ALBERT

Description: Samples of the squid Martialia hyadesi were collected aboard two Japanese squid-jigging vessels carrying out commercial fishing trials at the Antarctic Polar Frontal Zone, north Scotia Sea, in February 1989. The dissected stomachs of 61 specimens were classified according to fullness and the contents were examined visually. Identifiable food items included fish sagittal otoliths, crustacean eyes, the lappets on euphausiid first antennule segments and cephalopod sucker rings. The most frequent items in the squid's diet were the myctophid fishes Krefftichthys anderssoni and Electrona carlsbergi, the euphausiid Euphausia superba and a hyperiid amphipod, probably Themisto gaudichaudi. A small proportion of the sample had been feeding cannibalistically. Total lengths of the fish prey were estimated from sagittal otolith size using published relationships. All fish were relatively small; 7 to 35% of squid mantle-length. However, it is possible that some heads of larger fish are discarded by the squid and so are not represented by otoliths in the stomach contents. Over the size range of squid in the sample there was no relationship between size of fish prey and size of squid. Similarly, when the squid sample was divided into groups according to prey categories: crustaceans, crustaceans+fish, fish, cephalopod, there was no evidence that dietary preference was related to squid size. The prevalence of copepod-feeding myctophids in the diet of this squid, which is itself a major prey item of some higher predators in the Scotia Sea, suggests that a previously unrecognised food chain: copepod-myctophid-M. hyadesi-higher predator, may be an important component of the Antarctic oceanic ecosystem.

Description: The diet of the Wandering Albatross at Subantarctic Marion Island was studied by inducing recently fed chicks to regurgitate and by stomach flushing adults about to feed chicks. Liquid comprised 70.2% of stomach content mass recovered from chicks. Solid material comprised cephalopods (58.6% by mass), fish (36.5%) and crustacean, cetacean and seabird material as minor items. Twenty-three taxa of cephalopods were identified, the onychcteuthid squid Kondakovia longimana being the most important. Estimated average mass of squid was 694 g with a maximum of over 8 kg. Diet of the Wandering Albatross at Marion Island was broadly similar to that at other studied localities. The high proportion of cephalopods known to float after death in the diet, and the deep-water habits of the few fish identified, suggest that scavenging plays an important role in foraging behaviour.

Description: The reproductive strategy of the cirrate octopods Opisthoteuthis agassizii and O. vossi (collected off Namibia from 1988 to 1990) was analyzed. Ovarian oocyte size frequency analysis for both species revealed continuous egg production over the entire adult life span. Mature eggs were stored in the single oviducal gland and distal oviduct, but oviducal gland fullness was not related to body size (p〉0.2). All O. agassizii male specimens from 95 to 5400 g total weight were sexually mature, as were all females from 190 to 1650 g, indicating that considerable growth takes place after the onset of sexual maturity. “Continuous spawning” is defined as a single, extended and continuous period of egg maturation and spawning. This model of reproductive strategy is previously unreported in cephalopods. All O. vossi male specimens from 750 to 3050 g total weight, and females from 800 to 1300 g, were sexually mature. Mature males and females of both species were collected in all seasons of the year. The adaptation of cirrate octopods to non-scasonal deep-sea environments is considered. The sexual maturity characteristics of males were analyzed, and examination of the spermatophore revealed opercular structures previously unreported in cephalopods. For females, the micropyle of the eggs are described and the mineral analysis of the egg shell disclosed that sulphur was the major element present.

Description: Silicon is one of the most important elements in the current age of the anthropocene. It has numerous industrial applications, and supports a high-tech multi-billion Euro industry. Silicon has a fascinating biological and geological cycle, interacting with other globally important biogeochemical cycles. In this review, we bring together both biological and geological aspects of the silicon cycle to provide a general, comprehensive review of the cycling of silicon in the environment. We hope this review will provide inspiration for researchers to study this fascinating element, as well as providing a background environmental context to those interested in silicon.

Description: Turbulent fluxes have been measured in the atmospheric surface layer from a boom extending upwind from the Dutch offshore research platform Meetpost Noordwijk (MPN) during HEXMAX (Humidity Exchange over the Sea Main Experiment) in October–November, 1986. We started out to study eddy flux of water vapour, but discrepancies among simultaneous measurements made with three different anemometers led us to develop methods to correct eddy correlation measurements of wind stress for flow distortion by nearby objects. We then found excellent agreement among the corrected wind stress data sets from the three anemometers on the MPN boom and with eddy correlation measurements from a mast on a tripod. Inertial-dissipation techniques gave reliable estimates of wind stress from turbulence spectra, both at MPN and at a nearby ship. The data cover a range of wave ages and the results yield new insights into the variation of sea surface wind stress with sea state; two alternative formulas are given for the nondimensional surface roughness as a function of wave age.

Description: Studies of laboratory cultures of Chordaria linearis (Hooker et Harvey) Cotton from southernmost South America revealed that this species has an obligate sexual life history in which a macroscopic sporophyte alternates with a monoecious microscopic gametophyte. Sexual reproduction is isogamous and under photoperiodic control. Gametes are produced only in short days, whereas in long days, asexual zoospores are formed that recycle the gametophyte generation. Unfused gametes develop into gametophytes, and sporophytes originate only from zygotes. Unlike other sexual members of the Chordariales, gametes of C. linearis have a reduced stigma and do not show phototaxis. They are released at the beginning of the night, not in the morning. In nature, C. linearis seems to be regularly infected by a dictyosiphonalean epiphyte resembling the rare arctic species Trachynema groenlandicum (Lund) Pedersen. The epiphyte is responsible for previous contradictory results obtained in laboratory cultures of C. linearis. This is the first record of Trachynema in the southern hemisphere.

Description: In tropical and subtropical regions of the world, jellyfish stings cause fatalities by means of venom injecting nematocysts. For nematocyst discharge an adequate combination of chemical and mechanical stimulation is required. In order to test whether skin care products can protect against nematocyst discharge, we tested two sunscreens and one lotion applied to pieces of live human skin and exposed them to Cyanea capillata tentacles. (Test specimens were collected in 1990 along the shore of Rømø, Denmark and in the Flensburger Förde.) The fine structure analysis of the cnidom of C. capillata showed a high grade of variation in shape and size. The basic distinctive characteristic for stomocnides and astomocnides, the terminal opening at the tubule tip, could not be found. The identification of spines at the basal tubule of atrichous isorhizas suggested that these should be characterized as basitrichous isorhizas. An association between nematocyst morphology and a special function such as penetration or entanglement was not observed. All nematocyst types penetrated unprotected skin. Parafilm (an inert material) and unprotected skin substrates served as controls. The discharged nematocysts on the skin and Parafilm surfaces were counted using scanning electron microscopy. The percentage of discharged nematocysts on test substance protected skin surfaces ranged from only 7.7 to 38.2%, compared to 100% on the unprotected control skin. In addition to this marked reduction in nematocyst discharge, the relatively few discharged nematocysts on protected skin showed malfunctions, and the injection of venom would have failed because the tubules of the nematocysts did not penetrate the skin. The results indicate a general possibility that human skin may be protected against nematocyst discharge of jellyfish with the application of sunscreen or lotion.

Description: The constancy of postmoult/premoult ratios of measures of linear size during ontogeny in insect and other arthropods is widely known as Dyar's rule. We tested this rule in nine species of the waterstrider genera Gerris and Aquarius (Heteroptera: Gerridae), using two size variables: head width and a multivariate measure derived from the pattern of multivariate allometry common to the species considered. Allometric patterns were similar in two independent datasets of laboratory-reared and field-caught specimens. Although our data strictly followed Dyar's rule injust a few instances, all growth ratios varied within a limited range only. Growth ratios for head width differed more between moults than those for multivariate size. The relationship between growth ratios for the two size measures conformed to the predictions based on allometry. We discuss hypotheses of the possible adaptive significance of growth ratios, such as their relation to mobility and systematic differences between hemimetabolous and holometabolous insects, and emphasize the importance of allometry. Since Dyar's rule is consistent with available evidence of physiological mechanisms underlying growth and moulting control of insects and crustaceans, it can be used as a general frame of reference to test alternative growth models.

Description: The ultimate cause of the onset of glaciations remains elusive, but in the case of northem hemisphere glaciation it is probable that several factors acted in combination. General global cooling resulted from reduction of atmospheric C02 by weathering of silicate rocks exposed by erosion of late Cenozoic uplifts. Uplifts in south Asia, southwestern North America and Scandinavia occurred at distances appropriate for the generation of quasi-permanent Rossby waves in the atmosphere. The resulting winds, given suitable moisture sources, were favourable for causing large-scale precipitation at mid-latitudes on the northern continents. Moisture sources were provided by the closure of the Central American isthmus. Gulf Stream flow increased, carrying warm subtropical waters to high latitudes. The Denmark Strait deepened permitting greater outflow of deep water from the Norwegian-Greenland Sea. The relative importance of each of these factors should be investigated by additional atmospheric and ocean climate model sensitivity studies.

Description: Samples of the squid Martialia hyadesi were collected aboard two Japanese squid-jigging vessels carrying out commercial fishing trials at the Antarctic Polar Frontal Zone, north Scotia Sea, in February 1989. The dissected stomachs of 61 specimens were classified according to fullness and the contents were examined visually. Identifiable food items included fish sagittal otoliths, crustacean eyes, the lappets on euphausiid first antennule segments and cephalopod sucker rings. The most frequent items in the squid's diet were the myctophid fishes Krefftichthys anderssoni and Electrona carlsbergi, the euphausiid Euphausia superba and a hyperiid amphipod, probably Themisto gaudichaudi. A small proportion of the sample had been feeding cannibalistically. Total lengths of the fish prey were estimated from sagittal otolith size using published relationships. All fish were relatively small; 7 to 35% of squid mantle-length. However, it is possible that some heads of larger fish are discarded by the squid and so are not represented by otoliths in the stomach contents. Over the size range of squid in the sample there was no relationship between size of fish prey and size of squid. Similarly, when the squid sample was divided into groups according to prey categories: crustaceans, crustaceans+fish, fish, cephalopod, there was no evidence that dietary preference was related to squid size. The prevalence of copepod-feeding myctophids in the diet of this squid, which is itself a major prey item of some higher predators in the Scotia Sea, suggests that a previously unrecognised food chain: copepod-myctophid-M. hyadesi-higher predator, may be an important component of the Antarctic oceanic ecosystem.

Description: Specimens of the squidAbralia veranyi were collected off the Bahamas in 1989. The bioluminescence of the ventral photophores was recorded on videotape at 11 to 12°C and 24°C, in conjunction with measurements of the spectral emission at the same temperatures. At 11 °C, the spectrum was unimodal, peaking at 490 nm with a narrow bandwidth. At the higher temperature a shoulder at about 440 nm appeared in the emission spectrum. The short, bright flashes from the subocular photophores had a broader bandwidth and a shorter wavelength emission maximum (475 nm) than that of the ventral photophores. Video recordings at the two temperatures showed no changes in either the identities of the luminescing photophores or their relative intensities. One structurally distinct type of photophore was not illuminated. We conclude that the observed spectral changes were produced within one group of photophores, and that recruitment of the unilluminated photophores would produce an additional spectral component, previously reported from another species ofAbralia (A. trigonura).

Description: King Penguins are the second largest of all diving birds and share with their congener, Emperor Penguins, breeding habits strikingly different from other penguins. Our purpose was to determine the feeding behavior, energetics of foraging and the prey species, and compare these to other sympatric species of subantarctic divers. We determined: (1) general features of foraging behavior using time—depth recorders, velocity meters, and radio transmitters, (2) energetics by doubly labeled water, (3) food habits and energy content from stomach lavage samples, and (4) resting and swimming metabolic rate by oxygen consumption measurements. The average foraging cycle was ≈6 d, during which the mass gain of 30 birds was ≈2 kg. When at sea, the birds exhibit a marked pattern of shallow dives during the night, whereas deep dives of 〉100 m only occurred during the day. Maximum depth measured from 34 birds and 18 537 dives was 304 m, and maximum dive duration from 23 birds and 11 874 dives was 7.7 min. The frequency distribution of dive depth was bimodal, with few dives between 40 and 100 m. Overall, swim velocities when a bird was at sea averaged 2.1 m/s (N = 5), while descent and ascent rates of change in depth averaged 0.6 m/s for dives 〈60 m (N = 74) and 1.4 m/s for dives 〉150 m (N = 90). Night feeding dives occurred at a rate of ≈20 dives/h, and deep dives occurred at a rate of ≈5 dives/h. The energy consumption rate while resting ashore was 3.3 W/kg (N = 3) or 1.6 times the predicted standard metabolic rate (SMR). The average energy consumption rate while away from the colony was 10 W/kg (N = 8) or 4.6 x SMR, compared to 4.3 x SMR estimated from a time—energy budget. The latter value is based on an average metabolic rate of 4.2 W/kg for three birds while resting in 5°C water and 9.6 W/kg while swimming at 2 m/s, which was extrapolated from the average of three birds swimming at 1 m/s. The average energy intake based on 9 stomach content samples was nearly 24.6 kJ/g dry mass. The main prey by number are myctophid fish of the species Krefftichthys anderssoni and Electrona carlsbergi. It was concluded that: (1) feeding begins ≈28 km from the colony, (2) prey is pursued night and day through its vertical movements, (3) vertical distribution of the prey is reflected closely by diving habits of the birds, (4) deep—diving, for unknown reasons, is an important component of foraging success, (5) diving capacities of King Penguins are remarkable compared to other birds and many pinnipeds, and (6) calculated foraging energetics can be closely estimated from time—energy budgets.

