL-2 and TNF-α are able to induce nitric oxide synthase. PDGF-AB and TGF-β1 provoke an increase in neutral endopeptidase-24.11 (NEP)-like activity in membrane preparations from mollusk immunocytes, while NEP deactivates the PDGF-AB- and TGF-β1-induced cell shape changes. Cytokines are also involved in invertebrate stress response in a manner extremely similar to that in vertebrates. Several studies suggest the existence on the mollusk immunocyte membrane of an ancestral receptor capable of binding both IL-2 and CRH. Furthermore, the competition found between CRH and a large number of cytokines supports the idea that invertebrate cytokine receptors show a certain degree of promiscuity. The multiple functions of cytokines detected in invertebrates underline another characteristic of mammalian cytokines, i.e. their great pleiotropicity. Altogether, the studies on the function of the invertebrate humoral factors show a close overlapping with those found in vertebrates, and the hypothesized missing correlation between invertebrate and vertebrate cytokine genes that is emerging from the limited molecular biology data present in literature might represent a very peculiar strategy followed by Nature in the evolution of cytokines.

Description: The European Water Framework Directive (WFD) requires the definition of reference conditions, i.e. pristine conditions, for all surface waters. As the present state of Danish coastal waters cannot be referred to as pristine, reference conditions have to be assessed by analysis of historical data or by the use of models. Using Randers Fjord as an example, the aim of this work was i) to demonstrate possibilities and restrictions of assessing reference conditions by historical data and by modelling; and ii) to demonstrate how ecological conditions have changed along with eutrophication. The ample historical data from Randers Fjord allowed us to assess reference conditions with respect to benthic macrophytes and benthic fauna. Models of varying complexity enabled us to assess reference conditions for nutrients, chlorophyll a, Secchi depth, and eelgrass. We conclude that models can be a useful supplement to assess reference conditions, though they are presently restricted by the lack of quantitative links between eutrophication and species composition.

Description: The effects of culture density on growth and survival of juvenile cuttlefish were tested. Groups of 1, 3 and 5 hatchlings were placed in small containers with bottom surface of 80 cm2, obtaining individual densities of 125, 375 and 625 cuttlefish m−2, respectively. Additionally, groups of 5 hatchlings were placed in containers with 2 different bottom areas (80 and 240 cm2), providing culture densities of 625 and 42 cuttlefish m−2, respectively. A total of 120 hatchlings were used and experiments lasted for 40 days. No differences were found in growth between any of the densities tested throughout the experiment until 35 days old. After this, cuttlefish placed in isolation grew significantly larger. A second experiment was conducted in a flow through system, using two rectangular tanks with bottom surface of 0.5 m2. Two groups of 25 cuttlefish hatchlings were used in this experiment, which lasted for 40 days. Both groups were fed live juvenile shrimp (Crangon crangon) during the first 5 days. Afterwards, one group was fed live fish fry of different species, while the other continued to be fed shrimp. After day 10 and until the end of the experiment, hatchlings fed shrimp grew significantly larger than those fed fish fry. Survival of hatchlings fed shrimp or fish fry after 40 days was of 100% and 68%, respectively. Total protein content of both prey types was similar. Therefore, the higher polar lipid content, especially due to the higher phosphatidylcholine and phosphatidylethanolamine levels observed in the shrimp, compared to fish fry could possibly be one of the major factor to explain the significantly higher growth rates for S. officinalis juveniles fed shrimp. Also, the percentage of polar lipids in the shrimp (47.4%) was closer to the one of juvenile cuttlefish (38.1%) than the composition of polar lipids in fish fry (10.4%). This could also be an important factor to explain the poor growth and survival obtained when feeding fish fry to the cuttlefish.

Description: The winter diet and foraging range of gentoo penguins, Pygoscelis papua, were studied at Kidney Cove, Falkland Islands. The mean wet mass of the 56 stomach-content samples collected from May to October was 32.7±47.4 g. The diet consisted generally of cephalopods, crustaceans and fish, as well as two other molluscs. Among the six cephalopod species identified, the commercially fished Patagonian squid, Loligo gahi, had the highest abundance and was also the main prey by reconstituted mass (53% of the total reconstituted mass). Lobster krill, Munida gregaria, one of five species of crustaceans, was the most abundant prey species by frequency of occurrence and by number (68% and 60%, respectively). Rock cod, Patagonotothen ramsayi, accounted for the majority of the fish diet with 34% of the total reconstituted mass. Most prey species identified in the winter diet were also abundant diet components during the breeding season. However, the known biology of the prey species and their rate of digestion indicated that, in winter, adults may forage further offshore than during the breeding season. This assumption was supported by the results obtained from two birds satellite-tracked during the study period. Both birds remained mainly in inshore waters and returned frequently ashore, but one penguin foraged up to 276 km from the coast. The differences in the foraging behaviour of the two birds were reflected in significant differences with regard to time spent underwater, distance travelled per day and calculated travelling speed. Furthermore, the progress of cohorts of L. gahi over the winter is consistent with results from life-cycle studies in this region and suggests that birds have been foraging in the feeding grounds of L. gahi.

