ALBERT

Description: A multiproxy study of palaeoceanographic and climatic changes in northernmost Baffin Bay shows that major environmental changes have occurred since the deglaciation of the area at about 12 500 cal. yr BP. The interpretation is based on sedimentology, benthic and planktonic foraminifera and their isotopic composition, as well as diatom assemblages in the sedimentary records at two core sites, one located in the deeper central part of northernmost Baffin Bay and one in a separate trough closer to the Greenland coast. A revised chronology for the two records is established on the basis of 15 previously published AMS 14C age determinations. A basal diamicton is overlain by laminated, fossil-free sediments. Our data from the early part of the fossiliferous record (12 300–11 300 cal. yr BP), which is also initially laminated, indicate extensive seasonal sea-ice cover and brine release. There is indication of a cooling event between 11 300 and 10 900 cal. yr BP, and maximum Atlantic Water influence occurred between 10 900 and 8200 cal. yr BP (no sediment recovery between 8200 and 7300 cal. yr BP). A gradual, but fluctuating, increase in sea-ice cover is seen after 7300 cal. yr BP. Sea-ice diatoms were particularly abundant in the central part of northernmost Baffin Bay, presumably due to the inflow of Polar waters from the Arctic Ocean, and less sea ice occurred at the near-coastal site, which was under continuous influence of the West Greenland Current. Our data from the deep, central part show a fluctuating degree of upwelling after c. 7300 cal. yr BP, culminating between 4000 and 3050 cal. yr BP. There was a gradual increase in the influence of cold bottom waters from the Arctic Ocean after about 3050 cal. yr BP, when agglutinated foraminifera became abundant. A superimposed short-term change in the sea-surface proxies is correlated with the Little Ice Age cooling.

Description: The diet composition of Emperor Penguin Aptenodytes forsteri chicks was examined at Auster and Taylor Glacier colonies, near Australia's Mawson station, Antarctica, between hatching in mid-winter and fledging in mid-summer by “water-offloading” adults. Chicks at both colonies were fed a similar suite of prey species. Crustaceans occurred in 82% of stomach samples at Auster and 87% of stomachs at Taylor Glacier and were heavily digested: their contribution to food mass could not be quantified. Fish, primarily bentho-pelagic species, accounted for 52% by number and 55% by mass of chick diet at Auster, and squid formed the remainder. At Taylor Glacier the corresponding values were 27% by number and 31% by mass of fish and 73% by number and 69% by mass of squid. Of the 33 species or taxa identified, the fish Trematomus eulepidotus and the squid Psychroteuthis glacialis and Allu-roteuthis antarcticus accounted for 64% and 74% of the diets by mass at Auster and Taylor Glacier, respectively. The sizes of fish varied temporally but not in a linear manner from winter to summer. Adult penguins captured fish ranging in length from 60 mm (Pfeura-gramma antarcticum) to 250 mm (T. eulepidotus) and squid (P. glacialis) from 19 to 280 mm in mantle length. The length-frequency distribution of P. glacialis showed seasonal variation, with the size of squid increasing from winter to summer. The energy density of chick diet mix increased significantly prior to “fledging”.

Description: The Denmark Strait Overflow (DSO) today compensates for the northward flowing Norwegian and Irminger branches of the North Atlantic Current that drive the Nordic heat pump. During the Last Glacial Maximum (LGM), ice sheets constricted the Denmark Strait aperture in addition to ice eustatic/isostatic effects which reduced its depth (today ∼630 m) by ∼130 m. These factors, combined with a reduced north-south density gradient of the water-masses, are expected to have restricted or even reversed the LGM DSO intensity. To better constrain these boundary conditions, we present a first reconstruction of the glacial DSO, using four new and four published epibenthic and planktic stable-isotope records from sites to the north and south of the Denmark Strait. The spatial and temporal distribution of epibenthic δ18O and δ13C maxima reveals a north-south density gradient at intermediate water depths from σ0∼28.7 to 28.4/28.1 and suggests that dense and highly ventilated water was convected in the Nordic Seas during the LGM. However, extremely high epibenthic δ13C values on top of the Mid-Atlantic Ridge document a further convection cell of Glacial North Atlantic Intermediate Water to the south of Iceland, which, however, was marked by much lower density (σ0∼28.1) The north-south gradient of water density possibly implied that the glacial DSO was directed to the south like today and fed Glacial North Atlantic Deep Water that has underthrusted the Glacial North Atlantic Intermediate Water in the Irminger Basin.

Description: This first quantitative study of the diet of Emperor penguins is based on 29 stomach contents collected with a water off-loading method in Adelie Land. The Emperor is largely ichthyophagous (65% by number and 95% by weight) and feeds extensively on small nototheniids (97% of the fish are 40–125 mm in overall length). These results and data on meal size and feeding frequency of the chick suggest that Emperors are off-shore foraging birds offering little competition for food with other sea-birds or mammals.

Description: The diet of King Penguins Aptenodytes patagonicus at Macquarie Island was studied between November 1984 and November 1985 based on stomach flushed samples (obtaining 93% of the total stomach content) from ten birds each month. The mean stomach content mass of the 118 samples was 923 0 g. Percentage by number, percentage by weight and dietary coefficient analysis all showed the main prey of the penguins to be myctophid lantern fish of the species Electrona carlsbergi and Krefftichthys anderssoni. Juvenile fish of both species were eaten from December to July, and adults in August and September. Cephalopods were relatively unimportant in contrast to previous indications. The amount of food brought ashore and the composition of the diet varied over the year, with K. anderssoni the dominant food in all but the winter months when E. carlsbergi replaced it as the principal food item.

Description: In the past decade, a major trawl fishery for the squid Loligo gahi has developed in the vicinity of Beauchêne Island, an internationally important breeding site for the Black-browed Albatross Diomedea melanophris. The breeding season diet of this albatross in the Falklands and its use of discards generated by the Loligo fishery were investigated. Albatross chicks are fed extensively on commercially exploited species of squid and fish including Loligo gahi and southern blue whiting Micromesistius australis. The quantity of waste generated by the Loligo fishery amounts to c. 5% of the reported catch and just over 50% of this waste, mainly Loligo and nototheniid fish, is scavenged by adult Black-browed Albatrosses. The total quantity scavenged during the chick rearing period amounts to 1000–2000 tonnes per year. This is equivalent to 10–15% of the total food requirement of the breeding Black-browed Albatross population on Beauchene Island during the period when the fishery is operating. Although the Loligo fishery currently provides a significant quantity of food to these albatrosses, its net effect may be detrimental to them, as it is a much greater predator of Loligo stocks than the albatrosses are estimated to have been prior to the fishery's development.

Description: Sections of the lateral line organ, primary and secondary blood vessels and skin from the Atlantic cod Gadus morhua, Linnaeus 1758, were examined by light and transmission electron microscopy (TEM). The lateral line organ showed a structural analogy to the semicircular canals of the mammalian inner ear. A pericanalicular sinus (PCS), a canal of very loose connective tissue, surrounded the lateral line canal (LLC), separated by a multilayered epithelial wall. Located dorsal and ventral to the lateral line organ secondary vessels of capillary dimensions were found in association with the PCS. TEM of the wall of these dorso-ventral vessels showed single tight junction contacts between the endothelial cells, allowing paracellular fluid exchange between the secondary vascular system and the PCS, an indication supported by horseradish peroxidase (HRP) tracer experiments, which showed reaction products in the PCS within 2 h after injecting HRP into the systemic circulation. The multilayered epithelial wall of the LLC showed multiple tight junctions between cells, making this boundary permeable only through transcellular transport.

Description: Control of lacustrine phytoplankton biomass by phosphorus is one of the oldest and most stable paradigms in modern limnology. Even so, evidence from bioassays conducted by multiple investigators at numerous sites over the last three decades shows that N is at least as likely as P to be limiting to phytoplankton growth. A number of important flaws in the evidence supporting the phosphorus paradigm have contributed to an unrealistic degree of focus on phosphorus as a controlling element. These include insufficient skeptism in interpretation of: 1) the phosphorus: chlorophyll correlation in lakes, 2) the results of whole-lake fertilization experiments, and 3) stoichiometric arguments based on total N:total P ratios for inland waters. A new paradigm based on parity between N and P control of phytoplankton biomass in lakes seems more viable than the P paradigm. The new paradigm renews interest in the degree to which plankton communities are molded in composition by small differences in relative availability of N and P, the mechanisms that lead to a high frequency of N limitation in oligotrophic lakes, and the failure of aquatic N-fixers to compensate significantly for N deficiency under most conditions. A new N/P paradigm still must acknowledge that suppression of P loading often will be the most effective means of reducing phytoplankton biomass in eutrophic lakes, even if N is initially limiting.

Description: Blennolides A–G (2–8), seven unusual chromanones, were isolated together with secalonic acid B (1) from Blennoria sp., an endophytic fungus from Carpobrotus edulis. This is the first reported isolation of the blennolides 2 and 3 (hemisecalonic acids B and E), the existence of which as the monomeric units of the dimeric secalonic acids had long been postulated. A compound of the proposed structure 4 (β-diversonolic ester) will need to be revised, as its reported data do not fit those of the established structure of blennolide C (4). Other monomers, the blennolides D–F (5–7) seem to be derived from blennolides A (2) and B (3) by rearrangement of the hydroaromatic ring. The heterodimer 8, composed of the monomeric blennolide A (2) and the rearranged 11-dehydroxy derivative of blennolide E (6), extends the ergochrome family with an ergoxanthin type of skeleton. The structures of the new compounds were elucidated by detailed spectroscopic analysis and further confirmed by an X-ray diffraction study of a single crystal of 2. The absolute configurations were determined by TDDFT calculations of CD spectra, including the solid-state CD/TDDFT approach. Preliminary studies showed strong antifungal and antibacterial activities of these compounds against Microbotryum violaceum and Bacillus megaterium, respectively. They were also active against the alga Chlorella fusca and the bacterium Escherichia coli.