Description: The concentrations of 11 heavy metals (Ag, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) were measured in the tissues (digestive gland, branchial hearts, gills, digestive tract, kidney, genital tract, muscle, skin, shell) of the two cephalopods Eledone cirrhosa (d'Orb.) and Sepia officinalis (L.) collected from the French coast of the English Channel in October 1987. The tissues of both species displayed a similar pattern of heavy-metal accumulation: the digestive gland, branchial hearts and kidney were the major sites of concentration for all 11 metals; the digestive gland accumulated silver, cadmium, cobalt, copper, iron, lead and zinc, the branchial hearts high concentrations of copper, nickel and vanadium, and the kidney high concentrations of manganese, nickel and lead. The digestive gland, which constituted 6 to 10% of the whole-animal tissue, contained 〉80% of the total body burden of Ag, Cd and Co and from 40 to 80% of the total body burden of the other metals. The ratios between heavy metal concentrations in the digestive gland and those in the muscle separated the elements into three groups, those with a ratio ≤10 (Cr, Mn, Ni, Pb, V, Zn), those with a ratio 〉10 to 〈50 (Co, Cu, Fe), and those with a ratio ≥50 (Ag, Cd). The digestive gland of cephalopods (carnivorous molluscs whose age can be easily calculated with great accuracy) would seem to constitute a good potential indicator of heavy metal concentrations in the marine environment.

Description: Dissolved and particulate metals (Ag, Cd, Co, Cu, Ni, and Zn) and nutrients (PO4, NO3, and H4SiO4) were measured in Todos Santos Bay (TSB) in August 2005. Two sources producing local gradients were identified: one from a dredge discharge area (DDA) and another south of the port and a creek. The average concentrations of dissolved Cd and Zn (1.3 and 15.6 nM, respectively) were higher by one order of magnitude than the surrounding Pacific waters, even during upwelling, and it is attributed to the presence of a widespread and long-lasting red tide coupled with some degree of local pollution. A clear spatial gradient (10 to 6 pM), from coast to offshore, of dissolved Ag was evident, indicating the influence of anthropogenic inputs. The particulate fraction of all metals, except Cu, showed a factor of ~3 decrease in concentrations from the DDA to the interior of the bay. The metal distributions were related to the bay’s circulation by means of a numerical model that shows a basically surface-wind-driven offshore current with subsurface compensation currents toward the coast. Additionally, the model shows strong vertical currents over the DDA. Principal component analysis revealed three possible processes that could be influencing the metal concentrations within TSB: anthropogenic inputs (Cd, Ag, and Co), biological proceses (NO3, Zn, and Cu), and upwelling and mixing (PO4, H4SiO4, Cd, and Ni). The most striking finding of this study was the extremely high Cd concentrations, which have been only reported in highly contaminated areas. As there was a strong red tide, it is hypothesized that the dinoflagellates are assimilating the Cd, which is rapidly remineralized and being concentrated on the stratified surface layers.

Description: The complement system has long been known to be a major element of innate immunity. Traditionally, it was regarded as the first line of defense against invading pathogens, leading to opsonization and phagocytosis or the direct lysis of microbes. However, from the second half of the twentieth century on, it became clear that complement is also intimately involved in the induction and “fine tuning” of adaptive B- and T-cell responses as well as lineage commitment. This growing recognition of the complement system’s multifunctional role in immunity is consistent with the recent paradigm that complement is also necessary for the successful contraction of an adaptive immune response. This review aims at giving a condensed overview of complement’s rise from a simple innate stop-and-go system to an essential and efficient participant in general immune homeostasis and acquired immunity.

Description: Jamaica Bay, NY, is a highly urbanized estuary within the boroughs of New York City conspicuously lacking published information on dissolved trace metal concentrations. The current study examines the distribution and cycling of trace metals in that embayment with data gathered during cruises in November 2004, April 2005, and June 2006. Most of the metal distributions (Fe, Zn, Co, Ag, Cu, Pb, Ni) in the water column are explained by the input of substantial volumes of treated wastewater effluent. However, several lines of evidence suggest that submarine groundwater discharge (SGD) is also an important source of dissolved Fe, Zn, Co, Ni, and isotopically distinct stable Pb ratios (206Pb, 207Pb, 208Pb) in the Bay. Conversely, the recirculated seawater component of SGD is an apparent sink for dissolved Mo. This study provides the first measurements of dissolved trace metals in the Jamaica Bay water column and subterranean estuary and provides evidence for trace metal input due to SGD.

Description: Adélie penguins (Pygoscelis adeliae) carrying dummy instruments were used to determine field metabolic rates using double-labelled water. All penguins injected with double-labelled water showed a marked loss of body mass (-4.5%) during the period of the experiments (20–131 h), irrespective of the time of the breeding season. Total body water averaged 57.3% and water flux estimates of field metabolic rates correlated with double-labelled water estimates of field metabolic rate (r2=0.68), indicating that Adélie penguins do not ingest significant amounts of sea water. Brooding Adélie penguins had a mean field metabolic rate of 10.1 W·kg-1 and at sea a field metabolic rate of 13.3 W·kg-1, both of which compare well with previously published estimates based on time/activity budgets and respirometry. Mean field metabolic rate in penguins with crèching chicks was 14.1 W·kg-1, and the birds spent 65 h absent from the nest as opposed to previous estimates of 7.1 W·kg-1 and 21 h. The effects of weather, disturbance and manipulation on the behaviour and field metabolic rate of penguins late in the breeding season are discussed. Adélie penguins (crèching chicks) equipped with externally attached instruments spent more time absent from the nest than noninstrumented controls (76 vs 54 h), but had a lower field metabolic rate.

Description: Routine oxygen consumption of turbot, Scophthalmus maximus, was determined in relation to temperature, salinity, body wet weight, and time of day. The highest routine oxygen consumption rates measured roughly followed a arabolic curve over the temperature range tested (8 to 24°C). The lowest rates showed a more linear refationship over the same temperature range. It is argued that lowest rates correspond to the standard oxygen consumption. Between 16 and 19°C, routine oxygen consumption reached a maximum. It is suggested that these temperatures correspond to the preferred ternerature of the species and are within the range of optimum temperature for growth of specimens weigkng about 100 g. Salinity effect on oxygen consumption rates was studied in five groups acclimated over 4 weeks to 8, 15, 22, 29, and 35%. salinity. Routine oxygen consumption rates were lowest at 8% salinity with no significant differences in higher acclimation salinities. Routine respiration of turbots showed conspicuous daily fluctuations. During spring, summer, and autumn, oxygen Consumption was higher during morning hours and at night. In winter, higher rates were measured only once (during morning and early afternoon). The relationship between routine oxygen consumption and body weight of turbots followed an exponential function with a slope of 0.7, which was lower compared to the slope of 0.8 usually given for roundfish-species.

Description: Haplogloia andersonii (Farlow) Levring is an anti-tropical species that occurs on cold and warm-temperate Pacific coasts of both Americas. In its habit it resembles the subantarctic species Chordaria linearis (Hooker et Harvey) Cotton. Culture studies show that the species differ in morphology and ecophysiology of their microscopic gametophytes and in gamete behavior. Details of sporophyte anatomy are presented that also allow the distinction of field plants. In South America, H. andersonii occurs only on the Pacific coast, from central Perú (14°S) to southern Chile (50°S). Chordaria linearis occurs on the Pacific coast from Chiloé Island (43°S) to Cape Horn (56°S). In the shared area the species may co-occur. On the Atlantic coast, C. linearis was newly collected at a locality in northern Patagonia (41°S). In addition, C. linearis occurs in Antarctica. Haplogloia moniliformis Richer, recently described from Macquarie Island, is probably synonymous with Chordaria linearis.

Description: We examined the temperature tolerance of microscopic phases from geographically disjunct isolates of eight species or closely related, putatively conspecific taxa of temperate brown algae with disjunct distributions. Maximum within-taxon differences were small and ranged from 1.6° to 4.3° C. Desmarestia aculeata and Sphaerotrichia divaricata, both with northern hemisphere amphioceanic distributions, showed little or no significant intraspecific variation between the mean upper survival limits (USL) of Atlantic and Pacific strains (δUSL ≤ 1.4°C), which would agree with a relatively recent separation of the respective populations. Among the plants with bipolar distributions, there was likewise very little difference (δUSL 0–1.1°C) between northern and southern hemisphere strains in Striaria attenuata and in the species pair Desmarestia viridis/D. willii. In Desmarestia ligulata, and in the species pairs Desmarestia firma/D. munda, Dictyosiphon foeniculaceus/D. hirsutus, and Scytothamnus australis/Scytothamnus sp., significant differences occurred, which indicate longer divergence times. δUSL in these cases ranged from 1.7° to 2.7°C, without overlap between strains from the northern and southern hemispheres. All species that passed the equator during cooler epochs had a USL of 26–27°C, at least in some geographical isolates. The NE Asian kelp Undaria pinnatifida, which passed the equator in recent times, had a USL of 29.6°C. We hypothesize that the mechanism of spreading in the amphipolar species studied was migration of vegetative microthalli. The more unlikely alternative hypothesis of continuous populations through the tropics during a cooler epoch would imply a drop in seawater temperatures to approximately 20° C in summer and 15° C in winter, which is not supported by paleoclimatic evidence.

Description: The effect of spray droplets in the marine surface layer on evaporation is considered. Independent evidence from energy constraints, from visibility and from sea salt content of air is used. The estimation shows that, except perhaps for hurricane wind strength, the increase of total evaporation from evaporating droplets is negligible. This is in agreement with recent experimental evidence.

Description: Rapid chemical profiling of the antitumour active crude dichloromethane extract of the marine sponge, Dactylospongia sp. was undertaken. A combination of both offline (HPLC followed by NMR and MS) and on-line (on-flow and stop-flow HPLC-NMR) chemical profiling approaches was adopted to establish the exact nature of the major constituents present in the dichloromethane extract of this sponge. On-flow HPLC-NMR analysis was employed to initially identify components present in the dichloromethane extract, while stop-flow HPLC-NMR experiments were then conducted on the major component present, resulting in the partial identification of pentaprenylated p-quinol (5). Subsequent off-line RP semi-preparative HPLC isolation of 5 followed by detailed spectroscopic analysis using NMR and MS permitted the complete structure to be established. This included the first complete carbon NMR chemical shift assignment of 5 based on the heteronuclear 2-D NMR experiments, together with the first report of its antitumour activity. This study represents one of the few reports describing the application of HPLC-NMR to chemically profile secondary metabolites from a marine organism.

Description: The location of spawning grounds of the squid Loligo vulgaris reynaudii (D'Orbigny) was investigated in the years 1988–1990. At least 39 spawning sites were found during this period along the inshore areas of the Eastern Cape coastline between Algoa Bay and Plettenberg Bay. The substrate chosen for egg laying was mostly fine sand or flat reef, frequently in large and relatively shettered bays. Spawning was found to occur sporadically throughout the year, and some spawning sites were used repeatedly within a particular year and in subsequent years. Squid migrate in discrete schools separated by sex in the vicinity of the spawning sites; these schools mix during spawning. Mating and egg deposition behaviour is described from observations made on the spawning grounds. Cannibalism was seen on a number of occasions, but no post-spawning mortality was recorded. Egg beds consisted mostly of large concentrations of egg strands (〉3 m in diameter), with smaller aggregations of one to ten egg strands surrounding these, with single strands in the immediate vicinity. Three basic patterns of echotraces were identified and interpreted according to diving observations. These patterns were classified as loose patches, dense patches, and complex patterns. The first two represent non-spawning schooling patterns and the third, mating and egg laying behaviour. This observation led to the general classification of squid aggregations: schools (non-spawning mode) and concentrations (spawning mode). Concentrations as far as Loligo vulgaris reynaudii was concerned were further divided into two patterns: suprabenthic and benthic (spawning) squid.