Description: Randomly amplified polymorphic DNA markers (RAPDs) were applied in a cephalopod population study. Samples of the squid Moroteuthis ingens taken from around the Falkland Islands and Macquarie Island were used to test a null hypothesis that M. ingens forms a single, panmictic population in the Southern Ocean. Six of the 8 arbitrary RAPD primers screened produced a total of 30 reproducible polymorphic bands. Analysis of RAPD allele frequencies demonstrated high levels of variation between individuals but little variation between two sample sites. Although the differentiation between the two sites was low, subtle population structure was detected and the null hypothesis was rejected. The implications of low genetic differentiation between the two sites are briefly discussed in terms of possible egg and paralarval drift facilitated via the circumpolar current.

Description: Dietary composition of the onychoteuthid squid Moroteuthis ingens at the Falkland Islands was related to predator size, as shown by stomach contents and fatty-acid analyses. Comparisons were made between two size classes of squid: those of mantle length 〈200 mm and those of mantle length 〉200 mm. Smaller squid had frequently consumed crustaceans and cephalopods; fish were of secondary importance. Larger squid consumed mostly fish and moderate amounts of cephalopods, but had rarely consumed crustaceans. These findings were supported by comparisons drawn between digestive-gland fatty-acid profiles and the fatty-acid profiles of potential prey species. Fatty-acid analyses indicated that the crustaceans Euphausia lucens, Munida gregaria and Themisto gaudichaudii were important prey items of smaller squid, whereas stomach content and fatty-acid analyses indicated that Gymnoscopelus nicholsi of around 100 mm standard length represented much of the fish prey of larger squid.

Description: The diet of black-browed albatrosses was studied at Gonzalo Island, Diego Ramirez, Chile, during the early chick-rearing periods of 2000, 2001, and 2002. Diet composition was determined by sampling chick-stomach contents during January and February of each year. Reconstituted meal mass was similar throughout the study, with diet being dominated by fish in all 3 years. Overall, the main items taken were the fishes Macruronus magellanicus (66–89% by mass) and Micromesistius australis (2.6–3.7% by mass), which are both fisheries-related species, and the squid Martialia hyadesi (8–20% by mass). The distribution of the prey species indicates that black-browed albatrosses obtained the bulk of their food over the South American continental shelf, but also foraged at the Antarctic Polar Front. The prevalence in the diet of fish species discarded from fishing operations, and the presence of fish hooks and fish bait species, indicate a strong association with fisheries in southern Chile.

Description: The giant Australian cuttlefish Sepia apama Gray, 1849 annually forms a massive and unique spawning aggregation in northern Spencer Gulf, South Australia, which has attracted commercial fishing interests in recent years. However, many basic life-history characteristics of S. apama are unknown, and anecdotal evidence suggests that there is more than one species. The present study assessed the population structure and species status of S. apama using data from allozyme electrophoresis, microsatellite loci, nucleotide sequences of the mitochondrial COXIII gene, multivariate morphometrics and colour patterns. Analyses of allozyme and microsatellite allele frequencies revealed two very divergent but geographically separated populations consisting of specimens from the east coast and southern Australia. However, the presence of a heterozygote in a putative contact zone between the east coast and southern Australia suggested that these populations were not reproductively isolated. Mitochondrial haplotypes seem to have introgressed further north into the contact zone than have nuclear alleles. Differences in colour patterns that previously had been attributed anecdotally to different geographic populations were, in fact, correlated with sexual dimorphism. These data are most consistent with S. apama being one species the populations of which were geographically isolated in the past (historical vicariance) and have come into secondary contact. Comparison of microsatellite allele frequencies among four South Australian samples indicated significant deviations from panmixia. South Australian samples were also reliably diagnosed by means of multivariate morphometrics. Significant differences in mantle length were observed among populations.