Description: Several trench-outer rise settings in subduction zones worldwide are characterized by a high degree of alteration, fracturing and hydration. These processes are induced by bending-related faulting in the upper part of the oceanic plate prior to its subduction. Mapping of P- and S-wave velocity structures in this complex tectonic setting provides crucial information for understanding the evolution of the incoming oceanic lithosphere, and serves as a baseline for comparison with seismic measurements elsewhere. Active source seismic investigations at the outer rise off Southern Central Chile (∼43°S) were carried out in order to study the seismic structure of the oceanic Nazca Plate. Seismic wide-angle data were used to derive 2-D velocity models of two seismic profiles located seaward of the trench axis on 14.5 Ma old crust; P01a approximately parallel to the direction of spreading and P03 approximately parallel to the spreading ridge and trench axes. We determined P- and S-velocity models using 2-D traveltime tomography. We found that the Poisson's ratio in the upper crust (layer 2) ranges between ∼0.33 at the top of the crust to ∼0.28 at the layer 2/3 interface, while in the lowermost crust and uppermost mantle it reaches values of ∼0.26 and ∼0.29, respectively. These features can be explained by an oceanic crust significantly weathered, altered and fractured. Relative high Poisson's ratios in the uppermost mantle may be likely related to partially hydrated mantle and hence serpentinization. Thus, the seismic structure of the oceanic lithosphere at the Southern Central Chile outer rise exhibits notable differences from the classic ophiolite seismic model (‘normal’ oceanic crust). These differences are primarily attributed to fracturing and hydration of the entire ocean crust, which are direct consequences of strong bending-related faulting at the outer rise. On the other hand, the comparison of the uppermost mantle P-wave velocities at the crossing point between the perpendicular profiles (∼90 km oceanward from the trench axis) reveals a low degree of Pn anisotropy (〈2 per cent).

Description: Anaerobic methane-oxidizing microbial communities in sediments at cold methane seeps are important factors in controlling methane emission to the ocean and atmosphere. Here, we investigated the distribution and carbon isotopic signature of specific biomarkers derived from anaerobic methanotrophic archaea (ANME groups) and sulphate-reducing bacteria (SRB) responsible for the anaerobic oxidation of methane (AOM) at different cold seep provinces of Hydrate Ridge, Cascadia margin. The special focus was on their relation to in situ cell abundances and methane turnover. In general, maxima in biomarker abundances and minima in carbon isotope signatures correlated with maxima in AOM and sulphate reduction as well as with consortium biomass. We found ANME-2a/DSS aggregates associated with high abundances of sn-2,3-di-O-isoprenoidal glycerol ethers (archaeol, sn-2-hydroxyarchaeol) and specific bacterial fatty acids (C16:1ω5c, cyC17:0ω5,6) as well as with high methane fluxes (Beggiatoa site). The low to medium flux site (Calyptogena field) was dominated by ANME-2c/DSS aggregates and contained less of both compound classes but more of AOM-related glycerol dialkyl glycerol tetraethers (GDGTs). ANME-1 archaea dominated deeper sediment horizons at the Calyptogena field where sn-1,2-di-O-alkyl glycerol ethers (DAGEs), archaeol, methyl-branched fatty acids (ai-C15:0, i-C16:0, ai-C17:0), and diagnostic GDGTs were prevailing. AOM-specific bacterial and archaeal biomarkers in these sediment strata generally revealed very similar δ13C-values of around −100. In ANME-2-dominated sediment sections, archaeal biomarkers were even more 13C-depleted (down to −120), whereas bacterial biomarkers were found to be likewise 13C-depleted as in ANME-1-dominated sediment layers (δ13C: −100). The zero flux site (Acharax field), containing only a few numbers of ANME-2/DSS aggregates, however, provided no specific biomarker pattern. Deeper sediment sections (below 20 cm sediment depth) from Beggiatoa covered areas which included solid layers of methane gas hydrates contained ANME-2/DSS typical biomarkers showing subsurface peaks combined with negative shifts in carbon isotopic compositions. The maxima were detected just above the hydrate layers, indicating that methane stored in the hydrates may be available for the microbial community. The observed variations in biomarker abundances and 13C-depletions are indicative of multiple environmental and physiological factors selecting for different AOM consortia (ANME-2a/DSS, ANME-2c/DSS, ANME-1) along horizontal and vertical gradients of cold seep settings.

Description: Transmission of top-down control from fish to phytoplankton via crustacean mesozooplankton is a cornerstone of limnetic plankton ecology. Such trophic cascades are less frequently reported from the marine pelagic. In this article a case is made for consideration of scale issues and for the distinction between full (affecting entire trophic levels) and partial (affecting only some functional groups) trophic cascades. Partial cascades are more widespread while the full cascades are either ephemeral or depend on the suppression of compensatory growth of the predation-resistant size-fractions of phytoplankton. This suppression can only be achieved if there is a persistent coexistence between zooplankton feeding on different parts of the phytoplankton size spectrum. This condition is fulfilled in plankton communities where microphageous cladocerans (mainly Daphnia) and microphageous copepods coexist (many lake communities) or where krill and copepods coexist (high latitude marine communities). It is not fulfilled in many temperate and low-latitude marine communities where copepods effectively suppress filter-feeding appendicularians. Thus, the observed difference in the frequency of marine and limnetic pelagic cascades is considered real. Are all trophic cascades wet?

Description: At convergent margins, the structure of the subducting oceanic plate is one of the key factors controlling the morphology of the upper plate. We use high-resolution seafloor mapping and multichannel seismic reflection data along the accretionary Sumatra trench system to investigate the morphotectonic response of the upper plate to the subduction of lower plate fabric. Upper plate segmentation is reflected in varying modes of mass transfer. The deformation front in the southern Enggano segment is characterized by neotectonic formation of a broad and shallow fold-and-thrust belt consistent with the resumption of frontal sediment accretion in the wake of oceanic relief subduction. Conversely, surface erosion increasingly shapes the morphology of the lower slope and accretionary prism towards the north where significant oceanic relief is subducted. Subduction of the Investigator Fracture Zone and the fossil Wharton spreading centre in the Siberut segment exemplifies this. Such features also correlate with an irregularly trending deformation front suggesting active frontal erosion of the upper plate. Lower plate fabric extensively modulates upper plate morphology and the large-scale morphotectonic segmentation of the Sumatra trench system is linked to the subduction of reactivated fracture zones and aseismic ridges of the Wharton Basin. In general, increasing intensity of mass-wasting processes, from south to north, correlates with the extent of oversteepening of the lower slope (lower slope angle of 3.8 degrees in the south compared with 7.6 degrees in the north), probably in response to alternating phases of frontal accretion and sediment underthrusting. Accretionary mechanics thus pose a second-order factor in shaping upper plate morphology near the trench.

Description: The distribution of egg masses of the freshwater snails Lymnaea stagnalis and Planorbarius corneus on the undersides of water lily leaves (e.g. Nuphar lutea) is related to the prevalence of the leaf-mining beetle Galerucella nymphaeae. When given the choice, Planorbarius significantly avoids leaves that were infested by the mining beetle. Conversely, Lymnaea did not discriminate against mined leaves. Intact Nuphar leaves block over 95% of incident ultraviolet radiation. Yet, ultraviolet transmission reaches almost 100% under beetle mining scars. These are several times wider than snail embryos. When exposed to natural sunlight, Lymnaea embryos proved to be resistant to ambient ultraviolet, while Planorbarius embryos were rapidly killed. Thus, one selective advantage of Planorbarius discrimination against mined leaves when depositing its eggs could be the avoidance of ultraviolet radiation passing through mining scars. Other mining-related modifications of the leaves, reduced area, decreased longevity, altered aufwuchs (i.e. biofilm and epibionts) are discussed but seem less relevant for the oviposition preference of Planorbarius. The discriminatory behaviour of this snail species was triggered by water-borne cues emitted by the damaged leaf, not by the eggs or larvae of the beetle. This study illustrates how environmental stress on a given species, ultraviolet radiation in this case, can be ecologically buffered (shading by Nuphar) or enhanced (reduction of Nuphar shading through beetle mining) by associated species. It highlights how the impact of a given stress depends on the identity of the target species as well as on the identity and role of other species in the community.

Description: The calcium isotopic composition of NIST SRM 915b and 1486 provided by the National Institute of Standards and Technology was analysed. The δ44/40Ca values of the two reference materials relative to NIST SRM 915a were: NIST SRM 915b =+0.72 ± 0.04‰ and NIST SRM 1486 =−1.01 ± 0.02‰. NIST SRM 1486 did not require any chemical separation prior to measurement. La composition isotopique du calcium de NIST SRM 915b et 1486, fournis par l'Institut National des Standards et de la Technologie (NIST), a été analysée. Les valeurs du δ44/40Ca obtenues sur ces deux matériaux de référence, relativement au NIST SRM 915a sont: NIST SRM 915b =+0.72 ± 0.04‰ et NIST SRM 1486 =−1.01 ± 0.02‰. Le NIST SRM 1486 n'a nécessité aucune séparation chimique avant analyse.

Description: The `plate tectonic mirror image' to the region of the Cocos and Nazca plates, which are currently being subducted beneath Central America, is preserved in the Central Pacific around 120°W just south of the equator. Cruise SO-180 investigated this remote area during project CENTRAL and acquired new magnetic and bathymetric data. A plate tectonic model for the ‘mirror image’ is presented based on the newly acquired as well as reprocessed existing data. Discordant magnetic anomaly patterns and bathymetric structures indicate at least two major reorganization events (19.5 and 14.7 Myr), which can be detected both in the Cocos-Nazca spreading system and in the East Pacific Rise. Irregularities in the anomaly pattern and curvilinear structures on the sea floor of the survey area are interpreted in terms of a fossil overlapping spreading centre at the location where the Farallon break-up originated.

Description: The prevalence of antigrazing defense induction and the cues triggering induction in marine macroalgae are generally not well understood. We examined the capacity of defense and the mechanisms of regulation in five common perennial macroalgal species from the Baltic Sea, Furcellaria lumbricalis (Huds.) J. V. Lamour., Delesseria sanguinea (Huds.) J. V. Lamour., Phyllophora pseudoceranoides (S. G. Gmel.) Newroth et A. R. A. Taylor, Fucus serratus L., and Fucus evanescens C. Agardh. Specifically, we investigated whether direct feeding and/or waterborne cues from feeding on neighboring conspecifics decreased the palatability of the tested algae. Direct feeding by the local isopod Idotea baltica triggered the induction of chemical defense in Fur. lumbricalis, D. sanguinea, P. pseudoceranoides, F. serratus, and F. evanescens. Conversely, we did not find any evidence for waterborne cues associated with feeding to trigger defense induction in neighboring conspecifics.