Description: Locomotion and fin coordination of the only living crossopterygian fish Latimeria chalumnae were studied with submersibles in the fish's natural habitat at around 200 m depth off Grand Comoro, western Indian Ocean. Latimeria is a highly specialized predatory fish adapted for nocturnal drift hunting with good fast start capability. Twelve different forward movements and manoeuvres were found and described. The movements of the paired and unpaired fins were analysed. Propulsion was accomplished with downstrokes of the pectoral fins and right-left or left-right strokes of the unpaired lobed fins. The paired fins were not used for walking on the bottom. Swimming velocity, stroke amplitudes and stroke duration were analysed from films and videos taken in the wild. Stroke duration of the paired and unpaired lobed fins was similar and varies between 1.9 to 5.8 sec. Paired fins alternated synchronously. The coordination at approximately ø = 180° between opposite paired fins is stable and independent of locomotory pattern and velocity. A phase deviation of about 90°–100° exists between paired and unpaired fins. A model is developed that describes the functional implication of this deviation as a method of producing a steady swimming performance which smooths recoil movements and prevents rotation of the body. The novel slow and fast swimming mode of Latimeria is named in accordance with Breder's (1926) descriptive nomenclature as ‘coelacanthiform’. This study indicates a primary swimming function for the primitive sarcopterygian fin and confirms earlier evolutionary assumptions of a more open-water life style of coelacanth fishes. Paleoethological models of the walking habits of Latimeria have to be rejected. Synchronous alternation of paired fins originating from hydrodynamic demands could be a pre-adaptation and a shared derived character in sarcopterygian fishes that facilitated the fish-tetrapod transition.

Description: The survival of cod Gadus morhua, plaice Pleuronectes platessa, and dab Limanda limanda was determined in relation to ambient oxygen saturation at 8° C and 35% m salinity. Mortalit rates were observed in fish exposed to constant oxygen levels for 24h. First mortality occurred around 60 % oxygen saturation in cod and around 30% oxygen saturation in dab and plaice. Below these thresholds mortality increased linearly with decreasing oxygen levels. If cod were infested with 1 or 2 individuals of Lernaeocera branchialis (Copepoda), their tolerance was significantly lower; under such circumstances the incipient lethal oxygen saturation was 66 %.

Description: The Gakkel Ridge in the Arctic Ocean with its adjacent Nansen and Amundsen Basins is a key region for the study of mantle melting and crustal generation at ultraslow spreading rates. We use free-air gravity anomalies in combination with seismic reflection and wide-angle data to compute 2-D crustal models for the Nansen and Amundsen Basins in the Arctic Ocean. Despite the permanent pack-ice cover two geophysical transects cross both entire basins. This means that the complete basin geometry of the world’s slowest spreading system can be analysed in detail for the first time. Applying standard densities for the sediments and oceanic crystalline crust, the gravity models reveal an unexpected heterogeneous mantle with densities of 3.30 × 103, 3.20 × 103 and 3.10 × 103 kg/m3 near the Gakkel Ridge. We interpret that the upper mantle heterogeneity mainly results from serpentinisation and thermal effects. The thickness of the oceanic crust is highly variable throughout both transects. Crustal thickness of less than 1 km dominates in the oldest parts of both basins, increasing to a maximum value of 6 km near the Gakkel Ridge. Along-axis heat flow is highly variable and heat flow amplitudes resemble those observed at fast or intermediate spreading ridges. Unexpectedly, high heat flow along the Amundsen transect exceeds predicted values from global cooling curves by more than 100%.

Description: Live-collected samples of four common reefbuilding coral genera (Acropora, Pocillopora, Goniastrea, Porites) from subtidal and intertidal settings of Heron Reef, Great Barrier Reef, show extensive early marine diagenesis where parts of the coralla less than 3 years old contain abundant macro- and microborings and aragonite, high-Mg calcite, low-Mg calcite, and brucite cements. Many types of cement are associated directly with microendoliths and endobionts that inhabit parts of the corallum recently abandoned by coral polyps. The occurrence of cements that generally do not precipitate in normal shallow seawater (e.g., brucite, low-Mg calcite) highlights the importance of microenvironments in coral diagenesis. Cements precipitated in microenvironments may not reXect ambient seawater chemistry. Hence, geochemical sampling of these cements will contaminate trace-element and stable-isotope inventories used for palaeoclimate and dating analysis. Thus, great care must be taken in vetting samples for both bulk and microanalysis of geochemistry. Visual inspection using scanning electron microscopy may be required for vetting in many cases.

Description: Sediment cores from the Central Pacific Basin were studied to determine (a) stratigraphic hiatuses, (b) sedimentation rates, and (c) their relationship to topography and the occurrence of deep-sea manganese nodules. The results of core studies and of detailed examination of two selected areas in the Central Pacific Basin led to the following conclusions. (1) Hiatuses of Neogene through Quaternary age occur widely in the Central Pacific Basin. A close relationship exists between the distribution pattern of the hiatuses and areas of low sedimentation rate, indicating the strong influence of a bottom current on sedimentation processes. (2) The hiatuses within the cores are dated as late Miocene, late Pliocene, and latest Pliocene to early Pleistocene. (3) The areas where the hiatuses are most common, and where sedimentation rate varies locally, are divided into two types: topographic highs in flat basin plains (“abyssal hill type”), and narrow, elongated topographic lows (“valley type”). They show different styles of sedimentation and hiatus formation related to the intensity of bottom current. (4) Local variation in the style of occurrence of manganese nodules depends on the relative importance of the bottom current. The differences in the manganese nodule types (r- and s-types) reflect the chemical environment where nodules have been formed. The r- and s-type nodules are related to poorly oxygenated and well oxygenated environments, respectively. Sedimentation rate is the main control on the chemical environment and nodule characteristics, determining the positions of nodule growth in the vicinity of the water-sediment interface; sedimentation rate varies inversely with the support strength of the surface sediments.

Description: Analysis of ten- and four-year datasets for the large, shallow, subtropical, and eutrophic Lakes Okeechobee (USA) and Taihu (China), respectively, suggest that resource-ratio explanations for cyanobacteria dominance may not apply to these two lakes. Datasets were examined to identify relationships between nutrient ratios [total nitrogen (TN):total phosphorus (TP) and ammonium (NH4+):oxidized N (NOx)] and phytoplankton community structure (as proportions of cyanobacteria and diatoms to total phytoplankton biomass). Datasets were pooled by sampling month, averaged lake-wide, and analyzed with linear regression. In Okeechobee, the cyanobacteria proportion increased and the diatom proportion decreased with increasing TN:TP. In Taihu, cyanobacteria decreased with increasing TN:TP, but the opposite trend observed for diatoms was marginally significant. Okeechobee cyanobacteria increased and diatoms decreased with increasing NH4+:NOx, but no significant relationships between phytoplankton and NH4+:NOx were observed in Taihu. Both lakes had significant relationships between phytoplankton community structure and total nutrients, but these relationships were the opposite of those expected. Relationships between phytoplankton community structure and water quality parameters from the previous month resulted in improved relationships, suggesting a predictive capability. Statistical analysis of the entire datasets (not pooled) supported these and additional relationships with other parameters, including temperature and water clarity.

Description: The responses of sea ice microalgae to variation in ambient irradiance (0 to 150 μE · m−2· s−1), temperature (–6° to + 6° C), and salinity (0 to 100 ppt) were tested to determine whether these variables act independently or in concert to influence rates of microalgal photosynthesis. The photosynthetic efficiency and maximum photosynthetic rate for sea ice microalgae increased as a function of incubation temperature between -6° and + 6° C. Furthermore, photosynthetic efficiency, maximum photosynthetic rate, and quantum yield were greatest at salinities between SO and 50 ppt. In contrast, the mean specific absorption coefficients were lowest near seawater salinities, and the saturating irradiance, Is, appeared to be inversely proportional to salinity. Results also suggest that the effects of salinity on the growth of sea ice microalgae are independent of those elicited by temperature or light, and that the functional relationship between salinity and light or temperature is multiplicative. This information is essential to the proper formulation of algorithms used to describe algal growth in environments where light, temperature, and salinity are changing simultaneously, such as within sea ice or within the water column at the marginal ice edge zone.

Description: This study examined stocking with three early life stages of brown trout, Salmo trutta L., in the context of rehabilitating a native lineage. Experimental sections in five streams were stocked successively with three stages (I: unfed fry at the end of the reabsorption phase, II: fed fry measuring 2–3 cm and III: fed fry measuring 4–5 cm) derived from a hatchery stock bred from wild spawners. The three stages were distinguished by single or multiple fluoromarking of the otoliths with alizarin redS. The index of relative stocking efficiency was greater for stage II than for stage I in all sections and equivalent or greater than that for stage III. Stage II achieved significantly larger mean length and weight in autumn than stage III stockings.

Description: Sections PDFPDF Tools Share Abstract Many trophically transmitted parasites have complex life cycles: they pass through at least one intermediate host before reproducing in their final host. Despite their economic and theoretical importance, the evolution of such cycles has rarely been investigated. Here, combining a novel modeling approach with experimental data, we show for the first time that an optimal transfer time between hosts exists for a “model parasite,” the tapeworm Schistocephalus solidus , from its first (copepod) to its second (fish) intermediate host. When transferring between hosts around this time, (1) parasite performance in the second intermediate host, (2) reproductive success in the final host, and (3) fitness in the next generation is maximized. At that time, the infected copepod's behavior changes from predation suppression to predation enhancement. The optimal time for switching manipulation results from a trade‐off between increasing establishment probability in the next host and reducing mortality in the present host. Our results show that these manipulated behavioral changes are adaptive for S. solidus , rather than an artifact, as they maximize parasite fitness.

Description: Polymorphicgenesofthemajorhistocompatibilitycomplex(MHC)areregardedasessential genes for individual fitness under conditions of natural and sexual selection. To test this hypothesis, we investigated the ultimate individual fitness trait — that of reproductive success. We used three-spined sticklebacks (Gasterosteus aculeatus) in seminatural enclosures, located in natural breeding areas where the experimental fish had been caught. During their reproductive period, fish were exposed continuously to their natural sympatric parasites. By genotyping almost 4000 eggs with nine microsatellites, we determined parenthood and inferred female mating decision. We found that with reference to their own MHC profile, female sticklebacks preferred to mate with males sharing an intermediate MHC diversity. In addition, males with a specific MHC haplotype were bigger and better at fighting a common parasite (Gyrodactylus sp.). This translated directly into Darwinian fitness since fish harbouring this specific MHC haplotype were more likely to be chosen and had a higher reproductive output. We conclude that females also based their mating decision on a specific MHChaplotype conferring resistance against a common parasite. This identifies and supports ‘good genes’. We argue that such an interaction between host and parasite driving assortative mating is not only a prerequisite for negative frequency-dependent selection — a potential mechanism to explain the maintenance of MHC polymorphism, but also potentially speciation.

Description: The published mean δ34S values of ore-related pyrites from orogenic gold deposits of the Eastern Goldfields Province, Yilgarn Craton lie between −4‰ and +4‰. As for orogenic gold deposits worldwide, most deposits have positive means and a restricted range of δ34S values, but some have negative means and wider ranges of δ34S values. Wall-rock carbonation and back-mixing of similar-source fluids with different fluid pathways can explain some of the more negative δ34S signatures. However, structural setting appears to be the most important factor controlling ore-fluid oxidation state and hence the distribution of δ34S values in gold-related pyrites. Shear-hosted deposits appear to have experienced fluid-dominated processes such as phase separation, whereas stockwork, vein-hosted or disseminated deposits formed under conditions of greater rock buffering. At Victory-Defiance, in particular, negative δ34S values are more common in gently dipping dilational structures, compared to more compressional steeply dipping structures. It appears most likely that fluid-pressure fluctuations during fault-valve cycles establish different fluid-flow regimes in structures with different orientations. Rapid fluid-pressure fluctuations in dilational structures during seismic activity can cause partitioning of reduced gas phases from the ore fluid during extreme phase separation and hence are an effective method of ore-fluid oxidation, leading to large, local fluctuations in oxidation state. It is thus not necessary to invoke mixing with oxidised magmatic fluids to explain δ34S signatures indicative of oxidation. In any case, available, robust geochronology in the Eastern Goldfields Province does not support the direct involvement of oxidised magmatic fluids from adjacent granitic intrusions in orogenic gold genesis. Thus, negative mean δ34S values and large variations in δ34S values of ore-related pyrites in world-class orogenic gold deposits are interpreted to result from multiple mechanisms of gold precipitation from a single, ubiquitous ore fluid in varying structural settings, rather than from the involvement of oxidised ore fluids from a different source. Such signatures are indicative, but not diagnostic, of anomalously large orogenic gold systems.