Description: The culture of Sepia officinalis hatchlings and juveniles at different densities and enriched environments was investigated. Experiments were conducted to determine effects of culture density and the use of a substrate on growth and survival. Experiment I studied the effect of three different densities (52, 515 and 1544 hatchlings m−2). Experiment II tested the effects of the enriched environment, using a sandy bottom with pvc shelters. Experiment III tested the effects of density on growth, survival, feeding rates and food conversions. Cuttlefish were fed live grass shrimp at rates of 20% body weight per day (BW d−1). Grass shrimp (Palaemonetes varians) was supplied ad libitum as food in all experiments. In experiment I, growth was different between the three densities, with highest growth for density of 515 hatchlings m−2. IGR was of 8.8, 9.6 and 9.2% BW d−1 for the three densities tested, respectively. Both groups of experiment II had similar growth. IGR was of 10.1 and 9.7% BW d−1 for enriched and non-enriched environments, respectively. Densities of 10, 45 and 120 juvenile m−2 were used in experiment III. Significant differences in feeding rates were only found between densities of 10 and 120 cuttlefish m−2 during the last week. Results indicate that culture of cuttlefish hatchlings could be done in a non-enriched environment, with densities not exceeding 500 hatchlings m−2 and minimum bottom areas of about 600 cm2. Densities of 120 juveniles m−2 in a minimum area of about 1083 cm2 should be considered for juveniles between 5 and 25 g.

Description: The characteristics and habitat of the Patagonian toothfish (Dissostichus eleginoides) are typical of fish that accumulate high concentrations of mercury. In this study, mercury determinations were made on samples of muscle tissue from Macquarie Island toothfish and the Southern Ocean deepwater warty squid (Moroteuthis ingens). The analysis of mercury in the biological tissues was made by cold vapour-atomic absorption spectrometry following acid digestion. Performance of the analytical procedure was assessed by analysis of certified reference material (DORM-2, dogfish muscle). Mercury concentrations of 16 Macquarie Island toothfish ranged from 0.12 mg kg–1 (550 g, 381 mm TL) to 0.59 mg kg–1 (6,100 g, 823 mm TL), with a mean concentration of 0.33±0.12 mg kg–1. A significant correlation was found between mercury and either toothfish weight or total length. The fish analysed were juveniles, which suggests that larger individuals would have higher mercury concentrations well exceeding food standard code limits for mercury in fish (typically 0.5 mg kg–1). Warty squid, also from around Macquarie Island, had a low mean mercury concentration of 0.086 mg kg–1 in mantle tissue; no significant correlation existed between mercury concentration and either squid mantle length or total weight. It is postulated that the squid have a mechanism, possibly involving the digestive gland, that prevents bioaccumulation of mercury in the mantle, and presumably other body tissues.

Description: The zone of continental margins is most important for the ocean’s productivity and nutrient budget and connects the flow of material from terrestrial environments to the deep-sea. Microbial processes are an important “filter” in this exchange between sediments and ocean interior. As a consequence of the variety of habitats and special environmental conditions at continental margins an enormous diversity of microbial processes and microbial life forms is found. The only definite limit to microbial life in sedimentary systems of continental margins appears to be high temperatures in the interior earth or in fluids rising from the interior. Many of the catalytic capabilities which microorganisms possess are still only incompletely explored and appear to continuously expand as new organisms are discovered. Recent discoveries at continental margins such as the microbial life in the deep sub-seafloor, microbial utilization of hydrate deposits, highly specialized microbial symbioses and the involvement of microbial processes in the formation of carbonate mounds have extended our understanding of the Earth’s bio- and geosphere dramatically. The aim of this paper is to identify important scientific issues for future research on microbial life in sedimentary environments of continental margins.

Description: The population structure of the California market squid Loligo opalescens was studied for the Channel Islands region off Southern California between June 1998 and March 2000. During this time Californian waters were exposed to an extraordinary El Niño event that was possibly the most dramatic change in oceanographic conditions that occurred last century. There was then a rapid transition to record cool La Niña conditions. Statolith increments were used to determine age parameters and increment periodicity was validated for the first 54 days of life. Based on statolith increment counts, the oldest males and females were 257 and 225 days respectively and individuals matured as young as 129 and 137 days respectively. No distinct hatching period was detected. There was a general trend of increasing body size throughout the study period. Squid that hatched and grew through the El Niño were strikingly smaller and had slower growth rates compared to squid that grew through the La Niña. This was related to oceanography and associated productivity. There was a positive correlation between squid mantle length and upwelling index and a negative correlation between mantle length and sea temperature. The 'live-fast die-young' life history strategy of squid makes them ideal candidates for following the effects of the dramatic changes in oceanographic conditions off California. We propose that squid can serve as ecosystem recorders and productivity integrators over time and space and are useful organisms to tie oceanography to biology.