Description: CORONA images have been used for the mapping of periglacial features on the Bykovsky Peninsula and adjacent Khorogor Valley in northeast Siberia. Features, mapped and analysed within a geographical information system, include thermokarst depressions, thermo-erosional valleys, thermo-erosional cirques, thermokarst lakes, thermokarst lagoons and pingos. More than 50% of the area is strongly influenced by thermally-induced subsidence. Thermokarst in the area is probably less active today than in the early-middle Holocene.

Description: Samples from three hot springs (Alla, Seya and Garga) located in the northeastern part of Baikal rift zone (Buryat Republic, Russia) were screened for the presence of thermophilic nitrifying bacteria. Enrichment cultures were obtained solely from the Garga spring characterized by slightly alkaline water (pH 7.9) and an outlet temperature of 75°C. The enrichment cultures of the ammonia- and nitrite oxidizers grew at temperature ranges of 27–55 and 40–60°C, respectively. The temperature optimum was approximately 50°C for both groups and thus they can be designated as moderate thermophiles. Ammonia oxidizers were identified with classical and immunological techniques. Representatives of the genus Nitrosomonas and Nitrosospira-like bacteria with characteristic vibroid morphology were detected. The latter were characterized by an enlarged periplasmic space, which has not been previously observed in ammonia oxidizers. Electron microscopy, denaturing gradient gel electrophoresis analyses and partial 16S rRNA gene sequencing provided evidence that the nitrite oxidizers were members of the genus Nitrospira.

Description: The potential for nitrification in the Mediterranean sponge Aplysina aerophoba was assessed using a combined physiological and molecular approach. Nitrate excretion rates in whole sponges reached values of up to 344 nmol g(-1) dry weight (wt) h(-1) (unstimulated) and 1325 nmol g(-1) dry wt h(-1) (stimulated). Addition of nitrapyrin, a nitrification-specific inhibitor, effectively inhibited nitrate excretion. Ammonium was taken up by sponges in spring and excreted in fall, the sponges thus serving as either an ammonium sink or ammonium source. Nitrosospira cluster 1 and Crenarchaeota group I.1A 16S rRNA and amoA genes were recovered from A. aerophoba and other sponges from different world's oceans. The archaeal 16S rRNA genes formed a sponge-specific subcluster, indicating that their representatives are members of the stable microbial community of sponges. On the other hand, clustering was not evident for Nitrosospira rRNA genes which is consistent with their presence in sediment and seawater samples. The presence of both Nitrosospira cluster 1 and crenarchaeal group 1 phylotypes in sponge tissue was confirmed using fluorescently labelled 16S rRNA gene probes. This study contributes to an ongoing effort to link microbial diversity with metabolic functions in the phylogenetically diverse, elusive and so far uncultivated microbial communities of marine sponges.

Description: Large-scale, spatially explicit models of adaptive radiation suggest that the spatial genetic structure within a species sampled early in the evolutionary history of an adaptive radiation might be higher than the genetic differentiation between different species formed during the same radiation over all locations. Here we test this hypothesis with a spatial population genetic analysis of Hypoplectrus coral reef fishes (Serranidae), one of the few potential cases of a recent adaptive radiation documented in the marine realm. Microsatellite analyses of Hypoplectrus puella (barred hamlet) and Hypoplectrus nigricans (black hamlet) from Belize, Panama and Barbados validate the population genetic predictions at the regional scale for H. nigricans despite the potential for high levels of gene flow between populations resulting from the 3-week planktonic larval phase of Hypoplectrus. The results are different for H. puella, which is characterized by significantly lower levels of spatial genetic structure than H. nigricans. An extensive field survey of Hypoplectrus population densities complemented by individual-based simulations shows that the higher abundance and more continuous distribution of H. puella could account for the reduced spatial genetic structure within this species. The genetic and demographic data are also consistent with the hypothesis that H. puella might represent the ancestral form of the Hypoplectrus radiation, and that H. nigricans might have evolved repeatedly from H. puella through ecological speciation. Altogether, spatial genetic analysis within and between Hypoplectrus species indicate that local processes can operate at a regional scale within recent marine adaptive radiations

Description: Late Quaternary sediments in a permafrost environment recovered from the Elgygytgyn Impact Crater were studied to determine regional palaeoenvironmental variability and infer past water-level changes of the crater lake. Stratigraphic analysis of a 5 m long permafrost core is based on various lithological (grain size, total organic carbon, magnetic susceptibility) and hydrochemical (oxygen isotope composition, major cation content) properties and pore ice content. The results show that alluvial sediments accumulated on top of cryogenically weathered volcanic rock. Changes in the hydrochemical properties reflect different stages of cryogenic weathering. The lithological characteristics mark the transition from an erosive site to a site with accumulation. This environmental change is linked to a relative lake level highstand at 〉13 000 yr BP, when a shoreline bar was formed leading to slope sedimentation. Lake level dropped by 4 m during the Holocene.

Description: For the understanding and assessment of recent and future carbon dynamics of arctic permafrost soils the processes of CH4 production and oxidation, the community structure and the quality of dissolved organic matter (DOM) were studied in two soils of a polygonal tundra. Activities of methanogens and methanotrophs differed significantly in their rates and distribution patterns among the two investigated profiles. Community structure analysis showed similarities between both soils for ester-linked phospholipid fatty acids (PLFAs) and differences in the fraction of unsaponifiable PLFAs and phospholipid ether lipids. Furthermore, a shift of the overall composition of the microbiota with depth at both sites was indicated by an increasing portion of iso- and anteiso-branched fatty acids related to the amount of straight-chain fatty acids. Although permafrost soils represent a large carbon pool, it was shown that the reduced quality of organic matter leads to a substrate limitation of the microbial metabolism. It can be concluded from our and previous findings first that microbial communities in the active layer of an Arctic polygon tundra are composed by members of all three domains of life, with a total biomass comparable to temperate soil ecosystems, and second that these microorganisms are well adapted to the extreme temperature gradient of their environment.

Description: Induced breeding of climbing perch, Anabas testudineus was conducted by synthetic hormone Wova-FH in the intensity level of 0.1, 0.2 and 0.3 mL kg−1 of body weight respectively. The brooders were injected one time and left to spawn in the spawning hapa in the sex ratio between male and female as 2:1. It was found that at all the intensity level hormone Wova-FH could enhance the fishes to breed and lay eggs whereas no breeding was observed in control set. The spawning time, quantity of the brooder spawn, fertilization rate, hatching rate and survival rate were quantified in each set of experiment. The egg output/female was significantly higher in 0.3 mL in comparison with 0.1 and 0.2 mL kg−1 of body weight. The statistical analysis showed significant (P≤0.05) effect between hormone dose on fertilization rate, egg output and hatching rate. The present experiment suggests that Wova-FH at the dose of 0.3 mL kg−1 body weight of fish is more effective which might be considered for raising captive population.

Description: The model marine crenarchaeote 'Cenarchaeum symbiosum' is until now the only ammonia-oxidizing archaeon known from a marine sponge. Here, phylogenetic analyses based on the 16S rRNA and ammonia monooxygenase subunit A (amoA) genes revealed the presence of putative ammonia-oxidizing archaea (AOA) in a diverse range of sponges from the western Pacific, Caribbean and Mediterranean. amoA diversity was limited even between different oceans, with many of the obtained sequences (75.9%; n(total) = 83) forming a monophyletic, apparently sponge- (and coral-) specific lineage, analogous to those previously inferred from comparative 16S rRNA gene studies of sponge-associated microbes. The presence of AOA in sponge larvae, as detected by 16S rRNA and amoA PCR assays as well as by fluorescence in situ hybridization, suggests they are vertically transmitted and thus might be of importance for ammonia detoxification within the sponge.

Description: This paper updates the analysis by Osborn et al. of trends in the contribution of heavy events to precipitation in the UK. We spatially extended the previous analysis of 110 rain gauges to a set of 689 rain gauges covering almost the whole UK, and updated the results to November 2006. For each station and season, we calculated ten time series of the contribution of ten precipitation amount categories to the total seasonal precipitation. A principal component analysis of post-1961 trends of all categories and stations is consistent with earlier results, namely, widespread shifts towards greater contribution from heavier precipitation categories during winter, and towards light and moderate categories during summer. Regional and UK average time series of the contribution from the category consisting of the heaviest events indicate that the increased winter intensity was sustained during the most recent ten years, but the trend did not continue at the rate reported previously for 1961–1995. For summer, the decreasing contribution from the heaviest rainfall category reported for 1961–1995 underwent a reversal during the most recent decade, returning towards the 1961–1995 reference level of intensity. Confidence intervals for these regional and UK average time series were estimated by a bootstrap approach and indicate that the sparser observations from the first half of the 20th century are still sufficient to estimate UK average change. These longer records support the existence of a long-term increase in winter precipitation intensity, and similar trends have now also become evident in spring and (to a lesser extent) autumn. The summer rainfall intensity has exhibited changes that are more consistent with inter-decadal variability than any overall trend. Copyright © 2008 Royal Meteorological Society

Description: Detailed studies of the behavior and location of free-ranging animals can be considerably enhanced with the use of animal-mounted devices. A few devices, such as data loggers, have to be recovered to access the data, whereas satellite tags or radiocollars often are left on the animal after the study period. Recovery of devices, which usually necessitates animal recapture, can be problematic, especially in larger species. This paper presents a new, non-electronic release mechanism, requiring no power source on the animal, that was successfully tested on South American sea lions (Otaria flavescens) in Argentina during the 2003–2004 austral summer. The system has potential for many larger terrestrial or aquatic animals.