Description: The construction of S-wave velocity models of marine sediments down to hundreds of meters below the seafloor is important in a number of disciplines. One of the most significant trends in marine geophysics is to use interface waves to estimate shallow shear velocities which play an important role in determining the shallow crustal structure. In marine settings, the waves trapped near the fluid-solid interface are called Scholte waves, and this is the subject of the study. In 1998, there were experiments on the Ninetyeast Ridge (Central Indian Ocean) to study the shallow seismic structure at the drilled site. The data were acquired by both ocean bottom seismometer and ocean bottom hydrophone. A new type of seafloor implosion sources has been used in this experiment, which successfully excited fast and high frequency (> 500 Hz) body waves and slow, intermediate frequency (〈 20 Hz) Scholte waves. The fundamental and first higher mode Scholte waves have both been excited by the implosion source. Here, the Scholte waves are investigated with a full waveform modeling and a group velocity inversion approach. Shear wave velocities for the uppermost layers of the region are inferred and results from the different methods are compared. We find that the full waveform modeling is important to understand the intrinsic attenuation of the Scholte waves between 1 and 20 Hz. The modeling shows that the S-wave velocity varies from 195 to 350 m/s in the first 16 m of the uppermost layer. Depths levels of high S-wave impedance contrasts compare well to the layer depth derived from a P-wave analysis as well as from drilling data. As expected, the P- to S-wave velocity ratio is very high in the uppermost 16 m of the seafloor and the Poisson ratio is nearly 0.5. Depth levels of high S-wave impedance contrasts are comparable to the layer depth derived from drilling data.

Description: The nitrogen cycling of Lake Cadagno was investigated by using a combination of biogeochemical and molecular ecological techniques. In the upper oxic freshwater zone inorganic nitrogen concentrations were low (up to ∼3.4 μM nitrate at the base of the oxic zone), while in the lower anoxic zone there were high concentrations of ammonium (up to 40 μM). Between these zones, a narrow zone was characterized by no measurable inorganic nitrogen, but high microbial biomass (up to 4 × 107 cells ml−1). Incubation experiments with 15N-nitrite revealed nitrogen loss occurring in the chemocline through denitrification (∼3 nM N h−1). At the same depth, incubations experiments with 15N2- and 13CDIC-labelled bicarbonate, indicated substantial N2 fixation (31.7–42.1 pM h−1) and inorganic carbon assimilation (40–85 nM h−1). Catalysed reporter deposition fluorescence in situ hybridization (CARD-FISH) and sequencing of 16S rRNA genes showed that the microbial community at the chemocline was dominated by the phototrophic green sulfur bacterium Chlorobium clathratiforme. Phylogenetic analyses of the nifH genes expressed as mRNA revealed a high diversity of N2 fixers, with the highest expression levels right at the chemocline. The majority of N2 fixers were related to Chlorobium tepidum/C. phaeobacteroides. By using Halogen In Situ Hybridization-Secondary Ion Mass Spectroscopy (HISH-SIMS), we could for the first time directly link Chlorobium to N2 fixation in the environment. Moreover, our results show that N2 fixation could partly compensate for the N loss and that both processes occur at the same locale at the same time as suggested for the ancient Ocean.

Description: NOD-like receptors (NLRs) exert pivotal roles in innate immunity as sensors of exogenous or endogenous cellular danger signals. The NLR protein family has a characteristic domain architecture comprising a central nucleotide binding and oligomerization domain (NOD), an N-terminal effector binding domain and C-terminal leucine-rich repeats (LRRs). Mutations in NLR genes are genetically associated with a number of chronic inflammatory diseases of barrier organs. In this chapter, we focus on the influence of NLR regulation and function in the complex pathophysiology of mucosal homeostasis. The understanding of NLR biology may guide our future understanding of how the interaction between the human genome and the metagenome of transient and resident microbiota precipitates into chronic inflammatory disorders, such as Crohn's disease or atopy.

Description: During the twentieth century sea surface temperatures in the Atlantic Ocean exhibited prominent multidecadal variations. The source of such variations has yet to be rigorously established—but the question of their impact on climate can be investigated. Here we report on a set of multimodel experiments to examine the impact of patterns of warming in the North Atlantic, and cooling in the South Atlantic, derived from observations, that is characteristic of the positive phase of the Atlantic Multidecadal Oscillation (AMO). The experiments were carried out with six atmospheric General Circulation Models (including two versions of one model), and a major goal was to assess the extent to which key climate impacts are consistent between the different models. The major climate impacts are found over North and South America, with the strongest impacts over land found over the United States and northern parts of South America. These responses appear to be driven by a combination of an off-equatorial Gill response to diabatic heating over the Caribbean due to increased rainfall within the region and a Northward shift in the Inter Tropical Convergence Zone (ITCZ) due to the anomalous cross-equatorial SST gradient. The majority of the models show warmer US land temperatures and reduced Mean Sea Level Pressure during summer (JJA) in response to a warmer North Atlantic and a cooler South Atlantic, in line with observations. However the majority of models show no significant impact on US rainfall during summer. Over northern South America, all models show reduced rainfall in southern hemisphere winter (JJA), whilst in Summer (DJF) there is a generally an increase in rainfall. However, there is a large spread amongst the models in the magnitude of the rainfall anomalies over land. Away from the Americas, there are no consistent significant modelled responses. In particular there are no significant changes in the North Atlantic Oscillation (NAO) over the North Atlantic and Europe in Winter (DJF). Additionally, the observed Sahel drying signal in African rainfall is not seen in the modelled responses. Suggesting that, in contrast to some studies, the Atlantic Multidecadal Oscillation was not the primary driver of recent reductions in Sahel rainfall.

Description: The genes and intergenic regions of the amoCAB operon were analyzed to establish their potential as molecular markers for analyzing ammonia-oxidizing betaproteobacterial (beta-AOB) communities. Initially, sequence similarity for related taxa, evolutionary rates from linear regressions, and the presence of conserved and variable regions were analyzed for all available sequences of the complete amoCAB operon. The gene amoB showed the highest sequence variability of the three amo genes, suggesting that it might be a better molecular marker than the most frequently used amoA to resolve closely related AOB species. To test the suitability of using the amoCAB genes for community studies, a strategy involving nested PCR was employed. Primers to amplify the whole amoCAB operon and each individual gene were tested. The specificity of the products generated was analyzed by denaturing gradient gel electrophoresis, cloning, and sequencing. The fragments obtained showed different grades of sequence identity to amoCAB sequences in the GenBank database. The nested PCR approach provides a possibility to increase the sensitivity of detection of amo genes in samples with low abundance of AOB. It also allows the amplification of the almost complete amoA gene, with about 300 bp more sequence information than the previous approaches. The coupled study of all three amo genes and the intergenic spacer regions that are under different selection pressure might allow a more detailed analysis of the evolutionary processes, which are responsible for the differentiation of AOB communities in different habitats.

Description: 10.1111/j.1439-0426.2009.01215.x

Description: Semi Permeable Membrane Device (SPMD) was deployed on an experimental basis for five days inside an Environmental Chemistry Laboratory and two sites outside the building in Kiel, Germany to understand the time-averaged contaminant profiles and concentrations of PCBs. Multi Dimensional High Resolution Gas Chromatography-Electron Capture Detection technique and high resolution clean up techniques were employed to SPMD derived triolein samples. Air concentrations were derived from well established mass transfer coefficients or rate constants for PCBs in SPMD. PCBs profiles in indoor and outdoor samples were distinctly different, exemplified by a particle free clean-up laboratory facility where particle associated higher chlorinated congeners were absent. SPMDs revealed the ‘occupational hazard’ to workers inside the building from chemical contamination derived from both building materials and chemicals used in the laboratory. Finger printing technique using principle component analysis (PCA) revealed that PCB contamination was derived from German commercial PCB mixtures. SPMD derived air concentrations in outdoor samples resembled levels recorded by similar devices in Europe. Ultimately, a simple sampling technique in combination with high resolution analytical techniques demonstrated the uptake of more than 60 PCB congeners within a short period of time.

Description: Lipid content, fatty acid composition, and feeding activity of the dominant Antarctic copepods, Calanoides acutus, Calanus propinquus, and Metridia gerlachei, were studied at a quasi-permanent station in the eastern Weddell Sea in December 2003. During 3 weeks of the spring phytoplankton development, total lipid levels of females and copepodite stages V (CVs) of C. acutus were almost doubled. Meanwhile, only a slight increase in total lipid content occurred in M. gerlachei, and no clear trend was observed in lipids of C. propinquus females. The pronounced increase of lipids in C. acutus was due to an accumulation of wax esters. The proportion of wax esters in the lipids of M. gerlachei was clearly lower, while triacylglycerols played a more important role. In C. propinquus, triacylglycerols were the only neutral lipid class. There were no pronounced changes in the feeding activity of M. gerlachei, whereas the feeding activity of C. acutus had rapidly increased with the development of the phytoplankton bloom in December, which explains its rapid lipid accumulation. The combination of gut content and fatty acid trophic marker analyses showed that C. acutus was feeding predominantly on diatoms. The typical diatom fatty acid marker, 16:1(n-7), slightly decreased and the tracer for flagellates, 18:4(n-3), increased in females and CVs of C. acutus. This shift indicates the time, when the significance of flagellates started to increase. The three copepod species exhibited different patterns of lipid accumulation in relation to their trophic niches and different duration of their active phases. The investigations filled a crucial data gap in the seasonal lipid dynamics of dominant calanoid copepods in the Weddell Sea in December and support earlier hypotheses on their energetic adaptations and life cycle strategies.

Description: Cryolithological, ground ice and fossil bioindicator (pollen, diatoms, plant macrofossils, rhizopods, insects, mammal bones) records from Bol'shoy Lyakhovsky Island permafrost sequences (73°20′N, 141°30′E) document the environmental history in the region for the past c. 115 kyr. Vegetation similar to modern subarctic tundra communities prevailed during the Eemian/Early Weichselian transition with a climate warmer than the present. Sparse tundra-like vegetation and harsher climate conditions were predominant during the Early Weichselian. The Middle Weichselian deposits contain peat and peaty soil horizons with bioindicators documenting climate amelioration. Although dwarf willows grew in more protected places, tundra and steppe vegetation prevailed. Climate conditions became colder and drier c. 30 kyr BP. No sediments dated between c. 28.5 and 12.05 14C kyr BP were found, which may reflect active erosion during that time. Herb and shrubby vegetation were predominant 11.6–11.3 14C kyr BP. Summer temperatures were c. 4 °C higher than today. Typical arctic environments prevailed around 10.5 14C kyr BP. Shrub alder and dwarf birch tundra were predominant between c. 9 and 7.6 kyr BP. Reconstructed summer temperatures were at least 4 °C higher than present. However, insect remains reflect that steppe-like habitats existed until c. 8 kyr BP. After 7.6 kyr BP, shrubs gradually disappeared and the vegetation cover became similar to that of modern tundra. Pollen and beetles indicate a severe arctic environment c. 3.7 kyr BP. However, Betula nana, absent on the island today, was still present. Together with our previous study on Bol'shoy Lyakhovsky Island covering the period between about 200 and 115 kyr, a comprehensive terrestrial palaeoenvironmental data set from this area in western Beringia is now available for the past two glacial–interglacial cycles.

Description: Lions were the most widespread carnivores in the late Pleistocene, ranging from southern Africa to the southern USA, but little is known about the evolutionary relationships among these Pleistocene populations or the dynamics that led to their extinction. Using ancient DNA techniques, we obtained mitochondrial sequences from 52 individuals sampled across the present and former range of lions. Phylogenetic analysis revealed three distinct clusters: (i) modern lions, Panthera leo; (ii) extinct Pleistocene cave lions, which formed a homogeneous population extending from Europe across Beringia (Siberia, Alaska and western Canada); and (iii) extinct American lions, which formed a separate population south of the Pleistocene ice sheets. The American lion appears to have become genetically isolated around 340 000 years ago, despite the apparent lack of significant barriers to gene flow with Beringian populations through much of the late Pleistocene. We found potential evidence of a severe population bottleneck in the cave lion during the previous interstadial, sometime after 48 000 years, adding to evidence from bison, mammoths, horses and brown bears that megafaunal populations underwent major genetic alterations throughout the last interstadial, potentially presaging the processes involved in the subsequent end-Pleistocene mass extinctions.

Description: Eight species of marine phytoplankton showed significant variation in the relative amount of some fatty acids (FAs) in response to variation in temperature. Large changes in relative amounts of certain FAs occurred as a result of a 15° C change in growth temperature. For example, 14:0 increased from ≃4% of total FAs at 10° C to 〉 20% at 25° C for Chaetoceros simplex and Isochrysis aff. galbana but decreased for Phaeodactylum tricornutum. The percentage of the polyunsaturated fatty acid (PUFA) 16:ω1 was consistently greater at 10° C than at 25° C, and the converse was usually true for 16: 4ω3. Calculated over all eight species, there was a modest but significant inverse relationship between the percentage of PUFAs and temperature. Only for Thalassiosira pseudonana was the percentage of either of the PUFAs and nutritionally essential fatty acids (EFAs) also an inverse function of temperature. For T. pseudonana, the percentage of the EFA 22:6ω3 decreased linearly with increasing temperature over the range from 10 to 25° C. For three species, the ratio of unsaturated/saturated FAs was correlated with growth rate when growth rate was controlled by variation in irradiance and temperature. Only for Thalassiosira pseudonana was the ratio of unsaturated/saturated FAs also an inverse function of temperature alone.