Description: Females of Tremoctopus violaceus, Argonauta argo and Ocythoe tuberculata in the Aegean Sea have larger eggs than specimens from the western Mediterranean and open ocean; the most probable reason is a shift in the reproductive strategies of Argonautoidea from the Aegean Sea toward the K-side, because of the high stability of this habitat in contrast to the unstable high seas. Potential fecundity of T. violaceus is 100,000–300,000; batch fecundity is 10,000–30,000, but at the beginning and at the end of spawning the batches are smaller. In A. argo potential fecundity is at least 85,000, with batch fecundity of some 2,000–4,000 eggs. The potential fecundity of small, mature O. tuberculata was 300,000 eggs. T. violaceus is an "intermittent terminal spawner", whereas both A. argo and O. tuberculata are "continuous spawners".

Description: This study explored the spawning dynamics of southern calamary (Sepioteuthis australis) by estimating small-scale temporal and spatial variability in egg production in an area known to attract spawning aggregations. Surveys of the seagrass beds (Amphibolis antarctica) over 14 months determined the timing and location of egg deposition, as well as estimating total egg production and loss of deposited egg masses from the spawning grounds. Egg laying in the inshore seagrass beds occurred predominantly during the austral spring and early summer. Egg production at one location (Hazards Bay) was very similar between the two years, but at the second location (Coles Bay) egg production was threefold less during the second summer. There was considerable spatial variability in egg production among seagrass beds within a kilometre of each other as well as within 10 km. Variability in the use of seagrass beds by the squid during each summer could not be attributed to differences in seagrass density or vegetation cover. Losses of deposited egg masses in the A. antarctica beds were detected on two occasions. On the first occasion the loss was correlated with storms; however, the second and smaller loss of egg masses was not correlated with storm activity. Information about the spatial and temporal patterns of egg production was used to make recommendations about the use of fishing closures to protect spawning adults from over-fishing.

Description: Cephalopods play an important role in the diet of many predators of the Southern Ocean. We investigated the cephalopod component of the diet of the wandering albatross, during breeding at South Georgia, from 269 boluses containing more than 34,000 beaks (corresponding to 19,452 individual cephalopods), collected between 1989 and 1999, and assessed the inter-annual variability of the cephalopod species, the level of scavenging on cephalopods by wandering albatrosses and the relationships between cephalopod availability and wandering albatross breeding parameters (breeding period, breeding success, fledging period, fledging success, egg mass and chick mass). We also proposed possible foraging areas of wandering albatrosses based on the cephalopods eaten. The cephalopod component of the diet of wandering albatrosses was relatively stable over the 11 years of the study. By number of lower beaks, three species predominated in the cephalopod component of the diet: Kondakovia longimana (29.5% of the total number of lower beaks; family Onychoteuthidae), Taonius sp. (20.4%; family Cranchiidae) and Histioteuthis sp. B (19.5%; family Histioteuthidae). K. longimana was consistently the predominant cephalopod species by mass in every year of the study (range 60.2–88.7% of mass contribution to diet). A minimum estimate of 30% of the number of cephalopods scavenged corresponded to 85% of the total mass of the cephalopods that contributed to the diet. Wandering albatrosses fed consistently more on "Antarctic" cephalopods than on "sub-Antarctic" or "subtropical" cephalopods in all years of the study, suggesting that Antarctic waters are an important foraging area for wandering albatrosses. Although some significant correlations between cephalopod abundance and wandering albatross breeding parameters existed (e.g. correlation between Taonius sp. by number and fledging success), none included K. longimana. When comparing groups of variables (using canonical analysis), no correlations were found between the most important cephalopod species (by number and by mass), total mass of squid consumed, cephalopod diversity index (H) for each year, and wandering albatross breeding parameters. This may reflect the possibility that other components in the diet (e.g. fish and carrion) are more important or, more likely, that the consistency across years of the wandering albatross breeding performance indicates that it is well buffered against fluctuations in prey availability.

Description: The diet of non-breeding male Antarctic fur seals, Arctocephalus gazella, was investigated at the Danco Coast, Antarctic Peninsula, by the analysis of 31 and 149 scats collected from January to March 1998 and 2000, respectively. Overall, fish and krill, followed by penguins and squids, were the most frequent prey and constituted the bulk of the diet. The importance of the remaining taxa represented in the samples (octopods, gastropods, bivalves, isopods, polychaetes and poriferans) was negligible. Among fish, channichthyids constituted the bulk of the diet, with Chionodraco rastrospinosus and Chaenodraco wilsoni, followed by the nototheniid, Pleuragramma antarcticum, being the main prey. The myctophid, Electrona antarctica, was the most frequent and numerous fish prey. The results are discussed and compared with those reported for the South Shetland Islands, the closest area for which similar information is available.