Description: The great cormorant Phalacrocorax carbo is thought to have a wettable plumage, providing low body insulation during foraging. Great cormorants should thus be constrained by water temperatures, and show high energy requirements. Surprisingly, this species has one of the widest breeding distributions of all diving birds, and does not require more food than these other species. We explored this apparent paradox by comparing the insulative properties of body plumage in four subspecies of great cormorants ranging from tropical to polar regions. We found that all subspecies retained an insulating air layer in their plumage, which was, however, much thinner than for other species of diving birds. Detailed examination of the plumage showed that each cormorant body feather has a loose, instantaneously wet, outer section and a highly waterproof central portion. This indicates that the plumage of great cormorants is only partly wettable, and that birds maintain a thin layer of air in their plumage. Our findings suggest an unusual morphological-functional adaptation to diving which balances the antagonist constraints of thermoregulation and buoyancy.

Description: A wide range of bicarbonate concentrations was used to monitor the kinetics of bicarbonate (HCO3−) use in both photosynthesis and calcification in two reef‐building corals, Porites porites and Acropora sp. Experiments carried out close to the P. porites collection site in Barbados showed that additions of NaHCO3 to synthetic seawater proportionally increased the calcification rate of this coral until the concentration exceeded three times that of seawater (6 mM). Photosynthetic rates were also stimulated by HCO3− addition, but these became saturated at a lower concentration (4 mM). Similar experiments on aquarium‐acclimated colonies of Indo‐Pacific Acropora sp. showed that calcification and photosynthesis in this coral were enhanced to an even greater extent than P. porites, with calcification continuing to increase above 8 mM HCO3−, and photosynthesis saturating at 6 mM. Calcification rates of Acropora sp. were also monitored in the dark, and, although these were lower than in the light for a given HCO3− concentration, they still increased dramatically with HCO3− addition, showing that calcification in this coral is light stimulated but not light dependent.

Description: We examined the genetic structure of the European sprat (Sprattus sprattus) by means of a 530-bp sequence of the mitochondrial control region from 210 fish originating from seven sampling localities of its distributional range. Phylogeographical analysis of 128 haplotypes showed a phylogenetic separation into two major clades with the Strait of Sicily acting as a barrier to gene flow between them. While no population differentiation was observed based on analysis of molecular variance and net nucleotide differences between samples of the Baltic Sea, the North Sea and the Bay of Biscay nor between the Black Sea and the Bosporus, a strong population differentiation between these samples and two samples from the Mediterranean Sea was found. Further, the biggest genetic distance was observed within the Mediterranean Sea between the populations of the Gulf of Lyon and the Adriatic Sea, indicating genetic isolation of these regions. Low genetic diversities and star-like haplotype networks of both Mediterranean Sea populations point towards recent demographic expansion scenarios after low population size, which is further supported by negative FS values and unimodal mismatch distributions with a low mean. Along the northeast Atlantic coast, a northwards range expansion of a large and stable population can be assumed. The history of a diverse but differentiated Black Sea population remains unknown due to uncertainties in the palaeo-oceanography of this sea. Our genetic data did not confirm the presently used classification into subspecies but are only preliminary in the absence of nuclear genetic analyses.

Description: In marine ecosystems, pelagic copepods, chaetognaths and jellyfish play a key role in matter and energy flow. While copepods support most food webs and the biological pump of carbon into the deep ocean, chaetognaths and jellyfish may affect the strength of the top‐down control upon plankton communities. In this study, we show that the main events in the long‐term variability of these functional groups in the Northwestern Mediterranean were tightly linked to changes of climate forcing of the North Atlantic sector. Large‐scale climate forcing has altered the pelagic food‐web dynamics through changes in biological interactions, competition and predation, leading to substantial changes manifested as bursts or collapses in zooplankton populations, and consequently to a major change ca. 1987. These events become more frequent in the 1980s and the early 1990s in the studied zooplankton functional groups suggesting a shift in the functioning of the pelagic ecosystem. The environmental modifications and the results reported here are therefore, indicators of a regime change pointing to a more regeneration‐dominated system in the study area. We suggest a chain of mechanisms, whereby climate variation has modified the long‐term dynamics of pelagic copepods, chaetognaths and jellyfish in the Ligurian Sea.

Description: The present study examines sedimentation rates in the eastern Gotland Basin using a variety of methods that reveal considerable heterogeneity in the rates, both spatially and temporally. High-resolution seismic recordings and correlation with long sediment cores indicate increased thickness of strata and higher sedimentation rates (0.75 mm a-1) in the eastern part of the basin than in the western part (0.23 mm a-1) since the Littorina transgression some 8000 14C years BP. This difference is apparently a consequence of a counterclockwis e near-bottom circulation in the basin with periodically high current speeds that cause winnowing on the steep SE slope of the basin and differential settling of sediments in areas of low current speeds. On shorter time scales, recent sediment accumulation rates based on radiometric dating (210Pb) are in general twice as high as those observed 25 years ago using the same method. The higher modern rates, compared to those of the 1970s, may partly be due to increased eutrophication, as more carbon is buried in the sediment, and partly due to increased erosion in shallow water areas. However, strong lateral variations are evident. The average sediment accumulation rates vary between 119 and 340 gm-2 a-1 (corresponding to sedimentation rates of 2.1–2.5 mm a-1) in the deepest part of the basin. Very high rates (6100 g m-2 a-1, corresponding to sedimentation rates of 30 mm a-1) are observed on an intraslope basin site (offshore Latvia) at a water depth of only 70 m. The radiometrically determined sediment accumulation rates are up to three times higher than those estimated from average water column concentrations of suspended matter and from sediment trap flux rates. The discrepancy suggests that sedimentation in the deep basin may have a substantial contribution from near-bottom lateral transport.

Description: We characterized 37 single nucleotide polymorphism (SNP) makers for eelgrass Zostera marina. SNP markers were developed using existing EST (expressed sequence tag)-libraries to locate polymorphic loci and develop primers from the functional expressed genes that are deposited in The ZOSTERA database (V1.2.1). SNP loci were genotyped using a single-base-extension approach which facilitated high-throughput genotyping with minimal optimization time. These markers show a wide range of variability among 25 eelgrass populations and will be useful for population genetic studies including evaluation of population structure, historical demography, and phylogeography. Potential applications include haplotype inference of physically linked SNPs and identification of genes under selection for temperature and desiccation stress.

Description: 1. Tracer experiments with two diatoms labelled with 13C (Nitzschia palea) and 15N (Fragilaria crotonensis), were conducted to investigate feeding selectivity and interspecific competition between the grazers Asellus aquaticus (Isopoda, Crustacea) and Potamopyrgus antipodarum (Hydrobiidae, Gastropoda). Conventional methods, such as cell counts and estimated biovolume, were used first to detect feeding preferences within the different grazer treatments. 2. The results revealed a significant decline in algal biovolume in all grazer treatments and no indications of active selectivity were observed. In contrast to conventional methods, measurements based on isotope signatures showed strong differences in tracer uptake, thus indicating different degrees of assimilation and digestion by the two grazers. 3. The selectivity index Q, which provides information on the uptake ratio of 13C to 15N, showed a significant time effect for both grazer species and a significant difference between single- and mixed-grazer treatments for P. antipodarum. Thus, this technique enabled the direct quantification of the uptake by grazers and, therefore, served as an ideal tool for the detection of passive selectivity. 4. Our results indicate a shift in feeding preferences related to between-species competition and a potential divergence of trophic niches when species coexist.

Description: It is a well accepted fact that nutrient limitation of plants affects the growth and survival of herbivores, generally leading to lower performance of herbivores feeding on nutrient stressed plants. The effect of plants' growing conditions on predatory organisms, feeding one trophic level up, has been much less studied, and there is a general consensus that such effects would be small as herbivores often show relatively strong homeostasis with respect to their nutrient content. Here, we challenge this view, and show from several examples that despite the fact that herbivores buffer much of the variance in nutrient stoichiometry of their food, effects of growing conditions of the primary producers can travel up the food chain. We discuss the implications of these findings, and argue that phosphorus limitation of secondary consumers might be more common in marine than in freshwater systems.

Description: The monthly variation in reproductive cycle, condition factor (fatness), gonad index (GI), ovarian egg diameter and biochemical composition [RNA, DNA content and their ratio RNA/DNA (R/D)] were compared to determine the spawning season of the purplish Washington clam, Saxidomus purpuratus, collected from the west sea of Taean, Korea. All these factors were correlated to the spawning season from May to October. Monthly variation and concentration of the R/D ratio especially represented indicative information about the processes of gonad development and spawning patterns. The increases in R/D ratio in the ovaries corresponded with increases in ovarian egg diameters and the GI during the spawning season. The peak of R/D and RNA content in females was a good indicator of sexual maturation and the DNA content in males. During winter between November and January, the value of fatness, GI, egg size, RNA and DNA content were lower than in other seasons, indicating depletion of energy reserves and lower metabolic demands because of colder temperatures.

Description: 1 Several theoretical models predict under what conditions maximum species diversity can be maintained, and they are often used to develop effective ecosystem management plans. 2 Two models that are currently used to predict patterns of species diversity were empirically tested in marine subtidal benthic communities of different successional stages. 3 The two models were: the interactive effects of nutrient availability and disturbance frequency proposed by Kondoh (2001; Proceedings of the Royal Society London B, 268, 269–271), and the intermediate disturbance hypothesis (IDH) proposed by Connell (1978; Science, 199, 1302–1310). 4 Interactive effects were found to be transient and only occurred in the older communities, while the unimodal pattern suggested by the IDH was not supported in either successional stage. 5 It is concluded that these models are very general and thus lack sufficient explanatory power. Both models require a number of specific prerequisites for maximum diversity to be found, and though applicable in many different ecosystems they need to be refined as tools in order that they can be effectively used in habitat management plans.

Description: Local dynamics such as resource enhancement (e.g. nutrient supply) and stochastic events of destruction (disturbances that provide new space) are hypothesized to counteractively affect species diversity and composition.We tested the independent and interactive effects of nutrients and disturbance on the development of assemblages of epibiota attached to vertical surfaces in an oligotrophic system. Nutrient concentrations were manipulated at three levels (ambient, medium and high) while disturbance was manipulated by removing biomass at seven frequencies (0x, 2x, 3x, 4x, 5x, 7x, 12x). Nutrient and disturbance regimes had opposing effects on diversity such that species richness increased with resource enhancement (nutrients) and declined with disturbance. These results support the model that increased heterogeneity of distribution of limiting resources allows the coexistence of species with low and high resource requirements.