Description: Patiria miniata, a broadcast-spawning sea star species with high dispersal potential, has a geographic range in the intertidal zone of the northeast Pacific Ocean from Alaska to California that is characterized by a large range gap in Washington and Oregon. We analyzed spatial genetic variation across the P. miniata range using multilocus sequence data (mtDNA, nuclear introns) and multilocus genotype data (microsatellites). We found a strong phylogeographic break at Queen Charlotte Sound in British Columbia that was not in the location predicted by the geographical distribution of the populations. However, this population genetic discontinuity does correspond to previously described phylogeographic breaks in other species. Northern populations from Alaska and Haida Gwaii were strongly differentiated from all southern populations from Vancouver Island and California. Populations from Vancouver Island and California were undifferentiated with evidence of high gene flow or very recent separation across the range disjunction between them. The surprising and discordant spatial distribution of populations and alleles suggests that historical vicariance (possibly caused by glaciations) and contemporary dispersal barriers (possibly caused by oceanographic conditions) both shape population genetic structure in this species.

Description: The Siberian Laptev Sea shelf contains submarine permafrost, which was formed by flooding of terrestrial permafrost with ocean water during the Holocene sea level rise. This flooding resulted in a warming of the permafrost to temperatures close below 0°C. The impact of these environmental changes on methanogenic communities and carbon dynamics in the permafrost was studied in a submarine permafrost core of the Siberian Laptev Sea shelf. Total organic carbon (TOC) content varied between 0.03% and 8.7% with highest values between 53 and 62 m depth below sea floor. In the same depth, maximum methane concentrations (284 nmol CH4 g−1) and lowest carbon isotope values of methane (−72.2‰ VPDB) were measured, latter indicating microbial formation of methane under in situ conditions. The archaeal community structure was assessed by a nested polymerase chain reaction (PCR) amplification for DGGE, followed by sequencing of reamplified bands. Submarine permafrost samples showed a different archaeal community than the nearby terrestrial permafrost. Samples with high methane concentrations were dominated by sequences affiliated rather to the methylotrophic genera Methanosarcina and Methanococcoides as well as to uncultured archaea. The presented results give the first insights into the archaeal community in submarine permafrost and the first evidence for their activity at in situ conditions.

Description: Palytoxin (PTX), one of the most potent and chemically complex marine toxins, is predominantly found in zoanthid corals and sporadically in dinoflagellates. Its biosynthesis and metabolic pathways are largely unknown. However, the widespread occurrence of the toxin in phylogenetically distinct marine organisms is consistent with its production by microorganisms and subsequent accumulation in the food chain. To investigate a possible microbial origin, bacteria from two zoanthid corals (Palythoa caribaeorum, Zoanthus pulchellus) and one sponge (Neofibularia nolitangere) were isolated. More than 250 bacteria were screened for hemolysis using a newly developed PTX-screening assay of which 7% showed PTX-like hemolytic activity. 16S rRNA gene sequencing revealed that these bacterial isolates belonged to strains of Bacillus cereus group (n = 11) as well as the genera Brevibacterium (n = 4) and Acinetobacter (n = 2). The results indicate the presence of Na+/K+-ATPase toxins and possibly PTX in hemolytic bacteria from P. caribaeorum.

Description: Continental shelf systems are highly dynamic sedimentary environments, where sediments from biogenic production as well as from terrigenous sources are redistributed in the shelf depositional system, and partly exported off the shelf to the slope and the deep sea. The Golfe d’Arguin (Mauritania, NW Africa) is dominated by such redistribution processes, involving clastic silt imported as dust from the Sahara desert and biogenic carbonates of marine origin. Indeed, surface-sediment grain size and mineralogy show a clear north–south partitioning of sediment type. Fine material is winnowed from the northern part of the gulf, and transported toward the southern part off the Banc d’Arguin, where coarse silt settles on the outer shelf and upper slope, at least down to 600 m water depth. Particles of the fine silt fraction, estimated in terms of eolian material collected aboard the research vessel, are thought to be exported further offshore as they correspond to grain sizes previously reported from adjacent deep-sea sediments. These findings suggest that the interpretation of dust records from the continental slope and rise off NW Africa must consider reworking and partitioning processes active on the Mauritanian shelf.

Description: Lipopolysaccharides were isolated from the moderate halophilic Ectothiorhodospira shaposhnikovii slight to and Ectothiorhodospira mobilis and from the extremely halophilic Ectothiorhodospira halophila by the hot phenol-water and purified by the phenol-chloroform-petroleum ether methods. The isolated lipopolysaccharides of all three species contained 3-deoxy-d-manno-octulosonic acid and d-glycero-d-mannoheptose indicating the existence of a core. They contained additionally glucose and uronic acids (E. shaposhnikovii and E. mobilis) or glucose, uronic acids and threonine (E. halophila). Sodium deoxycholate gel-electrophoresis of the three lipopolysaccharides, each showing only one major band, indicated R-type character of the lipopolysaccharides of the three Ectothiorhodospira species. The lipid A fractions of the lipopolysaccharides from E. shaposhnikovii and E. mobilis represented phosphorylated “mixed” lipid A types with both 2,3-diamino-2,3-dideoxy-d-glucose and d-glucosamine. The lipid A from E. halophila contained also phosphate and 2,3-diamino-2,3-dideoxy-d-glucose but only traces of d-glucosamine, which would indicated lipid ADAG. The fatty acid spectra were characterized by amide-bound 3-OH-10:0 and 3-OH-12:0 (E. shaposhnikovii), 3-OH-10:0 (E. mobilis), or 3-OH-10:0,3-OH-14:0, and 3-oxo-14-0 (E. halophila). The predominant ester-bound fatty acids were 14:0 and 16:0 (E. shaposhnikovii and E. mobilis), or 12:0 and 14:1 (E. halophila).

Description: The Hindak strain of a Cryptomonas species (Cryptophyceae) produces extracellular polysaccharides. Because there is no information on the structure of these compounds in the Cryptophyceae we conducted structural studies. Gas–liquid chromatographic analyses showed that the polysaccharide is composed of fucose, rhamnose, xylose, mannose, glucose, galactose, galacturonic acid, glucuronic acid, and traces of 3-O-methyl galactose. The polysaccharide was separated into two subtractions by ion-exchange chromatography. Fraction A consisted mainly of 1,3-linked galactose units and 1,4-linked galacturonic acid. Unlike fraction B, fraction A did not have xylose, 3-O-methyl galactose, or glucuronic acid. Also, its degree of branching was low compared to that of fraction B. Only traces of sulfate were present infraction A, but fraction B was 10–15% sulfated. Protein was approximately 1% in both fractions. These polysaccharides appear to be a novel type of polymer in algae.

Description: The 14.1 Ma composite welded ignimbrite P1 (45 km3 DRE) on Gran Canaria is compositionally zoned from a felsic lower part to a basaltic top. It is composed of four component magmas mixed in vertically varying proportions: (1) Na-rhyolite (10 km3) zoned from crystal-poor to highly phyric; (2) a continuously zoned, evolved trachyte to sodic trachyandesite magma group (6 km3); (3) a minor fraction of Na-poor trachyandesite (〈1 km3); and (4) nearly aphyric basalt (26 km3) zoned from 4.3 to 5.2 wt% MgO. We distinguish three sites and phases of mixing: (a) Mutual mineral inclusions show that mixing between trachytic and rhyolitic magmas occurred during early stages of their intratelluric crystallization, providing evidence for long-term residence in a common reservoir prior to eruption. This first phase of mixing was retarded by increasing viscosity of the rhyolite magma upon massive anorthoclase precipitation and accumulation. (b) All component magmas probably erupted through a ring-fissure from a common upper-crustal reservoir into which the basalt intruded during eruption. The second phase of mixing occurred during simultaneous withdrawal of magmas from the chamber and ascent through the conduit. The overall withdrawal and mixing pattern evolved in response to pre-eruptive chamber zonation and density and viscosity relationships among the magmas. Minor sectorial variations around the caldera reflect both varying configurations at the conduit entrance and unsteady discharge. (c) During each eruptive pulse, fragmentation and particulate transport in the vent and as pyroclastic flows caused additional mixing by reducing the length scale of heterogeneities. Based on considerations of magma density changes during crystallization, magma temperature constraints, and the pattern of withdrawal during eruption, we propose that eruption tapped the P1 magma chamber during a transient state of concentric zonation, which had resulted from destruction of a formerly layered zonation in order to maintain gravitational equilibrium. Our model of magma chamber zonation at the time of eruption envisages a basal high-density Na-poor trachyandesite layer that was overlain by a central mass of highly phyric rhyolite magma mantled by a sheath of vertically zoned trachyte-trachyandesite magma along the chamber walls. A conventional model of vertically stacked horizontal layers cannot account for the deduced density relationships nor for the withdrawal pattern.

Description: We examine a statistical model for the description of the seasonal variation of extreme daily precipitation at 689 stations across the UK. The probability distribution for monthly maximum precipitation intensity is modelled with a generalised extreme-value distribution (GEV). Instead of modelling the distribution of precipitation maxima separately for every month, we propose an overall model with seasonally-varying location and scale parameters and a constant shape parameter. This model is tested against an augmented version with the shape parameter allowed to vary as well. Furthermore, we compare model adequacy for block length of one and two month and found no major improvements for the longer block-length. Based on this model, the 10 and 100-year return levels are calculated conditioned on the month of the year. The interpolation of return levels to a complete coverage of the UK allows for an identification of spatial patterns and their temporal evolution. These patterns suggest that different mechanisms for extreme precipitation are dominant in different regions of the UK.

Description: Otolith microchemistry is widely used as a tool to track individual migration pathways of diadromous fish under the assumption that the elemental composition of fish otoliths is directly influenced by the physicochemical properties of the surrounding water. Nevertheless, several endogenous factors are reported to affect element incorporation into fish otoliths and might lead to misinterpretations of migration studies. This study experimentally examined the influence of eight different diets on the microchemical composition of European eel (Anguilla anguilla) otoliths using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Seven natural prey types and one artificial diet were fed during 8 weeks in freshwater circuits. Results show for the first time that food has no significant influence on the incorporation of Na, Sr, Ba, Mg, Mn, Cu and Y into European eel otoliths. This indicates that the incorporation of elements usually chosen for migration studies is not affected by diet and that individual feeding behaviour of A. anguilla will not lead to any misinterpretation of migration pathways.

Description: Low pO(2) values have been measured in the perivitelline fluids (PVF) of marine animal eggs on several occasions, especially towards the end of development, when embryonic oxygen consumption is at its peak and the egg case acts as a massive barrier to diffusion. Several authors have therefore suggested that oxygen availability is the key factor leading to hatching. However, there have been no measurements of PVF pCO(2) so far. This is surprising, as elevated pCO(2) could also constitute a major abiotic stressor for the developing embryo. As a first attempt to fill this gap in knowledge, we measured pO(2), pCO(2) and pH in the PVF of late cephalopod (Sepia officinalis) eggs. We found linear relationships between embryo wet mass and pO(2), pCO(2) and pH. pO(2) declined from 〉 12 kPa to less than 5 kPa, while pCO(2) increased from 0.13 to 0.41 kPa. In the absence of active accumulation of bicarbonate in the PVF, pH decreased from 7.7 to 7.2. Our study supports the idea that oxygen becomes limiting in cephalopod eggs towards the end of development; however, pCO(2) and pH shift to levels that have caused significant physiological disturbances in other marine ectothermic animals. Future research needs to address the physiological adaptations that enable the embryo to cope with the adverse abiotic conditions in their egg environment.

Description: Various cnidarians have adapted their life style to interstitial habitats of marine sediments. Recently, for the first time a hydroid was reported from the interstitial brine channel system of Arctic fast ice. Due to its derived features, the new genus and species Sympagohydra tuuli was introduced. Here we describe findings of S. tuuli in sea ice at several sites within the central Arctic Ocean. In our view the results of this study do not allow assignment of Sympagohydra to any known family and we, therefore, suggest the introduction of a new family Sympagohydridae which is placed within the hydrozoan subclass Hydroidolina, order Anthomedusae, suborder Capitata. A first detailed histological analysis of S. tuuli is presented. In vivo analysis of locomotion and reproduction revealed a remarkable convergent evolution in S. tuuli and distant meiobenthic relatives. Shared traits are a flagellated epidermis enabling the animals to glide within small interstices by means of flagellar beating as well as an internalised embryogenesis. In S. tuuli gametogenesis occurs in the absence of gonophores inbetween gastro- and epidermis clearly separated from the epidermis. Budding was observed as the vegetative mode of reproduction. Documentation of feeding behaviour identified copepod nauplii and rotifers as prey items and demonstrates a high trophical position of the hydroids within the sympagic food web. Occurrence of reproducing individuals and pronounced tolerances towards changing temperatures and salinities indicate S. tuuli as a truly sympagic species.