Description: Rotifers, one of the smallest metazoans, are only seldom found in marine environments. Surprisingly, we discovered high abundances of at least two new species of rotifers settling in anoxic and highly sulphidic sediments associated with shallow gas hydrates (GH) at the southern crest of Hydrate Ridge off Oregon, NE Pacific, in a water depth of about 780 m. At basins adjacent to Hydrate Ridge, 1,285–2,304 m deep, we found rotifers co-occurring with the sulphide-oxidising bacteria Thioploca sp.

Description: A new concept based on analysis of dive depth data was developed to help estimate prey consumption in ten free-ranging Magellanic penguins (Spheniscus magellanicus) that were brooding chicks. By simultaneously analysing the undulations in the dive depth profile (measured by time-depth recorders, TDRs) and beak opening (obtained from the recently developed intra-mandibular angle sensors, IMASEN), it was possible to determine the proportions of the undulations in the dive profile that resulted (or not) in prey capture. This methodology allowed the number of prey consumed to be estimated with a mean error of 10±6% using TDR data alone. If the mean mass of prey is known, then the overall mass of prey consumed per unit time can be determined. Additionally, the method allows estimation of the depth at which prey is taken and thus indicates how penguins exploit the water column. Due to its simplicity, the proposed methodology has applications for other Spheniscus penguin species and should be considered for other marine endotherm divers that show undulations in the dive depth profile.

Description: Eastward-propagating patterns in anomalous potential temperature and salinity of the Southern Ocean are analyzed in the output of a 1000-year simulation of the global coupled atmosphere–ocean GCM ECHO-G. Such features can be associated with the so-called Antarctic Circumpolar Wave (ACW). It is found that time–longitude diagrams that have traditionally been used to aid the visualization of the ACW are strongly influenced by the width of the bandpass time filtering. This is due to the masking of considerable low-frequency variability that occurs over a broad range of time scales. Frequency–wavenumber analysis of the ACW shows that the eastward-propagating waves do have preferred spectral peaks, but that both the period and wavenumber change erratically when comparing different centuries throughout the simulation. The variability of the ACW on a variety of time scales from interannual to centennial suggests that the waiting time for a sufficient observational record to determine the time scale of variability of the real world ACW (and the associated decadal time scale predictability of climate for southern landmasses) will be a very long one.

Description: Phosphatase is a key-enzyme in the marine environment, although life in the sea is normally not P limited. Expression of phosphatase in algae is generally regulated by the prevailing external concentration of inorganic phosphate, but the internal N:P ratio may also play a role. For bacteria, additional mechanisms like their C and N demands may be important. This is suggested by high phosphatase activities occasionally measured in eutrophic or deep water in the presence of relatively high phosphate concentrations. The distribution of phosphatase activity among the particulate and the dissolved fractions is highly variable. In particular, the dissolved fraction can contribute considerably to the total phosphatase activity (up to 70%), which differs from the pattern of other hydrolytic ectoenzymes. Parts of this fraction may originate from marine protozoa. The contribution of bacteria and phytoplankton to the particle-associated fraction of phosphatase is extremely variable, depending on P-availability, the dominant organisms, water depth and environmental factors. Community analysis revealed that bacteria attached to marine snow and N2-fixing cyanobacteria were frequently strong producers of phosphatase. Field studies carried out on a great variety of marine regions suggest that phosphatase activity is generally a good indicator of the P status of phytoplankton. Several heat-stable or heat-labile phosphatases, isolated from marine organisms living in extreme or other environments have been recommended for biotechnological applications.

Description: Here we report on a mesocom study performed to compare the top-down impact of microphagous and macrophagous zooplankton on phytoplankton. We exposed a species-rich, summer phytoplankton assemblage from the mesotrophic Lake Schöhsee (Germany) to logarithmically scaled abundance gradients of the microphagous cladoceran Daphnia hyalina×galeata and of a macrophagous copepod assemblage. Total phytoplankton biomass, chlorophyll a and primary production showed only a weak or even insignificant response to zooplankton density in both gradients. In contrast to the weak responses of bulk parameters, both zooplankton groups exerted a strong and contrasting influence on the phytoplankton species composition. The copepods suppressed large phytoplankton, while nanoplanktonic algae increased with increasing copepod density. Daphnia suppressed small algae, while larger species compensated in terms of biomass for the losses. Autotrophic picoplankton declined with zooplankton density in both gradients. Gelatinous, colonial algae were fostered by both zooplankton functional groups, while medium-sized (ca. 3,000 µm3), non-gelatinous algae were suppressed by both. The impact of a functionally mixed zooplankton assemblage became evident when Daphnia began to invade and grow in copepod mesocosms after ca. 10 days. Contrary to the impact of a single functional group, the combined impact of both zooplankton groups led to a substantial decline in total phytoplankton biomass.