Description: In this article, we show by mesocosm experiments that winter and spring warming will lead to substantial changes in the spring bloom of phytoplankton. The timing of the spring bloom shows only little response to warming as such, while light appears to play a more important role in its initiation. The daily light dose needed for the start of the phytoplankton spring bloom in our experiments agrees well with a recently published critical light intensity found in a field survey of the North Atlantic (around 1.3 mol photons m−2 day−1). Experimental temperature elevation had a strong effect on phytoplankton peak biomass (decreasing with temperature), mean cell size (decreasing with temperature) and on the share of microplankton diatoms (decreasing with temperature). All these changes will lead to poorer feeding conditions for copepod zooplankton and, thus, to a less efficient energy transfer from primary to fish production under a warmer climate.

Description: Anaerobic oxidation of methane (AOM) in anoxic marine sediments is a significant process in the global methane cycle, yet little is known about the role of bulk composition, temperature and pressure on the overall energetics of this process. To better understand the biogeochemistry of AOM, we have calculated and compared the energetics of a number of candidate reactions that microorganisms catalyse during the anaerobic oxidation of methane in (i) a coastal lagoon (Cape Lookout Bight, USA), (ii) the deep Black Sea, and (iii) a deep-sea hydrothermal system (Guaymas basin, Gulf of California). Depending on the metabolic pathway and the environment considered, the amount of energy available to the microorganisms varies from 0 to 184 kJ mol−1. At each site, the reactions in which methane is either oxidized to inline image, acetate or formate are generally only favoured under a narrow range of pressure, temperature and solution composition – particularly under low (10−10 m) hydrogen concentrations. In contrast, the reactions involving sulfate reduction with H2, formate and acetate as electron donors are nearly always thermodynamically favoured. Furthermore, the energetics of ATP synthesis was quantified per mole of methane oxidized. Depending on depth, between 0.4 and 0.6 mol of ATP (mol CH4)−1 was produced in the Black Sea sediments. The largest potential productivity of 0.7 mol of ATP (mol CH4)−1 was calculated for Guaymas Basin, while the lowest values were predicted at Cape Lookout Bight. The approach used in this study leads to a better understanding of the environmental controls on the energetics of AOM.

Description: A bottom simulating reflector (BSR), which marks the base of the gas hydrate stability zone, has been detected for the first time in seismic data of the Black Sea. The survey area is in the northwestern Black Sea at 44°–45°N and 31.5°–32.5°E. In this paper, seismic wide-angle ocean bottom hydrophone (OBH) and ocean bottom seismometer (OBS) data are investigated with the goal to quantify the gas hydrate and free gas saturation in the sediment. An image of the subsurface is computed from wide-angle data by using Kirchhoff depth migration. The image shows the BSR at 205–270 m depth below the seafloor and six to eight discrete layer boundaries between the seafloor and the BSR. The top of the hydrate layer and the bottom of the gas layer cannot be identified by seismic reflection signals. An analysis of traveltimes and reflection amplitudes leads to 1-D P-wave velocity–depth and density–depth models. An average S-wave velocity of 160 m s−1 between the seafloor and the BSR is determined from the traveltime of the P to S converted wave. The normal incidence PP reflection coefficient at the BSR is −0.11, where the P-wave velocity decreases from 1840 to 1475 m s−1. Velocities and density are used to compute the porosity and the system bulk modulus as a function of depth. The Gassmann equation for porous media is used to derive explicit formulae for the gas hydrate and free gas saturation, which depend on porosity and on the bulk moduli of the dry and saturated sediment. A gas hydrate saturation–depth profile is obtained, which shows that there is 38 ± 10 per cent hydrate in the pore space at the BSR depth, where the porosity is 57 per cent (OBS 24). This value is derived for the case that the gas hydrate does not cement the sediment grains, a model that is supported by the low S-wave velocities. There is 0.9 or 0.1 per cent free gas in the sediment below the BSR, depending on the model for the gas distribution in the sediment. The free gas layer may be more than 100 m thick as a result of a zone of enhanced reflectivity, which can be identified in the subsurface image.

Description: The influence of fluctuating light on diversity and species number of a natural phytoplankton assemblage competing for nutrients was investigated for 48 days under semicontinuous culture conditions. Light conditions were either changed periodically from high (65 μmol photons·m−2·s−1) to low intensity (15 μmol photons·m−2·s−1) at intervals of 1, 3, 6, and 12 days or fixed at constant light conditions of intermediate intensity (40 μmol photons·m−2·s−1). Fluctuating light at intervals of 1–12 days significantly affected phytoplankton diversity. The development of phytoplankton communities differed in treatments with different light regimes. In treatments with long light intervals, species abundance oscillated with the light phases. Differences in the temporal development of phytoplankton communities resulted in hump‐shaped relations between the interval length of the light phases and both species number and diversity index and can be explained by the intermediate disturbance hypothesis. Fluctuating light tends to sustain phytoplankton diversity under nutrient limitation if the light regime changes in the order of several days. This indicates that temporal changes in weather regime are important in preventing competitive exclusion of phytoplankton species in nature.

Description: In marine ecosystems, pelagic copepods, chaetognaths and jellyfish play a key role in matter and energy flow. While copepods support most food webs and the biological pump of carbon into the deep ocean, chaetognaths and jellyfish may affect the strength of the top‐down control upon plankton communities. In this study, we show that the main events in the long‐term variability of these functional groups in the Northwestern Mediterranean were tightly linked to changes of climate forcing of the North Atlantic sector. Large‐scale climate forcing has altered the pelagic food‐web dynamics through changes in biological interactions, competition and predation, leading to substantial changes manifested as bursts or collapses in zooplankton populations, and consequently to a major change ca. 1987. These events become more frequent in the 1980s and the early 1990s in the studied zooplankton functional groups suggesting a shift in the functioning of the pelagic ecosystem. The environmental modifications and the results reported here are therefore, indicators of a regime change pointing to a more regeneration‐dominated system in the study area. We suggest a chain of mechanisms, whereby climate variation has modified the long‐term dynamics of pelagic copepods, chaetognaths and jellyfish in the Ligurian Sea.

Description: We are investigating effects of the depsipeptide geodiamolide H, isolated from the Brazilian sponge Geodia corticostylifera, on cancer cell lines grown in 3D environment. As shown previously geodiamolide H disrupts actin cytoskeleton in both sea urchin eggs and breast cancer cell monolayers. We used a normal mammary epithelial cell line MCF 10A that in 3D assay results formation of polarized spheroids. We also used cell lines derived from breast tumors with different degrees of differentiation: MCF7 positive for estrogen receptor and the Hs578T, negative for hormone receptors. Cells were placed on top of Matrigel. Spheroids obtained from these cultures were treated with geodiamolide H. Control and treated samples were analyzed by light and confocal microscopy. Geodiamolide H dramatically affected the poorly differentiated and aggressive Hs578T cell line. The peptide reverted Hs578T malignant phenotype to polarized spheroid-like structures. MCF7 cells treated by geodiamolide H exhibited polarization compared to controls. Geodiamolide H induced striking phenotypic modifications in Hs578T cell line and disruption of actin cytoskeleton. We investigated effects of geodiamolide H on migration and invasion of Hs578T cells. Time-lapse microscopy showed that the peptide inhibited migration of these cells in a dose-dependent manner. Furthermore invasion assays revealed that geodiamolide H induced a 30% decrease on invasive behavior of Hs578T cells. Our results suggest that geodiamolide H inhibits migration and invasion of Hs578T cells probably through modifications in actin cytoskeleton. The fact that normal cell lines were not affected by treatment with geodiamolide H stimulates new studies towards therapeutic use for this peptide.

Description: The population density of brown trout (Salmo trutta) in a small natural system was manipulated in six equal-length stream sections by stocking hatchery-reared 1+ brown trout (unstocked, tripled and quintupled) over two consecutive years. The results showed that hatchery-reared trout grew more slowly and were more mobile than resident trout, and that their growth was inversely density dependent. In contrast, growth of the resident trout was density independent. The recapture of 1+ resident and hatchery-reared trout was inversely density dependent. This is most likely a consequence of increased competition. However, after a single winter the population density returned to its base level prior stocking and older resident trout showed no density-dependent recapture. Thus, the advantage of stocking, here higher biomass, may have the detrimental effect of decreasing resident stocks of the same size class during summer.

Description: Planktic foraminiferal assemblages were studied qualitatively and quantitatively in 13 samples obtained at 3 cm intervals throughout the uppermost Pleistocene-Holocene deposits of Box core 123 (Eurydice Expedition, western equatorial Pacific Ocean). Absolute ages of these samples have previously been determined by the 14C method; the lowest sample dated from approximately 16,000 B.P. A curve based on the ratio between specimens of warm and warm-temperate vs. cold and cold-temperate water assemblages suggests that two temperature drops occurred during this time-span: at 11,OOO B.P. and around 4,000–2,OOO B.P. The former drop corresponds to the onset of the Younger Dryas cooling. An unexpectedly high dominance of Globigerinita clarkei (up to 60%, on the average 48.5%) was observed throughout the entire core. Isolated, small-sized and poorly developed specimens of typical cold water foraminifera were present in the materials investigated; their origin is most probably due to advection via equatorward subsurface currents.

Description: Because many forminiferologists pay little attention to the smallest planktic foraminiferal species, the role of Globigerinita clarkei (Rögl & Bolli) as a fauna making species has been largely overlooked. Although it is widely distributed throughout the world, even dominating the assemblages of many areas (at least in the Quarternarty deposits), it is missing from numerous reports based on materials where it must have been present.