Description: Conventional simultaneous CNS stable isotope abundance measurements of solid samples usually require high sample amounts, up to 1 mg carbon, to achieve exact analytical results. This rarely used application is often impaired by high C:S element ratios when organic samples are analyzed and problems such as incomplete conversion into sulphur dioxide occur during analysis. We introduce, as a technical innovation, a high sensitivity elemental analyzer coupled to a conventional isotope ratio mass spectrometer, with which CNS-stable isotope ratios can be determined simultaneously in samples with low carbon content (〈40 mu g C corresponding to similar to 100 mu g dry weight). The system includes downsized reactors, a temperature program-controlled gas chromatography (GC) column and a cryogenic trap to collect small amounts of sulphur dioxide. This modified application allows for highly sensitive measurements in a fully automated operation with standard deviations better than +/-0.47 parts per thousand for delta N-15 and delta S-34 and +/-0.12 parts per thousand for delta C-13 (n=127). Samples collected from one sampling site in a Baltic fjord within a short time period were measured with the new system to get a first impression of triple stable isotope signatures. The results confirm the potential of using delta S-34 as a stable isotope tracer in combination with delta N-15 and delta C-13 measurements to improve discrimination of food sources in aquatic food webs. Copyright (C) 2009 John Wiley & Sons, Ltd

Description: Klyuchevskoy volcano, in Kamchatka’s subduction zone, is one of the most active arc volcanoes in the world and contains some of the highest δ18O values for olivines and basalts. We present an oxygen isotope and melt inclusion study of olivine phenocrysts in conjunction with major and trace element analyses of 14C- and tephrochronologically-dated tephra layers and lavas spanning the eruptive history of Klyuchevskoy. Whole-rock and groundmass analyses of tephra layers and lava samples demonstrate that both high-Mg (7–12.5 wt% MgO) and high-Al (17–19 wt% Al2O3, 3–6.5 wt% MgO) basalt and basaltic andesite erupted coevally from the central vent and flank cones. Individual and bulk olivine δ18O range from normal MORB values of 5.1‰ to values as high as 7.6‰. Likewise, tephra and lava matrix glass have high-δ18O values of 5.8–8.1‰. High-Al basalts dominate volumetrically in Klyuchevskoy’s volcanic record and are mostly high in δ18O. High-δ18O olivines and more normal-δ18O olivines occur in both high-Mg and high-Al samples. Most olivines in either high-Al or high-Mg basalts are not in oxygen isotopic equilibrium with their host glasses, and Δ18Oolivine–glass values are out of equilibrium by up to 1.5‰. Olivines are also out of Fe–Mg equilibrium with the host glasses, but to a lesser extent. Water concentrations in olivine-hosted melt inclusions from five tephra samples range from 0.4 to 7.1 wt%. Melt inclusion CO2 concentrations vary from below detection (〈50 ppm) to 1,900 ppm. These values indicate depths of crystallization up to ~17 km (5 kbar). The variable H2O and CO2 concentrations likely reflect crystallization of olivine and entrapment of inclusions in ascending and degassing magma. Oxygen isotope and Fe–Mg disequilibria together with melt inclusion data indicate that olivine was mixed and recycled between high-Al and high-Mg basaltic melts and cumulates, and Fe–Mg and δ18O re-equilibration processes were incomplete. Major and trace elements in the variably high-δ18O olivines suggest a peridotite source for the parental magmas. Voluminous, highest in the world with respect to δ18O, and hydrous basic volcanism in Klyuchevskoy and other Central Kamchatka depression volcanoes is explained by a model in which the ascending primitive melts that resulted from the hydrous melt fluxing of mantle wedge peridotite, interacted with the shallow high-δ18O lithospheric mantle that had been extensively hydrated during earlier times when it was part of the Kamchatka forearc. Following accretion of the Eastern Peninsula terrains several million years ago, a trench jump eastward caused the old forearc mantle to be beneath the presently active arc. Variable interaction of ascending flux-melting-derived melts with this older, high-δ18O lithospheric mantle has produced mafic parental magmas with a spectrum of δ18O values. Differentiation of the higher δ18O parental magmas has created the volumetrically dominant high-Al basalt series. Both basalt types incessantly rise and mix between themselves and with variable in δ18O cumulates within dynamic Klyuchevskoy magma plumbing system, causing biannual eruptions and heterogeneous magma products.

Description: Preselected cyanobacterial strains (available from culture collections and our own isolates), belonging primarily to the heterocystous cluster, were screened for inhibitors against butyrylcholinesterase. About one-half of the extracts exhibited inhibitory activity. Nostocarboline, the responsible metabolite in Nostoc 78–12A, was studied in more detail as an acetylcholinesterase (AChE) inhibitor. The compound showed potent activity against this enzyme (IC50 = 5.3 µM), and the Michaelis-Menten kinetics indicated a non-competitive component in the inhibitory mechanism. In addition, nostocarboline turned out to be a potent inhibitor of trypsin (IC50 = 2.8 µM), and thus is the first described cyanobacterial serine protease inhibitor of an alkaloid structure. The function of nostocarboline in aquatic ecosystems and its potential as a lead compound for the development of useful therapeutic AChE inhibitors is discussed.

Description: The species diversity of the pelagic microcopepod family Oncaeidae collected with nets of 0.1-mm mesh size was studied at 6 stations along a west-to-east transect in the Mediterranean Sea down to a maximum depth of 1,000 m. A total of 27 species and two form variants have been identified, including three new records for the Mediterranean. In addition, about 20, as yet undescribed, new morphospecies were found (mainly from the genera Epicalymma and Triconia) which need to be examined further. The total number of identified oncaeid species was similar in the Western and Eastern Basins, but for some cooccurring sibling species, the estimated numerical dominance changed. The deep-sea fauna of Oncaeidae, studied at selected depth layers between 400 m and the near-bottom layer at 〉4,200 m depth in the eastern Mediterranean (Levantine Sea), showed rather constant species numbers down to ∼3,000 m depth. In the near-bottom layers, the diversity of oncaeids declined and species of Epicalymma strongly increased in numerical importance. The taxonomic status of all oncaeid species recorded earlier in the Mediterranean Sea is evaluated: 19 out of the 46 known valid oncaeid species are insufficiently described, and most of the taxonomically unresolved species (13 species) have originally been described from this area (type locality). The deficiencies in the species identification of oncaeids cast into doubt the allegedly cosmopolitan distribution of some species, in particular those of Mediterranean origin. The existing identification problems even of well-described oncaeid species are exemplified for the Oncaea mediacomplex, including O. media Giesbrecht, O. scottodicarloi Heron & Bradford-Grieve, and O. waldemari Bersano & Boxshall, which are often erroneously identified as a single species (O. media). The inadequacy in the species identification of Oncaeidae, in particular those from the Atlantic and Mediterranean, is mainly due to the lack of reliable identification keys for Oncaeidae in warm-temperate and/or tropical seas. Future efforts should be directed to the construction of identification keys that can be updated according to the latest taxonomic findings, which can be used by the non-expert as well as by the specialist. The adequate consideration of the numerous, as yet undescribed, microcopepod species in the world oceans, in particular the Oncaeidae, is a challenge for the study of the structure and function of plankton communities as well as for global biodiversity estimates.

Description: The feeding selectivity and the growth and reproductive success of the copepod Acartia tonsa have been studied in mesocosms fertilized at different Si:N ratios (0-1.75:1) and, therefore, at different compositions of the phytoplankton communities. Phytoplankton composition showed a strong response to nutrient ratios, with diatoms comprising > 90% at Si:N ratios > 1:1 of total biomass as opposed to 〈 20% at the lowest ratio. A. tonsa strongly preferred feeding on motile prey (flagellates and ciliates) to feeding on diatoms. Nevertheless, diatoms comprised a substantial part of the diet at the highest Si:N ratios. A. tonsa egg production and the final (after 4 weeks) abundance of adults and copepodites showed no response to Si:N ratios while nauplii production slightly increased with Si:N ratios. It is concluded that the frequently reported deleterious effect of diatoms on copepod reproduction is rather unusual when copepods are confronted with a naturally diverse phytoplankton assemblage instead of clonal cultures in the laboratory.

Description: Spatial and temporal changes of the copepod community have been investigated and related to the environmental variability of the Balearic Sea (Western Mediterranean). The period studied spans from 1994 to 1999 during which we analyzed the abundance and structure copepod variability over a cross-shore transect. Results showed a close link between hydrological changes and the variations of copepod abundance. The synchronous variability of copepods and hydrography indicated the rapid response of this zooplankton group to the inflow of cold and warm water masses coming through the study area. Cluster analysis revealed four main copepod assemblages that distinguished the coastal from the oceanic species and those species with different water masses preference. The copepod assemblage composed of Calanus helgolandicus, Clausocalanus arcuicornis, C. pergens, C. paululus, Calocalanus tenuis and Pleuromamma gracilis was associated with cool salty waters, whereas the assemblage formed by Temora stylifera, C. pavo, C. styliremis, Centropages bradyi and Acartia danae was related to warmer less saline Mediterranean waters. Moreover, it is suggested that changes in sea water temperature and salinity are linked to large-scale changes likely occurring at a basin scale, which is reflected in the Western Mediterranean mesoscale hydrographic changes. Therefore, it is stressed that changes in the Balearic copepod community can be used as potential tracers of the western Mediterranean water masses

Description: Precise U–Pb geochronology, Hf isotope compositions and trace element distributions in zircons are combined in the present study to define the timing and sources of the magmatism forming the Medet porphyry copper deposit, Bulgaria. ID-TIMS U–Pb-zircon dating demonstrates that ore-bearing magmatism extended for less than 1.12 Ma. As inferred from the field relationships, it started with the intrusion of a quartz-monzodiorite at 90.59 ± 0.29 Ma followed by granodiorite porphyries at 90.47 ± 0.30 and 90.27 ± 0.60 Ma and by crosscutting aplite dykes at 90.12 ± 0.36 Ma. These units were overprinted by potassic alteration and host economic copper-(Mo–Au) mineralization. The main magmatic–hydrothermal activity ceased after that, and a later quartz-granodiorite porphyry dyke, dated at 89.26 ± 0.32 Ma, only contains an uneconomic quartz–pyrite mineralization. Assimilation of Lower Paleozoic rocks with a mantle to mantle–crust signature is characteristic of the fertile magma in the Medet deposit, as defined by positive ɛ-Hf values of the inherited zircons. The positive Ce-anomalies and the higher Eu/Eu* ratios of the zircons in the mineralized Cretaceous rocks of Medet deposit argue for crystallization from a generally more oxidized magma compared to the later quartz-granodiorite porphyry dyke. A change in paleostress conditions occurred during the intrusion of the Medet pluton and its dykes. The initial stage reveals E–W extension associated with N–S compression, whereas the younger granodiorite dyke was emplaced during subsequent N–S extension. The large-scale switch of the extensional stress regime during the mineralization was favourable for ore deposition by channelling the fluids and increasing the effective permeability.

Description: We analyzed the seasonal variations of the ctenophore Mnemiopsis leidyi weekly collected since its first record in the western Baltic Sea in October 2006. The distribution pattern together with the seasonal dynamics and population outbreaks in late summer 2007 indicate recent successfully establishment of M. leidyi in this area. Seasonal changes showed two periods of high reproductive activity characterized by a population structure dominated by small size classes, followed by an increase of larger ones. These results further revealed that the bulk of the population remains in deep layers during the periods of low population density, whereas it appeared situated in upper layers during the proliferation of the species. We further emphasized the strength of the population outbreaks, which can reach abundances 〉10-fold higher in time periods shorter than a week. The predatory impact this species may have in pelagic ecosystems warns on the importance of its recent range of expansion.