Description: The Caucasian orogenic wedge formed as a consequence of the closure of the Tethyan Ocean, and numerous fields of active mud volcanoes pepper the area adjacent to the Black and Caspian Seas. Stable isotope ratios of boron, helium, and carbon have been measured for gas, fluid and sediment samples from active mud volcanoes of Taman Peninsula and Georgia to estimate the sources and mobilization depths of the fluid phase and mud. Boron concentrations in mud volcano fluids were found to be 5–35× higher than seawater. Fluid isotope ratios vary between δ11B=22 and 39‰, while isotope ratios of the smectite- and illite-rich extruded mud are considerably depleted in heavy 11B (δ11B=−8 to +7‰). B contents of these muds are ~8× higher than modern marine sediments. This suggests that liquefaction prior to mud volcanism was accompanied by both B enrichment and isotope fractionation, most likely at an intermediate depth mud reservoir at 2–4 km. The hydrocarbon-generating source beds to the mud volcanoes are located at 7 to 〉10 km depth in the folded Maikop Formation and are of proposed Oligocene–Miocene age. The most likely mechanism is re-hydration of these shales by both hydrocarbons and a geochemically mature fluid from greater depth within the orogenic wedge. Such a deep fluid source is supported by our results from gas analyses, which imply an admixture of minor amounts (less than 1%vol) of 3He (Georgia), thermogenic 13C in methane as well as "ultraheavy" 13C in CO2 (both Taman and Georgia). The overall results attest active local flow of geochemically different fluids along deep-seated faults penetrating the two study areas in the Caucasian orogenic wedge, with the waters as well as the gases coming from below the Maikop Formation.

Description: Keddy's competitive hierarchy model describes species distribution patterns along gradients under equilibrium conditions and can potentially serve as an explanation for zonation patterns of intertidal seaweeds on rocky shores. One of the assumptions of the model is a competitive hierarchy with the top competitor occupying the benign end of the gradient. Another assumption is the consistency of competitive ranks of species in all environmental conditions included in the shared parts of species' fundamental niches. In laboratory replacement series experiments, the competitive ranks of pairs of Fucus species that occupy adjacent zones in the field were analysed and compared to ranks found in previous field experiments. Unattached thalli of Fucus serratus versus F. vesiculosus or F. vesiculosus versus F. spiralis, respectively, were held in aerated beakers to establish the competitive ranking of the three congeners. Each replacement series was conducted at three total densities. F. vesiculosus was clearly competitively dominant over F. serratus. In competition with F. spiralis, F. vesiculosus was only dominant at its lowest absolute input frequencies, but at higher frequencies dominance was reversed. At high densities, the total ranking was F. spiralis 〉 F. vesiculosus 〉 F. serratus, which is the opposite order to that which would be expected from Keddy's model. Although all three species thrived well under the laboratory conditions, the results did not reflect in situ competitive dominances, which may be an effect of nutrient competition in the laboratory. Keddy's assumption that competitive ranks are consistent over the whole range of fundamental niches cannot be supported for Fucus spp.

Description: Grab samples from the submarine Conical Seamount, located about 10 km south of the giant Ladolam gold deposit, Lihir Island, reveal the highest gold concentrations yet reported from the modern seafloor. Lavas from Conical Seamount are characterized by high K2O contents, high K2O/Na2O ratios, and high Ce/Yb ratios, which are typical of high-K igneous rocks from oceanic (island) arc-settings. The primitive character of the rocks from Conical Seamount implies a magmatic evolution related to a single eruptive phase, which contrasts with the more evolved rocks forming Lihir Island. Geochemical as well as mineral chemical data suggest that the melts from both Conical Seamount and Lihir Island originate from the same magma source. In common with the samples from Lihir Island, elevated oxygen fugacities of 0.7–2.5 log units above the FMQ buffer are recorded from the Conical Seamount lavas. There are distinct differences between the mineralization styles at Conical Seamount and at the Ladolam gold deposit, Lihir Island. While early-stage pyritic stockwork mineralization at Conical Seamount is hosted by clay-silica altered basaltic rocks with local alunite±kaolinite alteration, main-stage Au-mineralization occurs in sericite-alkali feldspar altered polymetallic sulfide-bearing siliceous veins. By contrast, early-stage pyritic stockwork mineralization at Ladolam is restricted to biotite–magnetite ± silica-altered monzodiorite, while the main-stage bulk-tonnage mineralization occurs as auriferous pyrite-bearing hydrothermal breccias which, in places, are cut by quartz–chalcedony–illite–adularia–pyrite±marcasite veins containing isolated bonanza gold grades.