Description: This paper presents a three‐dimensional (3D) seismic analysis of sediment remobilization and fluid migration in a 2000‐km2 area above the Gjallar Ridge located in the Vøring Basin, offshore Norway. Three distinct types of mounded structures have been identified as resulting from focused fluid/gas migration and associated mud remobilization and intrusion. Type A structures are gently mounded, and we infer that these structures formed because of in situ remobilization of Middle Eocene to Lower–Middle Oligocene fine‐grained sediments in response to fluid and minor sediment injection via deep‐seated normal faults. Type B structures comprise relatively steep‐sided mounds and are restricted to the pre‐Miocene interval. They are often located above narrow zones of discontinuous low‐amplitude reflections resembling gas chimneys. Some of the Type B structures are associated with stacked amplitude anomalies and possible mud volcanoes at the base Pleistocene indicating their long‐term significance as vertical fluid conduits. Type C structures comprise discrete mound features that seem to jack up the Top Palaeocene (Top Brygge) horizon. These are similar to hydrothermal mounds found elsewhere on the Norwegian Margin and associated with igneous sill intrusion during North Atlantic breakup. This study highlights the utility of 3D seismic data for mapping of fluid and sediment mobilization through time over large basinal areas.

Description: Six cores were selected from 46 collected in the SW part of the Atlantic Ocean to compare the three main methods of constructing Pleistocene paleoclimatic curves by means of planktic Foraminifera. It was found that the method based on a study of the whole fauna yields more details and represents the degree of the relative climatic changes better, whereas the method based on the ratio between the Globorotalia menardii complex and G. inflata exagerates the large scale temperature oscillations. However, this exaggeration makes the separation of glacial, interglacial, and interstadial epochs much easier. Paleoclimatic curves based on the sinistral: dextral ratio of Globorotalia truncatulinoides do not coinicde with those prepared utilizing the two previous methods. thus, the coiling direction of Globorotalia truncatulinoides cannot be utilized as a paleoclimatic criterion.

Description: The population density of brown trout (Salmo tnttta) in a small natural system was manipulated in six equal-length stream sections by stocking hatchery-reared 1 + brown traut (unstocked, tripled and quintupled) over two consecutive years. The results showed that hatchery~reared trout grew more slowly and were more mobile than resident trout, and that their growth was inversely density dependent. In contrast, growth of the resident traut was density independent. The · recapture of 1 + resident and hatchery-reared traut was inve_rsely density dependent. This is most lilcely a consequence of increased competition. However, after a single winter the population density retumed to its base Ievel prior stocking and older resident traut showed no densitydependent recapture. Thus, the advantage of stocking, here higher biomass, may have the detrirnental effect of decreasing resident stocks of the same size class during summer.

Description: The genomes of most economically important microbial cells are already sequenced and proteomic technologies can be applied during various process development steps, starting with the selection and optimization of the functions of the industrial strains, application of the knowledge of cell function in response to the changes of production parameters, validation of the downstream processing, and thorough characterization of the final product. Unfortunately, there are only a few direct examples in the literature that present the optimization of the production process based on proteomics. In this review, we discuss the potential of this technology for the design of future bioprocesses and for optimization of existing ones.

Description: At the western continental margin of the Barents Sea, 75°N, hemipelagic sediments provide a record of Holocene climate change with a time resolution of 10–70 years. Planktic foraminifera counts reveal a very early Holocene thermal optimum 10.7–7.7 kyr BP, with summer sea surface temperatures (SST) of 8°C and a much enhanced West Spitsbergen Current. There was a short cooling between 8.8 and 8.2 kyr BP. In the middle and late Holocene summer, SST dropped to 2.5°-5.0°C, indicative of reduced Atlantic heat advection, except for two short warmings near 2.2 and 1.6 kyr BP. Distinct quasi-periodic spikes of coarse sediment fraction (with large portions of lithic grains, benthic and planktic foraminifera) record cascades of cold, dense winter water down the continental slope as a result of enhanced seasonal sea ice formation and storminess on the Barents shelf over the entire Holocene. The spikes primarily cluster near recurrence intervals of 400–650 and 1000–1350 years, when traced over the entire Holocene, but follow significant 885–/840– and 505–/605-year periodicities in the early Holocene. These non-stationary periodicities mimic the Greenland-10Be variability, which is a tracer of solar forcing. Further significant Holocene periodicities of 230, (145) and 93 years come close to the deVries and Gleissberg solar cycles.

Description: Herbivory is particularly intense in tropical benthic communities, suggesting preference of constitutive, rather than inducible, anti-herbivory defense. The objective of the study was to examine whether anti-herbivore defenses in the red alga Hypnea pannosa J. Agardh and the brown algae Sargassum asperifolium Hering and G. Martens ex J. Agardh and Cystoseira myrica (S.G. Gmelin) C. Agardh could be induced and subsequently reduced in response to grazing by the amphipod Cymadusa filosa Savigny. During a 14-day treatment phase, algae were exposed to amphipod grazing or were left ungrazed (control). Subsequently, one subset of algae was used in feeding assays, whereas another was cultivated for additional 14 days without consumers (recovery phase). At the end of each phase, bioassays were conducted to detect defensive traits in terms of differences in consumption rates of grazed and control pieces of live algae and agar-based food containing nonpolar algal extracts. Consumption of grazed live S. asperifolium and H. pannosa specimens was lower than of control algae. Furthermore, nonpolar extracts of grazed S. asperifolium and C. myrica were less preferred than those from control algae. Defensive responses were exclusively detected after the treatment phase, although strong preference of ungrazed H. pannosa and C. myrica over grazed conspecifics continued throughout the recovery phase. These findings suggest that phenotypic plasticity in anti-herbivory defense of marine macroalgae 1) might be more common than previously shown, 2) could be switched on and off within 2 weeks, and 3) can be found in nonpolar algal extracts.

Description: Summary: • Glomus intraradices is a widespread arbuscular mycorrhizal fungus (AMF), which has been found in an extremely broad range of habitats, indicating a high tolerance for environmental factors and a generalist life history strategy. Despite this ecological versatility, not much is known about the genetic diversity of this fungal species across different habitats or over large geographic scales. • A nested polymerase chain reaction (PCR) approach for the mitochondrial rRNA large subunit gene (mtLSU), distinguished different haplotypes among cultivated isolates of G. intraradices and within mycorrhizal root samples from the field. • From analysis of 16 isolates of this species originating from five continents, 12 mitochondrial haplotypes were distinguished. Five additional mtLSU haplotypes were detected in field‐collected mycorrhizal roots. Some introns in the mtLSU region appear to be stable over years of cultivation and are ancestral to the G. intraradices clade. • Genetic diversity within G. intraradices is substantially higher than previously thought, although some mtLSU haplotypes are widespread. A restriction fragment length polymorphism approach also was developed to distinguish mtLSU haplotypes without sequencing. Using this molecular tool, intraspecific genetic variation of an AMF species can be studied directly in field plants.

Description: Trench-outer rise earthquakes occur by reactivation or creation of normal faults caused as the oceanic lithosphere approaches a subduction zone and bends into the deep-sea trench. These faults may cut deep enough into the mantle to allow sea water to penetrate into the lithosphere, causing serpentinization. The amount of water carried into the mantle is linked to the maximum depth that the tensional faults cut into the lithosphere, which in turn is directly linked to the maximum focal depths of outer rise normal faulting earthquakes. We analysed teleseismic P and S waves of seven earthquakes from the trench-outer rise offshore of Central America using teleseismic waveform inversion of broad-band data. For the computation of Green's functions for waveform inversion, probabilistic earthquake locations were calculated. To study the rupture process, earthquake centroid depths and focal mechanisms for a sequence of subevents were calculated. Both, hypocentral depths from the relocation process and the estimated centroid depths from the waveform inversion show that all events occur at shallow depths (〈30 km). Furthermore, the locations of the subevents relative to each other suggest that fault planes for Mw∼ 6 are in the order of 50 km in length and only 5–10 km in width. Rupture generally propagates downdip and the focal mechanisms change for most events from normal faulting to strike-slip or oblique thrusting with time. The depth at which this mechanism change is observed may represent the depth of the nodal plane between tensional and compressional regions in the incoming plate.

Description: River discharge of Ob and Yenisei to the Kara Sea is highly variable on seasonal and interannual time scales. River water dominates the shallow bottom water near the river mouths, making it warmer and less saline but seasonally and interannually more changeable than bottom water on the deeper shelf. This hydrographic pattern shows up in measurements and modelling, and in stable isotope records (δ18 O, δ13 C) along the growth axis of bivalve shells and in multiple analyses of single benthic foraminiferal shells. Average isotope ratios increase, but sample-internal variability decreases with water depth and distance from river mouths. However, isotope records of bivalves and foraminifera of a sediment core from a former submarine channel of Yenisei River reveal a different pattern. The retreat of the river mouth from this site due to early Holocene sea level rise led to increasing average isotope values up core, but not to the expected decrease of the in-sample isotope variability. Southward advection of cold saline water along the palaeo-river channel probably obscured the hydrographic variability during the early Holocene. Later, when sediment filled the channel, the hydrographic variability at the core location remained low, because the shallowing proceeded synchronously with the retreat of the river mouth.

Description: Phloem-mobile signals play a major role in plant nutrition, development and communication. In the latter context, phloem-mobile RNAs have been associated with signalling between plant tissues. In this study, we focused on the identification of transcripts in the shoot phloem of the model plant Arabidopsis thaliana. To isolate transcripts expressed in phloem parenchyma cells and in companion cell–sieve element complexes, we used laser microdissection coupled to laser pressure catapulting (LMPC). Mobile transcripts in sieve elements were isolated from leaf phloem exudates. After optimization of sampling and fixation, RNA of high quality was isolated from both sources. The modifications to the RNA amplification procedure described here were well suited to production of RNA of sufficient yield and quality for microarray experiments. Microarrays hybridized with LMPC-derived phloem tissue or phloem sap RNA allowed differentiation between phloem-expressed and mobile transcript species. Using this set of phloem transcripts and comparing them with microarrays derived from databases of light, hormone and nutrient treatment experiments, we identified phloem-derived RNAs as mobile, potential long-distance signals. Our dataset thus provides a search criterion for phloem-based signals hidden in the complex datasets of microarray experiments. The availability of these comprehensive phloem transcript profiles will facilitate reverse-genetic studies and forward-genetic screens for phloem and longdistance RNA signalling mutants.