Description: Four Paraeuchaeta species and three aetideids were frequently encountered along 51°30′S in the Atlantic sector of the Southern Ocean. Paraeuchaeta antarctica was most abundant close to the Antarctic Polar Front. Within the genera Paraeuchaeta and Gaetanus, congeners usually partitioned the water column. Euchaetidae had high lipid (≤37% dry mass, DM in adult females) and wax ester contents (≤22% DM). Fatty acid composition of Paraeuchaeta spp. was dominated by monounsaturated moieties, especially 16:1(n-7) and 18:1(n-9), while fatty alcohols were mainly saturated. Surprisingly, only the bathypelagic P. barbata contained moderate amounts of 20:1(n-9) and 22:1(n-11) fatty acids (≤14%) and high levels of the respective fatty alcohols (≤50%), generally considered trophic biomarkers for calanid copepods as prey. Thus, herbivorous calanid copepods seem to be a readily available prey source at bathypelagic depths, indicating that their seasonal vertical migration provides a “trophic shortcut” from primary production at the surface to the interior of the ocean. Aetideidae also contained substantial levels of total lipid (14–36% DM), but wax esters contributed only up to 12% DM in copepodite stages C5 of Gaetanus spp., whereas other stages of Gaetanus and Aetideopsis minor only contained ≤6% DM of wax esters. The fatty acid compositions of Aetideidae were more balanced with 16:0, 18:1(n-9), 20:5(n-3), and 22:6(n-3) as important components, indicating a generally omnivorous feeding behaviour.

Description: We examine micro-earthquake records from a dense temporary array of ocean bottom seismometers (OBS) and hydrophones that has been installed from September to November 2005 at the trench outer rise offshore Nicaragua. Approximately 1.5 locatable earthquakes per day within the array of 110 × 120 km show the high seismic activity in this region. Seismicity is restricted to the upper ∼15 km of the mantle and hence where temperatures reach 350–400 °C, which is smaller than values observed for large mantle intraplate events (650 °C). Determination of moment tensor solutions suggest a change of the stress region from tensional in the upper layers of the oceanic plate to compressional beneath. The neutral plane between both regimes is located at ∼6–9 km beneath Moho and thus very shallow. Fluids, which are thought to travel through the tensional fault system into the upper mantle, may not be able to penetrate any deeper. The earthquake catalogue, which seems to be complete for magnitudes above Mw = 1.6–1.8, suggests a strong change of the lithospheric rheology when approaching the trench. And b-factors, that is the ratio between small and large earthquakes increase significantly in the closest 20 km to the trench axis, implying that the crust and upper mantle is massively weakened and hence ruptures more frequently but under less release of stress. We explain this with a partly serpentinized upper mantle.

Description: Length–weight relationships are lacking for most deep-sea fishes. This study presents length–weight relationships for 42 species from the western Bering Sea. Results show significantly different relationships between females and males for 11 species and between juveniles and adults of four species. A plot of length–weight estimates, log a over b, showed the deep-sea fishes in this study to be more of the elongated shape compared with other marine fishes.

Description: Bacteria associated with the marine macroalga Laminaria saccharina, collected from the Kiel Fjord (Baltic Sea, Germany), were isolated and tested for antimicrobial activity. From a total of 210 isolates, 103 strains inhibited the growth of at least one microorganism from the test panel including Gram-negative and Gram-positive bacteria as well as a yeast. Most common profiles were the inhibition of Bacillus subtilis only (30%), B. subtilis and Staphylococcus lentus (25%), and B. subtilis, S. lentus, and Candida albicans (11%). In summary, the antibiotic-active isolates covered 15 different activity patterns suggesting various modes of action. On the basis of 16S rRNA gene sequence similarities >99%, 45 phylotypes were defined, which were classified into 21 genera belonging to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Phylogenetic analysis of 16S rRNA gene sequences revealed that four isolates possibly represent novel species or even genera. In conclusion, L. saccharina represents a promising source for the isolation of new bacterial taxa and antimicrobially active bacteria.

Description: The diversification of the teleost suborder Notothenioidei (Perciformes) in Antarctic waters provides one of the most striking examples of a marine adaptive radiation. Along with a number of adaptations to the cold environment, such as the evolution of antifreeze glycoproteins, notothenioids diversified into eight families and at least 130 species. Here, we investigate the genetic population structure of the humped rockcod (Gobionotothen gibberifrons), a benthic notothenioid fish. Six populations were sampled at different locations around the Scotia Sea, comprising a large part of the species’ distribution range (N = 165). Our analyses based on mitochondrial DNA sequence data (352 bp) and eight microsatellite markers reveal a lack of genetic structuring over large geographic distances (ΦST £ 0.058, FST £ 0.005, P values nonsignificant). In order to test whether this was due to passive larval dispersal, we used GPS-tracked drifter trajectories, which approximate movement of passive surface particles with ocean currents. The drifter data indicate that the Antarctic Circumpolar Current (ACC) connects the sampling locations in one direction only (west–east), and that passive transport is possible within the 4-month larval period of G. gibberifrons. Indeed, when applying the isolation-with-migration model in IMA, strong unidirectional west-east migration rates are detected in the humped rockcod. This leads us to conclude that, in G. gibberifrons, genetic differentiation is prevented by gene flow via larval dispersal with the ACC.

Description: The global decline of biodiversity caused by human domination of ecosystems worldwide is supposed to alter important process rates and state variables in these ecosystems. However, there is considerable debate on the prevalence and importance of biodiversity effects on ecosystem function (BDEF). Here, we argue that much of the debate stems from two major shortcomings. First, most studies do not directly link the traits leading to increased or decreased function to the traits needed for species coexistence and dominance. We argue that implementing a trait-based approach and broadening the perception of diversity to include trait dissimilarity or trait divergence will result in more realistic predictions on the consequences of altered biodiversity. Second, the empirical and theoretical studies do not reflect the complexity of natural ecosystems, which makes it difficult to transfer the results to natural situations of species loss. We review how different aspects of complexity (trophic structure, multifunctionality, spatial or temporal heterogeneity, and spatial population dynamics) alter our perception of BDEF. We propose future research avenues concisely testing whether acknowledging this complexity will strengthen the observed biodiversity effects. Finally, we propose that a major future task is to disentangle biodiversity effects on ecosystem function from direct changes in function due to human alterations of abiotic constraints.

Description: Crustal- and upper-mantle structures of the subduction zone in south central Chile, between 42 degrees S and 46 degrees S, are determined from seismic wide-angle reflection and refraction data, using the seismic ray tracing method to calculate minimum parameter models. Three profiles along differently aged segments of the subducting Nazca Plate were analysed in order to study subduction zone structure dependencies related to the age, that is, thermal state, of the incoming plate. The age of the oceanic crust at the trench ranges from 3 Ma on the southernmost profile, immediately north of the Chile triple junction, to 6.5 Ma old about 100 km to the north, and to 14.5 Ma old another 200 km further north, off the Island of Chiloe. Remarkable similarities appear in the structures of both the incoming as well as the overriding plate. The oceanic Nazca Plate is around 5 km thick, with a slightly increasing thickness northward, reflecting temperature changes at the time of crustal generation. The trench basin is about 2 km thick except in the south where the Chile Ridge is close to the deformation front and only a small, 800-m-thick trench infill could develop. In south central Chile, typically three quarters (1.5 km) of the trench sediments subduct below the decollement in the subduction channel. To the north and south of the study area, only about one quarter to one third of the sediments subducts, the rest is accreted above. Similarities in the overriding plate are the width of the active accretionary prism, 35-50 km, and a strong lateral crustal velocity gradient zone about 75-80 km landward from the deformation front, where landward upper-crustal velocities of over 5.0-5.4 km s〈SU-1〈/SU decrease seaward to around 4.5 km s〈SU-1〈/SU within about 10 km, which possibly represents a palaeo-backstop. This zone is also accompanied by strong intraplate seismicity. Differences in the subduction zone structures exist in the outer rise region, where the northern profile exhibits a clear bulge of uplifted oceanic lithosphere prior to subduction whereas the younger structures have a less developed outer rise. This plate bending is accompanied by strongly reduced rock velocities on the northern profile due to fracturing and possible hydration of the crust and upper mantle. The southern profiles do not exhibit such a strong alteration of the lithosphere, although this effect may be counteracted by plate cooling effects, which are reflected in increasing rock velocities away from the spreading centre. Overall there appears little influence of incoming plate age on the subduction zone structure which may explain why the M-w = 9.5 great Chile earthquake from 1960 ruptured through all these differing age segments. The rupture area, however, appears to coincide with a relatively thick subduction channel.

Description: An intercomparison is undertaken of the tropical behavior of 17 coupled ocean-atmosphere models in which at least one component may be termed a general circulation model (GCM). The aim is to provide a taxonomy—a description and rough classification—of behavior across the ensemble of models, focusing on interannual variability. The temporal behavior of the sea surface temperature (SST) field along the equator is presented for each model, SST being chosen as the primary variable for intercomparison due to its crucial role in mediating the coupling and because it is a sensitive indicator of climate drift. A wide variety of possible types of behavior are noted among the models. Models with substantial interannual tropical variability may be roughly classified into cases with propagating SST anomalies and cases in which the SST anomalies develop in place. A number of the models also exhibit significant drift with respect to SST climatology. However, there is not a clear relationship between climate drift and the presence or absence of interannual oscillations. In several cases, the mode of climate drift within the tropical Pacific appears to involve coupled feedback mechanisms similar to those responsible for El Niño variability. Implications for coupled-model development and for climate prediction on seasonal to interannual time scales are discussed. Overall, the results indicate considerable sensitivity of the tropical coupled ocean-atmosphere system and suggest that the simulation of the warm-pool/cold-tongue configuration in the equatorial Pacific represents a challenging test for climate model parameterizations.

Description: Whereas the predominance of El Nio Southern Oscillation (ENSO) mode in the tropical Pacific sea surface temperature (SST) variability is well established, no such consensus seems to have been reached by climate scientists regarding the Indian Ocean. While a number of researchers think that the Indian Ocean SST variability is dominated by an active dipolar-type mode of variability, similar to ENSO, others suggest that the variability is mostly passive and behaves like an autocorrelated noise. For example, it is suggested recently that the Indian Ocean SST variability is consistent with the null hypothesis of a homogeneous diffusion process. However, the existence of the basin-wide warming trend represents a deviation from a homogeneous diffusion process, which needs to be considered. An efficient way of detrending, based on differencing, is introduced and applied to the Hadley Centre ice and SST. The filtered SST anomalies over the basin (23.5N-29.5S, 30.5E-119.5E) are then analysed and found to be inconsistent with the null hypothesis on intraseasonal and interannual timescales. The same differencing method is then applied to the smaller tropical Indian Ocean domain. This smaller domain is also inconsistent with the null hypothesis on intraseasonal and interannual timescales. In particular, it is found that the leading mode of variability yields the Indian Ocean dipole, and departs significantly from the null hypothesis only in the autumn season.

Description: A thermobarometric and petrologic study of basanites erupted from young volcanic cones along the submarine portions of the three El Hierro rift zones (NE-Rift, NW-Rift and S-Ridge) has been performed to reconstruct magma plumbing and storage beneath the island. Mineral-melt thermobarometry applied to naturally quenched glass and clinopyroxene rims yields pressures ranging from 350 to 1070 MPa with about 80% of the calculated pressures being in the range of 600–800 MPa. This corresponds to a depth range of 19–26 km, implying that the main level of final crystal fractionation is within the uppermost mantle. No systematic dependence between sample locality and fractionation pressures could be observed. Olivine and clinopyroxene crystals in the rocks are complexly zoned and have, on an inter-sample as well as on an intra-sample scale, highly variable core and rim compositions. This can best be explained by mixing of multiply saturated (olivine, magnetite, clinopyroxene, ilmenite), moderately evolved magmas with more mafic magmas being either only saturated with olivine + spinel or with olivine + spinel + clinopyroxene. The inter-sample differences indicate derivation from small, isolated magma chambers which have undergone distinct fractionation and mixing histories. This is in contrast to oceanic intraplate volcanoes situated on plumes with high melt supply rates, e.g. Kilauea Volcano (Hawaii), where magma is mainly transported through a central conduit system and stored in a shallow magma chamber prior to injection into the rift zones. The plumbing system beneath El Hierro rather resembles the magma storage systems beneath, e.g. Madeira or La Palma, indicating that small, intermittent magma chambers might be a common feature of oceanic islands fed by plumes with relatively low fluxes, which results in only limited and periodic magma supply.

Description: The Fontana Lapilli deposit was erupted in the late Pleistocene from a vent, or multiple vents, located near Masaya volcano (Nicaragua) and is the product of one of the largest basaltic Plinian eruptions studied so far. This eruption evolved from an initial sequence of fluctuating fountain-like events and moderately explosive pulses to a sustained Plinian episode depositing fall beds of highly vesicular basaltic-andesite scoria (SiO2 〉 53 wt%). Samples show unimodal grain size distribution and a moderate sorting that are uniform in time. The juvenile component predominates (〉 96 wt%) and consists of vesicular clasts with both sub-angular and fluidal, elongated shapes. We obtain a maximum plume height of 32 km and an associated mass eruption rate of 1.4 × 108 kg s−1 for the Plinian phase. Estimates of erupted volume are strongly sensitive to the technique used for the calculation and to the distribution of field data. Our best estimate for the erupted volume of the majority of the climactic Plinian phase is between 2.9 and 3.8 km3 and was obtained by applying a power-law fitting technique with different integration limits. The estimated eruption duration varies between 4 and 6 h. Marine-core data confirm that the tephra thinning is better fitted by a power-law than by an exponential trend.