Description: The aim of this study was to determine whether the experimental nutrient enrichment of littoral rocky shore communities would be followed by a predicted accumulation of fast-growing opportunistic algae and a subsequent loss of perennial benthic vegetation. Inorganic nitrogen (N) and potassium (P) was added to eight concrete mesocosms inhabited by established littoral communities dominated by fucoids. The response to nutrient enrichment was followed for almost 2 1/2 years. Fast-growing opportunistic algae (periphyton and ephemeral green algae) grew significantly faster in response to nutrient enrichment, but the growth of red filamentous algae and large perennial brown algae was unaffected. However, these changes were not followed by comparable changes in the biomass and composition of the macroalgae. The biomass of opportunistic algae was stimulated only marginally by the nutrient enrichment, and perennial brown algae (fucoids) remained dominant in the mesocosm regardless of nutrient treatment level. Established rocky shore communities thus seem able to resist the effects of heavy nutrient loading. We found that the combined effects of the heavy competition for space and light imposed by canopy-forming algae, preferential grazing on opportunistic algae by herbivores, and physical disturbance, succeeded by a marked export of detached opportunistic algae, prevented the fast-growing algae from becoming dominant. However, recruitment studies showed that the opportunistic algae would become dominant when free space was available under conditions of high nutrient loading and low grazing pressure. These results show that established communities of perennial algae and associated fauna in rocky shore environments can prevent or delay the accumulation of bloom-forming opportunistic algae and that the replacement of long-lived macroalgae by opportunistic species at high nutrient loading may be a slow process. Nutrient enrichment may not, in itself, be enough to stimulate structural changes in rocky shore communities.

Description: The entrance of hot pyroclastic flows into water has been observed in a series of experiments in which shooting granular flows of hot ignimbrite ash (≤403 °C), of bulk density near that of water, run down a smooth chute and enter a water-filled tank at an angle of 26°. Flows of relatively cool ash (〈150 °C) impulsively displace some volume of near-shore water upon impact, generating a water wave that rapidly travels away from shore. The granular flow material then separates into two portions. (1) A fine-ash surge cloud is formed where the granular flow hits water and rapidly travels down-tank over the water. (2) The main portion of material penetrates the surface and mixes with the water, creating a turbulent mixing zone resembling a hydraulic jump, which advances downstream as long as the pyroclastic flow is maintained. Most pumice floats to the surface, lithics and coarse ash fall out onto the floor, but ash that remains in suspension forms a turbidity current that travels down the floor of the tank. With increasing ash temperature, an increasing fraction of incoming material is initially transported along the water surface; almost all material takes this path at temperatures 〉250 °C. Mixing across the water surface over some distance from shore generates steam explosions forming fountains of wet and dry ash and convectively rising fine-ash plumes. Steam explosions increase in strength and lateral extent towards higher ash temperatures and mass fluxes. The explosions generate water waves that remain driven by massive fountain fallout across some distance from shore. The ash fountains feed pyroclastic surges, which advance down tank over water at high speeds. Underwater plumes of sediment falling from the ash fountains and surges drop coarse load onto the floor whereas the finer load forms a turbidity current. High temperature and poor size sorting of pyroclastic flows are key parameters that determine the processes of interaction with water and the associated hazards. Poor sorting allows for the formation of ash-cloud surges moving over water, even from cool flows. High temperatures cause littoral explosions and facilitate extensive mass transport over water. All flows generate tsunami waves by different mechanisms.