Description: The behaviour of a series of hydroxamate siderophores - microbially produced iron complexes - was investigated using electrospray ionisation mass spectrometry (ESI-MS). Three groups of iron hydroxamate siderophores, namely the ferrioxamines, ferrichromes and coprogens/ fusigens, were separated by high-performance liquid chromatography (HPLC) prior to ESI and MS2 fragmentation. For the majority of the siderophores, both protonated molecules and sodium adducts were observed. The most abundant ion was selected for collision-induced fragmentation. Potential fragmentation mechanisms are postulated and discussed. Fragmentation patterns differed between siderophore groups; however, common fragmentation patterns were observed for siderophore ions within the groups examined. Cleavage frequently occurred at carbon-nitrogen or carbon-oxygen bonds. Fragmentation of the ions also involved cleavage of iron-oxygen bonds and transfer of the charge to iron.

Description: A total of 58 extracts of different polarity were prepared from various organs of 16 species of Turkish plants and screened for their antitrypanosomal, antileishmanial and antiplasmodial activities. No significant activity was observed against Trypanosoma cruzi, whereas many extracts showed appreciable trypanocidal potential against T. brucei rhodesiense, with the CHCl3-soluble portion of Phlomis kurdica being the most active (IC50 2.7 µg[sol ]mL). Almost all extracts, particularly the CHCl3 phases, exhibited growth inhibition activity against Leishmania donovani amastigotes. The CHCl3-solubles of Putoria calabrica roots (IC50 1.9 µg[sol ]mL), Wendlandia ligustroides leaves (IC50 2.1 µg[sol ]mL) and Rhododendronluteum leaves (IC50 2.3 µg[sol ]mL) displayed the highest leishmanicidal potential. The majority of the extracts also possessed antiplasmodial activity against the multi-drug resistant K1 Plasmodium falciparum strain. The most potent antiplasmodial activity was observed with the CHCl3 extracts of Phlomis kurdica (IC50 1.5 µg[sol ]mL), P. leucophracta (IC50 1.6 µg[sol ]mL), Scrophularia cryptophila (IC50 1.8 µg[sol ]mL), Morina persica (IC50 1.9 µg[sol ]mL) and the aqueous root extract of Asperula nitida subsp. subcapitellata (IC50 1.6 µg[sol ]mL). Twenty-one extracts with significant antimalarial activity (IC50 〈 5 µg[sol ]mL) were also tested for their ability to inhibit the purified enoyl-ACP reductase (FabI), a crucial enzyme in the fatty acid biosynthesis of P. falciparum. The CHCl3 extract of Rhododendronungernii leaves (IC50 10 µg[sol ]mL) and the H2O-soluble portion of Rhododendronsmirnovii leaves (IC50 0.4 µg[sol ]mL) strongly inhibited the FabI enzyme. The preliminary data indicate that some (poly)phenolic compounds are responsible for the FabI inhibition potential of these extracts. The presented work reports for the first time the antiprotozoal activity of nine different genera as well as a target specific antimalarial screening for the identification of P. falciparum FabI inhibitors from medicinal plant extracts.

Description: Understanding how environmental forcing has generated and maintained large-scale patterns of biodiversity is a key goal of evolutionary research and critical to predicting the impacts of global climate change. We suggest that the initiation of the global thermohaline circulation provided a mechanism for the radiation of Southern Ocean fauna into the deep sea. We test this hypothesis using a relaxed phylogenetic approach to coestimate phylogeny and divergence times for a lineage of octopuses with Antarctic and deep-sea representatives. We show that the deep-sea lineage had their evolutionary origins in Antarctica, and estimate that this lineage diverged around 33 million years ago (Ma) and subsequently radiated at 15 Ma. Both of these dates are critical in development of the thermohaline circulation and we suggest that this has acted as an evolutionary driver enabling the Southern Ocean to become a centre of origin for deep-sea fauna. This is the first unequivocal molecular evidence that deep-sea fauna from other ocean basins originated from Southern Ocean taxa and this is the first evidence to be dated.

Description: Aim  One of the most recognized ecological paradigms on earth is the increase in species richness from the poles towards the equator. Here we undertake a comprehensive survey of the latitudinal gradients of species richness (LGSR) of coastal cephalopod fauna in the western (WA) and eastern margins (EA) of the Atlantic Ocean, and test climate and non-climate theories to explain the variation in diversity. Location  The coastal Atlantic Ocean. Methods  The diversity and geographical ranges of coastal cephalopods were investigated by means of an exhaustive survey of the primary literature, reports and on-line data bases. In order to test the productivity, ambient energy and area hypotheses, we investigated the relationship between diversity and net primary production (NPP), sea surface temperature (SST; measure of solar energy input) and continental shelf area, respectively. Results  LGSR of cephalopod molluscs are present at both Atlantic coasts, but are quite distinct from each other. Historical processes (rise of the Central American Isthmus, formation of ‘Mare Lago’ and glaciations) explained much of the shape and the zenith of LGSR. Contemporary climate and non-climate variables also each explained over 83% and 50% of the richness variation in WA and EA, respectively, and the best fitted models accounted for 〉 92% of the variance. By combining latitude with depth a strong Rapoport effect was observed in WA but not in EA. Main conclusions  Besides the evolutionary history, we demonstrate that the contemporary environmental gradients (SST and NPP), shelf area and extent of coral habitat can predict many of the diversity patterns. The longitudinal difference in Rapoport's bathymetric rule is attributed to western fauna specialization to shallow coral reef habitats and greater ecological tolerance of eastern fauna to upwelling ecosystem dynamics. A combined approach of historical biogeography and species–area–energy theories was essential to fully understand broad-scale variation in cephalopod biodiversity.

Description: King Penguins Aptenodytes patagonicus which were rearing chicks were studied during three summers from November 1991 to March 1994 at South Georgia. Stomach samples (n=115) collected by flushing had a mean mass of 1308 g. Fish mass was allocated to each species based on the relationship between fish mass and otolith length. Three mesopelagic lanternfishes (Myctophidae), Krefftichthys anderssoni, Electrona carlsbergi and Protomyctophum choriodon, dominated the diet both by numbers and mass. They were small fish with mean mass of 3–7 g. Overall, K. anderssoni dominated the diet in terms of numbers and mass. Although Barracudina Notolepis coatsi occurred in 〈3% of the diet by numbers, it was large (106 g) and was second most important in terms of mass. Squid represented 〈3% of the diet by mass. Although the chick‐rearing success was poor in the 1993–1994 summer, meal size was not reduced but foraging trips were longer. In the 1993–1994 summer, a larger proportion of the otoliths were not identifiable because they were more completely digested. Fewer otoliths were identified as being those of K. anderssoni, but we argue that about 90% of the unidentified otoliths were K. anderssoni. There was also more squid and N. coatsi in the diet during the poor summer. A consistent trend was that P. choriodon was rare or absent in early summer but more important later in the year, and at the end of 1992–1993, it was the dominant prey. We conclude that myctophid fish, especially K. anderssoni, are the main summer prey of King Penguins rearing chicks at South Georgia, as found in other recent studies in the Southern Ocean.

Description: Loligo vulgaris is a commercially important squid throughout the Mediterranean region and is a candidate species in biomedical and aquaculture research. Some loligo species (L. opalescens, L. forbesi, Sepiteuthis lessoniana) have now been cultured through some successive generations in closed, recirculating seawater systems. The effects of salinity on hatching European Squid (L. vulgaris Lamarck, 1798) eggs were investigated during November 2004. The egg capsules were incubated directly in salinity of 32, 34, 36, 38, 40, 42 and 37 g L−1 (control group) at 19.8°C (SD 1.2°C), and a photoperiodicity of 12 h light:12 h dark for 16–23 days before hatching. In all treatments, the eggs were developed and hatched normally after 16–22 days at 32 g L−1, 17–22 days at 34, 18–21 days at 42 g L−1, 18–22 days at 36 and 40 g L−1, 19–22 days at 37 g L−1 and 19–23 h at 38 g L−1. In the experiments, the highest hatching rate and hatching success (HS) of the eggs were obtained at 38 g L−1 (hatching rate: 100% (SD 0%) and HS: 96.7% (SD 3.5%)) and the lowest hatching rate at 42 g L−1 (hatching rate: 3% (SD 6%) and HS: 0%). Dorsal mantle lengths (DML) of new hatchlings ranged from 2.08 to 2.80 mm. The present study showed that salinity affects the hatching rate and HS of eggs and first hatching time and DML of paralarvae in L. vulgaris. The squid eggs at stage 11 (I) can tolerate 5 g L−1 reduction and 3 g L−1 increase in salinity.

Description: The Galápagos volcanic province (GVP) includes several aseismic ridges resulting from the interaction between the Galápagos hotspot (GHS) and the Cocos–Nazca spreading centre (CNSC). The most prominent are the Cocos, Carnegie and Malpelo ridges. In this work, we investigate the seismic structure of the Carnegie ridge along two profiles acquired during the South American Lithospheric Transects Across Volcanic Ridges (SALIERI) 2001 experiment. Maximum crustal thickness is ∼19 km in the central Carnegie profile, located at ∼85°W over a 19–20 Myr old oceanic crust, and only ∼13 km in the eastern Carnegie profile, located at ∼82°W over a 11–12 Myr old oceanic crust. The crustal velocity models are subsequently compared with those obtained in a previous work along three other profiles over the Cocos and Malpelo ridges, two of which are located at the conjugate positions of the Carnegie ones. Oceanic layer 2 thickness is quite uniform along the five profiles regardless of the total crustal thickness variations, hence crustal thickening is mainly accommodated by layer 3. Lower crustal velocities are systematically lower where the crust is thicker, thus contrary to what would be expected from melting of a hotter than normal mantle. The velocity-derived crustal density models account for the gravity and depth anomalies considering uniform and normal mantle densities (3300 kg m−3), which confirms that velocity models are consistent with gravity and topography data, and indicates that the ridges are isostatically compensated at the base of the crust. Finally, a two-dimensional (2-D) steady-state mantle melting model is developed and used to illustrate that the crust of the ridges does not seem to be the product of anomalous mantle temperatures, even if hydrous melting coupled with vigorous subsolidus upwelling is considered in the model. In contrast, we show that upwelling of a normal temperature but fertile mantle source that may result from recycling of oceanic crust prior to melting, accounts more easily for the estimated seismic structure as well as for isotopic, trace element and major element patterns of the GVP basalts.