Description: Harzburgitic xenoliths cut by pyroxenite veins from Avachinsky volcano, Kamchatka, are derived from the sub-arc mantle and record element transfer from the slab to the arc. Olivine and orthopyroxene in the harzburgites have Li isotopic compositions (δ7Li = +2.8 to +5.6) comparable to estimates of the upper mantle (δ7Li ~ +4 ± 2). The pyroxenite veins, which represent modal metasomatism and may therefore provide information about the metasomatic agent, have mantle-normalized trace element characteristics that suggest overprinting of their mantle source by an aqueous, slab-derived fluid. These include relative enrichments of Pb over Ce, U over Th and Sr over Nd. Li is enriched relative to the HREE, and ortho- and clinopyroxene from the veins are in Li elemental and isotopic equilibrium with each other and the surrounding harzburgite. Vein samples (δ7Li = +3.0 to +5.0) do not record a significant slab-derived δ7Li signature. These observations can be reconciled if slab Li diffusively re-equilibrates in the mantle wedge. Modeling demonstrates that Li equilibration of small (1–2 cm width) veins or melt conduits is achieved at mantle wedge temperatures within 101–105 years. We conclude that strongly fractionated Li isotopic signatures cannot be sustained for long periods in the sub-arc mantle, at least at shallow (〈70 km) depths.

Description: Preexisting developmental plasticity in feeding larvae may contribute to the evolutionary transition from development with a feeding larva to nonfeeding larval development. Differences in timing of development of larval and juvenile structures (heterochronic shifts) and differences in the size of the larval body (shifts in allocation) were produced in sea urchin larvae exposed to different amounts of food in the laboratory and in the field. The changes in larval form in response to food appear to be adaptive, with increased allocation of growth to the larval apparatus for catching food when food is scarce and earlier allocation to juvenile structures when food is abundant. This phenotypic plasticity among full siblings is similar in direction to the heterochronic evolutionary changes in species that have greater nutrient reserves within the ova and do not depend on particulate planktonic food. This similarity suggests that developmental plasticity that is adaptive for feeding larvae also contributes to correlated and adaptive evolutionary changes in the transition to nonfeeding larval development. If endogenous food supplies have the same effect on morphogenesis as exogenous food supplies, then changes in genes that act during oogenesis to affect nutrient stores may be sufficient to produce correlated adaptive changes in larval development.

Description: Dinoflagellate cysts and other palynomorphs were studied from ODP Hole 1002C in the Cariaco Basin over the past 30 000 years. The assemblage shifts between a dominance of heterotrophic dinoflagellate cysts (mainly Brigantedinium spp., Lejeunecysta spp., Selenopemphix nephroides and Stelladinium reidii) and autotrophic dinoflagellate cysts (mainly Spiniferites ramosus, Lingulodinium machaerophorum and Operculodinium centrocarpum). These assemblage shifts are associated with stronger upwelling during stadials and stronger river influx during interstadials. Increases in productivity caused by enhanced upwelling are coupled to improved preservation and vice versa. More stratified water is indicated by higher abundances of L. machaerophorum and succeeds Heinrich events. The average process length of L. machaerophorum can be used to track changes in salinity, since this shows a similar pattern as the δ18OSW (paired Mg/Ca −δ18O) reconstruction. During the last glacial, conditions were more saline than during the current interglacial. On a millennial scale, changes in salinity are opposite to open ocean salinities and the hydrological proxies, which can be explained by a modulation of the signal by stratification, isolation of the Basin or advection of freshwater masses. These results highlight both generalities and particularities of the palaeoecological record of this tropical semi-enclosed basin.

Description: Enzymatic activity and quantity of the protease trypsin were measured in individual herring larvae (Clupea harengus L.). The enzymatic activity assay was done using a fluorescence technique, and a radioimmunoassay was used for quantification of trypsin. The results are compared and the differences between the techniques discussed. Both methods gave similar results, as high or low values in trypsin quantity were reflected in high or low values of tryptic activity. Quantity and activity were linearly and positively correlated, but small differences between methods were found at the lowest detection limits. Both techniques reflect high variability between individual larvae.

Description: The Mediterranean Sea is located in a crossroad of mid-latitude and subtropical climatic modes that enhance contrasting environmental conditions over both latitudinal and longitudinal ranges. Here, we show that the large-scale environmental forcing is reflected in the basin scale trends of the adult population of the calanoid copepod Centropages typicus. The species is distributed over the whole Mediterranean basin, and maximal abundances were found in the north-western basin associated to oceanic fronts, and in the Adriatic Sea associated to shallow and semi enclosed waters. The peak of main abundances of C. typicus correlates with the latitudinal temperature gradient and the highest seasonal abundances occurred in spring within the 14-18A degrees C temperature window. Such thermal cline may define the latitudinal geographic region where C. typicus seasonally dominates the > 200 mu m-sized spring copepod community in the Mediterranean Sea. The approach used here is generally applicable to investigate the large-scale spatial patterns of other planktonic organisms and to identify favourable environmental windows for population development.

Description: New geochemical data from the Cocos Plate constrain the composition of the input into the Central American subduction zone and demonstrate the extent of influence of the Galapagos Hotspot on the Cocos Plate. Samples include sediments and basalts from Ocean Drilling Program (ODP) Site 1256 outboard of Nicaragua, gabbroic sills from ODP Sites 1039 and 1040, tholeiitic glasses from the Fisher Ridge off northwest Costa Rica, and basalts from the Galapagos Hotspot Track outboard of Central Costa Rica. Site 1256 basalts range from normal to enriched MORB in incompatible elements and have Pb and Nd isotopic compositions within the East Pacific Rise MORB field. The sediments have similar Pb-206/Pb-204 and only slightly more radiogenic Pb-207/Pb-204 and Pb-208/Pb-204 isotope ratios than the basalts. Altered samples from the subducting Galapagos Hotspot Track have similar Nd and Pb isotopic compositions to fresh Galapagos samples but have significantly higher Sr isotopic composition, indicating that the subduction input will have a distinct geochemical signature from Galapagos-type mantle material that may be present in the wedge beneath Costa Rica. Gabbroic sills from Sites 1039 and 1040 in East Pacific Rise (EPR) crust show evidence for influence of the Galapagos Hotspot similar to 100 km beyond the morphological hotspot track

Description: Future levels in ultraviolet-B (UVB) radiation are expected to increase directly due to stratospheric ozone depletion and under water indirectly by, for example, global warming effects on DOC concentrations, altered trophic interactions in the plankton, or reduced eutrophication. While detrimental UV effects have been reported at the cellular level, little to nothing is known about community-wide effects of ambient and future UVB radiation. In a 4-month field experiment, the ambient UV regime was (i) reduced by cut-off filters which removed either UVB or total UV from the solar spectrum or (ii) increased to predicted future levels by UVB lamps. To allow relating the effects of present and future UV regimes to another important ecological control of community structure and diversity in subtidal marine habitats, consumer effects were quantified by an exclusion treatment under ambient light regimes. Ambient UV regimes did not affect community structure, biomass accrual, and diversity. In contrast, under enhanced UVB levels, the dominance of the competitively superior blue mussels increased and species richness and biomass accrual decreased. Species composition of the assemblages differed between the two UV regimes. Effects of enhanced UVB radiation and of consumption on biomass accrual, diversity, and structure of the community were comparable in magnitude and timing, but of opposite direction. In contrast, the effects of enhanced UVB radiation on growth and abundance of mussels were in the same direction, but shorter and weaker than consumer effects. Most UV effects were transitory and vanished within the first 2 months of succession. Our results indicate that present and future UVB levels may be of limited importance and not stronger in effect size than other ecological controls in structuring the shallow-water low-diversity macrobenthic communities in temperate regions.

Description: Sediment samples were obtained from areas of diffuse hydrothermal venting along the seabed in the Tonga sector of the Tonga-Kermadec Arc, southwest Pacific Ocean. Sediments from Volcano 1 and Volcano 19 were analyzed by X-ray diffraction (XRD) and found to be composed primarily of the iron oxyhydroxide mineral, two-line ferrihydrite. XRD also suggested the possible presence of minor amounts of more ordered iron (hydr)oxides (including six-line ferrihydrite, goethite/lepidocrocite and magnetite) in the biogenic iron oxides (BIOS) from Volcano 1; however, Mössbauer spectroscopy failed to detect any mineral phases more crystalline than two-line ferrihydrite. The minerals were precipitated on the surfaces of abundant filamentous microbial structures. Morphologically, some of these structures were similar in appearance to the known iron-oxidizing genus Mariprofundus spp., suggesting that the sediments are composed of biogenic iron oxides. At Volcano 19, an areally extensive, active vent field, the microbial cells appeared to be responsible for the formation of cohesive chimney-like structures of iron oxyhydroxide, 2–3 m in height, whereas at Volcano 1, an older vent field, no chimney-like structures were apparent. Iron reduction of the sediment material (i.e. BIOS) by Shewanella putrefaciens CN32 was measured, in vitro, as the ratio of [total Fe(II)]:[total Fe]. From this parameter, reduction rates were calculated for Volcano 1 BIOS (0.0521 day−1), Volcano 19 BIOS (0.0473 day−1), and hydrous ferric oxide, a synthetic two-line ferrihydrite (0.0224 day−1). Sediments from both BIOS sites were more easily reduced than synthetic ferrihydrite, which suggests that the decrease in effective surface area of the minerals within the sediments (due to the presence of the organic component) does not inhibit subsequent microbial reduction. These results indicate that natural, marine BIOS are easily reduced in the presence of dissimilatory iron-reducing bacteria, and that the use of common synthetic iron minerals to model their reduction may lead to a significant underestimation of their biological reactivity.

Description: The Gakkel Ridge in the Arctic Ocean with its adjacent Nansen and Amundsen Basins is a key region for the study of mantle melting and crustal generation at ultraslow spreading rates. We use free-air gravity anomalies in combination with seismic reflection and wide-angle data to compute 2-D crustal models for the Nansen and Amundsen Basins in the Arctic Ocean. Despite the permanent pack-ice cover two geophysical transects cross both entire basins. This means that the complete basin geometry of the world’s slowest spreading system can be analysed in detail for the first time. Applying standard densities for the sediments and oceanic crystalline crust, the gravity models reveal an unexpected heterogeneous mantle with densities of 3.30 × 103, 3.20 × 103 and 3.10 × 103 kg/m3 near the Gakkel Ridge. We interpret that the upper mantle heterogeneity mainly results from serpentinisation and thermal effects. The thickness of the oceanic crust is highly variable throughout both transects. Crustal thickness of less than 1 km dominates in the oldest parts of both basins, increasing to a maximum value of 6 km near the Gakkel Ridge. Along-axis heat flow is highly variable and heat flow amplitudes resemble those observed at fast or intermediate spreading ridges. Unexpectedly, high heat flow along the Amundsen transect exceeds predicted values from global cooling curves by more than 100%.

Description: Newly isolated strains Bacillus sp. FME 1 and FME 2 were evaluated for the cellulolytic enzymes production during submerged fermentation (SmF) of different substrates including rice husk, Whatman filter paper and cellulose powder CF 11. Extracellular enzyme assays for CMCase, FPase and β-glucosidase were examined up to 8 days of submerged fermentation. Among the three substrates, rice husk was the most suitable substrate for higher production of cellulolytic enzymes. Maximum titers of 100, 45, and 3.5 U/mL in respect of CMCase, FPase and β-glucosidase in Bacillus sp. FME 2 were recovered as against 45, 12, and 0.39 U/mL in Bacillus sp. FME 1 respectively, at their respective peak time intervals. Bacillus sp. FME 2 was found to produce higher cellulolytic enzyme activities than Bacillus sp. FME 1.

Description: Amino acid analysis is used to determine the amino acid content of amino acid–, peptide- and protein-containing samples. With minor exceptions, proteins are long linear polymers of amino acids connected to each other via peptide bonds. The first step of amino acid analysis involves hydrolyzing these peptide bonds. The liberated amino acids are then separated, detected, and quantified. The method was first developed by Moore, Stein and coworkers in the 1950s using HCl acid hydrolysis, and, despite considerable effort by many workers, the basic methodology remains relatively unchanged. This unit provides an overview and strategic planning for amino acid analysis, discussing a range of methodologies and issues. In addition, several common methods used for analysis of l-amino acids are described in detail, including: HCl acid hydrolysis, performic acid oxidation for methionine and cysteine analysis, base hydrolysis for tryptophan analysis, analysis of free amino acids, and analysis of reactive lysine.