Description: Two distinct modes of development in the common polychaete Scoloplos armiger (O. F. Müller, 1776) occur in the North Sea region: holobenthic development in egg cocoons and pelagic larvae hatching from suspended eggs. In the northern Wadden Sea near the island of Sylt, we observed that egg cocoons are produced intertidally while pelagic larvae originate from the adjacent subtidal zone. A previous genetic comparison between these subtidal and intertidal populations revealed distinct gene pools, suggesting that reproductive differences are not phenotypic but heritable. In this study, crossbreeding experiments show that intertidal and subtidal populations are reproductively isolated. Couples with males and females from different habitats had no offspring. Production of egg cocoons is determined by female origin from the intertidal zone. Pelagic larvae occurred only in couples with subtidal females and subtidal males. Intertidal males have spermatozoa with heads twice as long as those from subtidal males and a significantly shorter flagellum. We suspect that deviating sperm morphology may cause the reproductive breakdown at the fertilization stage. Juveniles hatching from cocoons have shorter anal cirri compared to juveniles that metamorphosed from pelagic larvae. We conclude there to be two sympatric sibling species in S. armiger: 'type I' in intertidal areas, which have egg cocoons, no pelagic larvae, elongated sperm heads, shortened sperm flagella and anal cirri; and a subtidal 'type S', lacking egg cocoons but with pelagic larvae, short sperm heads, long sperm flagella and anal cirri.

Description: In marine invertebrates multiple modes of development, or poecilogony, may occur in a single species. However, after close examination, many of such putative cases turned out to be sibling species. A case in point may be the cosmopolitan orbiniid polychaete Scoloplos armiger, which inhabits marine shallow sediments. In addition to the well-known direct, holobenthic development from egg cocoons, pelagic larvae have also been described. Our culture experiments revealed a spatially segregated source of the two developmental modes. All females of an intertidal population produced egg cocoons and no pelagic larvae. All but 2 out of 15 females of an adjacent subtidal population produced pelagic larvae and no egg cocoons. Based on these results we performed a molecular genetic analysis (RAPD-PCR) on three intertidal and four subtidal populations in the North Sea. Selected samples from all sites were analysed also by the AFLP method. We found significantly higher genetic diversity within subtidal than within intertidal populations. This is consistent with a wider dispersal by pelagic larvae and a smaller effective population size when development is holobenthic. Total genetic divergence is not related to distance but to the intertidal/subtidal division. We suggest that S. armiger actually represents two sibling species.

Description: The Sorokin Trough (Black Sea) is characterized by diapiric structures formed in a compressional tectonic regime that facilitate fluid migration to the seafloor. We present acoustic data in order to image details of mud volcanoes associated with the diapirs. Three types of mud volcanoes were distinguished: cone-shaped, flat-topped, and collapsed structures. All mud volcanoes, except for the Kazakov mud volcano, are located above shallow mud diapirs and diapiric ridges. Beyond the known near-surface occurrence of gas hydrates, bottom simulating reflectors are not seen on our seismic records, but pronounced lateral amplitude variations and bright spots may indicate the presence of gas hydrates and free gas.

Description: The sedimentological study of thirteen sediment cores from the periplatform setting surrounding Pedro Bank (Northern Nicaragua Rise, Caribbean Sea) shows that during the last 300 ka turbidite deposition is controlled by at least four factors: (1) late Quaternary sea level fluctuations, (2) prolific fine-grained sediment production and export resulting in oversteepening of the upper slope environment, (3) the proximity to the bank margin, and (4) local slope and seafloor morphology. The most intriguing finding of this study is the paucity of turbidites, with only 101 turbidites in 13 cores in this tectonically active setting near the Caribbean plate boundary. Throughout the last 300 ka, the frequency of turbidite input during interglacial stages is three times higher than during glacial stages. Also it is obvious that changes in sea level influence the timing of turbidite deposition. This is especially evident during the transgressions resulting in rapid renewed bank-top flooding, subsequent neritic sediment overproduction, and offbank export. The flooding event during each transgression is usually recorded by the onset of turbidite deposition at various sites along several platform-to-basin transects in down- and upcurrent slope settings. Overall, however, more turbidites are deposited during the regressive rather than the transgressive phases in sea level, probably as a result of sediment reorganisation on the slope resulting in slope failure. Five cores show "highstand bundling" of calciturbidites, i.e. higher number of turbidites during highstands than during lowstands in sea level.

Description: The first systematic rock sampling of volcanoes along the Galápagos hotspot tracks (the aseismic Cocos, Carnegie, Malpelo and Coiba ridges and adjacent seamounts) in the area between the Galápagos Islands and Central and South America was carried out on R/V Sonne cruise 144-3. Guyot-shaped seamounts, paleo-beach or intertidal wave-cut platform deposits, the structure and texture of volcanic rocks, and low sulfur contents of fresh glasses dredged at these volcanoes imply that ocean islands existed continuously above the Galápagos hotspot for at least the past 17 million years. These new data significantly extend the time period over which the unique endemic Galápagos fauna could have evolved, providing a complete solution to the long-standing enigma of the evolution of Galápagos land and marine iguanas