Description: We studied the physiological response of Pseudocalanus sp. under four different temperature elevation regimes: +0, +2, +4 and +6 °C above the decadal average temperature in the Western Baltic Sea. We measured fecal pellet (FP) production rates, which was taken as a proxy of ingestion, egg production (EPR) and respiration rates. Experiments lasted from mid‐February to end April, corresponding most of the observations to the postspring bloom phase. We combined small scale incubations with the use of big (ca. 1400 L) mesocosms, which have previously been shown to be appropriate when studying phyto‐ and zooplankton succession, and the water used for the incubations was taken from the mesocosm tanks. Given that the phytoplankton succession varied between the four thermal scenarios, we evaluated (excepting in the case of the respiration rates, where incubations were carried out using 0.2 μm filtered water) both the temperature and the associated food concentration effects. Respiration and ingestion rates were found to increase with temperature. As for EPR, they also increased with temperature during the bloom, but remained at low and constant values during the postbloom in all the four treatments due to the food limitation. Linked to the temperature rise, we also detected an increase in instantaneous mortality rates and a reduction in the net growth efficiency. Finally, we discuss the potential implications of our findings for the spring phyto‐ and zooplankton succession under the forecasted climate warming, as well as for the fisheries in the Baltic Sea, where Pseudocalanus sp. is a key species.

Description: Spawner-recruit relationships are important components of fisheries management. The two most widely used models have been criticized for unsatisfactory fits and biologically unreasonable extrapolations. A simple hockey stick model has been shown to provide more robust predictions, however, this model is not widely used, possibly because the abrupt change from density-dependence to density-independence is unrealistic and the piecewise model is difficult to fit. Here I present a continuous two-parameter model that resembles a smoothed hockey stick and provides parameter estimates similar to the piecewise hockey stick. The new model is easily parameterized with regular curve-fitting routines.

Description: The management of Baltic sprat is challenged by highly variable recruitment success and hence large stock fluctuations. Recent studies have identified the larval and early juvenile life stages to be critical for the survival rate of a sprat year class. Although prey abundance was found to be linked to larval survival success, an analysis identifying the functional relationship and relative importance of other environmental factors is still missing. Sprat larval feeding was investigated in 2002 during three cruises, covering the main spawning time in the Bornholm Basin, Baltic Sea. The aim of the study was to identify the key environmental factors determining the feeding success of larval sprat taking their potential interactions explicitly into account. An extension of generalized additive models (GAMs) was adopted that allows the inclusion of interaction terms in a non-parametric regression model. The final model of sprat larval feeding success explained ∼80% of the variance in the data and was based on the following environmental factors: bottom depth, cubed wind speed as proxy for small-scale turbulence rates, degree of cloudiness as proxy for light conditions and prey density in combination with a feeding period–cloudiness interaction term. Our study demonstrates that the feeding success of sprat larvae in the Baltic Sea is controlled by a number of simultaneously acting key environmental factors

Description: In small planktonic organisms, large census sizes (Nc) suggest large effective population sizes (Ne), but reliable estimates are rare. Here, we present Ne/Nc ratios for two freshwater copepod species (Eudiaptomus sp.) using temporal samples of multilocus microsatellite genotypes and a pseudo-likelihood approach. Ne/Nc ratios were very small in both Eudiaptomus species (10−7–10−8). Although we hypothesized that the species producing resting eggs (E. graciloides) had a larger Ne than the other (E. gracilis), estimates were not statistically different (E. graciloides: Ne = 672.7, CI: 276–1949; E. gracilis: Ne = 1027.4, CI: 449–2495), suggesting that the propagule bank of E. graciloides had no detectable influence on Ne.

Description: Disturbance and productivity are often cited as the main factors determining temporal and spatial patterns in species distribution and the diversity of communities. A field experiment was conducted to test the role of these factors in the structuring of early successional fouling communities in a nutrient limited system at the south coast of Madeira Island. Macro-benthic sessile communities, established on artificial settlement substrata, were manipulated and surveyed over a 9-week period. We applied mechanical disturbances of four different frequencies crossed with three levels of inorganic nutrient enrichment. Fertilization enhanced community diversity by favouring the establishment and growth of macroalgae. Disturbance reduced diversity by eliminating species – but only at the highest nutrient level. This is explained by a multiple-stressor model; species most sensitive to nutrient deficiency (only present in the highest enrichment treatment) were simultaneously the most sensitive to disturbance

Description: The two agar-producing red algae, Gracilaria chilensis C. J. Bird, McLachlan & E. C. Oliveira and Gracilaria conferta (Schousboe ex Montagne) Montagne, responded with hydrogen peroxide (H2O2) release when agar oligosaccharides were added to the medium. In G. conferta, a transient release was observed, followed by a refractory state of 6 h. This response was sensitive to chemical inhibitors of NADPH oxidase, protein kinases, protein phosphatases, and calcium translocation in the cell, whereas it was insensitive to inhibitors of metalloenzymes. Transmission electron microscopic observations of the H2O2-dependent formation of cerium peroxide from cerium chloride indicated oxygen activation at the plasma membrane of G. conferta. A putative system, consisting of a receptor specific to agar oligosaccharides and a plasma membrane-located NADPH oxidase, appears to be responsible for the release of H2O2 in G. conferta. Subcellular examination of G. chilensis showed that the H2O2 release was located in the cell wall. It was sensitive to inhibitors of metalloenzymes and flavoenzymes, and no refractory state was observed. The release was correlated with accumulation of an aldehyde in the algal medium, suggesting that an agar oligosaccharide oxidase is present in the apoplast of G. chilensis. The presence of this enzyme could also be demonstrated by polyacrylamide electrophoresis under nondenaturating conditions and proven to be variable. Cultivation of G. chilensis at 16 to 17°C resulted in significantly stronger expression of agar oligosaccharide oxidase than cultivation at 12°C, which indicates that the enzyme is used under conditions that generally favor microbial agar macerating activity.

Description: We investigated the effects of ircinin-1, a lipid compound (a C25 sesterterpene tetronic acid) isolated from marine sponges (Sarcotragus sp.), on the modulation of cell cycle and induction of apoptosis in SK-MEL-2 human skin cancer cells (mutant p53). Ircinin-1 treatment on SK-MEL-2 cells resulted in a dose-dependent inhibition of cell growth and induced apoptotic cell death. Flow cytometric analysis revealed that ircinin-1 resulted in G1 arrest in cell cycle progression which was associated with a marked decrease in the protein expression of D-type cyclins and their activating partners Cdk 4 and 6 with concomitant inductions of p21WAF1/CIP1 and p27KIP1. The induction of p21WAF1/CIP1 appears to be transcriptionally upregulated and is p53-independent. In addition, ircinin-1 suppressed the phosphorylation of pRb protein and increased the co-association of pRb or proliferating cell nuclear antigen (PCNA) with p21WAF1/CIP1 in these cells. Ircinin-1 treatment also resulted in induction of apoptosis as determined by morphological changes, DNA fragmentation, alternated ratio of Bax/Bcl-2, cleavages of poly(ADP-ribose) polymerase and PLC-γ1, and flow cytometric analysis. Ircinin-1 also induced cytochrome c release, cleavage activations of caspase-3 and -9, and upregulation of Fas and Fas-L. Even though the inhibitor of apoptosis protein (IAP) was expressed in ircinin-1-untreated or -treated SK-MEL-2 cells, only the level of cIAP-1, but not XIAP or cIAP-2, was decreased during ircinin-1-induced apoptosis at Western blot and RT-PCR studies. Taken together, these findings suggest that ircinin-1 has strong potential for development as an agent for prevention against skin cancer

Description: Structure and growth of the Izu‐Bonin‐Mariana arc crust: 1. Seismic constraint on crust and mantle structure of the Mariana arc–back‐arc system Narumi Takahashi Institute for Research on Earth Evolution Japan Agency for Marine‐Earth Science and Technology Kanagawa Japan Shuichi Kodaira Institute for Research on Earth Evolution Japan Agency for Marine‐Earth Science and Technology Kanagawa Japan Yoshiyuki Tatsumi Institute for Research on Earth Evolution Japan Agency for Marine‐Earth Science and Technology Kanagawa Japan Yoshiyuki Kaneda Institute for Research on Earth Evolution Japan Agency for Marine‐Earth Science and Technology Kanagawa Japan Kiyoshi Suyehiro Institute for Research on Earth Evolution Japan Agency for Marine‐Earth Science and Technology Kanagawa Japan A high‐resolution seismic velocity model is presented for the crust and upper mantle of the Mariana arc–back‐arc system (MABS) based on active source seismic profiling. The major characteristics are (1) slow mantle velocity of 〈8 km s −1 in the uppermost mantle, especially, and deep reflectors under the Mariana arc (MA) and the West Mariana Ridge (WMR), (2) a deep reflector in the upper mantle beneath the relative thick crust of the Mariana Trough (MT) axis, (3) distribution of lower‐velocity lower crusts (6.7–6.9 km s −1 ) beneath the volcanic front and adjacent to the MT, and (4) high‐velocity lower crust (7.2–7.4 km s −1 ) beneath the boundary regions between the MA and MT, and between the WMR and the Parece Vela Basin (PVB), adding to structural characteristics of crust and upper mantle beneath the MABS. Of the characteristics described above, characteristic 1 suggests that the origins of the slow mantle velocity and the deep reflectors be explained by transfer of the lower crustal residues to the upper mantle across the Moho, considering that the WMR is extinct arc currently. On the other hand, characteristic 2 suggests that the origin of deep reflectors beneath the MT axis might be lower velocity materials due to the diffractive signals with strong amplitudes, characteristic 3 suggests that the lower‐velocity lower crust advanced crustal growth and characteristic 4 suggests that the high‐velocity lower crust beneath arc–back‐arc transition zone is composed of mafic/ultramafic materials created by extensive partial melting of mantle peridotites or last stage of the arc magmatism rather than serpentinized peridotite.